الفهرس 
introductionOnly 14 pages are availabe for public view
 |  | from | 195 |  |  |
| | | from | 195 | | |
Abstract
This work studies the chemical constituents of the jamaican marine sponge Plakortis sp. Sponges of the genus Plakortis are well known among marine chemists as prolific producers of biologically active secondary metabolites. The sponge specimens were collected at depths of 10 to 20 m in the Discovery Bay, Jamaica, on 7 July 1998. The methanol chloroform (1:1) extract of the sponge was evaporated under vacuum to afford ~ 10 g of a brown oily residue. This oil was chromatographed on silica gel column, eluting first with hexane followed by a gradient of hexane <U+2013> ethyl acetate, yielded four fractions IIV Scheme 1). Further purification of these fractions by sequential preparative TLC, MPLC, and HPLC was performed in order to obtain the pure eleven products in order of increasing time / polarity (1a, 2a, 3a, 4, 5, 6, 7, 8, 1b, 2b and 3b). (Scheme 2) One of the isolated products was new compound and reported here for the first time, which was identified as methyl3, 6 epoxy4, 8diethyl6methyl2,4,9dodecatrienoate (7). The structure of the new compound was mainly established by interpretation of spectral data, such as 1D & 2D 1HNMR, 13CNMR, and High resolution Mass spectroscopy. The other ten metabolites were known and identified as: Plakortide H (1a) plakortide G (2a), plakortide F (3a), plakortin (4), 3epiplakortin (5), methyl (2Z,6R,8R,9E)3,6epoxy4,6,8triethyl2,4,9dodecatrienoate (6), plakortone (8), plakortide H (1b) plakortide G (2b) and plakortide F (3b). Their structures were determined by interpretation of spectral data, and were also confirmed by comparison of their spectral data with those of the corresponding published data. Cytotoxic assays of the individual compounds after purification were performed using two proliferating mouse cell lines, NIH3T3, KA3IT and one Verocells. Compounds (68) exhibited moderate cytotoxicity on all cell lines, but compounds (1b) and (3b) exhibited high cytotoxicity on all cell lines.