Studies On The Secondary Metabolites From Litters Of Casuarina Equisetifolia And Their Bioactivities

Casuarina equisetifolia,which belongs to the genus Casuarina Adans of the family Casuarinaceae,is one of the important forest tree species and mainly distributed in south and southeast China.It was reported that the litters of C.equisetifolia disintegrated slowly,that lead to the little nutrient return to land and poor condition for plant growing.So far,little studies on the secondary metabolites of C.equisetifolia have been reported.In order to further rational development and utilization of the litters of C.equisetifolia,the phytochemical studies on the litters of C.equisetifolia were carried out.This study is expected to enrich the secondary metabolites constituesnts of the litters of C.equisetifolia and their bioactivities,and then further provide the scientific and theoretical basis for the development and utilization of C.equisetifolia.Compounds 1-21 were isolated from the ethyl acetate(Et OAc)extract of the litters of C.equisetifolia by various column chromatographies,and the structures were elucidated by UV,IR,MS,1D and 2D NMR.They were identified as 4,9,11,17-tetrahydroxy diphenyl ether cycloheptane(1),2,8,13,15-tetrahydroxy-4-methoxy-diaryl-11-ring heptyl ketone(2),2,9,11,12,17-pentahydroxy-diaryl-cycloheptane(3),2,8,11,12,17-pentahydroxy-diaryl cycloheptane(4),casuarmondtol(5),alnusdiol(6),kaempferol(7),kaempferol 3-O-?-L-rhamnopyranoside(8),4''-trans-p-coumaroyl-kaempferol-3-O-?-rhamnopyranoside(9),4''-cis-p-coumaroyl-kaempferol-3-O-?-rhamnopyranoside(10),3?-(p-Hydroxy-trans-cinna moyl)(11),3-O-(E)-coumaroylerythrodiol(12),dandelion terpene ketone(13),7,16,21-trihydroxyolesn-12-en-3-one(14),dancosterol(15),benzoic acid,2,4-dihydroxy-6-methyl-,(1)-2-[(1)-2-(3,5-dihydroxy phenyl)-1-methyl ethyl-3,5-dihydroxy phenyl]-1-methyl ethyl ester(16),isolariciresinol(17),protocatechuic acid methyl ester(18),p-coumaric acid(19),hydroxy benzene methanol(20)and 2-methyl-5-methoxy galactoside(21).Compounds 1-4 were new compounds.Compounds 5-7,9-10,13 and 15-18 were obtained from C.equisetifolia for the first time.The cytotoxic activities(K562,BEL-7402,SGC-7901 and Hela)of the compounds 1-21 were measured in vitro by MTT method.The results showed that compounds 9 and 11 presented cytotoxicity against human chronic myelogenous leukemia cells line(K562),human hepatoma cell line(BEL-7402)and human gastric cancer cell line(SGC-7901).While compound 9 displayed cytotoxicity against human cervical cancer cell line(Hela).The acetylcholinesterase(ACh E)inhibitory activity of the compounds 1-21 were tested in vitro by Ellman's method.The experimental results demonstrated that compounds 4-7,9-12 and 16 exhibited moderate ACh E inhibitory activity.The ?-glucosidase inhibitory activity of the compounds 1-21 were assayed in vitro by PNPG method,and the results revealed that compounds 1,5-6,8 and 11 exhibited significant ?-glucosidase inhibitory activity.