Cell Growth Arrest and Protective Effects of Myrianthus arboreus P. Beauv. (Cecropiaceae) Methanolic Extract on benzo(a)pyrene-Induced Prostate Cancer in Adult Wistar Rats.

Prostate cancer is the second most frequently diagnosed malignancy in men globally, with over 1.4 million new cases and approximately 397,430 deaths in 2022. Despite available treatments, incidence and mortality remain high, underscoring the need for novel, cost-effective therapeutic options. Myrianthus arboreus P. Beauv. (Cecropiaceae) is traditionally employed in Cameroonian herbal medicine for cancer-related conditions. This study assessed the anti-prostate cancer activity of aqueous and methanolic bark extracts of M. arboreus on LNCaP, DU145, and PC3 human prostate cancer cell lines and in a benzo(a)pyrene (B[a]P)-induced prostate cancer rat model. In vivo, 48 male Wistar rats were randomized into six groups (n = 8) receiving distilled water, casodex (13.5 mg/kg), or M. arboreus methanolic extracts (50, 100, or 200 mg/kg) orally for 196 days following B[a]P-induced carcinogenesis. In vitro, both extracts inhibited cancer cell growth in time- and concentration-dependent manner, with M. arboreus methanolic extracts showing greater potency. M. arboreus methanolic extracts promoted apoptosis in LNCaP and DU145 cells, suppressed clonogenicity, migration, and invasion in DU145 cells, and enhanced adhesion to collagen and fibronectin matrices. M. arboreus methanolic extracts significantly reduced tumor incidence, mass, volume, and PSA levels, and reversed B[a]P-induced oxidative stress, inflammation, dyslipidemia, and hepatorenal dysfunction. These findings indicate that M. arboreus methanolic extracts exerts potent chemopreventive and anti-proliferative effects in prostate cancer models, supporting its development as a plant-based therapeutic candidate against prostate cancer.