Studies On The Chemical Constitutents And Bioactivities Of The Sinularia Acuta

The Sinularia acuta is a sessile animal of the Genus Sinularia, FamilyAlcyoniidae, Suborder Alcyoniina, Order Alcyonacea, Subclass Octocorallia, ClassAnthozoa, Phylum Cnidaria. The species is rich in resources, widely distributed in theworld ocean. Literature search confirmed that about50species of the genus Sinulariahave been sudied, and many steroids, terpenoids, ceramides, alkaloids and a few rarepolyketides have been discovered. In recent years, some cyclopentenone derivativesand butenolide derivatives also have been discovered, showing that the genusSinularia has a rich chemical and biological diversity. In order to find natural productswith unique structural features and pronounced biological activities, we haveperformed a systematic investigation on the chemical components and biologicalactivities of the Sinularia acuta collected from Weizhou islands of Guangxi in China,in October,2010.Isolation and structure determination: By bioassay-guided isolation, theMeOH extract of the Sinularia acuta was chromatographed on TLC, Sephadex LH-20,silica gel and semi-preparative HPLC, respectively. Then Thirty-five compounds wereisolated and purified from the Sinularia acuta, among which twenty-sevencompounds were identified by way of spectral methods (NMR、MS、UV、IR、CD) andtheir physicochemical properties. Among them there are four new polyhydroxy sterols(SA-1~SA-4), one pair of new cyclopentenone derivatives sinularone J ((+)-SA-5�'�(-)-SA-5), two new natural products (SA-6~SA-7), thirteen sterols (SA-8~SA-20),one cyclopentenone derivative sinularone D (SA-21), one butenolide derivativebutenolide (SA-22), two pyrimidines： uracil (SA-23), thymine (SA-24), twonucleoside(SA-25~SA-26).Biological activities: The main compounds were evaluated for theircytotoxicities against HeLa (human cervical carcinoma cells), HL-60(humanleukemia cells) and K562(chronic myelogenous leukemia cell lines of the original)cancer cell lines by the MTT and SRB methods with the doxorubicin as a positivecontrol. The results indicated that only the3β,5α,6β-triol steroids SA-1SA-3, SA-8 and SA-9showed potent cytotoxicities against the selected tumor cell lines.Compounds SA-2and SA-8showed potent cytotoxicities against HL-60cell lineswith IC50values of7.28and9.91M, respectively. Compounds SA-8and SA-9showed moderate activities against K562cell lines with IC50values of10.87and11.65M, while compounds SA-1, SA-2, and SA-9showed weak activities againstHeLa cell lines with respective IC50values of44.82,27.14, and18.24M. The resultssuggested that the3β,5α,6β-triol oxidation pattern could be a critical pharmacophorefor steroids.