Characterization And Bioactivity Of Secondary Metabolites From Euphorbia Pulcherrima

Euphorbia pulcherrima is a plant of Euphorbia genus in Euphorbiaceae.As a traditional Chinese medicine,it is mainly used to treat diseases such as menorrhagia,wind cold cough,fracture,traumatic injury,trauma,and bleeding.According to the literature,terpenoids and steroids are the main secondary metabolites of E.pulcherrima,which have biological activities such as cytotoxicity,anti-Alzheimer’s disease,inhibition of osteoclast formation,and so on.However,chemical research of natural pharmaceutical chemists on E.pulcherrima is very limited,so its effective components need to be further explored.In order to explore more natural organic small-molecule compounds with novel structure and good biological activity,chemical constituents of the aerial parts of E.pulcherrima were studied systematically.A total of 56 compounds,including 10 new ones,were isolated by using silica gel column chromatography,Sephadex LH-20 column chromatography,chiral HPLC,and C18 reverse-phased silica gel column chromatography.The structures were characterized by NMR(nuclear magnetic resonance),MS(mass spectrometry),and CD(circular dichroism)techniques.Among them,the new compounds were identified as four indanones,Seupulcherene A(1),R-and S-7-methyleupulcherene A(2a and 2b),and eupulcherene B(3),two indanone derivatives,{7S,8S,9S)-and(7R,8R,9R)-eupulcherene C(4a and 4b),three sesquiterpenoids,S-and R-eupulcherene D(5a and 5b),(2S,3S)-eupulcherene E(6)and one coumarin compound,eupulcherin(7).In addition,46 known compounds were also isolated from E.pulcherrima,including six triterpenoids,germanicyl acetate(8),3-acetylaleuritolic acid(9),oleana-11,13(18)-dien-3β-yl acetate(10),cycloart-23-ene-3β;25-diol(11),supinenolone A 3-acetate(12),and teuviscin A(13),seven steroids,β-stigmasterol(14),stigmastane-3,6-dione(15),sitostenone(16),stigmast-4-en-3,6-dione(17),ergost-6,22-diene-3β,5α,8α-triol(18),6βhydroxy-4-campesten-3-one(19),and 24-propylcholestan-3-one(20),two diterpenoids,inumakoic acid(21)and 15-hydroxydehydroabietic acid(22),four sesquiterpenoids,cylindrene(23),pubinernoid A(24),boscialin(25),and(3S,5R,6S,7E)-3,5,6-trihydroxy-7-megastigmen9-one(26),one monoterpenoid,(-)-loliolide(27),nine lignans,(-)-evofolin B(28),(-)-ficusal(29),(+)-syringaresinol(30),medioresinol(31),(+)-lariciresinol(32),tomentosanan A(33),2,6,2’,6’-tetramethoxy-4,4’-bis(2,3-epoxy-1-hydroxypropyl)biphenyl(34),(2S,3R)-ceplignan(35),and rel-(2α,3β)-7-O-methylcedrusin(36),one alkaloid,indol-3-carboxylic acid(37),one pyrone compound,decumbic acid(38),two coumarin,fraxidin(39)and scopoletin(40),five polyketides,(3S)-lasiodiplodin(41),des-O-methyllasiodiplodin(42),3ξ-(1ξ-hydroxyethyl)-7hydroxy-l-isobenzofuranone(43),botryosphaeridione(44),and cis-4-hydroxymellein(45),four aromatic compounds,syringic aldehyde(46),trans-coniferyl aldehyde(47),3’,5’dimethoxy-4’-hydroxy-(2-hydroxy)acetophenone(48),and ω-hydroxypropioguaiacone(49),as well as four fatty acids,rabdosia acid A(50),(E)-11-oxo-octadeca-12-enoic acid(51),2anhydromevalonic acid(52),and 1-dodecanol(53).The new compounds 1-7 and known compounds 11-13,17-18,20-24 were tested for inhibiting LPS-induced NO production in mouse macrophages(RAW 264.7 cells)in vitro,and the results showed that compounds 1,2a/2b,3,6,7,12,13,18,20,and 22-24 showed different degrees of inhibitory activity.At the same time,the new compounds 1-7 were tested for their antioxidant activities by quinone reductase inducing assay,and compounds 2a,3,and 6 exhibited significant antioxidant activities.