| The Thymelaeaceae plants are distributed all over the world,and some of them used as folk medicines.Since mezerein and daphnotoxin were obtained from the genus Daphne in early 1970s which showed possessed anticancer activity,the genus Daphne have received the most attention.In this paper,the study on the chemical constituents of two medicinal plants from genus Daphne was carried on,and 66 compounds were obtained and identified.Among these compounds,20 of them were new compounds,including 5 daphnane-type diterpenes and 15 flavanes.The cytotoxicity of all daphnane-type diterpenes against the ten selected human cancer cell lines in vitro was assayed.Daphne genkwa Sieb.et Zucc.belonged to family Thymelaeaceae and genus Daphne.The air-dried flower buds of D.genkwa(8 kg)were refluxed with 95%EtOH for 3 x 30 L×2 h,followed by sequential solvent partitioning between organic and aqueous phases to obtain CH2Cl2 and n-butyl alcohol layers.40 compounds were obtained by various chromatographic methods including VLC,Sephadex LH-20,MCI CHP20P,ODS C-18 and Prep-HPLC.All of them,including 25 diterpenes,3 lignans,10 flavones and 2 amides were identified by 1H,13C NMR,HSQC,HMBC,NOESY,MS,CD and molecular modeling as below:genkwadanes A-E(1-5),pimelea factor P2(6),wikstroelide E(7),pimelotide A(8),pimelotide C(9),yuanhuadine(10),yuanhuafine(11),genkwadaphnine(12),yuanhuacine(13),simplexin(14),yuanhuahine(15),yuanhualine(16),isoyuanhuadine(17),yuanhuapine(18),yuanhuatine(19),orthobenzoate 2(20),genkwanine M(21),yuanhuaoate B(22),genkwanine F(23),daphnane-type diterpene ester-7(24),genkwanine J(25),(-)-medioresinol(26),(-)-syringaresinol(27),(-)-pinoresinol(28),tiliroside-7-O-β-D-glucoside(29),luteolin-3’,4’,7-trimethyl ether(30),kaempferol-3-O-β-D-glucoside(31),tiliroside(32),apigenin(33),luteolin(34),campherol(35),genkwanin(36),genkwainin-5-O-β-D-glucoside(37),genkwainin-5-O-β-D-primeveroside(38),2S,2’S-asperphenamate(39),aurantiamide acetate(40).Among them,compounds 1-5 were new.Compounds 6-9,14,26,30-31 were obtained from genus daphne for the first time.The cytotoxicity of compounds 1-25 were evaluated against ten human cancer cell lines HeLa(human cervical cancer cell line),HepG2(human hepatocellular carcinoma cell line),HT-1080(human sarcoma cell line),HCT116(human colon cancer cell line),A375-S2(human melanoma cell line),MCF-7(human breast adenocarcinoma cell line),A549(human lung adenocarcinoma cell line),U-937(human histiocytic lymphoma cell line),K562(human chronic myelogenous leukemia cell line),and HL60(human promyelocytic leukaemia cell line).The results showed that compounds 12-13,17,19,21-22 exhibited pronounced cytotoxicity in all ten cell lines,and most interestingly,compounds 1-25 revealed preferred cytotoxicities on the HT-1080 cell line and displayed much stronger inhibitory activities(IC50<30.95 μM)compared with positive control 5-fluorouracil(IC50 = 35.62 μM),particularly,compounds 10-12,14,18 and 21 exhibited the strongest cytotoxicity activities against the HT-1080 cell line(IC50<0.1μM).The structure-activity relationship of daphne-type diterpenes was discussed.As a whole,the presence of a 1,2 double bond in ring A,6,7-epoxide group in ring B,a benzoyl moiety at C-12 and 2E,4E-decadiene in the orthoester chain are beneficial to the inhibitory activity.The presence of benzoyl moiety in the molecular may be an important pharmacophore of inhibitory activity.Daphne giraldii Nitsche belonged to family Thymelaeaceae and genus Daphne also.The dried stem and root bark of D.giraldii was exhaustively extracted with 95%EtOH at room temperature.31 compounds were isolated and purified from the 95%EtOH extracts(986 g)by various chromatographic methods.Among them,26 compounds were identified by extensively spectroscopic and spectrometric methods,including 19 flavanes,4 coumarins,1 amide,1 biphenyl and 1 phenyl as below:daphnegirin A(41),daphnegirin C(42),daphnegirin E(43),daphnegirin G(44),daphnegirin I(45),daphnegirins K-T(46-55),7,4’-dihydroxyflavane(56),7,4’-dihydroxy-3’-methoxyflavane(57),7,3’-dihydroxy-4’-methoxyflavane(58),kazinol B(59),nodakenetin(60),8-methoxymarmesin(61),5,7-dihydroxy-6,8-di-(3,3-dimethylallyl)-coumarin(62),8-hydroxyxanthyletin(63),aurantiamide acetate(64),2,2’-dihydroxy-4,5,6,4’,5’,6’-hexamethoxybiphenyl(65),3,4,5-trimethoxy-phenol(66),and compounds 41-55 were new.Compounds 59-63 were obtained from genus daphne for the first time. |
