Application of the Herbal chemical Marker Ranking System (Herb MaRS) to standardization of herbal pharmaceutical raw materials-a case study

Introduction Phytochemical standardization of herbal materials involves establishing consistent levels of one or more active ingredients or markers. It ensures the authenticity and quality ofherbal materials, extracts, and medicinal products. We successfully applied the Herbal chemical Markers ranking system (Herb MaRS) originally proposed for quality assurance of complex herbal products, to establish markers for controlling the quality of herbal raw materials. We used the most commercially consumed plant materials in Uganda, as a case study. Methods The assessment of compounds for suitability as markers were based on the Herb MaRS, with minor modifications as follows: For more objective scoring, evidence of biological activity of the potential marker compound (s) was determined at three levels based on the number of symptoms of the disease condition a compound can treat or alleviate; (i) one symptom (1 point), two symptoms (2 points), 3 and more symptoms (3 points). We also scored the reported concentrations of the compounds (concentration not determined (0 points), concentration ≥5ppm (1 point), (concentration ≥50ppm, 2 points) and availability of analytical standards (1 point); lastly, we scored the compounds for the availability of an analytical method (1 point). Compounds scored from 0 to 8; where 8 indicated the most suitable chemical marker. Results The selected markers were as follows: Eucalyptus globulus (aromadendrine, α-terpineol, globulol, and 1-8, cineol); Aloe barbadensis (aloin, aloe emodin, acemannan) , Albizia coriaria (lupeol, lupenone, betulinic acid, betulin, and catechin); Mangifera indica (mangiferin, catechin, quercetin, and gallic acid); Warburgia ugandensis (polygodial); Azadirachta indica (azadirachtin, nimbin, nimbidin) ; and Zingiber officinalis (6, 8, 10-gingerols, and 6-shogaol). Conclusions Herb MaRScan be efficiently applied to select marker compounds for quality control of herbal materials. The markers identified should be incorporated into chromatographic fingerprints as well as quantitative methods and evaluated for applicability at the various stages of the production chain of herbal medicines. There is a need to build local capacity to isolate marker compounds, particularly those that are not sold by current vendors.