Characterization And Bioactivity Of Secondary Metabolites From Caesalpinia Cucullata Roxb.

Caesalpinia cucullata Roxb.belongs to the plant family of Fabaceae.It is often used to treat rheumatic paralysis and other diseases,and its medication is very extensive in China.In this paper,the chemical composition contained in the twigs and leaves of the plant is systematically studied.A total of 52 compounds were separated by recrystallization,column chromatography of silica gel,MCI,and Sephadex LH-20,as well as semi-preparative high performance liquid chromatography.One new compound was identified by spectroscopic methods,and the rest were identified as known compounds.In the study of biological activity,some compounds obtained were assayed in the in vitro anti-proliferative activity,NO production inhibitory activity,anti-oxidant activity,and α-glucosidase inhibitory activity,and some compounds were found to have good biological activity.The 95%ethanol extract of the twigs and leaves of the C.cucullata was separated by a variety of chromatographic techniques,and the structure of the obtained compounds was identified by spectroscopic techniques.A total of 52 known compounds were identified,including a new homoisoflavonoid compound,(3E)-7,8-dihydroxy-3-(3’-hydroxy-4’-methoxybenzylidene)chroman-4-one(1).The known compounds were identified as six triterpenoids,lupeol(2),lupeol acetate(3),methyl betulinate(4),betulinic acid(5),ursolic acid(6)and oleanolic acid(7);a diterpenoid,manool(8);four steroids,β-sitosterol(9),β-sitosterol acetate(10),stigmasterol(11)and β-sitostenone(12);fifteen flavonoids,intricatinol(13),isoliquiritigenin(14),baicalein(15),pectolinarigenin(16),kaempferol(17),quercetin(18),chrysin(19),apigenin(20),luteolin(21),acacetin(22),dihydromyricetin(23),naringenin(24),hesperetin(25),(-)-epicatechin(26)and(+)-catechin(27);a coumarin compound,esculetin(29);fourteen phenolic compounds,α-tocopherol(28),trans-resveratrol(30),p-coumaric acid(31),ferulic acid(32),propyl gallate(33),butyl gallate(34),ethyl protocatechuate(35),ethyl gallate(36),protocatechuic acid(37),gallic acid(38),methyl gallate(39),salicylic acid(40),vanillin(41)and vanillic acid(42);ten fatty acid compounds,linoleic acid(43),oleic acid(44),6,10,14-trimethylpentadecan-2-one(45),(7R,11R)-3,7,11,15-tetramethyl-l-hexadecen-3-ol(46),ethyl dodecanoate(47),palmitic acid(48),ethyl(6Z,9Z,11E)-6,9,11-octadecatrienoate(49),triacontanol(50),tricosanoic acid(51)and diethyl(2S)-2-hydroxybutanedioate(52).Among them,3,4,8,10-13,23,26-28,33,34,43-50,and 52 are found in this plant species for the first time.In the in vitro biological activity experiments,the results of LPS-induced NO production inhibition assay showed that compound 17 could significantly inhibit the production of NO in cells,and its IC50 value at 6.09 μM,and compounds 1,18 and 21 had medium inhibitory effects on the production of NO in cells with IC50 values at 15.66 μM,7.66 μM,and 7.13 μM,respectively.The results of anti-proliferative activity showed that compound 5 had strong anti-proliferative activity against human liver cancer HepG2 cells and human triple-negative breast cancer MDA-MB-231 cells,and their IC50 values were 12.30 μM and 17.81 μM,respectively.The results of α-glucosidase inhibition showed that compounds 1,13 and 18 inhibited the activity of α-glucosidase in a dose-dependent manner,with IC50 values of 6.68μM,14.37 μM and 11.87 μM,respectively,and the inhibitory effect of compounds 1 and 18 on α-glucosidase activity was better than that of the positive control acarbose.The results of anti-oxidant activity showed that compounds 2 and 24 exhibited only weak quinone reductase inducing activity.