Antibacterial activity and cytotoxicity of stem bark of two common plants of Bangladesh

Aim: The emergence and spread of antimicrobial resistance is a growing problem in both developing and developed countries and threatens to become a global crisis. In recent years, attempts have been made to investigate indigenous medicines used against infectious diseases, to help in developing safer antimicrobial and anticancer drugs. As part of the further advancement of this research arena, an attempt has been made to study the stem barks of Carica papaya Linn. ( C. papaya ; family: Caricaceae) and Tamarindus indica Linn. ( T. indica ; family: Fabaceae), two common plants of Bangladesh. The petroleum-ether, chloroform, and ethyl acetate extracts of the stem bark of both plants were investigated for their antibacterial activity and cytotoxicity. Materials and Methods: The antibacterial activity was evaluated using the disk diffusion method. Cytotoxicity was determined against brine shrimp nauplii. In addition, the minimum inhibitory concentration (MIC) was determined using the serial dilution technique to evaluate antibacterial potency. Results: All crude extracts of T. indica and the chloroform extract of C. papaya appeared very potent in terms of both zones of inhibition and spectrum of activity. However, all the extractives were also subjected to brine shrimp lethality bioassay for preliminary cytotoxicity evaluation. Here, the chloroform extract of C. papaya revealed the strongest cytotoxicity, LC 50 of 10.46 μg/mL. Conclusion: The stem barks of both C. papaya and T. indica show broad-spectrum antibacterial activity and may be potential sources of natural antimicrobial compounds and anticancer agents to be used in the treatment of various infectious diseases caused by resistant microorganisms and of cancer, respectively.