Subacute Toxicological Analysis of Hydroalcoholic Extract of Mikania micrantha (Asteraceae) Leaves in Wistar Rats

Abstract

Introduction: Mikania micrantha, traditionally used in Southeast Asia and India for its antiseptic, antimicrobial, antidiabetic, anti-inflammatory, wound healing, and antidotal properties, is known to contain various bioactive secondary metabolites. Although its therapeutic benefits are well recognized, comprehensive toxicological data remain limited. This study aimed to evaluate the subacute oral toxicity of the hydroalcoholic extract of Mikania micrantha leaves (MMLE) in Wistar rats following OECD Guidelines.

Methods: A 70% hydroalcoholic extract was prepared and analyzed by phytochemical screening and HPTLC. Acute toxicity studies showed MMLE to be safe up to 2000 mg/kg. For subacute toxicity assessment, rats were orally administered MMLE (500 or 1000 mg/kg) for 28 days, with clinical signs, body weight, and food and water intake monitored. Hematological, biochemical, and histopathological analyses were performed at the end of study.

Results: MMLE comprises alkaloids, flavonoids, phenolics, tannins, and saponins, while HPTLC analysis revealed the presence of Kaempferol as the predominant component (4.58 µg/ml). No mortality or significant alterations in growth, hematological, or biochemical parameters were observed at 500 mg/kg. Histological examination of major organs (liver, kidney, brain, heart, lungs, and spinal cord) showed no remarkable changes at this dose, while mild alterations were noted at 1000 mg/kg, suggesting moderate toxicity at higher levels.

Conclusion: Overall, the findings indicate that repeated oral administration of MMLE is safe up to 500 mg/kg, whereas higher doses may induce mild organ toxicity. These results support its traditional use within a safe dosage range and underscore the need for further chronic toxicity studies.