hapalosiphon sp. cells from stock were cultured in BG-11 liquid medium for 3 weeks with continuous illumination (23-29 μmol m-2s-1) by a cool-white fluorescent lamp at 25 c. Thereafter, they were transferred to a plastic pond for mass production of the cyanobacterial cell. The algae were harvested by filtration and dried at 60 c for 48 hours. The dried cells were ground into powder and extracted by 80% aqueous methanol at 25 c for 24 hours. The extract was centrifuged at 2300 rpm for 15 min and the suoernatant was subsequently used as the crude extract for further analyses