Thymol's Nanoencapsulation Reduces its Toxicity in Human Cells and Zebrafish Embryos

Abstract

Thymol, a monoterpenoid and a major bioactive constituent of essential oils (EOs) derived from the plants of Lamiacea family such as Thyme, garnered wider research interest for its diverse biological activity and industrial applications. However, thymol in its free form poses significant application challenges due to unfavorable physiochemical properties, including high volatility, low aqueous solubility, and pronounced lipophilicity. Thymol encapsulation has the potential to overcome these limitations, improving thymol’s stability, solubility, and controlled release. Despite these advantages, toxicity and biocompatibility of encapsulated thymol have not been comprehensively characterized. In-vitro cytotoxicity assays, provides an initial evaluation of concentration-dependent effects of both free and nanoencapsulated forms, while in-vivo assessment using zebrafish (Danio rerio) embryos-a well-established robust vertebrate model-enables comprehensive evaluation of developmental and systemic toxicity. The embryo’s high genetic similarity to humans (~ 75%) and aquatic physiology, makes them an ideal model for assessing both human health and environmental toxicological impacts, of free and nano-encapsulated forms of thymol.