| This paper reported the phytochemical investigation systematically on Dendrobium candidum,and bio-active screening results of the part chemical constituents isolated from Dendrobium candidum.In the meantime,this paper reported the progress of phytochemical studies on Dendrobium genus.By using the chromatography techniques,72 compounds were isolated from the EtOAc and EtOH extrats of this plant's stems.On the basis of chemical methods and spectroscopic techniques,63 of these compounds were elucidated as follows:27 stilbenoids:dendrocandin A(1),dendrocandin B(11),dendrocandin C(2), dendrocandin D(3),dendrocandin E(4),dendrocandin F(5),dendrocandin G(6), dendrocandin H(9),dendrocandin I(15),dendrocandin J(7),dendrocandin K(8), dendrocandin L(10),dendrocandin M(12),dendrocandin N(13),dendrocandin O(14), dendrocandin P(16),dendrocandin Q(17),4,4'-dihyxroxy-3,5-dimethoxybibenzyl(19), 3,4-dihydroxy-5,4'-dimethoxybibenzyl(20),3'-hydroxy-3,4,5'-trimethoxybibenzyl(21),4,4'-dihydroxy-3,3',5-trimethoxybibenzyl(22),3,4'-dihydroxy-5-methoxybibenzyl(23),3',4-dihydroxy-3,5'-dimethoxybibenzyl(24),dihydroresveratrol(25),dendromoniliside E(26), denbinobin(27),2,4,7-trihydroxy-9,10-dihydrophenanthrene(28).12 phenols:paprazine(29),moupinamide(30),dihydroconiferyl dihydro-p -cumarate(31),dihydro-feruloyltyramine(32),p-hydroxyphenylpropionyl tyramine(33), syringic acid(34),syringaldehyde(35),vanillic acid(36),p-hydroxy-phenylpropionic acid(37),p-hydroxy cinnamic acid(38),ferulic acid(39),and 4-hydroxybenzoic acid (40).4 lignans:(+)-syringaresinol-β-D-glucopyranoside(41),icariol A2-4-O-β-D-glucopyranoside (42),(+)-lyoniresinol-3a-O-β-D-glucopyranoside(43),and(-)-secoisolariciresinol (44).2 lactones:aduncin(46),and digiprolactone(47);2 flavanones:naringenin(48),and 3',5,5',7-tetrahydroxyflavanone(49).16 other compounds:dendrocandin R(18),erigesideⅡ(45),adenosine(50),uridine(51),sucrose(52),5-hydroxymethyl-furaldehyde(53), koaburaside(54),n-octacostyl ferulate(55),defuscin(56),n-triacontyl cis-p-coumarate(57), daucosterol(58),β-sitosterol(59),hexadecanoic acid(60),heptadecane(61),hentriacontane (62),heptadecanoic acid(63).Among these compounds,18 are new ones:dendrocandin A(1),dendrocandin B (11),dendrocandin C(2),dendrocandin D(3),dendrocandin E(4),dendrocandin F(5), dendrocandin G(6),dendrocandin H(9),dendrocandin I(15),dendrocandin J(7), dendrocandin K(8),dendrocandin L(10),dendrocandin M(12),dendrocandin N(13), dendrocandin O(14),dendrocandin P(16),dendrocandin Q(17),and dendrocandin R (18).As for the screening of antioxidant activity,most of the bibenzyls showed bio-activity;as for the screening of antitumour activity,only two compounds showed bio-activity.We concluded the relationship between the structures and the activities from the present results.The structural and spectroscopic characteristics of bibenzyl derivatives from Dendrobium genus were concluded,and we hope that will be helpful for the structural elucidation of this type compounds. |
