荔枝、龙眼的果皮和种子:成分、提取、生物活性和潜在利用

Pericarp and seed of litchi and longan fruits: constituent, extraction, bioactive activity, and potential utilization 荔枝、龙眼的果皮和种子:成分、提取、生物活性和潜在利用 1 first-author 2 3 1 1 1 corresp ‡Corresponding Author ‡Corresponding Author †E-mail:ymjiang@scbg.ac.cn †E-mail:ymjiang@scbg.ac.cn ymjiang@scbg.ac.cn Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Key Laboratory of Post-Harvest Handling of Fruits, Ministry of Agriculture, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Key Laboratory of Post-Harvest Handling of Fruits, Ministry of Agriculture, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China Institute of Post-harvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China Institute of Post-harvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China Agro-food Science and Technology Research Institute, Guangxi Academy of Agricultural Sciences, Nanning 530007, China Agro-food Science and Technology Research Institute, Guangxi Academy of Agricultural Sciences, Nanning 530007, China Litchi ( Litchi chinensis Sonn.) and longan ( Dimocarpus longan Lour.) fruits have a succulent and white aril with a brown seed and are becoming popular worldwide. The two fruits have been used in traditional Chinese medicine as popular herbs in the treatment of neural pain, swelling, and cardiovascular disease. The pericarp and seed portions as the by-products of litchi and longan fruits are estimated to be approximately 30% of the dry weight of the whole fruit and are rich in bioactive constituents. In the recent years, many biological activities, such as tyrosinase inhibitory, antioxidant, anti-inflammatory, immunomodulatory, anti-glycated, and anti-cancer activities, as well as memory-increasing effects, have been reported for the litchi and longan pericarp and seed extracts, indicating a potentially significant contribution to human health. With the increasing production of litchi and longan fruits, enhanced utilization of the two fruit by-products for their inherent bioactive constituents in relation to pharmacological effects is urgently needed. This paper reviews the current advances in the extraction, processing, identification, and biological and pharmacological activities of constituents from litchi and longan by-products. Potential utilization of litchi and longan pericarps and seeds in relation to further research is also discussed. 荔枝( Litchi chinensis Sonn.)和龙眼( Dimocarpus longan Lour.)果肉白色透明,深受消费者欢迎.荔枝和龙眼果实作为我国传统中草药,可用于缓解神经疼痛和肿胀.荔枝和龙眼的果皮和种子部分占整个果实干重约30%,含有丰富的生物活性物质.近年来研究发现,荔枝和龙眼的果皮和种子的提取物具有抑制酪氨酸酶活性、抗炎、免疫调节、抗糖化、抗癌以及增强记忆等功能.随着荔枝和龙眼果实在世界上种植面积和数量的迅速增加,加强对生物活性物质的利用尤其必要.本文综述了对荔枝和龙眼的果皮和种子中生物活性化合物的鉴定、提取和药理活性等方面研究的最新进展,并讨论了其资源潜在利用以及未来研究方向. Bioactive compound Extraction Litchi Longan Pharmacological activity Utilization 活性物质 提取 荔枝 龙眼 药理活性 利用 Introduction 1 Litchi ( Litchi chinensis Sonn.) and longan ( Dimocarpus longan Lour.) are subtropical evergreen trees belonging to the family Sapindaceae. The two fruits have an indehiscent pericarp surrounding a succulent edible aril with a dark brown seed. Litchi and longan fruits have gained popularity as specialty fruits in subtropical areas, and are accepted by consumers on the international markets with increasing demand for their excellent flavors and semi-translucent to white arils (Jiang et al., 2002 2002 , 2006 2006 ). The two fruits are grown commercially in some major countries, including China and Thailand, which account for most of the commercial litchi and longan production. Production of litchi and longan has increased greatly over recent decades because of significant improvements in crop practices and management. Increasing production of litchi and longan fruits requires prospects for better utilization of these two crops. Litchi and Longan fruits have commonly been used traditionally in China as herbs for improvement of neural pain, swelling, the immunomodulatory system, and cardiovascular disease. Their pulps are very high in nutritive value with carbohydrates, protein, fiber, fat, lipids, vitamins, amino acids, and minerals. The pericarp and seed portions of litchi and longan are estimated to contain approximately 30% of the dry weight of the entire fruit and consist of significant amounts of bioactive compounds. In recent years, the extracts from litchi and longan pericarps and seeds have exhibited excellent antioxidant ability and good anti-tyrosinase, anti-inflammatory, immunomodulatory, and anti-cancer activities (Li and Jiang, 2007 2007 ; Rangkadilok et al., 2007 2007 ; Prasad et al., 2009a 2009a ; Yang et al., 2009a 2009a , 2011 2011 ). Thus, the two fruits can be used as an easily accessible source of natural antioxidants from their by-products and/or possible agents in the cosmetic and pharmaceutical industry. To better utilize pericarps and seeds of litchi and longan fruits, this paper reviews the recent advances in structural identification and functional evaluation of bioactive constituents present in the two fruits in relation to their potential applications. Some novel biological functions of litchi and longan pericarps and seeds with regard to human health are also discussed. The objective of this paper was to help relevant scientists, farmers, and industries to better utilize litchi and longan by-products in the future. Phytochemical composition 1 Litchi and longan fruits contain a wide diversity of bioactive compounds. The major bioactive compounds consist of phenolics and polysaccharides, which have been shown to have potentially beneficial biological and pharmaceutical properties (Emanuele et al., 2017 2017 ). The bioactive constituents of litchi and longan fruits are greatly influenced by the climate, region, cultivation conditions, fruit maturity, fruit portion, and extraction and processing methods (Wang HC et al., 2011 2011 ). Although the potential health benefits of these bioactive constituents have achieved wide attention based on numerous in vitro studies, many reports have been conducted on the isolation, extraction, and identification of individual chemical compounds. Differences in the bioactive compositions of litchi and longan fruits could exist because of various cultivars, and extraction and processing methods. Litchi 2 2.1.1 Pericarp A broad spectrum of bioactive constituents has been isolated and identified in the litchi pericarp, as shown in Table 1 1 . One significant characteristic of these bioactive constituents is that they contain many flavonoids (Table 2 2 ). The flavonoids present in ripe litchi pericarp include mainly flavonols and anthocyanins. The flavonols identified in ripe litchi pericarps were (−)-epicatechin, (−)-epigallocatechin, procyanidin B2, procyanidin B4, (+)-catechin, and procyanidin B1, whereas the important anthocyanins were identified as cyanidin-3-rutinoside, cyanidin-3-glucoside, quercetin-3-rutinoside, and quercetin-3-glucoside (Sarni-Manchado et al., 2000 2000 ; Zhao et al., 2006 2006 ; Bai et al., 2019 2019 ). A novel compound, namely methylene-linked flavan-3-ol dimer, bis (8-epicatechinyl) methane, was also reported by Ma et al. ( 2014b 2014b ), together with eight compounds, dehydrodiepicatechin A, proanthocyanidin A1, proanthocyanidin A2, 8-(2-pyrrolidinone-5-yl)-(−)-epicatechin, (−)-epicatechin 8- C -β- D -glucopyranoside, naringenin, 7- O -(2,6- O -α- L -rhamnopyranosyl)-β- D - glucopyranoside, and rutin. Furthermore, oligomeric procyanidins were isolated and then identified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) analysis, including their 12 dimers and 6 trimers. Although the major flavan-3-ol monomer and oligomeric procyanidins present in ripe litchi pericarps were characterized as (−)-epicatechin, A-type dimers and trimers (epicatechin-(4β-8,2β- O -7)-epicatechin-(4β-8)-epicatechin) and procyanidin A1 (epicatechin-(4β-8,2β- O -7)-catechin) were reported for the first time by Sui et al. ( 2016 2016 ). In particular, it is noted that the content of A-type procyanidins was much higher than that of B-type procyanidins. In addition, four lignans ((+)-isolariciresinol 9- O -α- L -arabinopyranoside, (−)-secoisolariciresinol 9- O -α- L -arabinopyranoside, burselignan 9- O -α- L -arabinopyranoside, and sisymbrifolin), a chromane (2α-methoxychroman-3α-5,7-triol), a benzophenone (garcimangosone D), and two sesquiterpenes (β- D -glucopyranosyldihydrophaseate and citroside A) were obtained from ripe litchi pericarps (Ma et al., 2014a 2014a ). Jiang et al. ( 2013b 2013b ) reported a novel phenolic compound, 2-(2-hydroxy-5-(methoxycarbonyl) phenoxy)benzoic acid, together with kaempferol, isolariciresinol, stigmasterol, 3,4-dihydroxybenzoate, butylated hydroxytoluene, methyl shikimate, an ethyl shikimate. An interesting result is that butylated hydroxytoluene was detected as a natural antioxidant in this work. Thus, a great difference in the identification of these chemical compositions from litchi pericarps might be caused by the various cultivars and extractions. Portion Phytochemicals Pericarp Gallic acid, procyanidin B2, procyanidin B4, (−)-epicatechin, cyanidin-3-rutinoside, cyanidin-3-glucoside, brevifolin, quercetin-3-rutinoside, quercetin-3-glucoside, dehydrodiepicatechin A, proanthocyanidin A1, proanthocyanidin A2, 8-(2-pyrrolidinone-5-yl)-(−)-epicatechin, (−)-epicatechin 8- C -β- D -glucopyranoside, naringenin, rutin, kaempferol, isolariciresinol, 2-(2-hydroxy-5-(methoxycarbonyl)phenoxy)benzoic acid, butylated hydroxytoluene, 3,4-dihydroxybenzoate Seed Gallic acid, procyanidin B2, (−)-epicatechin, (−)-gallocatechin, (−)-epicatechin-3-gallate, 2α,3α-epoxy-5,7,3',4'-tetrahydroxyflavan-(4β-8-catechin), 2β,3β-epoxy-5,7,3',4'-tetrahydroxyflavan-(4α-8-epicatechin), 2,5-dihydroxy-hexanoic acid, 4- O -α- L -rhamnopyranosyl-ellagic acid, isoscopoletin, coumaric acid, protocatechuic acid, pterodontriol, narirutin, D -6- O -β- D -glucopyranoside, naringin, pinocembrin-7-neohesperidoside, pinocembrin-7-rutinoside Reprinted from Li and Jiang ( 2007 2007 )  Compound Relative percentage (%)  Gallic acid 0.4  Procyanidin B1 1.0  (+)-Catechin 1.6  (+)-Gallocatechin 1.1  Procyanidin B4 5.3  Procyanidin B2 11.4  (−)-Epicatechin 32.5  (−)-Epigallocatechin 10.9  (−)-Epicatechin-3-gallate 0.3  Cyanidin-3-glucoside 31.7 Yang et al. ( 2006 2006 ) reported that a large number of polysaccharides exist in ripe litchi pericarp tissues. In their study, DEAE anion-exchange column in combination with Sephadex G-50 gel-permeation column was used to obtain the major polysaccharides from ripe litchi pericarps. The greatest amount of the polysaccharide fraction depended largely on further purification by Sephadex G-50 filtration. The purified neutral polysaccharide exhibited a molecular weight of 14 kDa and consisted primarily of 65.6% mannose, 33.0% galactose, and 1.4% arabinose. The Smith degradation analysis identified 8.7% (1→2)-glycosidic linkages, 83.3% (1→3)-glycosidic linkages, and 8.0% (1→6)-glycosidic linkages in the polysaccharides. Biological analysis indicated that these various polysaccharide fractions from litchi fruit pericarp tissues exhibited strong antioxidant ability and anti-glycated activity (Yang et al., 2006 2006 , 2009a 2009a ; Gao et al., 2017 2017 ), suggesting that litchi polysaccharides could be explored as a new and potential alternative antioxidant. 2.1.2 Seed Litchi seed has also been applied in traditional Chinese medicine since ancient times. Using the conventional extraction, followed by the reverse phase high-performance liquid chromatography (HPLC) in combination with a diode array detector and ESI-MS, gallic acid, procyanidin B2, (−)-gallocatechin, (−)-epicatechin, and (−)-epicatechin-3-gallate partially similar to those identified from litchi pericarps were obtained, which suggested that litchi seed could potentially be used as a good source of natural antioxidants (Xu et al., 2010 2010 ). With increasing amount of seed samples used in this extraction, four novel compounds (2α,3α-epoxy-5,7,3',4'-tetrahydroxyflavan-(4β-8-catechin), 2β,3β-epoxy-5,7,3',4'-tetrahydroxyflavan-(4α-8-epicatechin), litchiol A, and litchiol B) and 12 known ones (2,5-dihydroxy-hexanoic acid, isoscopoletin, coumaric acid, protocatechuic acid, narirutin, naringin, pterodontriol, pinocembrin-7-rutinoside, pinocembrin-7-neohesperidoside, 2α,3α-epoxy-5,7,3',4'-tetrahydroxyflavan-(4β-8-epicatechin), D -6- O -β- D -glucopyranoside, and dihydrochalcone-4'- O -β- D -glucopyranoside) with protocatechuic acid, 2α, 3β-epoxy-5,7,3',4'-tetrahydroxyflavan-(4β-8-catechin), and 2β,3β-epoxy-5,7,3',4'-tetrahydroxyflavan-(4α-8-epicatechin) exhibited moderate antioxidant activity (Wang LJ et al., 2011 2011 ). Chemical analyses from A-type proanthocyanidins present in litchi seeds identified two new A-type trimeric proanthocyanidins containing two doubly bonded interflavanoid linkages, litchitannin A1 (epicatechin-(2β→ O →7,4β→6)-epicatechin-(2β→ O →7,4β→8)-catechin) and litchitannin A2 (epicatechin-(2β→ O →7,4β→6)-epicatechin-(2β→ O → 7,4β→6)-epicatechin), accompanied by aesculitannin A, proanthocyanidin A1, proanthocyanidin A2, proanthocyanidin A6, epicatechin, epicatechin-(2β→ O → 7,4β→8)-epiafzelechin-(4α→8)-epicatechin, and epicatechin-(7,8-bc)-4β-(4-hydroxyphenyl)-dihydro-2(3H)-pyranone (Wang LJ et al., 2011 2011 ). Moreover, litchitannin A2 was found to have in vitro antiviral activity against coxsackie virus B3, whereas aesculitannin A and proanthocyanidin A2 performed an herpes simplex virus 1 (HSV-1) activity (Xu et al., 2010 2010 ). Litchi seed contains rich polysaccharides. Chen et al. ( 2011 2011 ) used ultrasound-assisted extraction and obtained polysaccharides from litchi seeds and found that the litchi seed polysaccharides consisted of arabinose, fructose, galactose, glucose, and mannose, with glycosidic linkages between monosaccharides and the relative molar percentage. The bioactive polysaccharide exhibited substantial antioxidant activity and could be utilized as a novel antioxidant, but further research needs to be conducted for food and biomedical application. Longan 2 2.2.1 Pericarp Substantial amounts of bioactive constituents present in longan pericarps could be responsible for their different bioactivities. Table 3 3 presents the major phenolic compounds in ripe longan pericarps. The major phenolic compounds consisted of gallic acid, quercetin, corilagin, ellagic acid and its conjugates, (−)-epicatechin, 4- O -methylgallic acid, flavone glycosides, glycosides of quercetin and kaempferol, protocatechuic acid, isoscopoletin, and proanthocyanidins C1 (Sun et al., 2007 2007 ; Yang et al., 2011 2011 ; Bai et al., 2019 2019 ). The phenolic compounds present in longan pericarps were similar to those in litchi pericarps (Table 1 1 ), suggesting similar bioactive activities. Portion Phytochemicals Pericarp Gallic acid, corilagin, (−)-epicatechin, ellagic acid and its conjugates, quercetin, flavone glycosides, 4- O -methylgallic acid, flavone glycosides, glycosides of quercetin and kaempferol, protocatechuic acid, brevifolin Seed Gallic acid, corilagin, ellagitannins corilagin, ellagic acid 4- O -α- L -arabinofuranoside, isomallotinic acid, geraniin, ethyl gallate, grevifolinand, 4- O -α- L -rhamnopyranosyl-ellagic acid, p -coumaric acid-glycoside, isoscopoletin, proanthocyanidins C1, 1- O -galloyl- D -glucopyranose, ( S )-flavogallonic acid, methyl ellagic acid glucopyranoside Longan pericarps also have substantial amounts of polysaccharides (Jiang et al., 2009b 2009b ). Yang et al. ( 2009b 2009b ) isolated and obtained a polysaccharicle from longan pericarps. The structural identification by gas chromatography (GC) indicated that the longan polysaccharicle contained 33.7% D -galactopyranose, 32.8% L -arabinofuranose, 17.6% D -glucopyranose, and 15.9% D -galacturonic acid, whereas the backbone structure included →5)- L -Araf-(1→, →6)- D -GIcp-(1→, →3)- D - Galp-(1→, →3)- D -GalpA-(1→, and →6)- D -Galp-(1→, with a molar proportion of 2:1:1:1:1. The infrared spectra and nuclear magnetic resonance (NMR) spectra further confirmed the α-form of the configuration of L -arabinofuranose and the β-forms of D -glucopyranose, D -galactopyranose, and D -galacturonic acid. Furthermore, the purified longan polysaccharicle molecular weight was estimated to be approximately 420 kDa by gel permeation chromatography. The polysaccharicle exhibited a potential ability in inhibiting a glycation reaction in the in vitro test (Yang et al., 2009a 2009a ). In addition, two alkali-soluble polysaccharide fractions from longan pericarps were obtained. Four monosaccharides, namely Xyl, Ara, Glc, and Gal, were determined, whereas Xyl was identified as the dominant monosaccharide in the two alkali-soluble polysaccharides with a relative molar percentage of > 60%. Further analysis of glycosidic linkage indicated that Xyl had two linkages, →3)-Xyl-(1→ and →3,4)-Xyl-(1→, whereas the substitution at the C-4 position showed that Xyl was in the pyranose structure, with the β-linkage configuration (Jiang et al., 2009a 2009a ). These polysaccharides exhibited good antioxidant and tyrosinase inhibitory activities in a dose-dependent manner (Yang et al., 2008a 2008a , 2008b 2008b ; Jiang et al., 2009b 2009b ), which could be utilized for food additives and cosmetic products. 2.2.2 Seed Longan as a leading fruit crop in Thailand is rich in antioxidant compounds (Table 3 3 ), mostly gallic acid and ellagic acid (Panyathep et al., 2013 2013 ). Dried longan seed contains much larger amounts of antioxidant polyphenols than fresh seed. Major four compounds, p -coumaric acid-glycoside, ( S )-flavogallonic acid, ellagic acid derivatives, and methyl ellagic acid glucopyranoside, were reported for the first time in longan seed using HPLC-ESI-MS (Sudjaroen et al., 2012 2012 ). Chen et al. ( 2014 2014 ) reported that ellagic acid and its derivative and p -coumaric acid-glycoside contributed mainly to the antioxidant activity of longan seed extract, but gallic acid, corilagin, ethyl gallate, ( S )-flavogallonic acid, and methyl ellagic acid glucopyranoside had little contribution. Furthermore, Sudjaroen et al. ( 2012 2012 ) reported the compositions of polyphenolic fraction from ground longan seed, i.e. 80.90 g/kg on dry weight basis was 25.84 g/kg ellagic acid, followed by 13.31 g/kg ellagitannins corilagin, 13.06 g/kg chebulagic acid, 9.93 g/kg ellagic acid 4- O -α- L -arabinofuranoside, 8.56 g/kg isomallotinic acid, and 5.79 g/kg geraniin, indicating ellagic acid as the dominate phenolic compound. With increasing attention to pharmacological benefits of plant polysaccharides, polysaccharides from longan seed were reported by Jiang et al. ( 2013a 2013a ). The structural analysis indicated that four monosaccharides, namely arabinose, galactose, glucose, and mannose, were major components of longan seed polysaccharides, with →6)-Gal-(→1, Glc-(→1, and →6)-Glc-(1→ glycosidic linkages. These polysaccharides exhibited strong antioxidant and immunomodulatory activities (Jiang et al., 2013b 2013b ; Zhang JC et al., 2017 2017 ), which could be utilized further in the functional food industry. Impacts of extraction and processing on phytochemical yields and compositions 1 Extraction as the key first step in isolating and obtaining various types of bioactive constitutes from fruit and vegetable tissues plays an important role in phytochemical yield and composition (Bao et al., 2016 2016 ). In general, drying is necessary prior to extraction, but strongly affects the phytochemical compositions and bioactive activity. Yang et al. ( 2008c 2008c ) evaluated the effects of various drying treatments on water-soluble polysaccharides, water-soluble total saccharides, and total phenols in pericarp tissues of three major longan cultivars, and found that the water-soluble polysaccharide content in a decreasing order was microwave radiation > solar radiation > lyophilization, whereas the content of total phenols was in a reducing order of lyophilization > microwave radiation > solar radiation. In practice, the ideal extraction method is quantitative, non-destructive, and time-saving. There are various types of extraction methods, but there is no universal method for the effective extraction of the bioactive constituents from plant tissues because each method has its own advantage and disadvantage (Sun et al., 2011 2011 ). It is also noted that a good extraction method in terms of a balance of yield and bioactive activity should be considered. Recently, application of green technology, such as ultrasonic extraction and high-pressure extraction, has been reported for extraction of bioactive constituents from various litchi and longan fruit tissues (Prasad et al., 2009b 2009b , 2009c 2009c , 2010a 2010a , 2010b 2010b ; Yang et al., 2009c 2009c ). Prasad et al. ( 2009b 2009b ) and Gao et al. ( 2017 2017 ) reported that application of high-pressure extraction had higher extraction efficiency in terms of extraction yield, compound content, and antioxidant activity from litchi and longan pericarps and seeds, compared with the conventional and ultrasonic extraction. Furthermore, Zhang RF et al. ( 2017 2017 ) have optimized the ultra-high pressure assisted extraction procedures of procyanidins from litchi pericarps, which greatly increased the extraction yield and bioactive activity of the extract. In addition, Kessy et al. ( 2018 2018 ) reported that the enzyme-assisted extraction using hydrolytic enzymes, such as hydropectinase, β-glucosidase, and tannase, can greatly increase enrichment and biotransformation of phenolic substituents from litchi pericarps. Lin et al. ( 2013 2013 ) found the increased bioactivity, such as improved growth of Lactobacillus bulgaricus and Streptococcus thermophilus , and increased antioxidant activity of litchi pericarp polysaccharides biotransformed by Aspergillus awamori because of a significant change in the relative content of glucose, arabinose, galactose, rhamnose, xylose, and mannose, which suggested that A. awamori was very effective in degrading the polysaccharides into a bioactive mixture with lower molecular weight. Further study indicated that A. awamori transformed B-type condensed tannin (condensed flavan-3-ol via C4–C8 linkage) but exhibited little capacity to degrade the condensed tannin with A-type linkage subunits (C4–C8 coupled C2– O –C7 linkage) (Lin et al., 2016 2016 ). In addition, biotransformation could effectively produce some new bioactive compounds. Lin et al. ( 2014 2014 ) reported that two bioactive compounds, i.e. nigragillin and dihydrophaseic acid, at high levels were obtained from litchi pericarps via A. awamori fermentation. Furthermore, the two compounds exhibited antioxidant activity, a DNA protection effect, and an anti-cancer property, which suggested that the biotransformation by A. awamori is a potential way to produce bioactive constituents. Pharmacological activity 1 The litchi and longan pericarp and seed extracts exhibit many biological activities, as summarized in Table 4 4 . It has been reported that litchi fruit exhibits pharmacological properties. As mentioned above, litchi pericarps contain significant amounts of phenolic compounds, such as anthocyanins and flavanols. These anthocyanins and flavanols present in litchi pericarps could reduce the oxidation by chelating the metal ions and then forming copigment-metal complexes, and directly scavenging superoxide anions. Thus, litchi pericarp extract can be used as a strong natural antioxidant. Based on the recognition that litchi pericarp extracts were more effective than O -(β-hydroxyethyl) rutin in reducing anti-inflammatory and anti-edema ability and capillary permeability, it is suggested that anthocyanins or flavanols instead of rutin and its derivatives should be considered in the treatment of illnesses involving tissue inflammation and capillary fragility and swelling (Li and Jiang, 2007 2007 ; Baskaran et al., 2018 2018 ). Wang et al. ( 2006a 2006a , 2006b 2006b ) found that litchi pericarp extract showed potential anti-cancer activity against hepatocellular carcinoma in vitro and in vivo, and human breast cancer. It is interesting to note that the aglycones, as the most abundant anthocyanins present in litchi pericarp tissues, exhibited the potential to inhibit the growth of human tumor cells in vitro in the micromolar range, but two anthocyanins, malvidin-3-β-glucoside and cyanidin-3-β-galactoside, had little effect on tumor cell growth (Wang et al., 2006a 2006a ; Li and Jiang, 2007 2007 ). Thus, further identification and fine elucidation of individual and combined anthocyanins accounting for the anti-cancer property against tumor cell growth require investigation. Similarly, the anti-cancer ability of flavanols present in litchi pericarp tissues is almost the same as that of anthocyanins. The anti-breast cancer activities of epicatechin, procyanidin B2, procyanidin B4, and the ethyl acetate fraction from litchi pericarps were evaluated in in vitro test by Zhao et al. ( 2007 2007 ), who found that procyanidin B4 and ethyl acetate fractions exhibited stronger inhibition on human embryonic lung fibroblast (HELF) than on human breast cancer cell MCF-7, whereas epicatechin and procyanidin B2 showed lower cytotoxicity to MCF-7 and HELF than paclitaxel. Thus, Emanuele et al. ( 2017 2017 ) suggested that it is possible that epicatechin and procyanidin B2 could be employed as components of anti-cancer agents. In addition to anti-cancer activity, Chen et al. ( 2017 2017 ) found a hepatoprotective activity of litchi procyanidin A2 against carbon tetrachloride-induced liver injury in ICR mice. Recently, Choi et al. ( 2017 2017 ) reported that litchi seeds could be a cost-effective medicinal food agent in terms of recyclable resources and might act as a natural alternative medicine against type-2 diabetes. 2 Pharmacological properties 3 Portion Litchi 2 Longan  Antioxidant activity 2 Pericarp and seed Pericarp and seed  Antimicrobial activity 2 Seed  Anti-cancer activity 2 Pericarp  Anti-inflammatory property 2 Pericarp  Immunomodulatory activity 2 Pericarp Pericarp  Anti-diabetes 2 Pericarp and seed Pericarp  Anti-cardiovascular activity 2 Pericarp  Anti-edema 2 Pericarp  Anti-fragility 2 Pericarp  Anti-liver injury 2 Pericarp  Antiviral activity 2 Seed Longan also exhibits some good biological activities, including antioxidant ability and tyrosinase inhibitory activity from pericarps and seeds (Rangkadilok et al., 2007 2007 ; Yang et al., 2008a 2008a , 2008b 2008b ; Li et al., 2014 2014 ; Tseng et al., 2014 2014 ), metalloproteinase activity from seeds (Panyathep et al., 2013 2013 ), anti-inflammatory property from pericarps (Kunworarath et al., 2016 2016 ), and antibacterial activity from seeds (Rangkadilok et al., 2012 2012 ), which have been conducted by combined in vitro and/or in vivo pharmacological studies (Table 4 4 ). The bioactive polysaccharides from litchi and longan pericarps and seeds have attracted much attention by consumers and researchers because of their potential pharmaceutical properties and good safety, such as tyrosinase inhibition activity from litchi pericarps (Gao et al., 2017 2017 ) and from longan pericarps (Yang et al., 2008a 2008a , 2008b 2008b ; Prasad et al., 2010a 2010a , 2010b 2010b ), anti-glycated activity from longan pericarps (Yang et al., 2009a 2009a ), anti-cardiovascular diseases, immune modulation, and immunomodulatory activity from litchi and longan pericarps (Li and Jiang, 2007 2007 ; Jiang et al., 2009b 2009b ; Yang et al., 2011 2011 ; Zhang JC et al., 2017 2017 ). However, further identification of individual and combined polysaccharide responsible for these pharmaceutical properties needs to be investigated in the future. Potential applications 1 Different portions of litchi and longan fruits are valuable sources of biological substituents from their by-products. The by-products from litchi and longan pericarps and seeds contain significant amounts of active compounds, which raises the need for further use and development of new products with added-commercial value in the cosmetic, food, and pharmaceutical industries (Li and Jiang, 2007 2007 ; Yang et al., 2011 2011 ; Kanlayavattanakul et al., 2012 2012 ). As discussed above, litchi and longan pericarps and seeds contain many beneficial substituents with antioxidant ability, cancer prevention, anti-microbial, anti-inflammatory, and immunomodulatory functions. Thus far, the extracts from litchi and longan pericarps and seeds have been developed as functional food additives, cosmetic products, and Chinese herbs for the relief of neural pain and swelling. Although the pharmacological activities of litchi and longan pericarps and seeds have recently been documented, only a few reports have been conducted on the isolation, identification, evaluation, and elucidation of individual polysaccharides, and similarly, only a few in vivo tests have been conducted to evaluate the beneficial effects of these bioactive compounds present in the pericarps and seeds. Furthermore, although litchi or longan pericarp extract is a source of anti-tumor compounds that inhibit tumor cell viability in in vitro and in vivo models, data about the physiological and biochemical mechanisms responsible for the effects are quite fragmentary (Emanuele et al., 2017 2017 ). Therefore, further utilization of valuable substituents from litchi and longan by-products is important work for researchers towards the development in producing food additives, and cosmetic and drug agents at a large scale. The investigations about the medicinal effects of extracts of litchi and longan by-products through in vitro and in vivo experiments and clinical trials in relation to safety evaluation of the new products are also very important. Conclusions and future perspectives 1 It has been documented that the non-edible portions of litchi and longan fruits contain large amounts of health-enhancing substituents with substantial application potential in the cosmetic, food, and pharmaceutical industries. Unfortunately, very limited attention has been paid to some underutilized and neglected fruits, such as litchi and longan. On the basis of litchi and longan by-products as an excellent source of bioactive constitutes, their uses should be a prioritized scientific and technological problem in agricultural waste management from both economic and environmental viewpoints. Therefore, the utilization of valuable constitutes from litchi and longan by-products as food additives and cosmetic and drug agents is an important work for scientists. Additionally, the development of effective extraction technology with an emphasis on eco-friendly recovery techniques should be considered. Identification and elucidation of these physiologically key substances in relation to pharmaceutical functions from litchi and longan by-products need to be further investigated. It is also important to understand the bioavailability of these bioactive constitutes in living organisms. With the development of biotechnology, molecular genetic approaches can greatly improve the levels of bioactive compounds by selective breeding of new cultivars. Meanwhile, these industries should continue to develop new approaches for greater utilization of litchi and longan by-products to increase economic benefits. References XL Bai , R Pan , MZ Li , 等 . HPLC profile of longan (cv. Shixia) pericarp-sourced phenolics and their antioxidant and cytotoxic effects . Molecules , 2019 . 24 ( 3 ): 619 DOI: 10.3390/molecules24030619 http://doi.org/10.3390/molecules24030619 . HPLC profile of longan (cv. Shixia) pericarp-sourced phenolics and their antioxidant and cytotoxic effects T Bao , Y Wang , YT Li , 等 . Antioxidant and antidiabetic properties of tartary buckwheat rice flavonoids after in vitro digestion . J Zhejiang Univ-Sci B (Biomed & Biotechnol) , 2016 . 17 ( 12 ): 941 - 951 . DOI: 10.1631/jzus.b1600243 http://doi.org/10.1631/jzus.b1600243 . Antioxidant and antidiabetic properties of tartary buckwheat rice flavonoids after in vitro digestion XR Baskaran , AV Geo Vigila , SZ Zhang , 等 . A review of the use of pteridophytes for treating human ailments . J Zhejiang Univ-Sci B (Biomed & Biotechnol) , 2018 . 19 ( 2 ): 85 - 119 . DOI: 10.1631/jzus.b1600344 http://doi.org/10.1631/jzus.b1600344 . A review of the use of pteridophytes for treating human ailments JY Chen , ZZ Ge , W Zhu , 等 . Screening of key antioxidant compounds of longan ( Dimocarpus longan Lour.) seed extract by combining online fishing/knockout, activity evaluation, Fourier transform ion cyclotron resonance mass spectrometry, and high-performance liquid chromatography electrospray ionization mass spectrometry methods . J Agric Food Chem , 2014 . 62 ( 40 ): 9744 - 9750 . 25220361 DOI: 10.1021/jf502995z http://doi.org/10.1021/jf502995z . Screening of key antioxidant compounds of longan (Dimocarpus longan Lour.) seed extract by combining online fishing/knockout, activity evaluation, Fourier transform ion cyclotron resonance mass spectrometry, and high-performance liquid chromatography electrospray ionization mass spectrometry methods LG Chen , CW Chang , JG Tsay , 等 . Hepatoprotective effects of litchi ( Litchi chinensis ) procyanidin A2 on carbon tetrachloride-induced liver injury in ICR mice . Exp Ther Med , 2017 . 13 ( 6 ): 2839 - 2847 . 28587348 DOI: 10.3892/etm.2017.4358 http://doi.org/10.3892/etm.2017.4358 . Hepatoprotective effects of litchi (Litchi chinensis) procyanidin A2 on carbon tetrachloride-induced liver injury in ICR mice YY Chen , HY Luo , AP Gao , 等 . Ultrasound-assisted extraction of polysaccharides from litchi ( Litchi chinensis Sonn.) seed by response surface methodology and their structural characteristics . Innov Food Sci Emerg Technol , 2011 . 12 ( 3 ): 305 - 309 . DOI: 10.1016/j.ifset.2011.03.003 http://doi.org/10.1016/j.ifset.2011.03.003 . Ultrasound-assisted extraction of polysaccharides from litchi (Litchi chinensis Sonn.) seed by response surface methodology and their structural characteristics SA Choi , JE Lee , MJ Kyung , 等 . Anti-diabetic functional food with wasted litchi seed and standard of quality control . Appl Biol Chem , 2017 . 60 ( 2 ): 197 - 204 . DOI: 10.1007/s13765-017-0269-9 http://doi.org/10.1007/s13765-017-0269-9 . Anti-diabetic functional food with wasted litchi seed and standard of quality control S Emanuele , M Lauricella , G Calvaruso , 等 . Litchi chinensis as a functional food and a source of antitumor compounds: an overview and a description of biochemical pathways . Nutrients , 2017 . 9 ( 9 ): 992 DOI: 10.3390/nu9090992 http://doi.org/10.3390/nu9090992 . Litchi chinensis as a functional food and a source of antitumor compounds: an overview and a description of biochemical pathways WH Gao , PZ Lin , XA Zeng , 等 . Preparation, characterisation and antioxidant activities of litchi ( Litchi chinensis Sonn.) polysaccharides extracted by ultra-high pressure . Int J Food Sci Technol , 2017 . 52 ( 8 ): 1739 - 1750 . DOI: 10.1111/ijfs.13447 http://doi.org/10.1111/ijfs.13447 . Preparation, characterisation and antioxidant activities of litchi (Litchi chinensis Sonn.) polysaccharides extracted by ultra-high pressure GX Jiang , KN Prasad , YM Jiang , 等 . Extraction and structural identification of alkali-soluble polysaccharides of longan ( Dimocarpus longan Lour.) fruit pericarp . Innov Food Sci Emerg Technol , 2009 . 10 ( 4 ): 638 - 642 . DOI: 10.1016/j.ifset.2009.06.006 http://doi.org/10.1016/j.ifset.2009.06.006 . Extraction and structural identification of alkali-soluble polysaccharides of longan (Dimocarpus longan Lour.) fruit pericarp GX Jiang , YM Jiang , B Yang , 等 . Structural characteristics and antioxidant activities of oligosaccharides from longan fruit pericarp . J Agric Food Chem , 2009 . 57 ( 19 ): 9293 - 9298 . 19739643 DOI: 10.1021/jf902534v http://doi.org/10.1021/jf902534v . Structural characteristics and antioxidant activities of oligosaccharides from longan fruit pericarp GX Jiang , S Lin , LR Wen , 等 . Identification of a novel phenolic compound in litchi ( Litchi chinensis Sonn.) pericarp and bioactivity evaluation . Food Chem , 2013 . 136 ( 2 ): 563 - 568 . 23122098 DOI: 10.1016/j.foodchem.2012.08.089 http://doi.org/10.1016/j.foodchem.2012.08.089 . Identification of a novel phenolic compound in litchi (Litchi chinensis Sonn.) pericarp and bioactivity evaluation GX Jiang , LR Wen , F Chen , 等 . Structural characteristics and antioxidant activities of polysaccharides from longan seed . Carbohyd Polym , 2013 . 92 ( 1 ): 758 - 764 . DOI: 10.1016/j.carbpol.2012.09.079 http://doi.org/10.1016/j.carbpol.2012.09.079 . Structural characteristics and antioxidant activities of polysaccharides from longan seed YM Jiang , ZQ Zhang , DC Joyce , 等 . Postharvest biology and handling of longan fruit ( Dimocarpus longan Lour.) . Postharvest Biol Technol , 2002 . 26 ( 3 ): 241 - 252 . DOI: 10.1016/s0925-5214(02)00047-9 http://doi.org/10.1016/s0925-5214(02)00047-9 . Postharvest biology and handling of longan fruit (Dimocarpus longan Lour.) YM Jiang , Y Wang , L Song , 等 . Postharvest characteristics and handling of litchi fruit–an overview . Aust J Exp Agric , 2006 . 46 ( 12 ): 1541 - 1556 . DOI: 10.1071/ea05108 http://doi.org/10.1071/ea05108 . Postharvest characteristics and handling of litchi fruit–an overview M Kanlayavattanakul , D Ospondpant , U Ruktanonchai , 等 . Biological activity assessment and phenolic compounds characterization from the fruit pericarp of Litchi chinensis for cosmetic applications . Pharm Biol , 2012 . 50 ( 11 ): 1384 - 1390 . 22889092 DOI: 10.3109/13880209.2012.675342 http://doi.org/10.3109/13880209.2012.675342 . Biological activity assessment and phenolic compounds characterization from the fruit pericarp of Litchi chinensis for cosmetic applications HNE Kessy , K Wang , L Zhao , 等 . Enrichment and biotransformation of phenolic compounds from litchi pericarps with angiotensin I-converting enzyme (ACE) inhibition activity . LWT , 2018 . 87 301 - 309 . DOI: 10.1016/j.lwt.2017.09.003 http://doi.org/10.1016/j.lwt.2017.09.003 . Enrichment and biotransformation of phenolic compounds from litchi pericarps with angiotensin I-converting enzyme (ACE) inhibition activity N Kunworarath , N Rangkadilok , T Suriyo , 等 . Longan ( Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-κB and AP-1 signaling pathways . J Ethnopharmacol , 2016 . 179 156 - 161 . 26721218 DOI: 10.1016/j.jep.2015.12.044 http://doi.org/10.1016/j.jep.2015.12.044 . Longan (Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-κB and AP-1 signaling pathways JR Li , YM Jiang . Litchi flavonoids: isolation, identification and biological activity . Molecules , 2007 . 12 ( 4 ): 745 - 758 . 17851427 DOI: 10.3390/12040745 http://doi.org/10.3390/12040745 . Litchi flavonoids: isolation, identification and biological activity XN Li , JL Huang , ZD Wang , 等 . Alkaline extraction and acid precipitation of phenolic compounds from longan ( Dimocarpus longan L.) seeds . Sep Purif Technol , 2014 . 124 201 - 206 . DOI: 10.1016/j.seppur.2014.01.030 http://doi.org/10.1016/j.seppur.2014.01.030 . Alkaline extraction and acid precipitation of phenolic compounds from longan (Dimocarpus longan L.) seeds S Lin , LR Wen , B Yang , 等 . Improved growth of Lactobacillus bulgaricus and Streptococcus thermophilus as well as increased antioxidant activity by biotransforming litchi pericarp polysaccharide with Aspergillus awamori . BioMed Res Int, 2013:413793 , 2013 . DOI: 10.1155/2013/413793 http://doi.org/10.1155/2013/413793 . Improved growth of Lactobacillus bulgaricus and Streptococcus thermophilus as well as increased antioxidant activity by biotransforming litchi pericarp polysaccharide with Aspergillus awamori S Lin , JR He , YM Jiang , 等 . Production of nigragillin and dihydrophaseic acid by biotransformation of litchi pericarp with Aspergillus awamori and their antioxidant activities . J Funct Foods , 2014 . 7 278 - 286 . DOI: 10.1016/j.jff.2014.02.001 http://doi.org/10.1016/j.jff.2014.02.001 . Production of nigragillin and dihydrophaseic acid by biotransformation of litchi pericarp with Aspergillus awamori and their antioxidant activities S Lin , Q Li , B Yang , 等 . Transformation of litchi pericarp-derived condensed tannin with Aspergillus awamori . Int J Mol Sci , 2016 . 17 ( 7 ): 1067 DOI: 10.3390/ijms17071067 http://doi.org/10.3390/ijms17071067 . Transformation of litchi pericarp-derived condensed tannin with Aspergillus awamori Q Ma , HH Xie , S Li , 等 . Flavonoids from the pericarps of Litchi chinensis . J Agric Food Chem , 2014 . 62 ( 5 ): 1073 - 1078 . 24450594 DOI: 10.1021/jf405750p http://doi.org/10.1021/jf405750p . Flavonoids from the pericarps of Litchi chinensis Q Ma , HH Xie , YM Jiang , 等 . Phenolics and sesquiterpenes from litchi pericarp . J Funct Foods , 2014 . 9 156 - 161 . DOI: 10.1016/j.jff.2014.04.020 http://doi.org/10.1016/j.jff.2014.04.020 . Phenolics and sesquiterpenes from litchi pericarp A Panyathep , T Chewonarin , K Taneyhill . Antioxidant and anti-matrix metalloproteinases activities of dried longan ( Euphoria longana ) seed extract . Sci Asia , 2013 . 39 ( 4 ): 12 - 18 . DOI: 10.2306/scienceasia1513-1874.2013.39.012 http://doi.org/10.2306/scienceasia1513-1874.2013.39.012 . Antioxidant and anti-matrix metalloproteinases activities of dried longan (Euphoria longana) seed extract KN Prasad , J Hao , J Shi , 等 . Antioxidant and anticancer activities of high pressure-assisted extract of longan ( Dimocarpus longan Lour.) fruit pericarp . Innov Food Sci Emerg Technol , 2009 . 10 ( 4 ): 413 - 419 . DOI: 10.1016/j.ifset.2009.04.003 http://doi.org/10.1016/j.ifset.2009.04.003 . Antioxidant and anticancer activities of high pressure-assisted extract of longan (Dimocarpus longan Lour.) fruit pericarp KN Prasad , B Yang , MM Zhao , 等 . Application of ultrasonication or high-pressure extraction of flavonoids from litchi fruit pericarp . J Food Process Eng , 2009 . 32 ( 6 ): 828 - 843 . DOI: 10.1111/j.1745-4530.2008.00247.x http://doi.org/10.1111/j.1745-4530.2008.00247.x . Application of ultrasonication or high-pressure extraction of flavonoids from litchi fruit pericarp KN Prasad , E Yang , C Yi , 等 . Effects of high pressure extraction on the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp . Innov Food Sci Emerg Technol , 2009 . 10 ( 2 ): 155 - 159 . DOI: 10.1016/j.ifset.2008.11.007 http://doi.org/10.1016/j.ifset.2008.11.007 . Effects of high pressure extraction on the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp KN Prasad , B Yang , M Zhao , 等 . Effects of high pressure or ultrasonic treatment on extraction yield and antioxidant activity of pericarp tissues of longan fruit . J Food Biochem , 2010 . 34 ( 4 ): 838 - 855 . DOI: 10.1111/j.1745-4514.2010.00335.x http://doi.org/10.1111/j.1745-4514.2010.00335.x . Effects of high pressure or ultrasonic treatment on extraction yield and antioxidant activity of pericarp tissues of longan fruit KN Prasad , B Yang , J Shi , 等 . Enhanced antioxidant and antityrosinase activities of longan fruit pericarp by ultra-high-pressure-assisted extraction . J Pharm Biomed Anal , 2010 . 51 ( 2 ): 471 - 477 . 19345542 DOI: 10.1016/j.jpba.2009.02.033 http://doi.org/10.1016/j.jpba.2009.02.033 . Enhanced antioxidant and antityrosinase activities of longan fruit pericarp by ultra-high-pressure-assisted extraction N Rangkadilok , S Sitthimonchai , L Worasuttayangkurn , 等 . Evaluation of free radical scavenging and antityrosinase activities of standardized longan fruit extract . Food Chem Toxicol , 2007 . 45 ( 2 ): 328 - 336 . 17049706 DOI: 10.1016/j.fct.2006.08.022 http://doi.org/10.1016/j.fct.2006.08.022 . Evaluation of free radical scavenging and antityrosinase activities of standardized longan fruit extract N Rangkadilok , S Tongchusak , R Boonhok , 等 . In vitro antifungal activities of longan ( Dimocarpus longan Lour.) seed extract . Fitoterapia , 2012 . 83 ( 3 ): 545 - 553 . 22245574 DOI: 10.1016/j.fitote.2011.12.023 http://doi.org/10.1016/j.fitote.2011.12.023 . In vitro antifungal activities of longan (Dimocarpus longan Lour.) seed extract P Sarni-Manchado , E le Roux , C le Guerneve , 等 . Phenolic composition of litchi fruit pericarp . J Agric Food Chem , 2000 . 48 ( 12 ): 5995 - 6002 . 11312772 DOI: 10.1021/jf000815r http://doi.org/10.1021/jf000815r . Phenolic composition of litchi fruit pericarp Y Sudjaroen , WE Hull , G Erben , 等 . Isolation and characterization of ellagitannins as the major polyphenolic components of longan ( Dimocarpus longan Lour) seeds . Phytochemistry , 2012 . 77 226 - 237 . 22277734 DOI: 10.1016/j.phytochem.2011.12.008 http://doi.org/10.1016/j.phytochem.2011.12.008 . Isolation and characterization of ellagitannins as the major polyphenolic components of longan (Dimocarpus longan Lour) seeds Y Sui , Y Zheng , XP Li , 等 . Characterization and preparation of oligomeric procyanidins from Litchi chinensis pericarp . Fitoterapia , 2016 . 112 168 - 174 . 27282208 DOI: 10.1016/j.fitote.2016.06.001 http://doi.org/10.1016/j.fitote.2016.06.001 . Characterization and preparation of oligomeric procyanidins from Litchi chinensis pericarp J Sun , J Shi , YM Jiang , 等 . Identification of two polyphenolic compounds with antioxidant activities in longan pericarp tissues . J Agric Food Chem , 2007 . 55 ( 14 ): 5864 - 5868 . 17579438 DOI: 10.1021/jf070839z http://doi.org/10.1021/jf070839z . Identification of two polyphenolic compounds with antioxidant activities in longan pericarp tissues J Sun , L Li , XR You , 等 . Phenolics and polysaccharides in major tropical fruits: chemical compositions, analytical methods and bioactivities . Anal Methods , 2011 . 3 ( 10 ): 2212 - 2220 . DOI: 10.1039/c1ay05342f http://doi.org/10.1039/c1ay05342f . Phenolics and polysaccharides in major tropical fruits: chemical compositions, analytical methods and bioactivities HC Tseng , WT Wu , HS Huang , 等 . Antimicrobial activities of various fractions of longan ( Dimocarpus longan Lour . Fen Ke) seed extract . Int J Food Sci Nutr , 2014 . 65 ( 5 ): 589 - 593 . 24533783 DOI: 10.3109/09637486.2014.886181 http://doi.org/10.3109/09637486.2014.886181 . Antimicrobial activities of various fractions of longan (Dimocarpus longan Lour. Fen Ke) seed extract HC Wang , ZQ Hu , Y Wang , 等 . Phenolic compounds and the antioxidant activities in litchi pericarp: difference among cultivars . Sci Hort , 2011 . 129 ( 4 ): 784 - 789 . DOI: 10.1016/j.scienta.2011.05.042 http://doi.org/10.1016/j.scienta.2011.05.042 . Phenolic compounds and the antioxidant activities in litchi pericarp: difference among cultivars LJ Wang , GD Lou , ZJ Ma , 等 . Chemical constituents with antioxidant activities from litchi ( Litchi chinensis Sonn.) seeds . Food Chem , 2011 . 126 ( 3 ): 1081 - 1087 . DOI: 10.1016/j.foodchem.2010.11.133 http://doi.org/10.1016/j.foodchem.2010.11.133 . Chemical constituents with antioxidant activities from litchi (Litchi chinensis Sonn.) seeds XJ Wang , SL Yuan , J Wang . Anticancer activity of litchi fruit pericarp extract against human breast cancer in vitro and in vivo . Toxicol Appl Pharmacol , 2006 . 215 ( 2 ): 168 - 178 . 16563451 DOI: 10.1016/j.taap.2006.02.004 http://doi.org/10.1016/j.taap.2006.02.004 . Anticancer activity of litchi fruit pericarp extract against human breast cancer in vitro and in vivo XJ Wang , YQ Wei , SL Yuan , 等 . Potential anticancer activity of litchi fruit pericarp extract against hepatocellular carcinoma in vitro and in vivo . Cancer Lett , 2006 . 239 ( 1 ): 144 - 150 . 16300877 DOI: 10.1016/j.canlet.2005.08.011 http://doi.org/10.1016/j.canlet.2005.08.011 . Potential anticancer activity of litchi fruit pericarp extract against hepatocellular carcinoma in vitro and in vivo XY Xu , HH Xie , YF Wang , 等 . A-type proanthocyanidins from lychee seeds and their antioxidant and antiviral activities . J Agric Food Chem , 2010 . 58 ( 22 ): 11667 - 11672 . 20964424 DOI: 10.1021/jf1033202 http://doi.org/10.1021/jf1033202 . A-type proanthocyanidins from lychee seeds and their antioxidant and antiviral activities B Yang , JS Wang , MM Zhao , 等 . Identification of polysaccharides from pericarp tissues of litchi ( Litchi chinensis Sonn.) fruit in relation to their antioxidant activities . Carbohyd Res , 2006 . 341 ( 5 ): 634 - 638 . DOI: 10.1016/j.carres.2006.01.004 http://doi.org/10.1016/j.carres.2006.01.004 . Identification of polysaccharides from pericarp tissues of litchi (Litchi chinensis Sonn.) fruit in relation to their antioxidant activities B Yang , MM Zhao , J Shi , 等 . Effect of ultrasonic treatment on the recovery and DPPH radical scavenging activity of polysaccharides from longan fruit pericarp . Food Chem , 2008 . 106 ( 2 ): 685 - 690 . DOI: 10.1016/j.foodchem.2007.06.031 http://doi.org/10.1016/j.foodchem.2007.06.031 . Effect of ultrasonic treatment on the recovery and DPPH radical scavenging activity of polysaccharides from longan fruit pericarp B Yang , MM Zhao , YM Jiang . Optimization of tyrosinase inhibition activity of ultrasonic-extracted polysaccharides from longan fruit pericarp . Food Chem , 2008 . 110 ( 2 ): 294 - 300 . 26049219 DOI: 10.1016/j.foodchem.2008.01.067 http://doi.org/10.1016/j.foodchem.2008.01.067 . Optimization of tyrosinase inhibition activity of ultrasonic-extracted polysaccharides from longan fruit pericarp B Yang , MM Zhao , J Shi , 等 . Variations in water-soluble saccharides and phenols in longan fruit pericarp after drying . J Food Process Eng , 2008 . 31 ( 1 ): 66 - 77 . DOI: 10.1111/j.1745-4530.2007.00142.x http://doi.org/10.1111/j.1745-4530.2007.00142.x . Variations in water-soluble saccharides and phenols in longan fruit pericarp after drying B Yang , MM Zhao , YM Jiang . Anti-glycated activity of polysaccharides of longan ( Dimocarpus longan Lour.) fruit pericarp treated by ultrasonic wave . Food Chem , 2009 . 114 ( 2 ): 629 - 633 . DOI: 10.1016/j.foodchem.2008.09.099 http://doi.org/10.1016/j.foodchem.2008.09.099 . Anti-glycated activity of polysaccharides of longan (Dimocarpus longan Lour.) fruit pericarp treated by ultrasonic wave B Yang , YM Jiang , MM Zhao , 等 . Structural characterisation of polysaccharides purified from longan ( Dimocarpus longan Lour.) fruit pericarp . Food Chem , 2009 . 115 ( 2 ): 609 - 614 . DOI: 10.1016/j.foodchem.2008.12.082 http://doi.org/10.1016/j.foodchem.2008.12.082 . Structural characterisation of polysaccharides purified from longan (Dimocarpus longan Lour.) fruit pericarp B Yang , YM Jiang , R Wang , 等 . Ultra-high pressure treatment effects on polysaccharides and lignins of longan fruit pericarp . Food Chem , 2009 . 112 ( 2 ): 428 - 431 . DOI: 10.1016/j.foodchem.2008.05.097 http://doi.org/10.1016/j.foodchem.2008.05.097 . Ultra-high pressure treatment effects on polysaccharides and lignins of longan fruit pericarp B Yang , YM Jiang , J Shi , 等 . Extraction and pharmacological properties of bioactive compounds from longan ( Dimocarpus longan Lour.) fruit–a review . Food Res Int , 2011 . 44 ( 7 ): 1837 - 1842 . DOI: 10.1016/j.foodres.2010.10.019 http://doi.org/10.1016/j.foodres.2010.10.019 . Extraction and pharmacological properties of bioactive compounds from longan (Dimocarpus longan Lour.) fruit–a review JC Zhang , GM Yang , YZ Wen , 等 . Intestinal microbiota are involved in the immunomodulatory activities of longan polysaccharide . Mol Nutr Food Res , 2017 . 61 ( 11 ): 1700466 DOI: 10.1002/mnfr.201700466 http://doi.org/10.1002/mnfr.201700466 . Intestinal microbiota are involved in the immunomodulatory activities of longan polysaccharide RF Zhang , DX Su , FL Hou , 等 . Optimized ultra-high-pressure-assisted extraction of procyanidins from lychee pericarp improves the antioxidant activity of extracts . Biosci Biotechnol Biochem , 2017 . 81 ( 8 ): 1576 - 1585 . 28471298 DOI: 10.1080/09168451.2017.1321953 http://doi.org/10.1080/09168451.2017.1321953 . Optimized ultra-high-pressure-assisted extraction of procyanidins from lychee pericarp improves the antioxidant activity of extracts MM Zhao , B Yang , JS Wang , 等 . Identification of the major flavonoids from pericarp tissues of lychee fruit in relation to their antioxidant activities . Food Chem , 2006 . 98 ( 3 ): 539 - 544 . DOI: 10.1016/j.foodchem.2005.06.028 http://doi.org/10.1016/j.foodchem.2005.06.028 . Identification of the major flavonoids from pericarp tissues of lychee fruit in relation to their antioxidant activities MM Zhao , B Yang , JS Wang , 等 . Immunomodulatory and anticancer activities of flavonoids extracted from litchi ( Litchi chinensis Sonn.) pericarp . Int Immunopharmacol , 2007 . 7 ( 2 ): 162 - 166 . 17178382 DOI: 10.1016/j.intimp.2006.09.003 http://doi.org/10.1016/j.intimp.2006.09.003 . Immunomodulatory and anticancer activities of flavonoids extracted from litchi (Litchi chinensis Sonn.) pericarp Compliance with ethics guidelines Xiang-rong ZHU, Hui WANG, Jian SUN, Bao YANG, Xue-wu DUAN, and Yue-ming JIANG declare that they have no conflict of interest. This article does not contain any studies with human and animal subjects performed by any of the authors. 10.1631/jzus.B1900161 Project supported by the National Natural Science Foundation of China (No. 31770726) and the National Key Research and Development Program of China (No. 2016YFD0400904) 2019-03-31 2019-04-21 2022-01-05 Copyright © Zhejiang University and Springer-Verlag GmbH Germany, part of Springer Nature 2019 2019 Journal of Zhejiang University-SCIENCE B (Biomedicine and Biotechnology) 06 20