Potential Health Benefits of Piceatannol-Rich Extracts from Passiflora edulis f. flavicarpa Seeds on Modulating Gene Expressions Related to Fat Metabolism and Muscle Development in C2C12 Myotubes

Abstract Yellow passion fruits are widely cultivated in many countries. Throughout industrial manufacturing operations, seeds are frequently disposed of as byproducts. Passion fruit seeds are an abundant natural source of piceatannol, which is known for its antioxidant properties and its ability to modulate protein turnover. This study investigated the potential benefits of passion fruit (PF) extract from pulp and juice, as well as piceatannol-rich (PIC) extract from passion fruit seeds, on palmitic acid (PA)-induced myosteatosis-related muscle atrophy in C2C12 myotubes at the transcriptional level. The PIC extract yielded 5.1% (w/w) with a piceatannol concentration of 0.37% (w/w). The result showed that the PIC extract was more effective in free radical scavenging than the piceatannol standard. Additionally, the results demonstrated that PA promoted lipid accumulation while impairing the muscle formation and glucose absorption. However, both PF and PIC extracts demonstrated a significant reduction in PA-induced lipid accumulation, accompanied by suppression of diacylglycerol acyltransferase 1 (Dgat1) expression without altering sirtuin 1 (Sirt1) and uncoupling protein 3 (Ucp3). In addition, both extracts tended to enhance the expression of myosin heavy chain 1 (Myh1) and glucose transporter type 4 (GLUT4), while markedly reducing myostatin (Mstn) expression, suggesting improvements in muscle development and glucose uptake. Furthermore, the PIC extract suppressed pancreatic lipase activity, which minimizes spikes in postprandial triglycerides in the blood circulation of rats. These findings emphasize the potential health benefits of PF and PIC extracts in enhancing glucose absorption and inhibiting fat synthesis in C2C12 myotubes, suggesting potential to mitigate lipid accumulation-related muscle development. The promising findings from cell culture suggest further in vivo investigation for studying their physiological relevance to muscle wasting caused by fat accumulation in obesity.