Browsing by Author "Williams, Roderick"

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    Activity of Compounds from Temperate Propolis against Trypanosoma brucei and Leishmania mexicana
    (MDPI, 2021-06-26) Alotaibi, Adullah; Ebiloma, Godwin U.; Williams, Roderick
    Ethanolic extracts of samples of temperate zone propolis, four from the UK and one from Poland, were tested against three Trypanosoma brucei strains and displayed EC50 values < 20 g/mL. The extracts were fractionated, from which 12 compounds and one two-component mixture were isolated, and characterized by NMR and high-resolution mass spectrometry, as 3-acetoxypinobanksin, tectochrysin, kaempferol, pinocembrin, 40-methoxykaempferol, galangin, chrysin, apigenin, pinostrobin, cinnamic acid, coumaric acid, cinnamyl ester/coumaric acid benzyl ester (mixture), 40,7- dimethoxykaempferol, and naringenin 40,7-dimethyl ether. The isolated compounds were tested against drug-sensitive and drug-resistant strains of T. brucei and Leishmania mexicana, with the highest activities 15 M. The most active compounds against T. brucei were naringenin 40,7 dimethyl ether and 40methoxy kaempferol with activity of 15–20 M against the three T. brucei strains. The most active compounds against L. mexicana were 40,7-dimethoxykaempferol and the coumaric acid ester mixture, with EC50 values of 12.9 3.7 M and 13.1 1.0 M. No loss of activity was found with the diamidine- and arsenical-resistant or phenanthridine-resistant T. brucei strains, or the miltefosineresistant L. mexicana strain; no clear structure activity relationship was observed for the isolated compounds. Temperate propolis yields multiple compounds with anti-kinetoplastid activity.