Formulation and optimization study of nanodelivery system encapsulating guava wild leaf extract for potential anti-inflammatory properties

Psidium guajava L. (Myrtaceae) has long been used in folk medicine as a potent therapeutic agent for the treatment of inflammation. Despite its potential, the application of this natural source remains limited because of its instability and poor permeability through biological barriers. Among different available strategies, niosomes, a surfactant-based nanovesicular system, may help maximize the application of this plant extract. The aim of this study was to develop and optimize a formulation of a niosomal system for encapsulating guava leaf extract (GLs-N) for anti-inflammatory applications. The niosomes were fabricated using the ethanol injection method and optimized in terms of the surfactant, cholesterol, and GLs content using an experimental design model. The finalized niosomes were physicochemically characterized and tested for their encapsulation capacity (EE), stability, permeability, and in vitro and in vivo anti-inflammatory activities in a zebrafish model. As a result, the optimized niosomes were of 167.9 ± 1.845 nm in size, with a PDI of 0.212 ± 0.005, negatively charged, and with an EE of 65.54%. Compared to free GLs, GLs-niosomes presented a significant increase in permeability and possessed good stability over 28 days at both 4 and 25 0C. Most importantly, in vitro and in vivo anti-inflammatory studies confirmed that the anti-inflammatory activity of GLs-niosomes was much stronger than that of free GLs, and 4.2 fold stronger than that of ibuprofen. Collectively, this study was successful in developing and optimizing a potent niosomal structure for an effective delivery of wild guava leaf extract in the treatment of inflammation.&#xD.