Studies On Chemical Constituents And Bioactivities Of The Gorgonian Echinogorgia Flora

The genus Echinogorgia is a sessile animal of the Family Paramuriceidae, OrderGorgonacea, Subclass Octocorallia, Class Actinozoa, Phylum Cnidaria. This genuscontains about30species, widely distributed in the southwest of Pacific Ocean and theSouth China Sea. Studies on chemical constituents of this genus began in the late1980sand the secondary metabolites found mainly polyhydroxy sterols as well as few othernovel structure types of sesquiterpenes and alkaloids, which showed rich chemicaldiversity and potential research value of marine natural products. In oder to search fornatural products with unique structural features and unprecedented biological activities,we have performed a comprehensive investigation on the chemical constituents andbiological activities of the Echinogorgia flora collected from weizhou islands in theSouth China Sea, in October,2010.By biological activity-oriented isolation, the MeOH extract of the Echinogorgiaflora was chromatographed on TLC, silica gel, and LH-20Sephadex, and semi-preparative HPLC, respectively. Then forty-one compounds were isolated and purifiedfrom the Echinogorgia flora, among wich thirty-eight compounds were identified bymeans of spectral methods (UV, IR, MS, NMR, CD, et al.) and their physicochemicalproperties. Among them there are thirteen guaiane-type sesquiterpenes (2~6,7~14);fourteen sterols (5~28); one polyketide (29); one ceramide (30); two glycerol ethers(31~32); one benzene derivative (33); six alkaloids (1、34~38). What is remarkable is thata new carbon skeleton guaipyridine sesquiterpene alkaloid and five new guaiane-typesesquiterpenes (2~6) was obtained. The known compounds (7~33) were first isolatedfrom the Echinogorgia flora and compounds (8~10,12~25,27~28) were first found fromthe genus Echinogorgia.Biological activities: Fourteen guaiane-type sesquiterpene compounds wereevaluated for their cytotoxicities against K562(chronic myelogenous leukemia cell line original), A-549(lung cancer cell line), HL-60(human leukemia cells), HeLa (humancervical carcinoma), HCT-116(human colon cancer cells), HO-8910(human ovariancancer) and L-02(embryonic liver cells) by the MTT and SRB methods with the5-fluorouracil as a positive control. The fourteen compounds were also evaluated for theirantiviral activities against H1N1(influenza virus) by the MTT and CPE methods with theribavirin as a positive control. The results indicated that the guaiane-type sesquiterpenecompounds had not anti-cancer activity. The compounds (1,2,5,8,9,13) showed weakanti-influenza virus activity.