Antifungal potential of extracts, fractions and compounds from Uvaria comperei (Annonaceae) and Oxyanthus unilocularis (Rubiaceae)

Abstract

Phytochemical study of Uvaria comperei afforded an alkaloid, 8,9-dimethoxy-5H-phenanthridin-6-one (1), isolated and characterised (assignment of ¹H and ¹³C NMR) for the first time from a natural source along with two flavonoids, (2S)-5-hydroxy-7,8-dimethoxyflavanone (2) and (2S)-7-hydroxy-5-methoxy-6,8-dimethylflavone (3). Clethric acid (4), oleanoic acid (5), β-sitosterol 3-O-β-D-glucopyranoside (9), β-sitosterol palmitate (6) and a mixture of stigmasterol (7) and β-sitosterol (8) were isolated from Oxyanthus unilocularis. The structures of these compounds were elucidated using modern spectroscopic techniques including1D and 2D Nuclear Magnetic Resonance (NMR) Spectroscopy (¹H, ¹³C, ¹H-¹H COSY, HSQC, HMBC) and Mass Spectrometry. Some fractions and compounds from Uvaria comperei exhibited good antifungal activity against clinical isolates and standard strains of yeast species of Candida and Cryptococcus genera while extracts from Oxyanthus unilocularis displayed weak antifungal activity. The results obtained show that Uvaria comperei could be a potential source of antifungal drugs.

Graphical Abstract

Keywords:

• Uvaria comperei
• Oxyanthus unilocularis
• -dimethoxy-5H-phenanthridin-6-one
• antifungal activity

Acknowledgements

The authors are grateful to the Commission Universitaire pour le Développement (CUD) for providing a grant to Kayo Taboula Maurice to work at the Free University of Brussels, Belgium and University of Mons, Belgium in 2009, 2010 and 2011. We also thank Prof Pierre DUEZ and the Laboratory of Pharmacognosy, Bromatology and Human Nutrition of the Faculty of Pharmacy of the Free University of Brussels for hosting Kayo Taboula Maurice during his internships in Belgium.

Disclosure statement

No potential conflict of interest was reported by the authors.