title: Application of Coffee Silverskin in cosmetic formulations: physical/antioxidant stability studies and cytotoxicity effects.
abstract: BACKGROUND
  Currently, there is an increasing interest of cosmetic industry on natural extracts. The inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with aging. Also, questions of sustainability are leading to the study of new cosmetic ingredients obtained from food by-products. Coffee Silverskin (CS) is a food by-product with established antioxidant activity that has not yet been incorporated into a topical formulation.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the physical and microbiological stabilities and antioxidant activity of a hand cream formulation containing 2.5% (w/w) of CS extract upon production and after 6 months of shelf-life and in vitro safety/cytotoxicity on skin cell lines after production.
  
  
  METHODS
  The in vitro cytotoxicity was evaluated with MTS and LDH assays, at different concentrations, in HaCaT and HFF-1 cells. Formulations were stored at 25 °C/65% RH and 40 °C/75% RH. Physical, microbiological, and antioxidant stabilities were evaluated by centrifugation, viscosity, total colony count, DPPH and total phenolic content (TPC).
  
  
  RESULTS
  The hand cream containing 2.5% (w/w) of CS extract showed stable physical characteristics independently of the storage conditions. The DPPH activity and TPC of the CS formulation were significantly higher compared with those of the base formulation. However, during storage, the antioxidant activity decreases slightly. Microbiological quality was also confirmed. No cytotoxic effects were observed.
  
  
  CONCLUSIONS
  It is possible to suggest that this formulation is stable under extreme conditions and safe for topical use.
authors.affiliation: a REQUIMTE, Faculty of Pharmacy, University of Porto , Porto , Portugal.|b Fourmag Lda, Parque Industrial do Cruzeiro , Moreira de Cónegos , Portugal.
authors.forename: Francisca
authors.initials: F
authors.lastname: Rodrigues
authors.affiliation: c CICS-UBI - Health Sciences Research Centre, Avenida Infante D. Henrique, University of Beira Interior , Covilhã , Portugal.|d Labfit-HPRD:Health Products Research and Development Lda, Avenida Infante D. Henrique, Health Sciences Faculty , University of Beira Interior , Covilhã , Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Gaspar
authors.affiliation: c CICS-UBI - Health Sciences Research Centre, Avenida Infante D. Henrique, University of Beira Interior , Covilhã , Portugal.|d Labfit-HPRD:Health Products Research and Development Lda, Avenida Infante D. Henrique, Health Sciences Faculty , University of Beira Interior , Covilhã , Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Palmeira-de-Oliveira
authors.affiliation: e INEB - Institute of Biomedical Engineering, University of Porto , Porto , Portugal.|f Department of Pharmaceutical Sciences , CESPU - Institute for Research and Advanced Training in Health Sciences and Technologies, Instituto Superior de Ciências da Saude-Norte , Gandra-PRD , Portugal , and.
authors.forename: Bruno
authors.initials: B
authors.lastname: Sarmento
authors.affiliation: g Department of Drug Sciences, Faculty of Pharmacy , University of Porto , Porto , Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Helena Amaral
authors.affiliation: a REQUIMTE, Faculty of Pharmacy, University of Porto , Porto , Portugal.
authors.forename: M Beatriz
authors.initials: MB
authors.lastname: P P Oliveira
mesh_terms: D000279:Administration, Cutaneous; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D040503:Coffea / Q000737:chemistry*; D003358:Cosmetics / Q000737:chemistry*; D004355:Drug Stability; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D063465:Skin Cream / Q000737:chemistry
chemical_list: D000975:Antioxidants; D003358:Cosmetics; D010936:Plant Extracts
keywords: Dermocosmetic; LDH; MTS; fibroblast; in vitro cytotoxicity; keratinocytes; topical formulation