Costus speciosus and Coccinia grandis: Traditional medicinal remedies for diabetes

•Therapeutic effects of Coccinia grandis and Costus speciosus are discussed.•Both plants possess anti-diabetic properties.•They have been historically used in traditional medicinal systems.•Both plants can be easily grown and are readily available in the tropics.•They are known to be effective therapeutic agents than current anti-diabetic drugs.

Diabetes mellitus is a major illness which has been implicated with numerous clinical manifestations. Herbal medicines have become a popular form of therapy for this disease and are now being engaged in complementary means together with the usual chemical or biochemical agents due to the fact that they are less toxic at recommended dosages than synthetic counterparts. Plants have the ability to synthesize phytochemicals of medicinal value and these products in turn can be used for therapeutic purposes especially in developing countries where resources are meagre. Costus speciosus and Coccinia grandis are plants which contain reservoirs of anti-diabetic effects as well as other medicinal properties. These plants have been known to demonstrate pharmacological activities such as anti-inflammatory, anti-microbial, antioxidant, anti-dyslipidemic and anti-cancer. This review discusses the morphology of these two herbs, uses of these plants in medicinal practices, their traditional methods of administration and the bioactive compounds which have been identified to possess the anti-diabetic properties.