title: Antioxidant and cytoprotective effects of an ethanol extract of Acalypha wilkesiana var. macafeana from Malaysia.
abstract: In the annals of biomedical theory perhaps no single class of natural product has enjoyed more ingenious speculation than antioxidants formally aimed at counteracting oxidative insults which are involved in the pathophysiology of Alzheimer's and Parkinson's disease, cancer, amyotrophic lateral sclerosis, skin ageing and wound healing. In pursuing our study of Malaysian traditional medicines with antioxidant properties, we became interested in Acalypha wilkesiana var. macafeana hort., used traditionally to heal wounds. To examine whether Acalypha wilkesiana var. macafeana hort. could suppress oxidation an ethanol extract was tested by conventional chemical in vitro assays i.e., ferric reducing antioxidant potential assay (FRAP), DPPH scavenging assay and beta-carotene bleaching (BCB) assay. To explore whether Acalypha wilkesiana var. macafeana hort. protected cells against oxidative injuries, we exposed human hepatocellular liver carcinoma (HepG2) cells to tert-butylhydroperoxide (t-BHP). In all the aforementioned experiments, the ethanol extracts elicited potent antioxidant and cytoprotective activities. To gain a better understanding of the phytochemical nature of the antioxidant principle involved, five fractions (F1-F5) obtained from the ethanol extract were tested using FRAP, DPPH and BCB assays. Our results provided evidence that F5 was the most active fraction with antioxidant potentials equal to 2.090 +/- 0.307 microg/mL, 0.532 +/- 0.041 microg/mL, 0.032 +/- 0.025 microg/mL in FRAP, DPPH and BCB assay, respectively. Interestingly, F5 protected HepG2 against t-BHP oxidative insults. To further define the chemical identity of the antioxidant principle, we first performed a series of phytochemical tests, followed by liquid-chromatography and mass spectrometry (LC/MS) profiling which showed that the major compound contained in F5 was geraniin. To the best of our knowledge, this is the first report showing that the wound healing property of Acalypha wilkesiana var. macafeana hort. is mediated by a geraniin containing extract. Furthermore, our data leads us to conclude that geraniin could be used as a potential pharmaceutical and/or cosmetic topical agent.
authors.affiliation: School of Biomedical Sciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia. khyx8wmd@nottingham.edu.my
authors.forename: Wardah M
authors.initials: WM
authors.lastname: Din
authors.forename: Jessica
authors.initials: J
authors.lastname: Chu
authors.forename: Garry
authors.initials: G
authors.lastname: Clarke
authors.forename: Khoo T
authors.initials: KT
authors.lastname: Jin
authors.forename: Tracey D
authors.initials: TD
authors.lastname: Bradshaw
authors.forename: Jeff R
authors.initials: JR
authors.lastname: Fry
authors.forename: Christophe
authors.initials: C
authors.lastname: Wiart
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D000431:Ethanol / Q000737:chemistry*; D019665:Euphorbiaceae / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D000431:Ethanol; D020122:tert-Butylhydroperoxide