Investigations into the cytotoxic effects of Bangladeshi medicinal plants

Abstract

Introduction: Natural products and related drugs are used to treat 87% of all categorised human diseases including bacterial infection, cancer and immunological disorders [1]. Twenty five per cent of prescribed drugs worldwide originate from plants [2]. Currently about 250 medicinal plants are used in the preparation of traditional herbal medicines in Bangladesh. Most of these preparations have not yet undergone chemical, pharmacological and toxicological studies to determine the bioactive component(s) [3]. Methods: Fifteen Bangladeshi medicinal plants were selected based on their traditional use and reported activities. The dried plant material was successively extracted with n-hexane, dichloromethane, methanol and water. The methanol and water extracts were assayed for cytotoxic activity against healthy mouse fibroblast (NIH3T3) and three human cancer cell lines (gastric: AGS; colon: HT-29; and breast: MDA-MB-435S) using the MTT assay with 25% DMSO as a positive control [4]. Results: Several extracts showed selective cytotoxicity, representing interesting candidates for further investigations. For example, the methanol extracts of Hygrophila auriculata and Clerodendron inerme showed no cytotoxic effects on healthy cells, but were highly cytotoxic against breast cancer (IC50 1.58 mg/mL) and gastric cancer cells (IC50 2.38 mg/mL), respectively. The aqueous extract of Limnophila indica displayed high cytotoxicity against gastric cancer (IC50 2.24 mg/mL) and breast cancer cells (IC50 1.25 mg/mL), but did not affect the growth of normal and colon cancer cells. Conclusion: For some of the plants their traditional use as anti-cancer treatments correlate with the cytotoxic screening results, whereas, for others so far unknown cytotoxic activities were identified.