Evaluation of Antioxidant, Cytotoxic, Antimicrobial, Membrane Stabilizing and Thrombolytic Activities of Polianthes tuberose Linn

Abstract

Aims: In the present study, the crude methanol extract of tuber of Polianthes tuberosa Linn along with its all Kupchan fractions were investigated for antioxidant, cytotoxic, antimicrobial, membrane stabilizing and thrombolytic activities. Place and Duration of Study: The study was carried out for one year in 2012 in the Department of Pharmacy, Manarat International University (MIU), Dhaka-1216, Bangladesh. Methodology: The antioxidant activity was evaluated by using free radical scavenging (DPPH) assay. Here, butylated hydroxytoluene (BHT) was used as standard antioxidant. The total phenolic content was also determined and expressed in gallic acid equivalent. Cytotoxicity and antimicrobial activity of the plant fractions were determined by brine shrimp lethality bioassay as well as by the disc diffusion method, respectively. The membrane stabilizing activity was assessed by hypotonic solution and heat-induced methods and was compared with standard acetyl salicylic acid (ASA). Results: In the free radical scavenging assay, the crude methanol extraxct showed significant free radical scavenging activity with IC50 value 71.23 μg/ml. The highest phenolic content was found in crude methanol extract (113.49 mg of GAE/gm of extractives). In the brine shrimp lethality bioassay, both the crude methanol extract and its carbon tetrachloride soluble fraction demonstrated strong cytotoxic activity with LC50 value of 3.56 and 9.31 μg/ml, respectively compared to that of 0.451 μg/ml exhibited by standard vincristine sulfate (VS). In the disc diffusion antibacterial assay, all the plant samples showed mild to moderate activity (zone of inhibition = 9.0-15.0 mm) against test pathogens. In membrane stabilizing activity test, the plant samples at 2.0 mg/ml inhibited the isotonic solution-induced hemolysis of RBC by 65.23% and heat-induced hemolysis of RBC by 35.61%. During assay for thrombolytic activity, the crude methanol extract revealed 52.6% lysis of clot while standard streptokinase (SK) used as positive control, demonstrated 66.8% lysis of clot. Conclusion: The plant possesses significant bioactivities which rationalize its use as folk medicine.