In vitro modulation of pancreatic insulin secretion, extrapancreatic insulin action and peptide glycation by Curcuma longa aqueous extracts

Diabetes mellitus is the most common metabolic disorder affecting millions worldwide. It is recognized as a global major health problem [1]. As alternatives to the available orthodox medicines, plants are considered a potential source for the treatment of diabetes within traditional ethnomedicine practices. Literature surveys summarize the benefit of several ethnobotanicals as anti-diabetic agents in the form of crude extracts and/or isolated pure compounds, which exhibit varying degrees of hypoglycemic or antihyperglycemic bioactivities [2]. Evidently, multiple medicinal herbs, both indigenous or imported, were promoted locally for diabetes traditional medicine. These were closely linked to appreciable prevalence of herbal use among diabetes patients on conventional medicaments in Jordan [3]. A spice originally common in the kitchen and folk medicine for multiple ailments, turmeric, also known as Curcuma longa Linn. (Zingiberaceae), exhibits diverse activities in the clinical trials of lupus nephritis, cancer, diabetes, irritable bowel syndrome, acne, and fibrosis [4-6]. Various phytochemical constituents have been isolated from C. longa, including polyphenols, sesquiterpenes, diterpenes, triterpenoids, sterols, and alkaloids [4,7]. Curcumin is a culinary and medicinal yellowish phenolic spice derived from the rhizome of C. longa, which constitutes 2-5% by weight. It is a natural antioxidant that has diverse pharmacological activities and is perhaps the most-studied component. Although some of the activities of C. longa can be mimicked by curcumin, other activities are curcumin-independent. Importantly, it has been proven that curcumin is a highly pleiotropic molecule, which can be a modulator of intracellular signaling pathways that control cell growth, inflammation and apoptosis [8]. In vitro modulation of pancreatic insulin secretion, extrapancreatic insulin action and peptide glycation by Curcuma longa aqueous extracts