| Lychee?Litchi chinensis Sonn.?,native to Guangdong and Fujian provinces of China,is a tropical and subtropical evergreen plant which belongs to the only species of the genus Litchi in Sapindaceae family.It is prevalent in global market as an important fruit attributing to its delicious arils and abundant nutritional value.Lychee seeds are mainly discarded as waste except a trifling amount is applied as traditional Chinese medicine to treat epigastric pain,testicular swelling and pain.In recent years,the chemical studies have suggested that lychee seeds contained large quantities of bioactive phytochemicals,such as flavonoids,sesquiterpenes,triterpenes,sterols,lignans,and etc.Previous pharmacological studies revealed that lychee seed possessed anti-hyperglycemic,anti-hyperlipidemic,anti-platelet aggregation,antitumor,antiviral,and antioxidant effects.In this study,lychee seeds were extracted with 70%ethanol,fractionated with different solvents,and then successively chromatographed on silica gel,ODS,Sephadex LH-20 and HPLC to obtain 52 compounds,and their structures were established on the basis of spectroscopic analysis including MS,1D and 2D NMR spectra.They were elucidated as four methyl jasmonates:?-?-?1R,2R,2?Z?-2-[5?-?acetyloxy?-2-penten-1-yl]-3-oxo-cyclopentaneacetic acid methyl ester?1*?,?-?-?1R,2R,2?Z?-2-?5-methoxy-5-oxo-2-penten-1-yl?-3-oxo-cyclopentaneacetic acid methyl ester?2*?,?+?-?1R,2R,3R,2?E?-3-hydroxy-2-?5-methoxy-5-oxo-2-penten-1-yl?-cyclopenta neacetic acid methyl ester?3*?,?-?-?1R,2R,2?Z?-methyl-2-?5?-hydroxy-pent-2?-enyl?-3-oxocyclopentaneacetate?4?;seventeenflavonoids:catechin?5?,epicatechin?6?,naringenin-7-O-?-D-glucopyranoside?7?,pinocembrin 7-O-rutinoside?8?,naringenin-7-O-rutinoside?9?,quercetin?10?,quercetin3-O-?-D-glucopiranoside?11?,quercetin-3-O-?-D-xylopyranoside?12?,quercetin 3-O-?-D-galactoside?13?,quercetin 3-O-?-D-rhamnoside?14?,isovitexin?15?,phloretin?16?,phloretinrutinoside?17?,2?,3?-epoxy-5,7,3?,4?-tetrahydroxyflavan-?4?-8?-epicatechin?18?,2?,3?-epoxy-5,7,3?,4?-tetrahydroxyflavan-?4?-8-catechin??19?,2?,3?-epoxy-5,7,3?,4?-tetrahydroxyflavan-?4?-8-epicatechin??20?,amentoflavone?21?;threelignans:?+?-?8S,7?S,8?S?-burselignan-9?-O-?-L-arabinoside?22*?,?7R,8S?-3,5?-dimethoxy-4?,7-epoxy-8,3?-neolignane-5,9,9?-triol?23?,?7R,8S?-dihydrodehydrodiconiferyl alchol 9?-O-?-D-glucopyranoside?24?;fifteen phenolics:protocatechuic acid?25?,4-hydroxybenzoic acid?26?,protocatechuic acid methyl ester?27?,ethyl-3,4-dihydroxybenzoic acid?28?,3-hydroxy-4-methoxybenzoic acid?29?,p-hydroxy benzeneacetate?30?,methylp-hydroxymandelate?31?,p-hydroxymandelicacid?32?,p-hydroxyphenylpropionicmethylester?33?,O-methyl-2-hydroxy-3-?4-hydroxy?-phenylpropionate?34?,?E?-p-hydroxycinnamic acid?35?,?E?ethyl p-hydroxycinnamate?36?,methyl5-O-p-coumaroylquinic acid?37?,methyl 4-O-p-coumaroylquinic acid?38?,ethyl 3,4,5-trihydroxybenzoate?39?;two triterpenes:lupeol?40?,arjunglucosideI?41?,twosterols:stigmasterol?42?,3?-hydroxy-7?-methoxy-24?-ethyl-cholest-5-ene?43?;ten other compounds:4-hydroxy-5-?9?-oxo-8?-pyrrolidinyl?-benzoic acid?44?,1-pyrrolidineacetic methylester?45?,phenylalaninemethylester?46?,2-hydroxyquinoline-4-carboxyicacid?47?,pumilasideA?48?,3,4-dihydroxy-cyclohexanecarboxylic acid-methyl ester?49?,1-methyl ester,butanedioic acid?50?,1,1-cyclopropanediacetic acid,1-methyl ester?51?,2-methoxycarbonyl-cyclopropaneacetic acid?52?,respectively.Among these constituents,compounds 1-4 are methyl jasmonates,compounds 5-21 are flavonoids,compounds 22-24 are lignans,compounds 25-39 are phenolic acids,compounds 40 and 41 are triterpenes,compounds 42?43 are sterols,compounds 44-52 are belong to other types.Among them,compounds 1-3 and22 are four new compounds.The anti-inflammatory and anti-proliferative activities against human cancer cell lines were measured for compounds 1-4,22.And antioxidant activities of compounds 1-22 were evaluated with DPPH assay,PMS/NADH-NB assay and FRAP assay.Ultimately,compounds 2 and 3exhibited anti-inflammatory capacities with IC50 values of 61.25±3.25?M and43.56±2.17?M;Compound 2 showed moderate anti-tumor effects against HL-60 cells with IC50 values of 76.01±1.08??.Compounds 5?6?10-12?18-20?22 exhibited pronounced antioxidant capacities in these three selected methods. |
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