Thevetia peruviana leaves, HPLC profile, isolation, and in vitro cytotoxicity

Abstract

Phytochemicals have played a significant role in the discovery of many clinically anticancer medicines. Thevetia peruviana being famous as an ornamental plant, widely cultivated, and including a wide variety of secondary metabolites this motivated us to explore more about its potential medical applications. In this study, the total methanol extract of T. peruviana leaves (family Apocyanaceae) was sequentially fractionated into hexane, methylene chloride, ethyl acetate, and butanol fractions. The total phenolic content of the methanol extract of T. peruviana was determined spectrophotometrically and found to be 72.37 mg g^-1, while the total flavonoid content was found to be 12.47 mg g^-1. Fourteen polyphenolic compounds were detected by the HPLC analysis of the methanol extract, in addition to five phenolic compounds, which were isolated and identified for the first time from the EtOAc extract. They were identified as gallic acid (C1), chlorogenic acid (C2), p-coumaric acid (C3), quercetin (C4), and rutin (C5). The structures were elucidated by NMR and EI/MS spectroscopic techniques. The cytotoxic activity of the methanol extract was evaluated in vitro by cell viability assay. The cytotoxicity results showed significant anticancer activity against human colon carcinoma HCT-116 with IC₅₀ 39.3 μg mL^-1 and lesser activity against human lung carcinoma A-549 and human breast carcinoma MCF-7 cell lines with IC₅₀ 93.4 and 110.3 μg mL^-1, respectively.

Fig. 1. Chemical structures of the isolated compounds (C1–C5) of the Thevetia peruviana leaves.

Fig. 2. Growth inhibition percent of the tested extracts against colon carcinoma HCT-116 cell line.

Fig. 3. Growth inhibition percent of the tested extracts against lung carcinoma A-549 cell line.

Fig. 4. Growth inhibition percent of the tested extracts against breast carcinoma MCF-7 cell line.