Phytochemical Mechanisms of Action Against Obesity and Strategies to Overcome Limitations

Phytochemicals - natural compounds such as synephrine, curcumin, capsaicin, and saponins - have gained significant attention for their potential anti-obesity effects through modulation of lipid metabolism and adipogenesis. Synephrine derived from Citrus aurantium exerts its anti-obesity effects by inhibiting adipogenesis (3T3-L1) and enhances fat oxidation through the adenosine monophosphate-activated protein kinase - forkhead box protein O1 signaling pathway. Similarly, curcumin, which is a polyphenolic compound from Curcuma longa, promotes fatty acid oxidation, inhibits preadipocyte differentiation, and modulates insulin resistance and hyperlipidemia. Capsaicin from Capsicum species, induces the browning of adipose tissue and enhances fat oxidation by activating channels, increasing sirtuin-1 expression, and promoting lipid catabolism. Saponins regulate fat absorption by inhibiting pancreatic lipase and modulate adipogenesis through the adenosine monophosphate-activated protein kinase signaling pathway, further contributing to the suppression of obesity. However, the clinical application of these phytochemicals is often limited by factors such as bioavailability, solubility, and potential toxicity. In this narrative review, the mechanisms by which these compounds affect metabolic pathways related to adipogenesis and lipid metabolism are discussed, as well as the challenges faced in their therapeutic use and potential strategies to overcome these limitations.