Anticancer and Antioxidant Properties of Vernonia amygdalina Delile and Citrus aurantifolia (Christm.) Swingle Juice Extracts: An In Vitro Study.

Abstract

Introduction: Vernonia amygdalina Delile (VAD), also known as bitter leaf, is widely utilized in traditional medicine for the treatment of various ailments, including cancer. The presence of bioactive compounds in VAD is believed to be responsible for its characteristic bitterness. In Ghana, it is a common practice to mitigate the bitterness of VAD by combining it with Citrus aurantifolia (Christm.) Swingle (lime) juice extracts, although this method lacks scientific evidence and documentation. Therefore, the antioxidant and anticancer activities of VAD and lime juice extracts (V5) and their combined effects were evaluated in vitro. Method: The antioxidant activity and cytotoxic effects of VAD extracts were determined against Jurkat, MCF-7, HepG2, and PNT2 cells using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to quantify antioxidant activity and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to assess cytotoxicity. The statistical analysis of the data was conducted using Microsoft Excel and GraphPad Prism 8.0. Linear regression was employed to determine the correlation between the concentration and the percentage of antioxidant activity, while p values were calculated using Student's t-test. Results: The laboratory analysis focused on the extracts V1, V2, V3, V4, and V5. Briefly, V1 and V2 contained equal amounts of saponins and terpenoids. Among these, V2 exhibited the highest free radical scavenging activity, as indicated by an EC50 value of 2.14 ± 0.06 mg/mL. V2 also demonstrated cytotoxicity against the MCF-7, HepG2, Jurkat, and PNT2 cell lines. On the other hand, V3 and V4 did not show any cytotoxic effects across all tested cell lines. In contrast, V5 was toxic to HepG2 and MCF-7 cells but had no cytotoxic effect on Jurkat cell lines. V2 exhibited dose-dependent cytotoxicity (0-1000 μg/mL), with the strongest inhibition observed against Jurkat cells (IC50 value = 96.341 μg/mL) and a selective index of 3.567. The difference in activity between the extracts from different parts of the plant and the extract combined with lime juice was significant (p < 0.05), indicating a synergistic effect of the phytochemicals in both VAD and lime juice. Conclusion: V2 and V5 demonstrated a remarkable antioxidant property, and they are effective in inhibiting cancer cell lines, respectively.