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Plant-derived substances are of great interest due to their versatile applications. Plants are the richest bio-resources of drugs used in traditional medical practice, modern medicine, nutraceuticals, food supplements, folk medicine, flavours, pharmaceutical intermediates and chemical entities for synthetic drugs ( Iwu, 2001; Ncube et al., 2008). Throughout recorded history, herbs and spices have been used for flavouring foods, beverages and for medicinal purposes (Droughon, 2004; Okwu, 1999, 2001). Biologically active compounds present in plants have always been of great interest (Ibrahim et al., 2012; Obasi et al., 2010; Roopashree et al., 2008). The value of these plants lies in the bioactive phytochemical constituents that produce definite physiological action on the human body (Akinmoladun et al., 2007), and thousands of these compounds have been isolated from plants (Cowan, 1999).

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