Studies on the bioactivity and elementology of marine algae from the coast of Karachi, Pakistan

Some species of marine benthic algae belonging to the Chlorophyta, Phaeophyta and Rhodophyta collected from different coastal areas of Karachi (Pakistan) were investigated for their antibacterial, antifungal, phytotoxic and insecticidal activities. Brown seaweeds showed greater antibacterial activity than the green and red ones. Botryocladia leptopoda (J. Ag.) Kylin exhibited the greatest antifungal activity and Codium shameelii Nizam. the least. The highest phytotoxic activity (95%) was displayed by Enteromorpha intestinalis (L.) Nees at 100 microg/mL concentration, while Osmundea pinnatifida (Huds.) Stack. showed the low insecticidal activity as compared to the other investigated species. Many elements e.g. Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Na, Pb, Zn were determined quantitatively. Among them Ca, Cr and Pb were found to occur in largest amount in green seaweeds, Co, Cu, Fe and Zn in greatest quantity in brown seaweeds, while Cd, K, Mg and Na in highest proportion in the investigated red seaweeds.