In vitro gastrointestinal biotransformation of a Devilʼs claw (Harpagophytum procumbens) extract

Roots of the Devilʼs claw (Harpagophytum procumbens D. C., Pedaliaceae) have traditionally been used to treat arthritis and rheumatic diseases and their anti-inflammatory activity was attributed to the presence of iridoid glycosides, of which harpagoside (Fig. 1) is the main representative [1]. However, while hydrolysis of the glycosidic bonds of the iridoid glycosides is required for displaying anti-inflammatory activity [2], the final active compounds are unknown.

Therefore, we aimed to determine the metabolic fate of a Devilʼs claw extract by means of an in vitro gastrointestinal model (GIM) [3]. 300 mg of H. procumbens extract was submitted to this model, which is comprised of a stomach, small intestine and colon phase. Samples were collected at different time points and experiments were performed in triplo. All samples were analyzed by UPLC-HRMS. An automated data analysis workflow allowed monitoring of the relative abundances of individual compounds over time.

The iridoid glycosides harpagoside and harpagide were identified in the 80% methanolic extract and were still present after passage through the GIM. However, a clear reduction of the tentatively identified iridoids pagoside and pagide could be observed after 48 h of colon fermentation. Also, various other iridoids were tentatively identified in the crude extract, as well as after the GIM experiment, including 8-O-(p-coumaroyl)-harpagide, procumbide and 6′-O-(p-coumaroyl)-procumbide. Levels of these compounds seem to reduce in particular during the small intestine and colon phases. Further data-processing is ongoing in order to derive more detailed information on the gastrointestinal biotransformation of the Devilʼs claw constituents.

Publication History

Article published online:
12 December 2022

• References

• 1 Tomassini L, Serafini M, Foddai S. et al. A new iridoid diglucoside from Harpagophytum procumbens. Nat Prod Res 2015; 30 (02) 157-161
• 2 Zhang L, Feng L, Jia Q. et al. Effects of β-glucosidase hydrolyzed products of harpagide and harpagoside on cyclooxygenase-2 (COX-2) in vitro. Biorgan Med Chem 2011; 19 (16) 4882-4886
• 3 Peeters L, Beirnaert C, Van der Auwera A. et al. Revelation of the metabolic pathway of hederacoside C using an innovative data analysis strategy for dynamic multiclass biotransformation experiments. J Chromatogr A 2019; 1595: 240-247