Melanin is a photoprotective skin pigment, and pathologies characterized by hypo or hyperpigmentation are common. New compounds that regulate melanogenesis are, therefore, opportune, and many natural products with this property, as polyphenols, have been described. Salvia officinalis L., Lamiaceae, is a widely used food spice that contains high amounts of phenol derivates, including rosmarinic acid. The aim of this work was to evaluate the contribution of rosmarinic acid in the melanogenic activity of sage extracts. Fluid and aqueous extracts of sage and purified rosmarinic acid were assayed for B16F10 cytotoxicity and, then, evaluated on melanin production and tyrosinase activity. While sage extracts showed a concentration-dependent ability to significantly increase melanin production without necessarily changing the enzymatic activity, rosmarinic acid showed a dual behavior on melanogenesis, increasing melanin biosynthesis and tyrosinase activity at low concentrations and decreasing it at higher levels. Rosmarinic acid may collaborate with sage extracts activity on melanogenesis, although other compounds may be involved. This is the first time that a dual action of rosmarinic acid on melanogenesis is reported, which may be useful in further studies for therapeutic formulations to treat skin pigmentation disorders.

A sálvia (Salvia officinalis) contém altos teores de ácido rosmarínico (RA), uma substância bioativa, bem como outros polifenóis. RA é facilmente oxidável e pode sofrer degradação durante a preparação da amostra para análise. O objetivo deste trabalho foi desenvolver e validar um método analítico para a determinação do RA em sálvia, usando planejamento fatorial para a otimização da preparação de amostras. Inicialmente foram determinadas as variáveis estatisticamente significativas para melhorar o rendimento da extração do RA, as quais foram depois otimizadas usando planejamento composto central (CCD). O método analítico foi validado e aplicado na análise de amostras comerciais de sálvia. O procedimento otimizado consistiu na extração com metanol aquoso (40%) contendo uma mistura antioxidante (ácido ascórbico e ácido etileno diamino tetracético (EDTA)), com sonicação a 45 ºC por 20 min. As amostras foram injetadas em um sistema contendo coluna C18, usando metanol (A) e ácido fosfórico aquoso 0.1% (B) em gradiente (45A:55B, 0-5 min; 80A:20B, 5-10 min) com fluxo de 1.0 mL min-1 e deteção em 330 nm. Utilizando estas condições, as concentrações do RA foram 50% maiores quando comparadas com extração na ausência de antioxidante (recuperação de 98,94 ± 1,07%). Auto-oxidação do RA durante a preparação da amostra foi evitada pelo uso de antioxidante levando a resultados analíticos mais confiáveis. O método foi então aplicado na análise de amostras comerciais de sálvia.

Sage (Salvia officinalis) contains high amounts of the biologically active rosmarinic acid (RA) and other polyphenolic compounds. RA is easily oxidized, and may undergo degradation during sample preparation for analysis. The objective of this work was to develop and validate an analytical procedure for determination of RA in sage, using factorial design of experiments for optimizing sample preparation. The statistically significant variables for improving RA extraction yield were determined initially and then used in the optimization step, using central composite design (CCD). The analytical method was then fully validated, and used for the analysis of commercial samples of sage. The optimized procedure involved extraction with aqueous methanol (40%) containing an antioxidant mixture (ascorbic acid and ethylenediaminetetraacetic acid (EDTA)), with sonication at 45 ºC for 20 min. The samples were then injected in a system containing a C18 column, using methanol (A) and 0.1% phosphoric acid in water (B) in step gradient mode (45A:55B, 0-5 min; 80A:20B, 5-10 min) with flow rate of 1.0 mL min-1 and detection at 330 nm. Using this conditions, RA concentrations were 50% higher when compared to extractions without antioxidants (98.94 ± 1.07% recovery). Auto-oxidation of RA during sample extraction was prevented by the use of antioxidants resulting in more reliable analytical results. The method was then used for the analysis of commercial samples of sage.