A 90-day placebo-controlled trial of a boswellia extract in people with knee osteoarthritis

What they did

Seventy-five people with knee osteoarthritis were randomly assigned to 100 mg a day of the extract (25 people), 250 mg a day (25) or placebo (25) for 90 days, with neither patients nor researchers knowing who had what. Pain and function were scored with standard tools (visual analogue scale, Lequesne's Functional Index and WOMAC) at the start and at days 7, 30, 60 and 90. The team measured MMP-3, a cartilage-degrading enzyme, in joint fluid, and ran blood, urine and haematology tests for safety.

What they found

Seventy people completed the study. Both doses produced clinically and statistically significant improvements in pain and physical function scores. In the 250 mg group, significant improvements showed as early as day 7. MMP-3 in joint fluid fell significantly. Safety measures were almost unchanged compared with placebo.

What it can't tell us

This trial tested one branded extract at two doses for 90 days, with 25 people per group. It measured MMP-3, a sister enzyme, not MMP13, and it scored pain and function rather than cartilage structure. Its results belong to this extract at these doses, not to boswellia in general or to anything containing a different amount or type of extract.

Why it matters

Most research on plant compounds and MMPs is in cells or animals. This is one of the placebo-controlled trials in people that measured a matrix metalloproteinase directly, here in joint fluid. It shows a boswellia extract has been studied in humans and not only in the lab, with MMP-3 as the enzyme measured.

The paper

1. Sengupta K, Alluri KV, Satish AR et al. A double blind, randomized, placebo controlled study of the efficacy and safety of 5-Loxin for treatment of osteoarthritis of the knee. Arthritis Res Ther 2008.
   PMID 18667054DOI 10.1186/ar2461

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