Nanoemulsion: Promising nanocarrier system for delivery of herbal bioactives

The herbal medicines have been popularized throughout the globe since time immemorial. Several plant based therapeutic leads have been produced through integrated approaches. Many herbal bioactives have several health benefits but limited therapeutic potential due to short half-life and low bioavailability profile. Plant derived molecules are either hydrophilic or lipophilic in nature. Highly hydrophilic bioactives have poor absorption via lipid membrane which slows down their biological efficacy and pharmacokinetics. The large molecular size of the plant bioactive compounds also limited their therapeutic uses due to low membrane permeability. Nanocarriers have the ability to potentiate the efficacy of herbal bioactives by improving their solubility, absorption profile, minimizing dose and side effects. The nanoemulsions can channel the herbal bioactives to the particular target site and maintain blood-plasma concentration for longer periods. However, the conventional drug delivery system failed to achieve these specific requirements. Nanoemulsions are promising to improve solubility, stability, permeability and bioavailability of the herbal bioactives through encapsulation. The present review describes the importance of nanoemulsions for delivery of herbal bioactives and highlights the various aspects of its formulation consideration, challenges and future perspective for the development of herbal bioactives.