Nanoencapsulation of epigallocatechin-3-gallate in silk fibroin nanoparticles to improve its activity

Abstract

The global obesity epidemic represents a significant health challenge, leading to various metabolic disorders and chronic diseases. Current treatments often involve drugs with limited efficacy and significant side effects. Epigallocatechin-3-gallate (EGCG), a polyphenol found in green tea, has demonstrated potential anti-obesogenic effects. However, its low bioavailability and stability limit its therapeutic applications. This study addresses these limitations by exploring the ncapsulation of EGCG in silk fibroin nanoparticles (SFNPs) to enhance its stability and bioactivity. The reverse microemulsion technique was employed to synthesize SFNPs, which were then loaded with EGCG using an adsorption method. The nanoparticles were characterized for their physicochemical properties, including size, polydispersity index (PDI), and zeta potential (ZP). Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (ATR-FTIR) were used to observe morphology and confirm EGCG encapsulation. The antioxidant capacity was evaluated using the ABTS assay, and cell viability was assessed using the Alamar Blue test on the 3T3-L1 cell line. The synthesized EGCG-loaded SFNPs showed slightly increased particle sizes with a low PDI, indicating homogeneous distribution. The zeta potential of EGCG-SFNPs increased compared to SFNPs alone, suggesting modified surface characteristics and potential stability improvement. EGCG retained its antioxidant activity after encapsulation, with increased radical scavenging activity at a 1:10 EGCG-SFNPs mass ratio. Cell viability assays indicated that EGCG-SFNPs were less cytotoxic than SFNPs alone, highlighting the EGCG potential to mitigate adverse effects. The encapsulation efficiency of EGCG in SFNPs was highest at a 1:10 mass ratio, primarily due to the gallate group's affinity for hydrogen bonding and hydrophobic interactions with the nanoparticles. This study demonstrates the potential of EGCG- SFNPs to enhance the stability and bioactivity of EGCG, offering a promising therapeutic strategy for obesity treatment. The findings suggest that encapsulated EGCG could serve as an effective anti-obesogenic agent highlighting the benefits of nanoparticle-based delivery systems in improving the efficacy of bioactive compounds.