BIOLOGICAL ACTIVITIES OF POLYGONUM FLACCIDUM

Polygonum flaccidum (Polygonaceae) is an annual herb widely distributed in Bangladesh, India, Bhutan, Sri Lanka, and Afghanistan. Objectives of the present study were to determine antioxidant, anthelmintic, cytotoxic, insecticidal and antibacterial activities of methanol extract of P. flaccidum. Antioxidant activity in terms of free radical scavenging ability was determined by DPPH free radical scavenging assay. Cytotoxic activity was performed by brine shrimp (Artemia salina) lethality bioassay. Anthelmintic efficacy was determined using adult Bangladeshi earthworm. Insecticidal activity was tested against rice weevil Sitophilus oryzae. Antibacterial activity was tested by the disc diffusion method. The extract exhibited significant antioxidant activity by scavenging DPPH free radical. The IC₅₀ value of the extract displayed 4.91μg/ml while standard ascorbic acid showed 2.69 μg/ml. The extract exhibited potent anthelmintic activity by causing paralysis (30 min) and death (45 min) of worms and the effect was found to be dose-dependent. In an insecticidal study, the lethal effect of methanol extract on Sitophilus oryzae was found to be dose-dependent manner. In cytotoxicity study, LC₅₀ value of the methanol extract was 1.5 μg/ml while the LC₅₀ value of vincristine sulfate was 0.52 μg/ml. On the other hand, the methanol extract also showed remarkable antibacterial activity against both the gram positive and negative bacteria but inactive against fungi. Further studies on isolation of constituents and their bio-efficacies in-vitro and in-vivo are under investigation.