Antibacterial activity of Cycas circinalis ovules - a naked seeded gymnosperm.

Cycas circinalis L commonly known as Queen Sago a member of the cycad family, was investigated for antibacterial activity against important human pathogenic bacteria viz., Bacillus cereus (MTCC 1272), Staphylococcus aureus (MTCC 7443), Escherichia coli (MTCC 7410) and important plant pathogenic bacteria Xanthomonas axonapodis pv malvacearum (Isolated from cotton plant). The ovule of Cycas circinalis L. has three layers. The outer most layer Sarcotesta, the middle layer Sclerotesta and the inner most layer endotesta. Endotesta is the edible part. All three different parts were separately extracted with water and successively with petroleum ether, chloroform and methanol. Each of these solvent extracts was subjected to antibacterial activity assay by agar cup diffusion method. Only methanol extract of Ovule-endotesta showed activity against all the test bacteria. The zone of inhibition against human pathogenic bacteria ranged between 14 mm to 18 mm. Comparison of the inhibitory activity of the extracts with the antibiotics Vancomycin and Penicillin against human pathogenic bacteria and Bacterimycin against plant pathogenic bacteria revealed that methanol extract of Cycas circinalis ovule was significantly higher than that of the antibiotics tested. The phytochemical analysis of the active extract revealed the presence of alkaloids, saponins and carbohydrates.