Geographical and seasonal phytochemical variation of Artemisia afra Jacq. ex Willd

IntroductionArtemisia afra Jacq. ex. Willd. (Asteraceae) is a popular traditional medicine in South Africa, mainly used in the form of an infusion, for the treatment of respiratory ailments. Quality control methods are limited and phytochemical variation for the infusion is not well known. ObjectiveTo develop a sensitive quality control method for A. afra infusions by validating a liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) method and quantitatively comparing six marker compounds in A. afra samples collected from different locations and over a 12-month period. Material and methodsThere was a multiple reaction monitoring method optimised and validated, according to ICH and FDA guidelines, to quantify the chemical markers present in infusions. ResultsThe chemistry differed significantly and interestingly, with an interchangeable trend between chlorogenic acid (CGA) and 4,5-dicaffeoylquinic acid (DCQA) observed in the samples collected monthly, elevated levels of CGA during winter and elevated levels of DCQA during summer. The remaining four markers showed a steady decrease as winter approached and a steady increase as summer approached. The ranges of the six markers were the following: CGA (0.68-14.68 mu g/mg), DCQA (0.005-8.110 mu g/mg), quercetin (0.01-0.65 mu g/mg), luteolin (0.05-1.30 ng/mg), scopoletin (0.10-1.14 mu g/mg), scopolin (0.03-1.21 mu g/mg). ConclusionsA sensitive LC-ESI-MS/MS method was developed, validated, and used to quantify six marker compounds. The results indicated a large degree of phytochemical variation occurred across all samples tested, which highlights the importance of producing herbal medicine under controlled conditions and the necessity of analytical quality control methods.

Automated summary

This study aimed to develop a sensitive quality control method for Artemisia afra infusions by validating a liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) method and quantitatively comparing six marker compounds in A. afra samples collected from different locations and over a 12-month period.