title: Interconverting flavanone glucosides and other phenolic compounds in Lippia salviaefolia Cham. ethanol extracts.
abstract: Four interconverting flavanone glycosides [(2R)- and (2S)-3',4',5,6-tetrahydroxyflavanone 7-O-β-D-glucopyranoside, and (2R)- and (2S)-3',4',5,8-tetrahydroxyflavanone 7-O-β-D-glucopyranoside], in addition to eight known flavonoids [naringenin, asebogenin, sakuranetin, 6-hydroxyluteolin 7-O-β-D-glucoside, (2R)- and (2S)-eriodictyol 7-O-β-D-glucopyranoside, aromadendrin and phloretin], three phenylpropanoid glycosides [forsythoside B, alyssonoside and verbascoside] and the epoxylignan lariciresinol 4'-O-β-D-glucopyranoside were isolated and identified in the EtOH extract of the aerial parts of Lippia salviaefolia Cham. The phytochemical study herein was guided by preliminary antioxidant tests, namely, β-carotene protection and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity. The crude extracts, their active fractions and the isolated compounds were assayed against intracellular reactive oxygen species (ROS) and human embryonic kidney HEK-293 and human melanoma M14 cancer cell growth. Aromadendrin and phloretin were able to counteract elevation of ROS induced by the oxidant t-butylhydroperoxide (t-BOOH) in HEK-293 cells, whereas phloretin strongly protected HEK-293 cells from ROS damage at 1 μM. Additionally, phloretin exhibited a significant growth inhibitory effect at 20-40 μM in both HEK-293 and M14 cells and induced a concentration dependent apoptosis at 20 μM in M14 cells, suggesting a selective action towards malignant cells. Due to their equilibria, the four interconverting flavanone glycosides were studied using 1D and 2D NMR, HPLC-CD-PDA and HRMS analyses.
authors.affiliation: Institute of Chemistry, São Paulo State University, CP 355, CEP 14801-970 Araraquara, SP, Brazil.
authors.forename: Cristiano Soleo
authors.initials: CS
authors.lastname: Funari
authors.forename: Thais Gaban
authors.initials: TG
authors.lastname: Passalacqua
authors.forename: Daniel
authors.initials: D
authors.lastname: Rinaldo
authors.forename: Assunta
authors.initials: A
authors.lastname: Napolitano
authors.forename: Michela
authors.initials: M
authors.lastname: Festa
authors.forename: Anna
authors.initials: A
authors.lastname: Capasso
authors.forename: Sonia
authors.initials: S
authors.lastname: Piacente
authors.forename: Cosimo
authors.initials: C
authors.lastname: Pizza
authors.forename: Maria Claudia Marx
authors.initials: MC
authors.lastname: Young
authors.forename: Giselda
authors.initials: G
authors.lastname: Durigan
authors.forename: Dulce Helena Siqueira
authors.initials: DH
authors.lastname: Silva
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D005591:Chemical Fractionation; D044950:Flavanones / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D032411:Lippia / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000737:chemistry
chemical_list: D044950:Flavanones; D016166:Free Radical Scavengers; D006027:Glycosides; D010936:Plant Extracts; D017382:Reactive Oxygen Species