Studies On The Chemical Constituents And Bioactivities Of Two Corals From South China Sea

Corals belonging to Cnidaria, Anthozoa are important parts of the coral reefecosystem in the shallow sea. Owing to evolution, corals have possessed many specialproperties, such as purification, anti-pollution, anti-adhesion and so on. All theseproperties depend on the active and novel secondary metabolites in the corals’ bodies.These secondary metabolites provides a new topic for the research and developmentof marine natural products. There are two important genera Echinogorgia andClavularia in Anthozoa, which had been reported a large number of active and novelnatural products. For genus Echinogorgia, active natural products were mainlyreported as guaiane sesquiterpenes and sterols active in antitumor, anti-inflammatory,bactericidal activity and so on; while lots of diterpenes, steroids and prostaglandinshave been obtained from genus Clavularia mainly active as anti-tumor,anti-inflammatory, antibacterial, antiviral activity and so on. In recent years, the SouthChina Sea has become a hot area of the research for marine secondary metabolites allover the world and the research on gorgonian and soft corals collected in this sea havefound plenty of secondary metabolites such as terpenoids, steroids, alkaloids,macrolides and so on and many of them showed anti-tumor, anti-oxidative,anti-inflammatory, bactericidal, immunomodulating activity. In order to find thepotential lead compounds in drug discovery, this paper did chemical constituents andbiological activities research on two kinds of corals Echinogorgia sassapo reticulataand Clavularia sp. collected from the South China Sea, by the separation methods ofTLC, column chromatography, HPLC, MPLC and so on, and modern spectroscopictechniques of1D and2D NMR, MS, IR, UV and CD. In the end,50compoundsincluding15new compounds had been separated and identified. In Echinogorgiasassapo reticulata,21compounds (ESR-1~21) have been isolated and identified which are three guaiane-type sesquiterpenes (ESR-1~3):(1S,5S,8S)-8-methoxy-Menelloide B，Menelloide B，ketolactone; thirteen steroids (ESR-4~16):(22E)-3β-hydroxycholesta-5,22-dien-7-one,3β-hydroxyergosta-5,24(28)-dien-7-one,(22E,24R)-3β-hydroxy-24-methylchlerta-5,22-dien-7-one,(22E,24S)-3β-hydroxy-24-methylchlerta-5,22-dien-7-one,3β-hydroxycholest-5-en-7-one, cholesterol, ergosta-5,24(28)-diene-3β-ol, stigmasta-5,24(28)-diene-3β-ol, cholest-5,22-diene-3β-ol,24(β)-(24S)-stigmast-5-en-3β-ol, cholesta-5,23-dien-3β-ol,(22E)-cholesta-7,22-dien-3β,5α,6β-triol(7),(22E)-stigmasta-7,22-dien-3β,5α,6β-triol; one glycerol ether (ESR-17):ɑ-23-alkyl glycerol ether, one fatty alcohol (ESR-18): hexadecan-1-ol, twoderivatives of benzene (ESR-19):2-hydroxy benzoic acid; two alkaloids(ESR-20~21): uracil, thymine, and including a new compound ESR-1. Also inClavularia sp.,29compounds (CV-1~13),±(CV-14~17),(CV-18~25) were isolatedwhich are thirteen dolabellane-type diterpenoids (CV-1~13),(CV-18~21): ClavirolideG-K, Clavudiol C, Clavirolide L, Clavirolide F, Clavudiol A, Clavirolide D,Clavirolide C, Clavulactone, Clavirolide E;8elemane-typesesquiterpenoids±(CV-14~17),(CV-18~21):±Clavulinin A-D, Hiiranlactone D,Hiiranlactone C, sericealactone, Clavulinin; one polyketide (CV-22):5-butyl-5-hydroxy-3,4-dimethylfuran-2(5H)-one;3alkaloid compounds (CV-23~25):thymine, thymine-2’-deoxynucleoside, adenine-2’-deoxynucleoside, including6newdolabellane-type diterpenoids(CV-1~6),4pairs of new elemane-type sesquiterpeneenantiomers±(CV-14~17), one new natural product (CV-7) and one spectral datarevised compound (CV-8).Selected three tumor cell lines K562(chronic myelogenous leukemia cell line),HL-60(human leukemia cells), HeLa (human cervical carcinoma) were tested for thecytotoxic activity for the pure compounds isolated from Echinogorgia sassaporeticulata. However, three are no significant cytotoxic activities shown for thesecompounds. Selected four tumor cell lines K562, HeLa, A-549(human lung cancercells), HL-60were tested for the cytotoxic activity for the pure compounds isolatedfrom Clavularia sp., however, found that only compound CV-9on4cell lines,compound CV-6on first three cell lines and CV-1on K562cell line showed cytotoxic activity. However antiviral tests of some compounds, CV-13was found with thesimilar antiviral inhibition rate compared to Ribavirin.