<p>In this study, lignin was extracted from the biomass of areca nut husk, which is frequently seen as waste by farmers. A proximate analysis of the husk was conducted to examine its composition. The extracted lignin was characterized using FTIR, TGA, and XRD spectroscopy. Lignin nanoparticles were prepared through a simple nanoprecipitation method, and their antioxidant activity was assessed by measuring total phenolic content, DPPH, ABTS, and nitric oxide scavenging activities, along with reducing power analysis. The UV protection property was also evaluated by calculating its SPF value. The findings from this study indicate that areca nut husk is a rich source of bioactive lignin, and the lignin nanoparticles derived from it demonstrate significant antioxidant activity. The SPF values varied from 2.75 to 16.6 based on the concentration of the lignin nanoparticles. Therefore, this research underscores the potential of areca nut husk, typically considered agricultural waste and discarded by farmers, as a sustainable and valuable resource for the healthcare and cosmeceutical industries, presenting prospects for the development of innovative value-added products. This method not only minimizes waste but also enhances potential economic sustainability.</p> Graphical Abstract <p></p>