316 Polyphenols from Avocado co-valuation product to improve dark circles appearance

Abstract

Evoking a fatigued and less youthfull appearance, under-eye dark circles are a major aesthetic concern for consumers. Although they may be the result of facial aging, dark circles can affect both men and women of all ages. The formation of dark circles is related to numerous factors among which vascular stasis, hyperpigmentation and loss of skin elasticity play an important role. From up-cycling of an avocado by-product, we obtained an eco-designed extract rich in polyphenols and demonstrated its biological activity on reducing dark circles using in vitro and clinical studies. In vitro, the extract significantly decreased IL8 and PGE2 production in keratinocytes, as well as LTB4 in neutrophils, induced respectively by Phorbol-Myristate-Acetate or zymosan. It significantly decreased lymphatic and microvascular hyperpermeability induced by IL1β on human dermal lymphatic or microvascular endothelial cells (HDLEC, HDMEC), as shown by FITC-Dextran permeability assay. The extract induced a dose-dependent increase in HDMEC of Angiotensin- I-Converting Enzyme activity, involved in vasoconstriction. And significantly inhibited tyrosinase activity as well as melanin production in melanocytes. A clinical study has been performed on 20 women (aged 24 to 66 y.o.) with pigmentary dark circles. After 28 days of twice daily application of Active or placebo (hemi face), assessment of dark circles pigmentation has been performed using standardized pictures (Visia-CR). The avocado extract significantly decreased brown spot counts by 9.7% and brown spots area by 21.5% compared to placebo which presented minor and non- significant effects. Clinical scoring also demonstrated a significant improvement of the color of dark circles treated with the avocado extract. We have shown in vitro that an extract from Avocado, rich in polyphenols, may have a positive effect on the main factors involved in dark circles formation: vasodilatation, vascular permeability, inflammation and hyperpigmentation. This was confirmed by the improvement of pigmented dark circles observed clinically.