Current evidence and future perspectives for curcumin and its analogues as promising adjuncts to oxaliplatin: state-of-the-art

Curcumin is a multifunctional phytochemical that has documented anti-oxidant, anti-inflammatory and antitumor properties. The anti-tumor effect of curcumin has been widely investigated, both as a single ingredient and in combination with chemotherapeutic agents. Oxaliplatin is a third-generation platinum agent with established effectiveness in multiple malignancies including gastroesophageal, colorectal, pancreas, ovarian, breast and head and neck cancers. The effects of curcumin and its synthetic analogues in combination with oxaliplatin have been studied in a variety of malignant cell lines in vitro and in vivo, providing evidence supporting the beneficial effects of curcumin as an adjunct to oxaliplatin, though dose, combination ratio and the timing of exposure to the agents are covariates that may affect the therapeutic efficacy and need to be determined. This review provides a summary of the studies investigating the effects of curcumin and its analogues, as adjuvants to oxaliplatin treatment in malignant cell lines and experimental tumor models. Addition of curcumin as an adjunct to oxaliplatin enhances oxaliplatin's toxicity in malignant cells, which potentially allows an oxaliplatin dose reduction and decreasing the adverse effects of chemotherapy. Curcumin has also been studied in several nonmalignant cell types and has been shown to exert cytoprotective properties against oxaliplatin's off-target toxicities. Despite all of the promising evidence to date, there is a scarcity of supportive evidence from clinical trials on the adjuvant use of curcumin, which needs future translational and clinical studies.