Phycochemical Studies on Fourteen Species of Phaeophycota from Karachi Coast of Pakistan

摘要

Fourteen species of brown algae (Canistrocarpus cervicornis, Colpomenia sinuosa, Cystoseira indica, Dictyopteris australis, Dictyota dichotoma, D, ciliolata, D. dumosa, D. hauckiana, Hincksia mitchelliae, Jolyna laminar-hides, Padina antillarum, Sargassum tenerrimum, Spatoglossum variabile and Stoechospermum polypodioides) were collected and extracted with CHCl_3-hexane and MeOH. The seaweed extracts revealed the presence of 12 saturated and 14 unsaturated fatty acids including 5 monosaturated, 4 di-unsaturated and 5 tri-unsaturated acids by GLC and GC-MS, 19 different sterols, 9 terpenoids and 4 metabolites by (El, FAB, FD, HR)-MS and ('H & ~(13)C)-NMR spectroscopy. Palmitic acid (C16.0) was found in maximum amounts and as the major acid, it was followed by oleic acid (CI8:1). Cholesterol and its 24-derivatives occurred quite frequently, loliolide or digiprolactone was the only monocyclic monoterpenoid, while the other 8 were tricylic diterpenoids, D-mannitol and three new metabolites i.e., padinolide, dicdichane and cystoseirene were also isolated. Apart from these, hauckiosterol, dictindiol, and dictintriol are new natural products isolated from a natural source.