Hydrophilic phytochemicals, such as flavonoids and phenolic acids, possess important biological activities, including antioxidant, anti-inflammatory, and anticancer effects. However, their application is hindered by low membrane permeability, poor chemical stability, and
limited skin penetration. This review provides a comprehensive analysis of advanced delivery strategies aimed at enhancing the solubility, bioavailability, and therapeutic efficacy of selected hydrophilic compounds. Specifically, it focuses on the encapsulation of flavonoids such as quercetin, luteolin, and apigenin, as well as phenolic acids including ferulic acid, caffeic acid, and chlorogenic acid. The review discusses various nanocarrier systems: liposomes, niosomes, exosomes, and polymeric nanoparticles (e.g., nanocapsules, nanospheres) and compares their structural characteristics, preparation methods, and functional benefits. These delivery systems improve the physicochemical stability of active compounds, enable controlled and targeted release, and enhance skin and cellular absorption. Despite certain challenges related to large-scale production and regulatory constraints, such approaches offer promising solutions for the pharmaceutical and cosmetic application of hydrophilic plant-derived compounds.
