Boswellic acids are a series of pentacyclic

terpenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes", ...

molecules that are produced by plants in the genus ''

Boswellia ''Boswellia'' is a genus of trees in the order Sapindales, known for its fragrant resin. The biblical incense frankincense is an extract from the resin of the tree ''Boswellia sacra'', and is now produced also from '' B. frereana''. Frankincens ...

''. Like many other

terpenes Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n > 1. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes ar ...

, boswellic acids appear in the

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...

of the plant that exudes them; it is estimated that they make up 30% of the resin of ''

Boswellia serrata ''Boswellia serrata'' is a plant that produces Indian frankincense. The plant is native to much of India and the Punjab region that extends into Pakistan. Sustainability ''Boswellia serrata'' is currently at risk of being eradicated because of n ...

''. While boswellic acids are a major component of the resin, the steam or hydro distilled frankincense essential oil does not contain any boswellic acid as these components are non-volatile and too large to come over in the steam distillation process (the essential oil is composed mainly of the much lighter monoterpene and sesquiterpene molecules with small amounts of diterpenoid components being the upper limit in terms of molecular weight).

Structure

The boswellic acids are

organic acid An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are re ...

s, consisting of a pentacyclic triterpene, a

carboxyl group In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...

and at least one other functional group. Alpha-boswellic acid and beta-boswellic acid, C₃₀H₄₈O₃ both have an additional

hydroxyl group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

; they differ only in their triterpene structure. Acetyl-alpha-boswellic acid and acetyl-beta-boswellic acid, C₃₂H₅₀O₄, replace the hydroxyl group with an

acetyl In organic chemistry, acetyl is a functional group with the chemical formula and the structure . It is sometimes represented by the symbol Ac (not to be confused with the element actinium). In IUPAC nomenclature, acetyl is called ethanoyl, ...

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 (AKBA) have been indicated in

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes includ ...

of cancer cells, in particular brain tumors and cells affected by

leukemia Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ...

colon cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel m ...

. Acetyl-boswellic acids also exhibit

anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as op ...

behaviour by inhibiting

leukotriene Leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase. Leukotrienes ...

synthesis. It inhibits the activity of the enzyme

5-lipoxygenase Arachidonate 5-lipoxygenase, also known as ALOX5, 5-lipoxygenase, 5-LOX, or 5-LO, is a non-heme iron-containing enzyme (EC 1.13.11.34) that in humans is encoded by the ''ALOX5'' gene. Arachidonate 5-lipoxygenase is a member of the lipoxygenase fa ...

through a non-

redox Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

reaction. Specifically the 3-acetyl-11-keto-beta-boswellic acid binds as an allosteric partial inhibitor, initiating a shift in regioselectivity of the catalyzed reaction. Clinical trials have investigated the effectiveness of boswellic acids in treating

ulcerative colitis Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and ...

, but a study on chemically induced colitis in mouse models showed little effectiveness. A latter study showed that low doses of ''Boswellia serrata'' extract may have hepatoprotective effects. The higher dose was found to have a milder hepatoprotective effect than the lower dose. Boswellic acids are also thought to decrease the symptoms of

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

; 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 A tincture is typically an extract of plant or animal material dissolved in ethanol (ethyl alcohol). Solvent concentrations of 25–60% are common, but may run as high as 90%.Groot Handboek Geneeskrachtige Planten by Geert Verhelst In chemistr ...

form, but no dosage guidelines have been developed. The risk of hepatotoxicity due to ''Boswellia'' administration has not been assessed. A meta-study of Indian Frankincense (Boswellia serrata) as a complementary therapy for arthritis found it had positive effect in all four trials reviewed.

References

External links

Lipid Molecular Structure Database
*{{ Cite journal , url = http://scidok.sulb.uni-saarland.de/volltexte/2012/4999/pdf/Dissertation_Fertig_211112.pdf , title = Chemotaxonomic Investigations on Resins of the Frankincense Species ''Boswellia papyrifera'', ''Boswellia serrata'' and ''Boswellia sacra'', respectively, ''Boswellia carterii'': A Qualitative and Quantitative Approach by Chromatographic and Spectroscopic Methodology , author = Paul, M. , journal = Dissertation , publisher = Saarland University , year = 2012 , doi = 10.22028/D291-22839 Triterpenes Beta hydroxy acids