Desenvolvimento de nanoemulsões contendo extrato hidroetanólico das folhas de Kalanchoe laciniata (L.) DC. e avaliação in vitro da atividade antioxidante

Abstract

Kalanchoe laciniata (L.) DC. species (Crassulaceae), popularly known as saião, is a small plant that is an easy cultivated plant that has in its chemical constitution metabolites that can be used in products to prevent the signs of skin aging. In cosmetics, the addition of plant active ingredients in nanoemulsified systems has received great prominence, due to the smaller droplet size, sensory and more pleasant physical aspect. Therefore, this work aimed to develop cosmetic nanoemulsions with antioxidant activity to prevent skin aging, using hydroethanolic extract of K. laciniata leaves. For this purpose, a hydroethanolic turboextraction with 50% ethanol (v/v) was carried out using fresh leaves in a 1: 1 ratio (plant:solvent) (w/v). The extract obtained was quantitatively characterized in relation to the concentration of phenolics and total flavonoids. The antioxidant in vitro potential of extract was evaluated using different antioxidant methodologies: 2,2-difenil-1-picrilhidrazil (DPPH) radical scavenging, 2,2′- Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS˖+) radical scavenging, total antioxidant capacity, reducing power, superoxide radicals scavenging, Cu2+ and Fe2+ chelation and hydroxyl radicals scavening. Nanoemulsions were obtained form an experimental design (2³ + 3PC) by low and high energy emulsification methods, characterized by droplet size, polydispersity and zeta potential and then evaluated for their preliminary and accelerated stability under different storage conditions. The extract showed the presence of phenolic compounds, flavonoids and antioxidant activity. A cosmetic nanoemulsion stable for 90 days was obtained by the high energy process, containing 20% of emollient, 5.0% of surfactants, 1% of preservative, 0.5% of the Kalanchoe laciniata hydroethanolic extract, and 73.5% distilled water. Accordingly, we conclude that the extract acted in different stages of the oxidative cascade indicating the antioxidant potential of the hydroethanolic extract of Kalanchoe laciniata as a cosmetic raw material for preventing the signs of skin aging, as well as demonstrating the viability of an innovative nanoemulsified cosmetic product.