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Start Over Author "Kirby, G. C." Journal planta medica
5 results on '"Kirby, G. C."'

3. Oxoaporphine alkaloids and quinones from Stephania dinklagei and evaluation of their antiprotozoal activities.

Author

Camacho MR, Kirby GC, Warhurst DC, Croft SL, and Phillipson JD

Subjects
Alkaloids chemistry, Alkaloids pharmacology, Animals, Antiprotozoal Agents chemistry, Antiprotozoal Agents pharmacology, Aporphines chemistry, Aporphines pharmacology, Humans, KB Cells, Leishmania donovani drug effects, Magnetic Resonance Spectroscopy, Plasmodium falciparum drug effects, Quinones chemistry, Quinones pharmacology, Trypanosoma brucei brucei drug effects, Alkaloids isolation & purification, Antiprotozoal Agents isolation & purification, Aporphines isolation & purification, Plants, Medicinal chemistry, Quinones isolation & purification
Abstract

Bioactivity-guided fractionation of Stephania dinklagei yielded six compounds including, two zwitterionic oxoaporphine alkaloids, N-methylliriodendronine, and 2-O,N-dimethylliriodendronine, two oxoaporphine alkaloids, liriodenine, and dicentrinone, one aporphine alkaloid, corydine, and one anthraquinone, aloe-emodin. Apart from corydine, the isolates have not been reported as constituents of S. dinklagei. N-Methylliriodendronine, and 2-O,N-dimethylliriodendronine are reported for the first time as natural products. All isolated compound were tested for antiprotozoal activity and cytotoxic activities in vitro. N-Methylliriodendronine was the most active against L. donovani amastigotes (IC50 = 36.1 microM). Liriodenine showed the highest activity against Leishmania donovani, and Plasmodium falciparum with IC50 values of 26.16 and 15 microM, respectively. Aloe-emodin was the only compound active (IC50 = 14 microM) against T. b. brucei.

Published
2000
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4. Bioactive compounds from Celaenodendron mexicanum.

Author

Camacho MR, Mata R, Castaneda P, Kirby GC, Warhurst DC, Croft SL, and Phillipson JD

Subjects
Animals, Antiprotozoal Agents chemistry, Antiprotozoal Agents pharmacology, Flavonoids chemistry, Flavonoids pharmacology, Inhibitory Concentration 50, Leishmania donovani drug effects, Magnetic Resonance Spectroscopy, Plant Extracts chemistry, Plant Leaves chemistry, Plasmodium falciparum drug effects, Triterpenes chemistry, Triterpenes pharmacology, Trypanosoma brucei brucei drug effects, Antiprotozoal Agents isolation & purification, Euphorbiaceae chemistry, Flavonoids isolation & purification, Triterpenes isolation & purification
Abstract

Bioactivity-directed fractionation of the CHCl3-MeOH extract of the leaves of Celaenodendron mexicanum by means of the brine shrimp lethality test and chromatographic techniques led to the isolation of three carboxylic acid triterpenes, the new tirucalla-type triterpene, 3 alpha-hydroxytirucalla-7,24Z-dien-26-oic acid, 3-oxotirucalla-7,24Z-dien-26-oic acid, and epi-oleanolic acid, and three biflavonoids amentoflavone, podocarpusflavone A, and podocarpusflavone B. Four non-active compounds friedelin, maytensifolin B, 3 beta-hydroxyfriedelan-16-one, and celaenodendrolide were also obtained. epi-Oleanolic acid was the most active against brine shrimps with LC50 value of 23.3 microM. In addition, all isolates were tested for in vitro antiprotozoal and cytotoxic activities. 3-Oxotirucalla-7,24Z-dien-26-oic acid and epi-oleanolic acid showed the highest activity against Leishmania donovani promastigotes with IC50 values of 13.7 and 18.8 microM, respectively. Only 3-oxotirucalla-7,24Z-dien-26-oic acid showed activity against Trypanosoma brucei brucei bloodstream forms with IC50 value of 16.8 microM.

Published
2000
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5. Bio-active compounds from Psychotria camponutans.

Author

Solis PN, Lang'at C, Gupta MP, Kirby GC, Warhusrst DC, and Phillipson JD

Subjects
Animals, Artemia drug effects, Cell Line, Cell Survival drug effects, Humans, Magnetic Resonance Spectroscopy, Plant Extracts chemistry, Plant Extracts isolation & purification, Plasmodium falciparum drug effects, Spectrophotometry, Ultraviolet, Plant Extracts pharmacology
Abstract

A new benzoquinone (1-hydroxybenzoisochromanquinone) and benz [g]isoquinoline-5, 10-dione have been isolated from the woody parts of Psychotria camponutans, as a result of bioactivity-guided fractionation. The compounds were characterized by UV, IR, EI-mass, 1H-, and 13C-NMR, and HETCOR NMR spectroscopy. Both compounds, together with acetylbenzoisochromanquinone, showed in vitro strong activity against brine shrimp, KB cells, and chloroquine-resistant P. falciparum.

Published
1995
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