Aqueous and flavonoid-rich Carica papaya leaf extracts modulate 7, 12-dimethylbenz[a]anthracene-induced breast carcinogenesis in rats: roles of oxidative stress, inflammation, and in silico docking

Abstract Purpose Carica papaya leaves (CPL), traditionally used in ethnomedicine to manage inflammatory conditions and as an adjuvant in therapies, have been reported to have anticancer potential. This study investigated the chemopreventive and immunomodulatory potentials of aqueous extract (AqCE) and flavonoid-rich extract (FRE) of CPL on 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer in female Wistar rats. Methods Thirty-five adult female Wistar rats were grouped into seven: control (1% Tween 80), DMBA-alone (80 mg/kg, administered intraperitoneally), DMBA + cyclophosphamide (20 mg/kg), DMBA + AqCE (250 and 500 mg/kg), and DMBA + FRE (150 and 300 mg/kg). Treatments were administered via oral gavage twice weekly for 17 weeks, followed by in vivo immunomodulatory and biochemical investigations. Phytochemical profiling and molecular docking of identified flavonoids against tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) were also performed. Results Five bioactive flavonoids were quantified in FRE. Molecular docking of the CPL flavonoids suggested stable, favorable predicted binding affinity with TDO/IDO enzymes, consistent with potential inhibitory interactions. DMBA significantly ( p < 0.05) decreased CD4⁺ counts, increased TDO/IDO activity and inflammatory cytokine levels, and increased antioxidant parameters. However, AqCE and FRE improved CD4⁺ counts, decreased TDO/IDO activity, modulated inflammation, and normalized the antioxidant parameters. The extracts also reduced DMBA-elevated tumor biomarkers relative to control ( p < 0.05). Furthermore, Histology confirmed severe invasive ductal carcinoma, and extract treatments markedly attenuated malignant changes, thereby preserving mammary architecture. Conclusions CPL extracts showed multi-targeted chemopreventive and immunomodulatory effects against DMBA-induced breast cancer, suggesting a potential candidate for plant-based immunotherapy.