Extractability of Rutin in Herbal Tea Preparations of Moringa stenopetala Leaves

The study examined the comparative rutin contents and antioxidant potentials of the two closely related Moringa species: the Ethiopian (Moringa stenopetala) and Indian Moringa (M. oleifera). It is demonstrated that M. stenopetala leaves extract was a far superior (more than five-fold better) antioxidant than M. oleifera. Rutin was the principal constituent of M. stenopetala leaves while the compound was not detected in the leaves of M. oleifera. Quantitative HPLC-based analysis of M. stenopetala leaves revealed the rutin level at a respectable 2.34% ± 0.02% (on dry weight basis), which is equivalent to many commercial natural sources of this highly sought-after bioactive compound. Comparative analysis of rutin in some common herbal tea preparations of M. stenopetala leaves revealed that it is readily extractible with the highest amount obtained (98.8% ± 2.4%) when the leaves (1 g) were boiled in water (200 mL). For a large-scale exploitation of rutin, a fast and economically-viable isolation approach using solid phase extraction followed by crystallization or flash chromatography is outlined. Overall, the Ethiopian Moringa is distinctively different from the Indian Moringa and could be exploited as an industrial source of rutin for nutritional and/or medical uses.