Coffee silverskin: A possible valuable cosmetic ingredient

Abstract

Context: Currently, there is a great tendency in cosmetic area to use natural extracts. Coffee silverskin (CS) is the most abundant solid by-product generated during roasting of coffee processing. Objectives: To evaluate different CS extracts as promising cosmetic ingredients, regarding antioxidant, antimicrobial, and cytotoxic properties. Materials and methods: Aqueous, hydroalcoholic and ethanolic CS extracts were obtained by an environmentally friendly procedure considering costs and pollution. Extracts were characterized for total phenolic and flavonoid contents (TPC and TFC, respectively), antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), antimicrobial activity expressed as minimal inhibitory concentration (MIC) and cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and lactate dehydrogenase (LDH) assays in two skin cell lines (fibroblasts and keratinocytes). Results: The TPC of extracts was 18.33-35.25 mg of gallic acid equivalents per g of material on a dry basis (mg GAE/g db). The TFC of extracts was 1.08-2.47 mg cathechin equivalents per g dry material (mg CE/g db). The antioxidant activity was high, with values ranging between 95.95 and 216.40 mmol Fe 2+ /g for aqueous and alcoholic samples, respectively. Preliminary assays for antimicrobial potential showed that extracts display antibacterial activity. The MIC varied from 31.3 to 250 mg/mL for Gram-positive, and from 31.3 to 1000 mg/mL for Gram-negative. Extracts did not affect in vitro cell viability, with values near 100% in all concentrations tested. Conclusion: Results seem show that CS is a safe source of natural antioxidants with antifungal and antibacterial activity and no cytotoxicity, with potential usefulness for cosmetic applications.

Castanea sativa Bur: An Undervalued By-Product but a Promising Cosmetic Ingredient

“…For this reason, gels with higher percentages of bur extract that showed greater TPC values should also present higher antioxidant activity. The incorporation of chestnut bur in a dermatological basis still presents high TPC, in the same range of some plant by-products, highlighting its potential source of polyphenols [7,8,23]. …”

Are coffee silverskin extracts safe for topical use? An in vitro and in vivo approach

“…The previous assays led us to select the hydro-alcoholic extract as the best one to be incorporated in cosmetic products, as it did not affect the morphology of skin and ocular models, with high cell viability for both assays and low IL-1a release. Also the CAF con-tent was higher than in the other extracts evaluated and, according to Rodrigues et al (2015), the antioxidant content and antimi-crobial activity is higher. Considering not only these results but also sustainability questions and other previous works regarding the antioxidant activity of these extracts, hydro-alcoholic extract seems to be the best one, being selected for the final patch test (Bresciani et al, 2014;Costa et al, 2014;Narita and Inouye, 2012).…”

“…This could be justified by the different solvents used in both studies. Considering the extract composition, reported by Rodrigues et al (2015), it is also expected no effect on skin cells, since the identified compounds did not inter-act with cells, presenting an high antioxidant activity and absence of cytotoxicity in keratinocytes and fibroblast. Also, washing proce-dures could not remove all materials and even lead to mechanical damage to the tissues, which results in an impaired prediction of the true skin irritation potential of the materials (Molinari et al, 2013).…”

“…CS was milled to particle size of approximately 0.1 mm using a A11 basic analysis mill (IKA Wearke, Staufen, Germany) and stored in silicone tubes at room temperature (25-28 • C) until extract preparation, as described by different authors (Costa et al, 2014;Rodrigues et al, 2015). Samples (1 g) were submitted to solvent extraction by maceration with 20 mL of water, ethanol:water (1:1, v/v) or ethanol for 30 min at 40 • C. The three different extracts obtained were filtered through Whatman No.…”

The Functional Benefit of Coffee for Being Healthy and Beautiful

“…Coffee can be used as a cosmetic (17). Ground coffee contains 15% coffee oil, of which 75% contains triacylglycerol, while some contain free fatty acids, waxes, sterols, tocopherol, ceramide, diterpenes and phosphatides [18].…”