title: Phosphodiesterase and thymidine phosphorylase-inhibiting salirepin derivatives from Symplocos racemosa.
abstract: A re-investigation of the chemical constituents of the stem bark of Symplocos racemosa Roxb. led to the isolation of four new glycosides, symplocomoside (1), symponoside (2), symplososide (3) and symploveroside (4). Benzoylsalireposide (5) and salireposide (6) were re-isolated from this plant. The structures of the new compounds were determined by 1D and 2D-homonuclear and heteronuclear NMR spectroscopy, chemical evidence, and by comparison with the published data of the closely related compounds. The glycosides 1-4 displayed in vitro inhibitory activity against phosphodiesterase I with IC50 values of 122 +/- 0.017, 698 +/- 0.06, 722 +/- 0.03, 909 +/- 0.09 microM, respectively. The compounds 1-6 also showed in vitro inhibitory activity against thymidine phosphorylase with IC50 values of 189.96 +/- 1.02, 195.56 +/- 2.36, 207.61 +/- 1.06, 488.89 +/- 4.10, 427.20 +/- 5.36, 354.2 +/- 5.69 microM, respectively while 1 was also found to be a urease inhibitor with an IC50 value of 54.13 +/- 0.71 microM.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi, Pakistan.
authors.forename: Muhammad Athar
authors.initials: MA
authors.lastname: Abbasi
authors.forename: Viqar Uddin
authors.initials: VU
authors.lastname: Ahmad
authors.forename: Muhammad
authors.initials: M
authors.lastname: Zubair
authors.forename: Naheed
authors.initials: N
authors.lastname: Fatima
authors.forename: Umar
authors.initials: U
authors.lastname: Farooq
authors.forename: Sajjad
authors.initials: S
authors.lastname: Hussain
authors.forename: Muhammad Arif
authors.initials: MA
authors.lastname: Lodhi
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D029791:Ericaceae; D006027:Glycosides / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D043264:Phosphodiesterase I / Q000037:antagonists & inhibitors; D008517:Phytotherapy; D024301:Plant Bark; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013939:Thymidine Phosphorylase / Q000037:antagonists & inhibitors; D014510:Urease / Q000037:antagonists & inhibitors
chemical_list: D004791:Enzyme Inhibitors; D006027:Glycosides; D010936:Plant Extracts; D013939:Thymidine Phosphorylase; D043264:Phosphodiesterase I; D014510:Urease