title: Doubly linked, A-type proanthocyanidin trimer and other constituents of Ixora coccinea leaves and their antioxidant and antibacterial properties.
abstract: Phytochemical investigation of the ethyl acetate fraction of the methanol extract of the leaves of Ixora coccinea led to the isolation and identification of an A-type trimeric proanthocyanidin epicatechin-(2β→O→7, 4β→8)-epicatechin-(5→O→2β, 6→4β)-epicatechin named ixoratannin A-2 along with seven known compounds, epicatechin, procyanidin A2, cinnamtannin B-1, and four flavon-3-ol rhamnosides viz: kaempferol-7-O-α-L-rhamnnoside, kaempferol-3-O-α-L-rhamnoside, quercetin-3-O-α-L-rhamnopyranoside, and kaempferol-3,7-O-α-L-dirhamnoside. The structures were elucidated by the application of IR, UV, MS, 1D-, and 2D-NMR spectroscopic analyses and by comparison with literature data. Antioxidant evaluation of isolated compounds revealed that ixoratannin A-2 and cinnamtannin B-1 were the most active compounds in DPPH, inhibition of lipid peroxidation and nitric oxide radical scavenging assays. Antibacterial activities were assessed by means of agar-diffusion assays using Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis. All tested compounds inhibited the growth of B. subtilis, while only epicatechin and quercetin-3-O-α-L-rhamnopyranoside inhibited the growth of E. coli.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
authors.forename: Thomas Oyebode
authors.initials: TO
authors.lastname: Idowu
authors.forename: Abiodun Oguntuga
authors.initials: AO
authors.lastname: Ogundaini
authors.forename: Abiola Oladimeji
authors.initials: AO
authors.lastname: Salau
authors.forename: Efere Martins
authors.initials: EM
authors.lastname: Obuotor
authors.forename: Merhatibeb
authors.initials: M
authors.lastname: Bezabih
authors.forename: Berhanu Molla
authors.initials: BM
authors.lastname: Abegaz
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D001713:Biphenyl Compounds / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009549:Nigeria; D009569:Nitric Oxide / Q000096:biosynthesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D010851:Picrates / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D044945:Proanthocyanidins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D019666:Rubiaceae / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006027:Glycosides; D010851:Picrates; D044945:Proanthocyanidins; C555286:ixoratannin A-2; C013221:proanthocyanidin; D009569:Nitric Oxide; C004931:1,1-diphenyl-2-picrylhydrazyl