Evaluation des effets protecteurs de l’extrait éthanolique de l’écorce de Omocarpum kirkii S. Moore (Fabaceae) contre le cancer du sein induit par le 7,12-dimethylbemz(a) anthracËne (DMBA) chez la rate Wistar

Abstract

Breast cancer treatment has made significant advances in recent decades thanks to the technological revolution. Nevertheless, breast cancer remains a global public health issue, particularly in developing countries due to the high cost of treatment, the unavailability of treatment, and resistance driving sick populations to turn to medicinal plants as an alternative. Omocarpum kirkii S. Moore (Fabaceae) is a plant used in African traditional medicine for the treatment of certain diseases, including cancer. It has shown cytotoxic activities against cancer cells in vitro.To the best of our knowledge, no study has been conducted on the chemopreventive properties of O. kirkii on breast cancer in vivo. Therefore, the objective of this study was to evaluate the anti-cancer properties of Omocarpum kirkii on breast cancer in Wistar rats. For this purpose, 48 female rats aged approximately 45 days and weighing ± 80 g were divided into 6 groups of eight animals each (n = 8) as follows: the normal and DMBA (7,12- dimethylbenz(a)anthracene) groups, respectively normal and negative controls, received the vehicle (distilled water), the reference drug tamoxifen at a dose of 3.3 mg/kg BW served as a positive control, while the test groups were treated with the ethanolic extract of O. kirkii bark at respective doses of 50, 100, and 200 mg/kg. After 10 days of pretreatment with the different substances, the rats were exposed to a single dose of 50 mg/kg BW of DMBA (diluted in olive oil) except for the normal group. The treatment continued until the 22nd week, and the evaluated criteria included tumor incidence, mass, and volume, tumor and mammary gland histology, breast cancer biomarker CA15-3 levels, as well as antioxidant status and inflammatory cytokine levels. The phytochemical analysis of the ethanolic extract of O. kirkii bark revealed the presence of phenolic compounds with a higher flavonoid content. A 100% tumor incidence was recorded in the rats of the DMBA group. Furthermore, the DMBA group showed a significant increase (p < 0.001) in tumor volume, tumor load, CA15-3 levels, as well as serum levels of pro- inflammatory cytokines (TNF-α, INF-γ, IL-6, and VEGF) and pro-oxidant markers MDA and NO. The O. kirkii extract at all tested doses significantly inhibited tumor incidence, tumor load, tumor volume, and CA 15-3 levels, as well as serum levels of pro-inflammatory cytokines. Additionally, it increased IL-10 (anti-inflammatory cytokine) levels, as well as catalase (antioxidant) activity against the decrease in pro-oxidant levels. It appears that Omocarpum kirkii has protective effects at all tested doses, with the best effect observed at a dose of 50 mg/kg against DMBA-induced breast cancer in Wistar rats. Its effects are likely due to its antioxidant and anti-inflammatory activities.