In vitro cytotoxicity and in vivo sub-acute toxicity studies on Vitex doniana (Verbenaceae) leaves extract in MCF-7 breast cancer cells and female Wistar rats

Abstract

Vitex doniana leaves are used in traditional medicine systems for the treatment of inflammatory-related disorders and breast cancer in West Africa. However, there is a dearth of scientific evidence on the effectiveness of the plant leaves on cancer cells or on the safety of the plant if used continuously. This study examined the effects of V. doniana extract on the growth of MCF-7 breast cancer cells, B16-F10 melanoma cells and sEnd.2 endothelial cells. As well, the study investigated the effects of the extract on breast cancer cell morphology, cell cycle progression, migration and invasion, and levels of apoptosis regulatory proteins (Bad, PARP and p53). In vivo, the sub-acute toxicity of the extract in female Wistar rats was examined. The effects of V. doniana extract on MCF-7 cell growth, cell morphology and cell cycle were studied using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, light microscopy and flow cytometry respectively. The multi-target enzyme-linked immunosorbent assay (ELISA) was used to study apoptosis proteins, and the XCELLigence system was used to measure cell invasion and migration. In the sub-acute toxicity study, female Wistar rats were administered 0, 50, 100 and 200 mg/kg of the extract daily for 28 days. Histopathology techniques were used to determine possible toxic effects of the extract on liver, kidney and mammary tissues. The MTT assay showed a concentration-dependent reduction in MCF-7 cell growth in the treated cells compared to the untreated control, and also inhibited the growth of melanoma cells. Furthermore, the results showed that the extract inhibited growth in cancer cells with more potency compared to the non-cancerous endothelial cells. Light microscopy revealed features of apoptosis in V. doniana–treated cells, while flow cytometry showed accumulation of MCF-7 cells in the G1 and sub-G1 phases of the cell cycle following treatment with the plant extract at 25 and 50 μg/ml respectively. In vivo sub-acute toxicity studies showed no significant (P>0.05) difference in serum alanine aminotransferase, gamma glutamyltransferase, urea and creatinine levels between the treatment group and the control, while histopathological examination showed normal architecture of liver, kidney and mammary tissues across the groups. This study provides evidence that V. doniana has anti-cancer effects against MCF-7 breast cancer cells and exhibits no toxic effects in rats at the tested doses. Therefore, V. doniana may have potential in the treatment of breast cancer, thereby necessitating further in vivo anti-cancer studies.