Potential Biological Activities of Clausena Essential Oils for the Treatment of Diabetes

Diabetes mellitus constitutes one of the most important public health problems. It is defined as a metabolic disorder characterized by a chronic hyperglycemic condition. The inhibition of α-glucosidase and inflammation effects is still considered a strategy for the treatment of diabetes. The aim of this study was to search for new and effective natural functional foods agents for the complementary treatment of diabetes and other related complications. The essential oils from the leaves of three Clausena plants collected in Thailand: C. harmandiana, C. guillauminii and C. excavata were obtained by hydrodistillation. The chemical compositions, antioxidant, anti-α-glucosidase and anti-inflammatory activities of these essential oils were evaluated. The C. excavata and C. harmandiana essential oils contained seselin and terpinen-4-ol, respectively, as the major components and showed strong inhibition of DPPH free radical, α-glucosidase, lipoxygenase and nitric oxide activities with the IC₅₀ values ranging from 0.031±0.005 to 0.702±0.003 mg/mL. From these results, it may be concluded that seselin and terpinen-4-ol are important for high antioxidant, anti-α-glucosidase, and anti-inflammatory activities. Therefore, these Clausena essential oils may be useful in industrial applications for the treatment of diabetes and other related complications.