Microbial Transformation of Hesperetin

W Herath; IA Khan

doi:10.1055/s-0031-1273556

Planta Medica, Table of Contents

Microbial Transformation of Hesperetin

W Herath ¹, IA Khan ¹^,²^,³

¹National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS 38677, USA
²Department of Pharmacognosy, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, University, MS 38677, USA
³Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia

Abstract

The Flavonoid, hesperetin is the aglycone of hesperidin found in sweet oranges [1]. It plays a significant role in inflammation and cancer inhibition [2]. The Nuclear Factor-kappa B (NF-κB) found in the cytoplasm promotes inflammation-associated cancer [2]. Since NF-κB can be inhibited by antioxidants, flavanoids with such properties hold promise for cancer prevention. One such compound is hesperetin. However, before choosing NF-κB as the target to prevent cancer it is vital to learn the bioavailability and selectivity of hesperetin and its metabolites [3]. Since, microorganisms can be used as predictive models for mammalian drug metabolism we investigated retrospectively the microbial transformation of Hesperetin (1) to obtain metabolites which may help to predict its fate in mammalian systems. In the present investigation, metabolites, 2-5 (Figure 1) of hesperetin were obtained with Mucor ramannianus. Isolation of 4 and 5 in this study showed that sulfation and glycosylation were the major pathways of metabolism of hesperetin by fungi as observed in several in vivo and in vitro investigations [1]. It indicated the ability of microbes to mimic mammalian metabolism. Formation of 5 was significant as homoeriodictyol conjugates had been detected in rat plasma [4], showing the possible conversion of hesperetin to eriodictyol (3) and to homoeriodictyol. Eriodictyol and 8-hydroxyhesperetin (2) detected in this study have strong antioxidant properties [5]. Isolation of 2 and 3 with higher antioxidant capacity than hesperetin (1) may be of help to evaluate the activity of 1 in terms of these metabolites hitherto not detected in vivo experiments.

Fig.1: Microbial Metabolites of Hesperitin

Acknowledgements: This research is supported in part by the United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No.58–6408–2-0009.

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