Estudo do potencial de aplicabilidades dos extractos de ginja na promoçao da saude e bem-estar cutaneos

Resumen

In recent years many studies on cherries have revealed that they are rich sources of bioactive compounds, mainly due to their polyphenolic phytochemicals. Sour cherry (Prunus cerasus L) from Óbidos and Alcobaça has unique morphological characteristics that arise primarily from specific climatic conditions of this portuguese region. It is from these cherries that the famous liquor "Ginjinha de Óbidos" comes. This liquor has a typical taste and is produced in several industrial units over the region. However, during the manufacturing process, many by-products are produced, which currently don’t have any valorization. The study of these by-products, their transformation into extracts and the potential of those extracts to promote skin health are not yet described in the literature. The aim of this work was to investigate the transformation of these by-products in extracts with biological properties that can act as functional ingredients of topical and cosmetic formulations. Several types of sour cherry liquor by-products, namely green by-products (stems, leaves, mixed) and pomace (skins and seeds), were extracted by maceration with different solvents. The resulting extracts were screened for their phenolic and anthocyanins content and their in vitro antioxidant activity was evaluated using DPPH and FRAP methods. The cytotoxicity of the extracts in human keratinocytes (HaCaT) was evaluated by the MTT colorimetric assay. The results obtained allowed the selection of the hydroalcoholic extracts as the most promising, either for their safety and for their phenolic content and antioxidant activity. Extracts prepared from stems, leaves and mixed by-products showed a higher antioxidant activity than those prepared from pomace. However, extracts from pomace, mainly those without seeds, presented a total phenolics content and an antioxidant activity similar to other varieties of cherry and sour cherry reported by several authors, which also shows the promising use of these extracts. Stems and mixed extracts presented an antioxidant capacity similar to the synthetic antioxidant BHT and, thus, can be seen as its potential substitute. Extracts were analyzed by HPLC. The major phenolics in stems, leaves and mixed extracts were phenolic acids, mainly: chlorogenic and caffeic acid, and flavonoids, especially flavanols: catechin; flavonols: quercetin-3-0-glucoside and kaempferol-3-0-ramno-glucoside, and flavanone naringin. In pomace extracts were identified mainly phenolic acids such as chlorogenic, caffeic, p - hydroxybenzoic, vanillic acid, and the flavanol (-) epicatechin. The antimicrobial activity of these extracts was assessed by solid medium diffusion assay and the minimum inhibitory concentration by the microdilution method. Extract composed by green by-products showed the highest antimicrobial activity, especially against Gram positive bacteria, particularly against Staphylococcus aureus, Staphylococcus aureus (MRSA), Staphylococcus epidermidis and Propionobacterium acnes. Pomace by-products only showed activity against Staphylococcus aureus, Staphylococcus aureus (MRSA) and Propionobacterium acnes. These results showed the potential of these extracts to be use as functional and active ingredients against these microorganisms in topical products. Subsequently, the preservative efficacy of the mixed extract when incorporated into a topical formulation was evaluated by the challenge test. The results showed that it may be used as an adjuvant in preserving cosmetic and topical products, allowing, thereby, a decrease in the concentration of chemical preservatives. Finally, to validate the antioxidant properties observed in vitro and to validate the applicability of these extracts as functional ingredients in topical products, in vivo efficacy trials in humans have been performed. The goal was to measure the protective effects of the mixed and pomance extracts using an irritant substance (methyl nicotinate). The intensity of the response was evaluated by measuring the intensity of erythema (colorimetry and laser Doppler flowmetry), and transepidermal water loss. Indeed, these extracts showed, when compared with the control, the ability to reduce the intensity of erythema and transepidermal water loss, induced by exposure to methyl nicotinate. Although both extracts presented efficacy in the in vivo assays, the mixed extracts showed a higher antioxidant and protective activity than pomace extracts, which is in agreement with the results obtained in the antioxidant activity in vitro. In summary, this study demonstrated that the analyzed sour cherry liquor by-products may be a promising and economic source of polyphenolic compounds, with potential for application in topical and cosmetic formulations