Evaluation of pharmacognostic and acute toxicity of Vernonia amygdalina leaves

Abstract

Vernonia amygdalina (Asteraceae) leaves have been traditionally used for managing numerous health conditions but lack standardized guidelines. This plant is known for its application in treating fever, cough, constipation, hypertension, vascular disorders, and diabetes. The current study seeks to assess the pharmacognostic features and acute toxicity of Vernonia amygdalina leaves, aiming to contribute to its standardization concerning quality, purity, and safety. Established methodologies for crude drug evaluation were employed to determine the pharmacognostic characteristics. Microscopic analysis showed anisocytic stomata and trichomes, while chemomicroscopy identified the presence of cellulose, tannins, starch, lignin, calcium oxalate, suberin, aleurone grains, and mucilage, but no calcium carbonate. Phytochemical analysis of the methanolic extract revealed the presence of flavonoids, alkaloids, tannins, saponins, steroids, triterpenes, carbohydrates, and phenols, with no glycosides or anthraquinones detected. The physico-chemical parameter averages were moisture content (5.10%), total ash (15.20%), acid-insoluble ash (15.20%), water-soluble ash (7.70%), alcohol extractive (2.60%), and water extractive (3.0%). The cytotoxicity assessment showed moderate cytotoxicity of the crude leaf extract (LC50: 29.65 μg/mL). Toxicity tests indicated LD₅₀ values above 5000 mg/kg, with no fatalities in the test rats. These results indicate that Vernonia amygdalina extract contains phytochemical compounds that may be useful in managing various health conditions.