ABSTRACT
New bioactive epimeric derivatives of oleuropein have been detected in olive fruits and structurally characterized by (1)H and (13)C NMR. These hydrolytic metabolites, obtained by enzymatic catalysis, can be molecular microcomponents, present in Mediterranean food, table olives, and olive oil, responsible for complex sensorial attributes and for pathogen natural defense.
Subject(s)
Pyrans/chemistry , Pyrans/metabolism , Vegetables/chemistry , Anti-Infective Agents , Iridoid Glucosides , Iridoids , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Conformation , Molecular Structure , Olive Oil , Plant Oils/chemistry , Pyrans/isolation & purificationABSTRACT
The oleuropein hydrolytic conversion, under biomimetic conditions, induced by the endogenous enzymatic system of the olive fruit, has been monitored by the intermediate derivative formation through (1)H and (13)C NMR spectra; the assigned molecular structures reveal the identity of new bioactive biophenolic metabolites, the hemiacetal aglycon, and the two epimeric dialdehydes, which influence the pathogen antagonism of olive fruits and the hedonistic-sensorial characteristics of olive oil.
Subject(s)
Pyrans/chemistry , Pyrans/metabolism , Carbon Isotopes , Hydrogen , Hydrolysis , Iridoid Glucosides , Iridoids , Magnetic Resonance Spectroscopy/methods , Molecular Structure , Phenols/chemistry , Vegetables/enzymologyABSTRACT
Three types of open ansa-chain rifamycin S derivatives have been prepared: derivatives with the ansa-chain open at C(29) and the original dihydrofuranone ring; derivatives with the ansa-chain open at C(29) and a furane ring; derivatives with the ansa-chain at open NH-C(15). Only derivatives of the first type are weak inhibitors of HIV-1 reverse transcriptase (IC50 ca.300 microM) while derivatives of the two other types are inactive. It has been hypothesized that the active derivatives inhibit the viral enzyme interacting through the groups C(14)H3, C(13)H3, and C(1)O at the same site as the well-known inhibitors TIBO and Nevirapine. In particular C(13)H3 must be unhindered and in an appropriate position out of the plane containing the chromophore-rings. The open ansa-chain seems to play the role of a lipophylic substituent.
Subject(s)
Antiviral Agents/chemistry , HIV-1/enzymology , RNA-Directed DNA Polymerase/drug effects , Reverse Transcriptase Inhibitors/chemistry , Rifamycins/chemistry , Rifamycins/pharmacology , Antiviral Agents/pharmacology , HIV Reverse Transcriptase , HIV-1/drug effects , Magnetic Resonance Spectroscopy , Reverse Transcriptase Inhibitors/pharmacology , Structure-Activity RelationshipABSTRACT
29 Rifamycins were tested for inhibition of Reverse Transcriptase (RT) as potential anti HIV drugs. Two purified commercial enzymes from M-MuLV and RAV-2 were used. Anti-RT activity was also measured on a crude lysate of HIV-1. The results show that some derivatives have interesting levels of activity on isolated M-MuLV and RAV-2 RTs, while they are less active on the RT in the crude HIV-1 lysate. The active derivatives include oximes and hydrazones, alkylaminoderivatives, open ansa-chain derivatives and derivatives carrying a modified nucleoside.
