Harpagoside is a bioactive compound found in the plant Harpagophytum procumbens, commonly known as Devil's Claw. This plant has a long history of traditional use in southern Africa for various inflammatory conditions, including joint pain and musculoskeletal disorders. Scientifically, harpagoside has been studied for its anti-inflammatory and analgesic effects, primarily in the context of osteoarthritis, back pain, and rheumatic disorders.

There is some scientific evidence suggesting that harpagoside may help reduce inflammation and pain through inhibition of cyclooxygenase-2 (COX-2) and other inflammatory mediators. A few randomized controlled trials and meta-analyses have reported that Devil's Claw extracts standardized to harpagoside content can modestly reduce pain and improve function in patients with musculoskeletal disorders. However, specific studies on bursitis are sparse or lacking. The rationale for its use in bursitis is generally extrapolated from its effects in related conditions involving joint inflammation and soft tissue pain.

Overall, while there is limited direct evidence supporting harpagoside for bursitis specifically, its anti-inflammatory actions and demonstrated efficacy in similar conditions provide a moderate scientific basis (rated 2/5) for its use. More targeted clinical trials are needed to establish its effectiveness for bursitis.