Quality control of herbal medicines used for arthritis: Identification and Quantification of COX Inhibitors by HPLC, GC-MS, LC-MS-MS, GC-FID

Abstract

The aim of the study was to challenge the common techniques utilized in the quality control of herbal products for the authentication of the two selected polyherbal products. Two polyherbal formulations, Voltarit® and Rheumax® commonly trade in the market to treat arthritis and related disorders, had been investigated regarding their quality control through selecting representative marker components from each drug. Different chromatographic procedures had been applied of which, a new validated HPLC method was developed for the simultaneous quantification of three active components (curcumin, demethoxycurcumin, bisdemethoxycurcumin, quercetin, and myristicin). Additionally, GC-FID was used for the relative quantification of fatty acids known for their anti-inflammatory activity in the hexane extract of the selected products. LC-MS-MS and GC-MS techniques were applied to tentatively identify some naturally occurring COX-2 inhibitors in methanol extract and fatty acid of the selected products, respectively. One of the products was adulterated by curcumin and surprisingly had no limonene or myristicin even it had celery seed as the pharmaceutical company said. The validation showed good linearity (R is between 0.9990 and 0.9998), sensitivity (LODs 0.1-0.4 μg), precision (RSD < 2%), and accuracy (99.82-101.4%) of the method. The developed HPLC method was proved to be a useful tool in the quality control of complex matrices of the selected polyherbal formulations. Many active components with anti-inflammatory effects were identified in the fixed oils, methanol, and hexane extracts of the HMs, so patients could take these herbal products with confidence about good quality and no chemical adulteration.