Abstract
Citrus limon is traditionally used for the treatment of several ailments including infectious diseases. This study was designed to evaluate antiproliferative and antimicrobial activities of Citrus limon stem bark extract. The plant material was collected, authenticated, air dried and pulverized. Two hundred grams of powdered plant material was extracted into distilled methanol by cold maceration and the extract was concentration in vacuo. The extract was subjected to in vitro phytochemical screening and bioassays including; antiproliferative (Sorghum bicolor radical and Allium cepa root growth inhibitory) and antimicrobial susceptibility against Escherichia coli, Staphylococcus aureus, Citrobacter ferundii and Candida albicans. Phytochemical evaluation detected the presence of alkaloids, flavonoids and cardiac glycoside in the crude extract. The extract displayed concentration dependent antiproliferative activity with an IC50 of 1.10±0.07 and 0.62±0.04 mg/mL compared to cyclophosphamide (IC50 of 0.17±0.02 and 0.83±0.08 mg/mL) in Sorghum bicolor radical growth and Allium cepa root growth inhibitory assays, respectively. The extract displayed antimicrobial activity with the highest effect against Escherichia coli and Citrobacter ferundii with activity indices of 0.68 and 0.59, respectively. Citrus limon stem bark extract displayed antiproliferative and antimicrobial activities.

Key words: Citrus limon, Antiproliferative, Antimicrobial, Escherichia coli, Citrobacter ferundii