Clove and Its Active Compound Attenuate Free Fatty Acid-Mediated Insulin Resistance in Skeletal Muscle Cells and in Mice

• Published in: Journal of medicinal food Vol. 20; no. 4; p. 335
• Main Authors: Ghaffar, Safina, Afridi, Shabbir Khan, Aftab, Meha Fatima, Murtaza, Munazza, Hafizur, Rahman M, Sara, Sara, Begum, Sabira, Waraich, Rizwana Sanaullah
• Format: Journal Article
• Language: English
• Published: United States 01.04.2017
• Subjects: Animals; Benzodioxoles - pharmacology; Chromatography, Liquid; Diabetes Mellitus, Experimental - drug therapy; Fatty Acids, Nonesterified - pharmacology; Female; Flowers - chemistry; Glucose - metabolism; Glucose Tolerance Test; Glycogen Synthase Kinase 3 - metabolism; Insulin Receptor Substrate Proteins - metabolism; Insulin Resistance; Insulin-Secreting Cells - drug effects; Mice; Mice, Inbred BALB C; Muscle Fibers, Skeletal - drug effects; Muscle Fibers, Skeletal - metabolism; Myoblasts, Skeletal - drug effects; Myoblasts, Skeletal - metabolism; Phosphorylation; Plant Extracts - pharmacology; Proto-Oncogene Proteins c-akt - metabolism; Reactive Oxygen Species - metabolism; Signal Transduction; Syzygium - chemistry; Tyrosine - chemistry; clove; insulin signaling; diabetes; insulin resistance; phosphorylation
• ISSN: 1557-7600
• DOI: 10.1089/jmf.2016.3835

Several reports indicate anti-hyperglycemic effects of Syzygium aromaticum. In the present study, we report for the first time that clove extract (SAM) and its compound nigricin (NGC) decreases free fatty acid-mediated insulin resistance in mouse myoblasts. In addition, NGC was able to diminish insulin resistance in a diabetic mouse model. We observed that SAM and its compound NGC exhibited significant antioxidant activity in murine skeletal muscle cells. They also modulated stress signaling by reducing p38 MAP kinase phosphorylation. NGC and SAM treatments enhanced proximal insulin signaling by decreasing serine phosphorylation of insulin receptor substrate-1 (IRS-1) and increasing its tyrosine phosphorylation. SAM and NGC treatments also modified distal insulin signaling by enhancing protein kinase B (PKB) and glycogen synthase kinase-3-beta (GSK-3 beta) phosphorylation in muscle cells. Glucose uptake was enhanced in muscle cells after treatment with SAM and NGC. We observed increased glucose tolerance, glucose-stimulated insulin secretion, decreased insulin resistance, and increased beta cell function in diabetic mice treated with NGC. The results of our study demonstrate that clove extract and its active agent NGC can be potential therapeutic agents for alleviating insulin resistance.