Elemental composition and bioactivity of seaweeds from Coastal Areas of Karachi, Pakistan

Abstract EN

Sixteen species of green, brown and red seaweeds from Pakistan were analyzed for their elemental composition by Atomic Absorption Spectrometry and several significant elements like Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Na, Pb and Zn were detected quantitatively.

Among these elements Ca, Fe, K, Mg, and Na, were found in large amount (13646-97006 ppm), Cr, Cu, Pb and Zn were present in small quantities (7.37-15.96 ppm) while Cd and Co, were detected in extremely small amounts (2.16- 5.89 ppm).

The average quantity of Na was found to be the highest among these algae (97006.543 ppm) followed by K (64119.75 ppm) and Ca (22735.47 ppm).

The average amounts of Co (5.89 ppm) and Cr (7.372 ppm) were quite low, Cd was detected in the lowest quantity (0.5-3.95).

Eight species of seaweeds were also tested for antifungal activity showing moderate activity against Aspergillus niger, Microsporum canis, Pseudallescheria boydii, Trichophyton simii, poor activity against Fusarium solani and Macrophomina phaseolina.

Sargassum vulgare appeared to be most active while Gracilaria corticata was the least active, Codium iyengarii, Ulva lactuca occupied intermediate position.

In general, human pathogens were most sensitive against the above four seaweeds and plant pathogens proved to be the least sensitive, while animal pathogens appeared to be as intermediate.