Abstract

The dried and pulverized shoot system of Acalypha segetalis was extracted with hexane, ethyl acetate and methanol using cold extraction technique. The three extracts were subjected to phytochemical, toxicity and antibacterial screening. Phytochemical studies revealed the presence of alkaloids, flavonoids, saponins, tannins, phenols, glycosides, steroids and resins. The toxicity activity was investigated using brine shrimp (Artemia salina) lethality assay. The toxicity test showed that ethyl acetate and methanol extracts showed moderate toxicity with LC₅₀ at 777.9711 and 221.8975 ppm respectively while hexane extract was non- toxic with LC₅₀ 8252.5750 ppm. Antibacterial activity was tested employing the disk diffusion method revealed that the extract exhibited significant antibacterial activity against all the organisms used. Antimicrobial assay was concentration dependent; at higher concentrations such as 200, 100 and 50 mg/ml, the extracts exhibited strong inhibition and expectedly at lower concentrations such as 25 and 12.5 mg/ml, the activity of the plant extracts was low. The three extracts showed activity against Pseudomonas aeruginosa and Klebsiella pneumoniae at all concentrations.

Key words: Acalypha segetalis, Euphorbiaceae, phytochemical, antimicrobial activity, brine shrimp lethality assay.