title: Bioassay-guided isolation of Poliovirus-inhibiting constituents from Zephyranthes candida.
abstract: BACKGROUND
  Plants of the Zephyranthes genus are globally used in folk medicine. In a previous study, Zephyranthes candida Linn. (Amaryllidaceae) was identified as having antiviral properties; this led to anti-poliovirus assay-guided isolation of compounds from crude methanol extract of the plant.
  
  
  OBJECTIVE
  Isolation of anti-poliovirus constituents from Z. candida.
  
  
  METHODS
  Active chloroform fraction from crude methanol extract of Z. candida (whole plant) was subjected to bioassay-guided fractionation; repeated column and preparative thin layer chromatography led to isolation of active compounds. Chemical structures were identified using spectroscopic techniques. Using serial two-fold dilution of maximum non-toxic concentration (MNTC) of each compound (0.0625-1 µg/mL for lycorine and 0.625-10 µg/mL for trisphaeridine and 7-hydroxy-3',4'-methylenedioxyflavan), the ability of extracts to inhibit viral-induced cell death in tissue culture was evaluated 72 h post-infection by the colorimetric method using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) dye. Regression analysis was used to determine 50% inhibitory concentration (IC50) and 50% cytotoxicity concentration (CC50), from which selective index (SI) was calculated.
  
  
  RESULTS
  From the chloroform fraction, three compounds were isolated and identified, namely lycorine (1), trisphaeridine (2), and 7-hydroxy-3',4'-methylenedioxyflavan (3) as the anti-polioviral components. Lycorine was the most active, with an IC50 value of 0.058 µg/mL followed by trisphaeridine (2) with an IC50 of 0.1427 µg/mL, and 7-hydroxy-3',4'-methylenedioxyflavan (3) with an IC50 of 0.2384 µg/mL.
  
  
  CONCLUSIONS
  The antipoliovirus activity of trisphaeridine (2) and 7-hydroxy-3',4'-methylenedioxyflavan (3) is established in this report; these compounds are of moderate toxicity and have very good SI. They could be a potential template for the development of a new antiviral agent.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy University of Ibadan , Ibadan , Nigeria .
authors.forename: Ogbole Omonike
authors.initials: OO
authors.lastname: Oluyemisi
authors.forename: Ajaiyeoba Edith
authors.initials: AE
authors.lastname: Oriabure
authors.forename: Adeniji J
authors.initials: AJ
authors.lastname: Adekunle
authors.forename: Kamdem Soup T
authors.initials: KS
authors.lastname: Ramsay
authors.forename: Sajan
authors.initials: S
authors.lastname: Shyyaula
authors.forename: Muhammad Iqbal
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D000470:Alkaloids / Q000302:isolation & purification / Q000494:pharmacology; D047151:Amaryllidaceae Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects; D004149:Dioxoles / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D019668:Liliaceae / Q000737:chemistry*; D010617:Phenanthridines / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D017955:Poliovirus / Q000187:drug effects*
chemical_list: D000470:Alkaloids; D047151:Amaryllidaceae Alkaloids; D000998:Antiviral Agents; D004149:Dioxoles; D010617:Phenanthridines; D010936:Plant Extracts; C462033:trispheridine; C015330:lycorine
keywords: 4′-methylenedioxyflavan; 7-hydroxy-3′; Amaryllidaceae; antiviral; trisphaeridine