Quality control, development and validation of HPLC analytical methodology for harpagoside content on dry extracts of Harpagophytum procumbens Burch DC

Abstract

Harpagophytum procumbens is found in Namibia, Botswana and Kalahari. It belongs to the Pedaliaceae family and is known as Devil's Claw. Its roots contain harpagoside and harpagid iridoids, triterpenes and flavonoids and are used as anti-inflammatory and analgesic. The objective was to evaluate the physicochemical and microbiological quality, to develop HPLC and TLC methodology of the dry extract of the plant. Two samples of the dry extract of H. procumbens from different suppliers were used, sample 15-18% (A) and 15% (B) of Harpagoside. Determination of aspect, loss by drying, heavy metals, apparent density, total ash and microbiological analyses were performed according to official compendia. The identification was performed by CCDA with mobile phase composed of ethyl acetate:methanol:water (77:15:8), revealed with sulfuric vanillin. The assay was performed by HPLC. The physicochemical analyses highlighted the appearance of yellowish to brown powder, loss by drying of 2.6-4.17%, apparent density of 0.347-0.635 g/mL and total ash of 1.05-3.79%. Growth within the limits, absence of pathogens and coliforms were observed. The samples under analysis presented violet band with the same retention factor (0.65), referring to harpagoside. The method was specific, precise, accurate (RSD <5%), linear (r=>0.9939) and robust, being suitable for the marker. The assay provided 15.94 ± 0.49 % (A) and 15.27 ± 1.34 % (B). The samples analyzed were in accordance with the specifications of each test performed. It was possible to affirm that the extracts of Harpagophytum procumbens used in the trials and marketed in Brazil presented results that prove their quality, safety and efficacy.