title: Phytochemical investigation of Cycas circinalis and Cycas revoluta leaflets: moderately active antibacterial biflavonoids.
abstract: Chemical examination of the methanolic extract of the leaflets of CYCAS CIRCINALIS L. led to the isolation of one new biflavonoid, (2 S, 2'' S)-2,3,2'',3''-tetrahydro-4',4'''-di- O-methylamentoflavone (tetrahydroisoginkgetin; 2), and 15 known compounds, 11 of which are reported for the first time from C. CIRCINALIS. Chromatographic separation of the chloroform extract of C. REVOLUTA Thunb. leaflets afforded 12 compounds, seven of which are reported for the first time from this species. The isolated compounds from both species include 14 biflavonoids, three lignans, three flavan-3-ols, two flavone- C-glucosides, two NOR-isoprenoids, and one flavanone. This is the first report of NMR and CD data of 2,3,2'',3''-tetrahydro-4'- O-methyl- and 2,3-dihydro-4'- O-methyl-amentoflavone ( 6) and ( 7). The effect of O-methylation on the chemical shifts of the neighboring carbons in the (13)C NMR spectra of the dihydro- and tetrahydro-amentoflavone skeletons provides a tool to identify the location of the methoxy groups. Compounds 2, 6, and 18 displayed moderate antibacterial activity against STAPHYLOCOCCUS AUREUS (IC (50) values of 3.9, 9.7, and 8.2 microM, respectively) and methicillin-resistant S. AUREUS (MRSA; IC (50) values of 5.9, 12.5, and 11.5 microM, respectively).
authors.affiliation: Department of Pharmacognosy and Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS, USA.
authors.forename: Abeer
authors.initials: A
authors.lastname: Moawad
authors.forename: Mona
authors.initials: M
authors.lastname: Hetta
authors.forename: Jordan K
authors.initials: JK
authors.lastname: Zjawiony
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Jacob
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hifnawy
authors.forename: Jannie P J
authors.initials: JP
authors.lastname: Marais
authors.forename: Daneel
authors.initials: D
authors.lastname: Ferreira
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D044946:Biflavonoids / Q000737:chemistry / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D029784:Cycas / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D018515:Plant Leaves / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000900:Anti-Bacterial Agents; D044946:Biflavonoids