Anacardic acids arephenolic lipids, chemical compounds found in the shell of the cashew nut (Anacardium occidentale). An acid form ofurushiol, they also cause an allergicskin rash on contact,[1] known asurushiol-induced contact dermatitis. Anacardic acid is a yellow liquid. It is partially miscible with ethanol and ether, but nearly immiscible with water. Chemically, anacardic acid is a mixture of several closely relatedorganic compounds. Each consists of asalicylic acid substituted with analkyl chain that has 15 or 17 carbon atoms. The alkyl group may besaturated or unsaturated; anacardic acid is a mixture of saturated and unsaturated molecules. The exact mixture depends on the species of the plant.[2] The 15-carbon unsaturated side chain compound found in the cashew plant is lethal toGram-positive bacteria.[citation needed]
Folk use fortooth abscesses, it is also active againstacne, some insects,tuberculosis, andMRSA. It is primarily found in foods such ascashew nuts, cashew apples, andcashew nutshell oil, but also inmangos andPelargonium geraniums.[3]
 | |
| Names | |
|---|---|
| Preferred IUPAC name 2-Hydroxy-6-[(8Z,11Z)-pentadeca-8,11,14-trienyl]benzoic acid | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| MeSH | anacardic+acid |
| UNII | |
| |
| |
| Properties | |
| C22H30O3 | |
| Molar mass | 342.4718 g/mol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
The side chain with three unsaturated bonds was the most active againstStreptococcus mutans, the tooth decay bacterium, in test tube experiments. The number of unsaturated bonds was not material againstCutibacterium acnes, the acne bacterium.[4] Eichbaum claims that a solution of one part anacardic acid to 200,000 parts water to as low as one part in 2,000,000 is lethal to Gram-positive bacteria in 15 minutesin vitro. Somewhat higher ratios killed tubercle bacteria oftuberculosis in 30 minutes.[5] Heating these anacardic acids converts them to the alcohols (cardanols) with reduced activity compared to the acids. Decarboxylation, such as through heating done in most commercial oil processing, results in compounds with significantly reduced activity.[6][7] It is said that the people of theGold Coast (now Ghana) use cashew leaves and bark for a toothache.[8]
Anacardic acid is the main component ofcashew nutshell liquid (CNSL), and finds use in the chemical industry for the production ofcardanol, which is used for resins, coatings, and frictional materials. Cardanol is used to makephenalkamines, which are used as curing agents for the durable epoxy coatings used on concrete floors.[9]
The first chemical analysis of the oil of the cashew nut shell from theAnacardium occidentale was published in 1847.[10] It was later found to be a mixture rather than one chemical, sometimes the plural anacardic acids is used.[citation needed]
Anacardic acid is synergistic withanethole from the seed ofanise (Umbelliferae) andlinalool from green teain vitro [Muroi & Kubo, p1782]. Thetotarol in the bark ofPodocarpus trees is synergistic with anacardic acid in its bactericidal effects.[11]
There is also a suspicion that inhibiting anacardic acids may arrest the growth of cancer tumors such asbreast cancer. [Kubo et al., 1993] Inhibition oflysine acetyltransferase by anacardic acid was shown to make cancer cells usingalternative lengthening of telomeres more sensitive toradiation.[12]
Anacardic acid (2-hydroxy-6-alkylbenzoic acid) provides resistance to small pest insects (aphids andspider mites).[13]
Anacardic acid killsmethicillin-resistantStaphylococcus aureus (MRSA) cells more rapidly thantotarol.[14]
