Active Constituents
Boswellia contains oils, terpenoids, sugars, and volatile oils. Up to 16 percent of the resin is essential oil, the majority being alpha-thujene and p-cymene. Four pentacyclic triterpene acids are also present, with beta-boswellic acid being the major constituent.
Mechanisms of Action
Animal studies performed in India show ingestion of a defatted alcoholic extract of Boswellia decreased polymorphonuclear leukocyte infiltration and migration, decreased primary antibody synthesis,1,2 and almost totally inhibited the classical complement pathway.3 In an in vitro study of the effects of beta-boswellic acid on the complement system, the extract demonstrated a marked inhibitory effect on both the classical and alternate complement pathways.4 An investigation of Boswellia’s analgesic and psychopharmacological effects noted marked sedative and analgesic effects in animal models.5In vitro testing reveals boswellic acids, isolated from the gum resin of Boswellia, in a dose-dependent manner block the synthesis of proinflammatory 5-lipoxygenase products, including 5-hydroxyeicosatetraenoic acid (5-HETE)and leukotriene B4 (LTB4),6 which cause bronchoconstriction, chemotaxis, and increased vascular permeability.7 Other anti-inflammatory plant constituents, such as quercetin, also block this enzyme, but they do so in a more general fashion, as an antioxidant; whereas, boswellic acids seem to be specific inhibitors of 5-lipoxygenase.8,9 Boswellia inhibits human leukocyte elastase (HLE), which may be involved in the pathogenesis of emphysema. HLE also stimulates mucus secretion and thus may play a role in cystic fibrosis, chronic bronchitis, and acute respiratory distress syndrome.10,11 Boswellic acids and triterpenoids from Boswellia serrata also have an inhibitory and apoptotic effect against the cellular growth of leukemia HL-60 cells.12-14 Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause a disruption of glycosaminoglycan synthesis, accelerating articular damage in arthritic conditions.15-18 An in vivo animal study examined Boswellia extract and ketoprofen for effects on glycosaminoglycan metabolism. Boswellia significantly reduced the degradation of glycosaminoglycans compared to controls; whereas, ketoprofen caused a decrease in total tissue glycosaminoglycan content.19
Clinical Indications
Inflammatory Bowel Disease
Ileitis
An animal study was conducted to determine the efficacy of Boswellia extract and one of its constituents, acetyl-11-keto-β-boswellic acid (AKBA), on leukocyte-endothelial cell interactions in inflammatory bowel disease.20 Ileitis was induced in Sprague-Dawley rats via subcutaneous injection of indomethacin. The animals were then given either Boswellia or AKBA at two different doses (low or high) or placebo. It was observed that Boswellia extract and both potencies of AKBA decreased rolling (up to 90%) and adherent leukocytes (up to 98%), attenuated tissue injury scores, and significantly reduced macroscopic and microscopic inflammation of the gut mucosa.
Ulcerative Colitis
Leukotrienes are believed to play a role in the inflammatory process of ulcerative colitis. Boswellia extract (350 mg three times daily) was compared to sulfasalazine (1 g three times daily) in ulcerative colitis patients. Patients on the Boswellia extract showed better improvements than patients on sulfasalazine; 82 percent of Boswellia patients went into remission compared with 75 percent on sulfasalazine.21 A follow-up study of chronic colitis patients taking gum resin of Boswellia (900 mg daily in three divided doses for six weeks) and sulfasalazine (3 g daily in three divided doses for six weeks) again showed similar improvements. Furthermore, 14 of 20 patients (70%) treated with Boswellia serrata gum resin went into remission compared to 4 of 10 patients (40%) treated with sulfasalazine.22
Crohn’s Disease
Chemical mediators of inflammation were addressed in a clinical trial comparing a Boswellia serrata extract with mesalazine in the treatment of acute Crohn’s disease. The protocol population included 44 patients treated with Boswellia extract and 39 patients treated
with mesalazine. Between enrollment and end of therapy, the Crohn’s Disease Activity Index decreased significantly with both Boswellia extract and mesalazine. Although the difference between the two treatments was not statistically significant, the Boswellia extract proved to be as effective as the pharmaceutical.23.
Asthma
In a 1998 study of Boswellia’s effects on bronchial asthma, 40 patients took 300 mg of a Boswellia preparation three times daily for six weeks, while another 40 patients took a placebo. Seventy percent of patients taking Boswellia demonstrated significant disease improvement, measured by symptomatology and objective measures of lung and immune function; only 27 percent of patients taking a placebo improved.24
Arthritis
In a double-blind, placebo-controlled trial, Boswellia demonstrated beneficial effect on knee osteoarthritis. Thirty patients were given either 1,000 mg Boswellia daily or placebo in three divided doses for eight weeks. Patients in the Boswellia group experienced a significant decrease in pain and swelling and increase in range of motion compared to placebo.25 In a double-blind, placebo-controlled, crossover study, Boswellia in combination with ashwagandha, turmeric, and zinc was studied in osteoarthritis patients.26 Forty-two patients received either the herbal-mineral formulation or placebo for three months, then switched to the other protocol after a 15-day washout period for another three months. The treatment group experienced significant decreases in pain severity (p<0.001) n="19)">Boswellia (n=18) study in rheumatoid arthritis patients found no significant differences between the two groups in any measured parameters. NSAID dosage, however, decreased 5.8 percent in the treatment group and 3.1 percent in the placebo group.27 The researchers concluded that controlled studies including a greater number of subjects are warranted.
Side Effects and Toxicity
Toxicity studies of Boswellia in rats and primates showed no pathological changes in hematological, biochemical, or histological parameters at doses up to 1,000 mg/kg. The LD50 has been established at >2 g/kg.28
Dosage
For inflammatory or asthmatic conditions, 300-400 mg of a standardized extract (containing 60% boswellic acids) three times daily is suggested.
References
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2. Sharma ML, Bani S, Singh GB. Anti-arthritic activity of boswellic acids in bovine serum albumin (BSA)-induced arthritis. Int J Immunopharmacol 1989;11:647-652.
3. Wagner H. Search for new plant constituents with potential antiphlogistic and antiallergic activity. Planta Med 1989;55:235-241.
4. Knaus U, Wagner H. Effects of boswellic acid of Boswellia serrata and other triterpenic acids on the complement system. Phytomedicine 1996;3:77-81.
5. Menon MK, Kar A. Analgesic and psychopharmacological effects of the gum resin of Boswellia serrata. Planta Med 1971;19:333-341.
6. Ammon HP, Mack T, Singh GB, Safayhi H. Inhibition of leukotriene B4 formation in rat
peritoneal neutrophils by an ethanolic extract of the gum resin exudate of Boswellia serrata. Planta Med 1991;57:203-207.
7. Robertson RP. Arachidonic acid metabolites relevant to medicine. In: Braunwald E, Isselbacher KJ, Petersdorf RG, et al, eds. Harrison’s Principles of Internal Medicine. 11th ed. New York, NY. McGraw- Hill; 1987:375.
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9. Ammon HP. Salai guggal – Boswellia serrata: from a herbal medicine to a specific inhibitor of leukotriene biosynthesis. Phytomedicine 1996;3:67-70.
10. Rall B, Ammon HP, Safayhi H. Boswellic acids and protease activities. Phytomedicine 1996;3:75-76.
11. Safayhi H, Rall B, Sailer ER, Ammon HP. Inhibition by boswellic acids of human leukocyte elastase. J Pharmacol Exp Ther 1997;281:460-463.
12. Shao Y, Ho CT, Chin CK, et al. Inhibitory activity of boswellic acids from Boswellia serrata against human leukemia HL-60 cells in culture. Planta Med 1998;64:328-331.
13. Bhushan S, Kumar A, Malik F, et al. A triterpenediol from Boswellia serrata induces apoptosis through both the intrinsic and extrinsic apoptotic pathways in human leukemia HL-60 cells. Apoptosis 2007;12:1911-1926.
14. Huang MT, Badmaev V, Ding Y, et al. Anti-tumor and anti-carcinogenic activities of triterpenoid, betaboswellic acid. Biofactors 2000;13:225-230.
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16. Palmoski MJ, Brandt KD. Effect of salicylate on proteoglycan metabolism in normal canine articular cartilage in vitro. Arthritis Rheum 1979;22:746-754.
17. Dekel S, Falconer J, Francis MJ. The effect of antiinflammatory drugs on glycosaminoglycan sulphation in pig cartilage. Prostaglandins Med 1980;4:133-140.
18. Brandt KD, Palmoski MJ. Effects of salicylates and other nonsteroidal anti-inflammatory drugs on articular cartilage. Am J Med 1984;77:65-69.
19. Reddy GK, Chandrakasan G, Dhar SC. Studies on the metabolism of glycosaminoglycans under the influence of new herbal anti-inflammatory agents. Biochem Pharmacol 1989;38:3527-3534.
20. Krieglstein CF, Anthoni C, Rijcken EJ, et al. Acetyl-11-keto-beta-boswellic acid, a constituent
of a herbal medicine from Boswellia serrata resin, attenuates experimental ileitis. Int J Colorectal Dis 2001;16:88-95.
21. Gupta I, Parihar A, Malhotra P, et al. Effects of Boswellia serrata gum resin in patients with ulcerative colitis. Eur J Med Res 1997;2:37-43.
22. Gupta I, Parihar A, Malhotra P, et al. Effects of gum resin of Boswellia serrata in patients with chronic colitis. Planta Med 2001;67:391-395.
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24. Gupta I, Gupta V, Parihar A, et al. Effects of Boswellia serrata gum resin in patients with bronchial asthma: results of a double-blind, placebo-controlled, 6-week clinical study. Eur J Med Res 1998;3:511-514.
25. Kimmatkar N, Thawani V, Hingorani L, Khiyani R. Efficacy and tolerability of Boswellia serrata extract in treatment of osteoarthritis of knee – a randomized double blind placebo controlled trial. Phytomedicine 2003;10:3-7.
26. Kulkarni RR, Patki PS, Jog VP, et al. Treatment of osteoarthritis with a herbomineral formulation: a double-blind, placebo-controlled, cross-over study. J Ethnopharmacol 1991;33:91-95.
27. Sander O, Herborn G, Rau R. Is H15 (resin extract of Boswellia serrata, “incense”) a useful supplement to established drug therapy of chronic polyarthritis? Results of a double-blind pilot study. Z Rheumatol 1998;57:11-16. [Article in German]
28. Singh GB, Atal CK. Pharmacology of an extract of salai guggal ex-Boswellia serrata, a new nonsteroidal anti-inflammatory agent. Agents Actions 1986;18:407-412.
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