Synthesis of lemongrass essential oil–chitosan nanoemulsions via ultrasonication with sodium tripolyphosphate and evaluation of antifungal activity

Abstract

This study presents the synthesis of various nanoemulsion systems using lemongrass essential oil (Cymbopogon spp.) and chitosan, employing ultrasound in conjunction with sodium tripolyphosphate (TPP) to enhance stability and antifungal properties. Nanoemulsion samples, both with and without TPP supplementation, were investigated for their nanosystem properties, stability over a 90-day storage period, and antifungal efficacy. Results indicate that the sample without TPP supplementation (nano TDS-Chi3) and the samples with TPP supplementation (nano TDS-Chi-TPP3 and nano TDS-Chi-TPP4) achieved droplet sizes below 200 nm and polydispersity index (pDi) values below 0.3, reflecting high homogeneity in particle structure. Notably, the sample nano TDS-Chi-TPP₃ demonstrated exceptional antifungal activity, achieving 100% inhibition against Colletotrichum musae QB6, the pathogen causing anthracnose in post-harvest bananas. The incorporation of TPP formed a stable cross-linking network among the chitosan particles, maintaining biological activity and preventing phase separation over time; specifically, the nano TDS-Chi-TPP3 sample retained its nanoemulsion characteristics after 90 days of storage. These findings highlight the potential for developing sustainable and safe biological solutions in agriculture, aimed at improving product quality and environmental protection.