Planta Med 2013; 79(06): 492-498
DOI: 10.1055/s-0032-1328298
Natural Product Chemistry
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Antiprotozoal Isoflavan Quinones from Abrus precatorius ssp. africanus

Yoshie Hata
1   Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
4   Departament of Pharmacy, Faculty of Sciences, National University of Colombia, Bogota D. C., Colombia
,
Melanie Raith
1   Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
,
Samad Nejad Ebrahimi
1   Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
5   Department of Phytochemistry, Medicinal Plant and Drugs Research Institute, Shahid Beheshti University, G. C., Tehran, Iran
,
Stefanie Zimmermann
1   Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
2   Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland
,
Tsholofelo Mokoka
3   Biosciences, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa
,
Dashnie Naidoo
3   Biosciences, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa
,
Gerda Fouche
3   Biosciences, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa
,
Vinesh Maharaj
3   Biosciences, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa
,
Marcel Kaiser
2   Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland
,
Reto Brun
2   Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland
,
Matthias Hamburger
1   Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
› Author Affiliations
Further Information

Publication History

received 18 July 2012
revised 09 January 2013

accepted 07 February 2013

Publication Date:
19 March 2013 (online)

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Abstract

A library of 206 extracts from selected South African plants was screened in vitro against a panel of protozoan parasites, Plasmodium falciparum, Trypanosoma brucei rhodesiense, and Leishmania donovani. A CH2Cl2/MeOH (1 : 1) extract of Abrus precatorius L. ssp. africanus strongly inhibited P. falciparum (98 %), T. b. rhodesiense (100 %), and L. donovani (76 %) when tested at a concentration of 10.0 µg/mL. The active constituents were tracked by HPLC-based activity profiling and isolated by preparative and semipreparative RP-HPLC chromatography. Structures were established by HR-ESIMS, and 1D and 2D NMR (1H, 13C, COSY, HMBC, HSQC, and NOE difference spectroscopy). Five compounds were obtained and identified as two isoflavan hydroquinones, abruquinone H (1) and abruquinone G (2), and three isoflavan quinones, abruquinone I (3), abruquinone B (4), and 7,8,3′‚5′-tetramethoxyisoflavan-1′,4′-quinone (5). Compounds 1 and 3 were new natural products. The absolute configuration of compounds was determined by comparison of electronic circular dichroism spectra with calculated ECD data. Compounds 3 and 4 showed strong activity against T. b. rhodesiense (IC50 values of 0.30 and 0.16 µM, respectively) and good selectivity (selectivity indices of 73.7 and 50.5, respectively).

Supporting Information