Rationale for the Use of Natural Anti-Inflammatory Agents in Cancer Chemotherapy

Abstract

Chemotherapeutic drugs have been conventionally used for the cancer treatments, but the efficacy of the therapy remains problematic. It has been strongly suggested that the anti-inflammatory drugs, such as COX-2 inhibitors, may enhance the anti-cancer efficacy of chemotherapeutic drugs and reduce the chemo-resistance. Herein, the rational of the use of anti-inflammatory agents in the cancer treatment is summarized. One of the most important inflammatory processes occurs during metabolism of the eicosanoids, which involved arachidonic acid (AA), cyclooxygenase 2 (COX-2), prostaglandins (PGs) and leukotriens (LTs). As the results of excessive up-regulation of COX-2 and production of PGE2, for example, the harmful inflammation may promote the cancer development. The inflammation also involve in the drug resistance of the chemotherapy. In fact, many in vitro and in vivo studies have showed the positive potentials using COX-2 inhibitors in the cancer treatment. However, the regular anti-inflammatory agents, mainly COX-2 inhibitors, may induce  serious  damages  to  stomach,  kidney  and  heart, which have restricted the clinical uses of these drugs. For the reason, growing numbers of studied have targeted on the natural anti-inflammatory substances and expected to find the effective adjuvant to the chemotherapeutic drugs without the safety concern. On the other hand, the counteraction between the chemotherapy and natural substances has been concerned clinically. Therefore, the natural substances, which were studied for their anti-inflammation effects, are listed. The potential enhancing effects of some of the national anti-inflammatory agents on chemotherapeutic agents are reviewed. A guideline for clinical use of these natural agents with chemotherapy is suggested although limited clinical trial data available. In conclusion, the existing evidences suggest that some natural anti-inflammatory substances have potential to be used as adjuvant agents to enhance the efficacy and reduce the resistance of the chemotherapy. But more research and clinical trials are needed to support the suggestions.