title: In vivo skin irritation potential of a Castanea sativa (Chestnut) leaf extract, a putative natural antioxidant for topical application.
abstract: Topical application of natural antioxidants has proven to be effective in protecting the skin against ultraviolet-mediated oxidative damage and provides a straightforward way to strengthen the endogenous protection system. However, natural products can provoke skin adverse effects, such as allergic and irritant contact dermatitis. Skin irritation potential of Castanea sativa leaf ethanol:water (7:3) extract was investigated by performing an in vivo patch test in 20 volunteers. Before performing the irritation test, the selection of the solvent and extraction method was guided by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging test and polyphenols extraction (measured by the Folin Ciocalteu assay). Iron-chelating activity and the phenolic composition (high performance liquid chromatography/diode array detection) were evaluated for the extract obtained under optimized conditions. The extraction method adopted consisted in 5 short extractions (10 min.) with ethanol:water (7:3), performed at 40 degrees. The IC(50) found for the iron chelation and DPPH scavenging assays were 132.94 +/- 9.72 and 12.58 +/- 0.54 microg/ml (mean +/- S.E.M.), respectively. The total phenolic content was found to be 283.8 +/- 8.74 mg GAE/g extract (mean +/- S.E.M.). Five phenolic compounds were identified in the extract, namely, chlorogenic acid, ellagic acid, rutin, isoquercitrin and hyperoside. The patch test carried out showed that, with respect to irritant effects, this extract can be regarded as safe for topical application.
authors.affiliation: Department of Pharmaceutical Technology, São Marcos Hospital, Braga, Portugal.
authors.forename: Isabel F
authors.initials: IF
authors.lastname: Almeida
authors.forename: Patrícia
authors.initials: P
authors.lastname: Valentão
authors.forename: Paula B
authors.initials: PB
authors.lastname: Andrade
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Seabra
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Pereira
authors.forename: M Helena
authors.initials: MH
authors.lastname: Amaral
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Costa
authors.forename: M Fernanda
authors.initials: MF
authors.lastname: Bahia
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D001713:Biphenyl Compounds; D002851:Chromatography, High Pressure Liquid; D029962:Fagaceae / Q000737:chemistry*; D005260:Female; D005419:Flavonoids / Q000009:adverse effects / Q000302:isolation & purification / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D007501:Iron / Q000378:metabolism; D007502:Iron Chelating Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D008297:Male; D010328:Patch Tests; D010636:Phenols / Q000009:adverse effects / Q000302:isolation & purification / Q000494:pharmacology; D010851:Picrates; D010936:Plant Extracts / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D018515:Plant Leaves; D059808:Polyphenols; D012867:Skin / Q000187:drug effects* / Q000378:metabolism; D012997:Solvents / Q000737:chemistry; D055815:Young Adult
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D005419:Flavonoids; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D059808:Polyphenols; D012997:Solvents; C004931:1,1-diphenyl-2-picrylhydrazyl; D007501:Iron