Análise da Composição Química e Atividades Antioxidante e Antimicrobiana dos Extratos da Espécie Lafoensia Replicata Pohl e Avaliação da Eficácia como Conservantes em Cosméticos

Abstract

The cosmetics market is constantly rising and one of its biggest objectives is to improve the lifespan of its products. To achieve this, chemical preservatives are used to avoid oxidation and inhibit the growth of microorganisms. Due to a tendency of a pro-ecological and healthy lifestyle, there is a growing search for a chemical preservative that serves as an alternative for the class of synthetic ones that is widely used in the industry (called parabens). In this way, natural products (NP), can serve as such an alternative. Given this context, this article's objective was to evaluate the antioxidant and antimicrobial activities for the extracts of the leaves, barks and branches of Lafoensia replicata Pohl, produced by maceration, as well as identify its components. In addition, the same parameters were evaluated in contrast with an extract prepared following methodologies defined by popular knowledge, commonly sold as dye. The ethanolic extracts and dyes showed high antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosas and against the fungus Candida albicans (minimum inhibitory concentration – MIC < 100 µg mL-1). Such extracts showed high content of phenols, which explains the high antioxidant activity (EC50 < 50 µg mL-1 by the method of the sequestration of the radical 2,2-diphenyl-1-picrylhydrazyl – DPPH – and values over 380 equivalents of Trolox in µmol g-1 of sample by the method of iron reduction capacity – FRAP). Given the results, body creams were produced using the plant extracts with the objective of measuring its preservative efficacy when compared against methylparaben, one of the chemical preservatives most used in the cosmetic industry. As a result, the antimicrobial activity of the extracts was comparable to that observed with the synthetic preservative. Through mass spectrometry (MS), was identified the chemical compounds present on the ethanolic extract. The main metabolite classes identified were flavonoids, tanines and phenolic acids, such as ellagic acid, gallic acid, punicalagin, pedunculagin, punicalin and HHDP glucose, which may be responsible for the observed activity. The results show that the extracts of L. replicata are a potentially good source of bioactives and that further study of their utility as chemical preservatives looks promising, as well as the contribution for the chemosystematics of the genus.