The comparative anti-obesity potential of Lagerstroemia speciosa (L.) leaf extracts and their synthesized gold nanoparticles by downregulation of PPAR-γ, C/EBP-α, and FABP4/aP2 gene expression

The rising worldwide obesity rate is associated with various metabolic disorders such as hypertension, stroke, type 2 diabetes, cancer, and exacerbation of health challenges throughout the world. Lagerstroemia speciosa offers multiple health benefits, including anticancer, cardiovascular, nephroprotective, hypertension, insulin sensitivity, anti-diabetic, and inflammation-related conditions. The present study explored the comparative anti-adipogenic effects of different extracts and spherical gold nanoparticles (Au-NPs) synthesized with fresh L. speciosa leaf (LS-Au-NPs) using 3T3-L1 mature adipocytes. Cell viability was assessed using an MTT assay, and reactive oxygen species (ROS) production was evaluated using the 2′,7′-dichlorodihydrofluorescein diacetate method. The gene expression pattern of key adipogenic genes, peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein alpha, and ap2 was quantified using reverse transcription polymerase chain reaction. Results demonstrated that leaf extracts and Au-NPs were non-toxic to 3T3-L1 cells up to a specific concentration and significantly reduced ROS generation, lipid accumulation, and triglyceride content in induced obese cells. Aqueous, supercritical fluid extraction (SFE) extract, and AuNPs exhibited the most potent effects, while the methanol extract showed moderate effects, and the n-hexane extract had negligible effects on gene expression regulation. Altogether, these results showed that all effective treatments significantly downregulated the transcriptional adipogenic genes, reflecting their potent anti-obesity potential. SFE exhibited more pronounced effects due to the non-toxicity of the solvent. Thus, the plant leaf is a rich source of phenolic and flavonoid compounds that coat the surface of Au-NPs and help to reduce excess lipid and triglyceride content in the cells.