title: Antioxidant activity-guided separation of coumarins and lignan from Melicope glabra (Rutaceae).
abstract: The ethyl acetate and methanol bark extracts of Melicope glabra were evaluated for their antioxidant capacities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and β-carotene bleaching/linoleic acid system. Both extracts exhibited strong inhibition against the DPPH radical (IC50 values of 24.81 and 13.01 μg ml(-1), respectively) and strong antioxidant activity in β-carotene bleaching assay. Both samples were found to have high phenolic content with values of 39 and 44 mg GAE/g as indicated by Follin-Ciocalteau's reagent. Antioxidant TLC assay-guided isolation on the methanol extract led to the isolation of a new pyranocoumarin, glabranin (1), umbelliferone (2), scopoletin (3) and sesamin (4), and their structures were determined by spectroscopy. Compounds (1-3) showed significant activities on DPPH free radical with the IC50 of 240.20, 810.02 and 413.19 μg ml(-1), respectively. However, in β-carotene bleaching assay, sesamin (4) showed higher inhibitory activity (1 mg ml(-1), 95%) than glabranin (1) (1 mg ml(-1), 74%), whilst umbelliferone (2) and scopoletin (3) were slightly pro-oxidant.
authors.affiliation: Chemistry Department, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Nur Kartinee
authors.initials: NK
authors.lastname: Kassim
authors.forename: Mawardi
authors.initials: M
authors.lastname: Rahmani
authors.forename: Amin
authors.initials: A
authors.lastname: Ismail
authors.forename: Mohd Aspollah
authors.initials: MA
authors.lastname: Sukari
authors.forename: Gwendoline Cheng Lian
authors.initials: GC
authors.lastname: Ee
authors.forename: Nadiah Md
authors.initials: NM
authors.lastname: Nasir
authors.forename: Khalijah
authors.initials: K
authors.lastname: Awang
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D002855:Chromatography, Thin Layer; D003374:Coumarins / Q000737:chemistry* / Q000302:isolation & purification; D017705:Lignans / Q000737:chemistry* / Q000302:isolation & purification; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D027821:Rutaceae / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D003374:Coumarins; D017705:Lignans; D010936:Plant Extracts