Boswellia/AKBA: The Powerful Anti-Inflammatory
Boswellia Relieves Rheumatoid Arthritis
Boswellic acids exhibited 25-46% inhibition of edema in rats and mice and exhibited 45-67% anti-arthritic activity in animal models.
Oral administration of Boswellia serrata gum resin extract (BSE) resulted in significantly reduced levels of inflammatory mediators in rats with rheumatoid arthritis.
Clinical trials of gum-resin of this herb showed improvement of symptoms in patients with osteoarthritis, and rheumatoid arthritis.
All patients with osteoarthritis of the knee receiving Boswellia reported a decrease in knee pain, increased knee flexion and increased walking distance.
In vitro studies and animal models show that boswellic acids were found to inhibit the synthesis of pro-inflammatory enzyme, 5-lipoxygenase (5- LO) including 5-hydroxyeicosatetraenoic acid (5- HETE) and leukotriene B4 (LTB-4), which cause bronchoconstriction, chemotaxis, and increased vascular permeability. Other antiinflammatory plant constituents, such as quercetin, also block this enzyme, but they do so in a more general fashion, as an antioxidant, where as boswellic acids seem to be specific inhibitor of 5-LO. 5-LO generates inflammatory leukotrienes, which cause inflammation by promoting free radical damage, calcium dislocation, cell-adhesion and migration of inflammation-producing cells to the inflamed body area. In contrast to non-steroidal antiinflammatory drugs (NSAIDS), which are well known to disrupt glycosaminoglycan synthesis, thus accelerating articular damage in arthritic conditions, boswellic acids have been shown to significantly reduce glycosaminoglycan degradation . In vivo study examining the effect of Boswellia extract and ketoprofen on glycosaminoglycan metabolism showed that Boswellia considerably reduced the degradation of glycosaminoglycans compared to controls, whereas ketoprofen caused a reduction in total tissue glycosaminoglycan content.
In vitro studies by Ammon et al. in 1993 also elucidated that boswellic acids were found to inhibit leukotriene synthesis via 5-LO, but did not affect the 12-lipoxygenase or cyclooxygenase activities, nor did they prevent peroxidation of arachidonic acid by iron or ascorbate. Boswellic acids were, therefore, shown to be specific, non-redox inhibitors of leukotriene synthesis, either interacting directly with 5-LO or blocking its translocation. Boswellic acids have also been observed to inhibit 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. HLE is a serine protease, which initiates injury to the tissues which, in turn, triggers the inflammatory process. This dual inhibitory action on the inflammatory process is unique to boswellic acids. Of these four boswellic acids, 3-acetyl-11-keto-β-boswellic acid (AKBA) is the most potent inhibitor of 5-LO, an enzyme responsible for inflammation.
Singh et al. studied the antiinflammatory activity of mixture of boswellic acids and observed 25- 46% inhibition of paw oedema in rats and mice. They have also reported that in chronic test of formaldehyde arthritis it exhibited 45-67% antiarthritic activity in a similar dose range. The fraction was effective in both adjuvant arthritis (35-59%) as well as established arthritis (54-84%). It also showed antipyretic effect, with no ulcerogenic effect. Kulkarni et al. and Chopra et al. have reported clinical trials of Boswellia’s antiinflammatory properties in combination with Withania somnifera, Zingiber officinate and Curcuma longa and the isolated effects of Boswellia on rheumatoid arthritis could not be revealed. However, the clinical trials of gum-resin of Boswellia alone have shown to improve symptoms in patients with osteoarthritis, and rheumatoid arthritis. The boswellic acid from Boswellia serrata, when tested on new model i.e. Papaya Latex Model, showed significant activity of mean 35% inhibition of inflammation. Since the new model is reported to be sensitive to slowly acting remission-inducing drugs, its effectiveness on boswellic acid throws some light on its mechanism of action, which seems to be unlike aspirin and steroidal drugs. Poeckel and Werz in 2006 have summarized the biological actions of boswellic acids on the cellular and molecular level and attempted to put the data into the perspectives of the beneficial effects manifested in animal studies and trials with human subjects related to inflammation and cancer. Sharma et al. have reported the effect of boswellic acids on bovine serum albumin (BSA)- induced arthritis in rabbits.
Gayathri et al. in 2007 have reported that pure compound from Boswellia serrata extract exhibits antiinflammatory property in human peripheral blood mononuclear cells (PBMCs) and mouse macrophages through inhibition of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), NO and mitogen activated protein (MAP) kinases. Incensole acetate, a novel antiinflammatory compound isolated from Boswellia resin inhibits nuclear factor-kappa B activation. Boswellic acids are direct 5-LO inhibitors that efficiently suppress 5-LO product synthesis in common in vitro test models. However, the pharmacological relevance of such interference in vivo seems questionable. Acetyl-11-keto-β- boswellic acid inhibits prostate tumor growth by suppressing vascular endothelial growth factor receptor 2- mediated angiogenesis.
A clinical trial conducted by Raychaudhuri and co-workers in India has shown that the extract of the plant, Boswellia serrata, can reduce pain and considerably improve knee-joint functions, in some cases providing relief even within seven days. Raychaudhuri and her colleagues described their study as the first to evaluate the efficacy of the extract enriched with a form of boswellic acid on osteoarthritis. Very recently, Pawar et al. in 2011 have reported a simple, rapid, accurate, reproducible, selective and economic HPTLC method for routine quality control analysis as also quantitative determination of β-boswellic acid from Boswellia serrata Roxb. (exudate) and its formulations.
Boswellia is generally taken as a capsule, tablet or its bark decoction orally. The recommended dosage is based on historical practice or available trials. Presently, it is not clear what the optimal dose is to balance safety and efficacy. The manufacturing of Boswellia products varies from one produce to the other and this makes it even more difficult for standardization to happen. It is important to note that most of the trials used various products made by various manufacturers, so clinical effects may not be comparable.