Vernonia calvoana Shows Promise towards the Treatment of Ovarian Cancer

The treatment for ovarian cancers includes chemotherapies which use drugs such as cisplatin, paclitaxel, carboplatin, platinum, taxanes, or their combination, and other molecular target therapies. However, these current therapies are often accompanied with side effects. Vernonia calvoana (VC) is a valuable edible medicinal plant that is widespread in West Africa. In vitro data in our lab demonstrated that VC crude extract inhibits human ovarian cancer cells in a dose-dependent manner, suggesting its antitumor activity. From the VC crude extract, we have generated 10 fractions and VC fraction 7 (F7) appears to show the highest antitumor activity towards ovarian cancer cells. However, the mechanisms by which VC F7 exerts its antitumor activity in cancer cells remain largely unknown. We hypothesized that VC F7 inhibits cell proliferation and induces DNA damage and cell cycle arrest in ovarian cells through oxidative stress. To test our hypothesis, we extracted and fractionated VC leaves. The effects of VC F7 were tested in OVCAR-3 cells. Viability was assessed by the means of MTS assay. Cell morphology was analyzed by acridine orange and propidium iodide (AO/PI) dye using a fluorescent microscope. Oxidative stress biomarkers were evaluated by the means of lipid peroxidation, catalase, and glutathione peroxidase assays, respectively. The degree of DNA damage was assessed by comet assay. Cell cycle distribution was assessed by flow cytometry. Data generated from the MTS assay demonstrated that VC F7 inhibits the growth of OVCAR-3 cells in a dose-dependent manner, showing a gradual increase in the loss of viability in VC F7-treated cells. Data obtained from the AO/PI dye assessment revealed morphological alterations and exhibited characteristics such as loss of cellular membrane integrity, cell shrinkage, cell membrane damage, organelle breakdown, and detachment from the culture plate. We observed a significant increase (p < 0.05) in the levels of malondialdhyde (MDA) production in treated cells compared to the control. A gradual decrease in both catalase and glutathione peroxidase activities were observed in the treated cells compared to the control. Data obtained from the comet assay showed a significant increase (p < 0.05) in the percentages of DNA cleavage and comet tail length. The results of the flow cytometry analysis indicated VC F7 treatment caused cell cycle arrest at the S-phase checkpoint. Taken together, our results demonstrate that VC F7 exerts its anticancer activity by inhibiting cell proliferation, inducing DNA damage, and causing cell cycle arrest through oxidative stress in OVAR-3 cells. This finding suggests that VC F7 may be a potential alternative dietary agent for the prevention and/or treatment of ovarian cancer.

The Lipid Lowering and Cardioprotective Effects of Vernonia calvoana Ethanol Extract in Acetaminophen-Treated Rats

Background: Paracetamol overdose/abuse as a result of self-medication is a common occurrence amongst people living in low/middle income countries. The present study was designed to investigate the hypolipidemic and cardioprotective potentials of Vernonia calvoana (VC) ethanol extract in acetaminophen (paracetamol)-treated rats. Methods: Thirty-five Wistar rats weighing 100–150 g were randomly assigned into five groups of seven rats each. Groups 2–5 received high doses of paracetamol to induce liver damage, while group 1 was used as normal control. Afterwards, they were allowed to receive varying doses of VC (group 3 and 4) or vitamin E (group 5), whilst groups 1 and 2 were left untreated. The treatment period lasted for twenty one days after which sera were harvested and assayed for serum lipid indices using standard methods. Results: Groups 3 to 5 treated animals indicated significant decrease (p < 0.001) in low density lipoprotein cholesterol (LDL-c), total cholesterol (TC) and triacylglycerol (TG) levels relative to the normal and acetaminophen-treated controls, the atherogenic index showed a significant decrease (p < 0.001) in all treated groups compared with normal and acetaminophen-treated controls. However, the VC- and vitamin E-treated groups showed significant (p < 0.001) increase in high density lipoprotein cholesterol (HDL-c) relative to the controls. Conclusions: Data from our study suggest that ethanol leaf extract of VC possesses probable hypolipidemic and cardioprotective effects.