Table 6.
Ex vivo experiments regarding analgesic/antinociceptive and anti-inflammatory effects of devil’s claw preparations and compounds.
| Study | Year | Reference |
|---|---|---|
| Human whole-blood anticoagulated with heparin; preincubated with Harpagophytum * extract or purified harpagoside; both dose-dependently inhibited cysteinyl-leukotriene and thromboxane B2 release after biotransformation. | 1996, 1997 | Tippler et al. [332,333] |
| Human whole-blood assay (healthy and osteoarthritic) for COX-1 and COX-2 activity and NO production; H. procumbens extract and harpagoside; increased the activity of baseline COX-1 and COX-2 without LPS, crude extract did not alter COX activity; harpagoside inhibited COX-1, COX-2, and NO. | 2007 | Anauate [334] |
| Freshly excised porcine skin; dermal and transcutaneous delivery and effect on COX-2 expression in Western blotting and immunocytochemical assays; Harpagophytum extract in various vehicles, harpagoside, harpagide, 8-coumaroylharpagide, and verbascoside; ratio-dependent inhibition of COX-2 expression, higher penetration of all compounds from ethanol/water. | 2008 | Abdelouahab and Heard [335,336] |
| Freshly excised porcine skin; transcutaneous delivery and effect on COX-2, PGE2, 5-LOX, and inducible NO synthase (iNOS) expression in Western blotting and immunocytochemical assays; commercial Harpagophytum extracts, harpagoside, harpagide, 8-coumaroylharpagide, and verbascoside; ratio-dependent inhibition of COX-2 expression and PGE2, no significant effect on 5-LOX and iNOS, relative proportions of anti- and pro-inflammatory compounds in commercial products varied. | 2009, 2010 | Ouitas and Heard [337,338,339] |
| LPS-stimulated human whole-blood assay (healthy) for COX-1 and COX-2 activity and NO production, incubation of isolated fractions obtained by flash chromatography monitored with HPLC, TLC, and identified by 1HNMR; fractions of H. procumbens extract; highest concentration of harpagoside inhibited COX-1, COX-2, and NO; iridoid pool increased COX-2 while NO and COX-1 activities remained unchanged, fraction containing cinnamic acid reduced NO only. | 2010 | Anaute et al. [340] |
* Species not specified; however, all specific attribution must be cautioned against due to the frequent admixture.