Unlocking chemical markers for the standardization of antimalarial medicinal plants and products: Application of the herbal marker ranking system (Herb MaRS)

Abstract

Herbal products lack standardization due to complex and variable phytochemical constituents. An approach to solving this the use of chemical markers to control quality and effectiveness. This study aimed at developing phytochemical standards for antimalaria herbal products documented in the Recommended Essential Herbal Medicines List of Ghana using the herbal marker ranking system (Herb MaRS). The products were reviewed, the frequently used raw materials were selected, and their evidence of safety and efficacy documented. Selecting bioactive compounds from the plants as potential markers were based on the Herb MaRS criteria. Compounds with of antimalarial activity scored 2 or 0 (not active); evidence of managing a symptom (1 or 0); concentration of the compound in the plant, <5µg/g, scored 1 point (too low), 2 points (5–50µg/g), or 3 points (>50 µg/g). Reference standards available (score 1), analytical method available (1 point). A toxic compound scored all 8 points. Compounds that scored 8 were considered as most suitable markers with those scoring 4 as appreciably suitable. All those scoring less than 3 were not considered. The selected markers include cryptolepine (in Cryptolepis sanguinolenta), echitamine, β-amyrin, boonein, loganin, and lupeol (in Alstonia boonei), azadirachtin, nimbolide, nimbin, and salanin (in Azadirachta indica), lucidin, alizarin, damnacanthal, Rubiadin and purpuroxanthin (in Morinda lucida), quercetin, caffeic acid, and quinovic acid (in Nauclea latifolia). The selected markers are the ideal compounds for the standardisation of antimalaria herbal products containing these plant materials. Herb MaRS criteria could be used to select chemical markers for herbal material quality control.