title: Inhibition of Moloney murine leukemia virus reverse transcriptase activity by tetrahydroxyxanthones isolated from the Chinese herb, Tripterospermum lanceolatum (Hyata).
abstract: Five tetrahydroxyxanthones (THXs) isolated from Tripterospermum lanceolatum (Hyata) have been shown to have a strong inhibitory effect on Moloney murine leukemia virus reverse transcriptase (Mo-MLV RT) activity when (rA)n-(dT)15 and (rC)n-(dT)12-18 were used as template-primers. 50% inhibitory concentrations of 1,3,5,6-THX, 2,3,6,7-THX 1,3,6,7-THX, 3,4,5,6-THX, and 3,4,6,7-THX were determined to be 0.15, 0.27, 0.58, 0.12, and 0.12 microM, respectively. Their effects were concentration-dependent, and the mode of inhibition was found to be by competitive inhibition with respect to template-primer. The tetrahydroxyl groups of THXs were shown to be important for their inhibitory activity. Acylation of THXs with various groups resulted in a moderate or strong decrease in their inhibitory activity.
mesh_terms: D000215:Acylation; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D008979:Moloney murine leukemia virus / Q000187:drug effects / Q000201:enzymology*; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D018894:Reverse Transcriptase Inhibitors; D014966:Xanthenes / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D004365:Drugs, Chinese Herbal; D018894:Reverse Transcriptase Inhibitors; D014966:Xanthenes; D012194:RNA-Directed DNA Polymerase; D004256:DNA Polymerase I