Identification, quantification of bioactive constituents, evaluation of antioxidant and in vivo acute toxicity property from the methanol extract of Vernonia cinerea leaf extract

Context: Vernonia cinerea (L.) Less [Compositae (Asteraceae)] is used traditionally for several medical purposes such as inflammation, pain, fever, and cancer. Objectives: The present study identified the bioactive constituents in the methanol extract of Vernonia cinerea leaf and evaluated its antioxidant activity and acute toxicity. Methods: The identification of phytochemicals was accomplished by GC-MS and the major antioxidant phenolic compounds in the extract were quantified by HPTLC analysis. To quantify the essential elements, atomic absorption spectrophotometeric analysis was carried out. Total phenol and flavonoid content was measured by Folin-Ciocalteau reagent and 2% aluminium chloride, respectively. Results: GC-MS analysis identified the presence of 27 phytoconstituents. The predominant phenolic compound in the extract as quantified by HPTLC was gallic acid (1.92 mg/g) followed by rutin (0.705 mg/g), quercetin (0.173 mg/g), caffeic acid (0.082 mg/g) and ferulic acid (0.033 mg/g). The following elements were quantified: Fe (0.050 ppm), Mn (0.022 ppm), Co (0.0180 ppm), Pb (0.029 ppm), Hg (3.885 ppm) and Se (4.5240 ppm). The antioxidant activity of the extract increased with increasing concentration and the correlation (r2) for all in vitro assays were satisfactory. Conclusions: V. cinerea extract has significant (p