Elevating Skincare Science: Grape Seed Extract Encapsulation for Dermatological Care.

The skin is the largest organ in the human body and serves multiple functions such as barrier protection and thermoregulation. The maintenance of its integrity and healthy structure is of paramount importance. Accordingly, technological advances in cosmetic sciences have been directed towards optimizing these factors. Plant-derived ingredients have been explored for their bioactivity profiles and sustainable sources. Grape by-products contain a group of bioactive molecules that display important biological activities. Nonetheless, many of these molecules (e.g., phenolic compounds) are unstable and susceptible to degradation. So, their encapsulation using nano/microsystems (i.e., microdispersions) has been explored as a promising solution. In this work, two grape seed extracts were obtained, one from a single grape variety (GSE-Ov) and another from a mix of five grape varieties (GSE-Sv). These extracts were analysed for their antioxidant and antimicrobial activities, as well as their chemical composition and molecular structure. The extract that showed the most promising properties was GSE-Ov with a DPPH IC 50 of 0.079 mg mL -1 . This extract was encapsulated in soy lecithin microdispersions coated with pectin, with an encapsulation efficiency of 88.8%. They showed an in vitro release of polyphenols of 59.4% during 24 h. The particles displayed a zeta potential of -20.3 mV and an average diameter of 13.6 µm. Microdispersions proved to be safe under 5 and 2.5 mg mL -1 in HaCaT and HDF cell models, respectively. Additionally, they demonstrated anti-inflammatory activity against IL-1α when tested at 2 mg mL -1 . This work enabled the valorisation of a by-product from the wine industry by using natural extracts in skincare products.