Macroscopic and microscopic features of diagnostic value for Warburgia ugandensis Sprague leaf and stem-bark herbal materials

Abstract

Warbugia ugandensis is among the ten most utilized medicinal plants in East Africa. Stem-bark and leaves are used as remedies for malaria, stomachache, coughs and several skin diseases. Consequently, the plant is endangered because of uncontrolled harvest from the wild and lack of domestication. There is therefore fear of poor quality commercialized products due to lack of quality control mechanisms. The objective of this study was to investigate features of diagnostic value that could be used to confirm its authenticity and purity. Samples in the study were obtained from six different geographical locations in Kenya by random purposive sampling. Macroscopic and microscopic studies of the leaf and stem-bark were done based on a modified method from the American herbal pharmacopoeia. The study revealed over five macroscopic and organoleptic characteristics for W. ugandensis leaf and stem-bark including strong aromatic odor and bitter peppery taste. Major microscopic characteristics of the leaf included anomocytic stoma, oil glands and trichomes. Microscopy of stem-bark revealed scaly outgrowths and parenchyma cells in addition to clusters of simple starch granules. Macroscopic and microscopic features of diagnostic value identified can be used to evaluate the quality of W. ugandensis herbal materials especially for confirmation of purity and authenticity.