ANTIOXIDANT, ANTIMICROBIAL AND ANTIPROLIFERATIVE ACTIVITIES OF LEAF EXTRACTS OF THE INDIAN TRADITIONAL MEDICINAL PLANT WRIGHTIA ARBOREA

Introduction: Wrightia arborea (Apocynaceae) has been used in traditional medicine to treat ailments such as menstrual and renal complaints, snake-bites, tooth-ache and diarrhea. Objective: This study aimed to evaluate the phytochemical constituents, antioxidant, antimicrobial and antiproliferative activities of W. arborea leaf extracts. Materials and Methods: Total phenolic and flavonoid contents of the leaf extracts were determined. The antioxidant activity of the extracts were investigated using DPPH, ABTS, nitric oxide scavenging assays, phosphomolybdenum assay, reducing power and metal chelating assay.  Antimicrobial activity was tested against MTCC strains and MDR clinical bacteria.  The antiproliferative activity was determined using MTT assay against three cancer cell lines. Results: Extracts showed high total phenolic content ranging from 85.7± 1.15 to 40.3± 0.6 gallic acid equivalents and flavonoid content ranging from 750±5.5 to 140±3.6 quercetin equivalents per gram of dry extract. Ethyl acetate extract showed highest DPPH scavenging activity with an EC₅₀ value of 330μg/ml. The antimicrobial effects of all the extracts were found to be genus specific – only against Klebsiella spp. The chloroform extract showed antiproliferative activity against K562 cells following 24 h exposure with an IC₅₀ value of 40±3μg/ml which progressively decreased to 26±2μg/ml and 5μg/ml on prolonged exposure at 48 and 72 h respectively. Conclusion: High levels of total phenolics, flavonoids, antioxidants and selective antimicrobial and antiproliferative activities of W. arborea leaf extracts have been detected in our study.  This first report validates its use in traditional medicine and as a potent bioresource for neutraceuticals and therapeutics.