Boswellic acid

Boswellic acids are a series of pentacyclic triterpene molecules which are produced by plants in the genus Boswellia. Like many other terpenes, boswellic acids appear in the resin of the plant which exudes them; it is estimated that they make up 30% of the resin of B. serrata.

Structure
The boswellic acids are organic acids, consisting of a pentacyclic triterpene, a carboxyl group and at least one other functional group. Alpha-boswellic acid and beta-boswellic acid, C30H48O3 both have an additional hydroxyl group; they differ only in their triterpene structure. Acetyl-alpha-boswellic acid and acetyl-beta-boswellic acid, C 32H50O4, replace the hydroxyl group with an acetyl group.

Other boswellic acids include the keto-boswellic acids and their acetyl counterparts.

Uses
Beta-boswellic acid, keto-beta-boswellic acid and acetyl-keto-beta-boswellic acid have been implicated in apoptosis of cancer cells, particularly brain tumors and cells affected by leukemia or colon cancer.

Acetyl-boswellic acids also exhibit anti-inflammatory behaviour by inhibiting leukotriene synthesis. Specifically, it inhibits the activity of the enzyme 5-lipoxygenase through a non-redox reaction. Clinical trials have investigated the effectiveness of boswellic acids in treating ulcerative colitis, but a study on chemically induced colitis in mouse models showed little effectiveness. This latter study also linked large doses of boswellic acids to hepatotoxicity and increased lipid accumulation. Paradoxically, low doses of Boswellia serrata extract may have hepatoprotective effects.

Boswellic acids are also thought to decrease the symptoms of asthma; a small 1998 placebo-controlled trial of Boswellia extract for the treatment of asthma showed good results. Boswellia extracts are sold in tablet, capsule and tincture form, but no dosage guidelines have been developed. The risk of hepatotoxicity due to Boswellia administration has not been assessed.