Bioassay-guided isolation and identification of cytotoxic compounds from Bolbostemma paniculatum. (1st July 2015)

• Record Type: Journal Article
• Authors: Tang, Yun; Li, Wei; Cao, Jiaqing; Li, Wei; Zhao, Yuqing
• Is Part Of: Journal of ethnopharmacology. Volume 169(2015)
• Page Start: 18
• Page End: 23
• Publication Date: 2015-07-01
• Subjects: B. paniculatum Bolbostemma paniculatum (Maxim.) Franquet -- EtOAc ethyl acetate -- n-BuOH n-butanol -- MTT 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylterazolium bromide -- IC50 half maximal inhibitory concentration -- 5-Fu fluorouracil -- ODS octadecylsilyl -- OD optical density -- SAR structure–activity relationship -- NMR nuclear magnetic resonance -- TLC thin layer chromatography -- HPLC high performance liquid chromatography -- CC column chromatography -- DMSO dimethyl sulfoxide -- MTT 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylterazolium bromide -- Rha rhamnose -- Ara arabinose -- Glc glucose -- Xyl xylose; Bolbostemma paniculatum -- Triterpenoid -- Tubeimoside -- Cyclic bisdesmosides -- Cytotoxicity; Ethnopharmacology -- Periodicals; Pharmacognosy -- Periodicals; Herbs -- Periodicals; Herbs -- Periodicals; Pharmacognosy -- Periodicals; Pharmacognosie -- Périodiques; Herbes -- Périodiques; 615.1
• DOI: 10.1016/j.jep.2015.04.003
• Languages: English
• ISSNs: 0378-8741

Abstract

Abstract: Ethnopharmacological relevance: Bolbostemma paniculatum (Maxim.) Franquet ( B. paniculatum ), also named "Tu-bei-mu" in Chinese folk medicines, has been described in application for the treatment of tumors, warts, inflammation and toxication in traditional Chinese medicinal books. The major constituents in B. paniculatum are triterpenoid saponins, which have been proved to possess dramatically cytotoxic activity and antivirus activity. The aim of this study is to isolate and identify the active triterpenoid saponin from the bulb of B. paniculatum by a bioassay-guided method. Materials and methods: Four cucurbitacine triterpenoid sapogenins and 11 triterpenoid saponins were isolated from the active EtOAc and n-BuOH extract of B. paniculatum by using bioassay-guided screening. Their structures were elucidated based on the spectroscopic methods and compared with published data. Cytotoxic activities of isolated compounds were determined by MTT assay. Results: Four cucurbitacine triterpenoid sapogenins, isocucurbitacin B(1 ), 23, 24-dihydroisocucurbitacin B(2 ), cucurbitacin E(3 ), 23, 24-dihydrocucurbitacin E(4 ), and 11 triterpenoid saponins, tubeimosideI(5 ), tubeimoside III(6 ), tubeimoside V(7 ), dexylosyltubeimoside III(8 ), lobatoside C(9 ), tubeimoside A(10 ), tumeimoside B(11 ), lobatoside A(12 ), tubeimoside C(13 ), tubeimoside IV(14 ), 7 β, 18, 20, 26-tetrahydroxy-(20 S )-dammar-24E-en-3- O - α- L -(4-acetyl)arabinopyranosyl-(1→2)- β- D -glucopyranoside(15 ) were isolated from the active EtOAc and n-BuOH extracts. Of them, compounds2, 4, 9 and12 were firstly isolated from the Bolbostemma genus. MTT assay revealed that compounds1, 3 and4 had significantly activities against HeLa and HT-29 human cancer cells with IC50 values ranging from 0.93 to 9.73 μM. It is worth mentioning that compound4׳ s activities against the two cell lines are 12- and 8-fold that of the positive control drug (5-Fu). Whereas, the cyclic bisdesmosides5 –9 exerted significantly activities on BGC-823, HeLa, HT-29 and MCF-7 cancer cells with IC50 values ranging from 1.30 to 15.64 μM. And6׳ s activities against the four cell lines are 6-, 3-, 10- and 16-fold that of 5-Fu and8׳ s activities against the four cell lines are 5-, 3-, 14- and 9-fold that of 5-Fu. Conclusion: The cytotoxic activity of the bulbs of B. paniculatum is mainly ascribable to cucurbitacine triterpenoid sapogenins (1–4) and the cyclic bisdesmosides (5–9). The cyclic bisdesmosides are the main anti-cancer active compounds of B. paniculatum . The above results provide scientific evidence to support, to some extent, the ethnomedicinal use of B. paniculatum as anticancer remedies in traditional Chinese medicine. Graphical abstract: Bioassay-directed separation of B. paniculatum led to the isolation of four cucurbitacine triterpenoid (1 –4 ) sapogenins and 11 triterpenoid saponins (5 –15 ). The cytotoxic activities of compounds1 –15 were tested. The results presented that the cyclic bisdesmosides are the main active compounds.