Introduction: We investigated the combinatorial chemopreventive efficacy of Azadirachta indica (AI) and Ocimum sanctum (OS) against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis, based on changes in oxidant-antioxidant status, cell proliferation, apoptosis and angiogenesis.
Methods: Male Wistar rats were assigned to four groups. Rats in groups 1 and 2 received MNNG (150 mg/kg body weight i.g.) three times with a gap of two weeks in between the treatment. Group 2 rats additionally received ethanolic AI (100 mg/kg body weight i.g.) and OS (150 mg/kg body weight i.g.) leaf extract three times per week for 26 weeks. Group 3 animals were given AI and OS leaf extract alone, whereas group 4 served as the control.
Results: Lipid and protein oxidation and status of the antioxidants, superoxide dismutases, catalase, reduced glutathione (GSH) and GSH-dependent enzymes together with markers of proliferation (proliferating cell nuclear antigen [PCNA], glutathione S-transferase-Pi [GST-P]), invasion (cytokeratin [CK]), angiogenesis (vascular endothelial growth factor [VEGF]) and apoptosis (Bcl-2, Bax, cytochrome C and caspase-3) were used to biomonitor chemoprevention. Rats administered MNNG developed forestomach carcinomas that displayed low lipid and protein oxidation coupled to enhanced antioxidant activities, and overexpression of PCNA, GST-P, CK, VEGF and Bcl-2 with downregulation of Bax, cytochrome C and caspase-3. Coadministration of AI and OS extract suppressed MNNG-induced gastric carcinomas accompanied by modulation of the oxidant-antioxidant status, inhibition of cell proliferation and angiogenesis, and induction of apoptosis.
Conclusion: The results of the present study suggest that chemoprevention by AI and OS combination may be mediated by their antioxidant, antiangiogenic, antiproliferative and apoptosis inducing properties.