Estimating Anticancer Effects of Yohimbine in DMBA-Induced Oral Carcinogenesis Hamster Model: Utilizing Biochemical and Immunohistochemical Techniques

Yohimbine is a potent bioactive indole alkaloid, isolated from a variety of biological sources and has long been used as a natural stimulant and aphrodisiac, particularly to treat erectile dysfunction. However, some literature also points toward its anticancer effect in different experimental models. The current study aimed to address a clinical concern on the therapeutic utilization of yohimbine as a repurposed drug. We employed 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis model juxtaposed with biochemical investigation of several detoxification and antioxidant markers, such as Cyt p450, Cyt b5, thiobarbituric acid reactive substance (TBARS), glutathione (GSH), glutathione reductase (GR), glutathione S transferase (GST), DT-diaphorase, vitamin C, vitamin E, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). The immunohistochemical assessment of cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), proliferating cell nuclear antigen (PCNA), and cyclin D1 expression were also performed to observe the effect of yohimbine on these markers. The hamsters treated with DMBA presented the growth of tumors in the buccal pouches, accompanied by significant changes in the liver and buccal mucosa levels of Phase I & II detoxification enzymes and lipid peroxidation (LPO). A significant rise in the range of 2- to 3.5-fold was observed in Cyt p450, Cyt b5, and LPO in DMBA-treated animals. However, oral administration of yohimbine significantly restored the LPO, antioxidant, and detoxifying enzyme activities. Additionally, the levels of COX-2, IL-6, PCNA, and cyclin D1 were also found to be downregulated by yohimbine treatment. In conclusion, yohimbine improved the biochemical and immunohistochemical markers of DMBA-induced oral cancer and reverted to near normal values via ameliorating the underlying inflammation and oxidative stress conditions. Our study highlighted the potential of yohimbine as anticancer agent, especially against oral cancer and suggested its possible use as repurposed drug.