Anacardium occidentale anacardic acid from

By way of comparison, we might consider the famesol/anacardic acid synergism against P. acnes. Its antibacterial activity against this follicular bacterium was significantly increased in combination with AMIC of anacardic acid isolated from the cashew Anacardium occidentale (Anacardiaceae) apple, nut and nut shell oil (32). More specifically, the MIC of famesol was lowered from 6.25 to 0.78 /tg/ml, in combination with 0.39 ftg/ml of anacardic acid. Interestingly, this synergism was found to be vice versa the MIC of anacardic acid was reduced from 0.78 to 0.2 /tg/ml when it was combined with 3.13 /tg/ml of famesol (33). The mode of action of the combination, however, remains unclear. 

The use of open-chain precursors for obtaining the benzenoid ring in anacardic and orsellinic acids has proved a fruitful approach. Ethyl 2-methoxy-6-methylbenzoate (synthesised through the Michael addition of ethyl acetoacetate virith but-2-en-al, followed by cyclisation and aromatisation), has been alkylated in an aprotic solvent after formation of the carbanion with lithium di-isopropylamide (refs. 113,114) to give the anacardic after hydrolysis and demethylation (a). In a similar way ethyl 2,4-dimethoxy-6-methylbenzoate (ethyl orsellinate), (formed from ethyl acetoacetate and ethyl crotonate followed by cyclisation aromatisation and methylation (ref. 115)), has been alkylated (ref. 116, 117). In this way the C.,5 orsellinic acid precursor [R = C14H29 in route (b)] of the component phenols in Anacardium occidentale has been synthesised (ref. 118) and the method indirectly affords another route to the cardol series. 

For natural CNSL from different regions the % composition of the components, anacardic acid, cardol and 2-methylcardol by HPLC has been found to vary although all were produced from Anacardium occidentale (ref. 221). 

Cashew nut shell liquid resin n. Resin derived fi om the liquid obtained from the shells of the nuts of the species, Anacardium occidentale, which grows chiefly in India and South America. The naturally occurring liquid is a mixture of a dihydroxy phenol cardol and anacardic acid. This acid readily decarboxylates on heating to yield a monohydroxy phenol with an unsaturated side chain, anacardol. 

Long-chain alkylphenols have been investigated extensively (33) by both adsorption and reversed-phase partition methods (34). The cashew phenols (from Anacardium occidentale) comprise cardanol (1), cardol (2), 2-methylcardol (3), and anacardic acid (4), each existing as a mixture of the saturated, 8 -monoene, 8 ,11 -diene, and 8 ,1 l ,14 -trieneconstituents. In ammoniated solvent [light petroleum-diethyl ether-ammonia (60 40 2)] the acidic compound anacardic acid remained practically on the baseline, whereas in an acidic solvent [light petroleum-diethyl ether-formic acid (70 30 1)] it migrated toward the solvent front as an intramolecularly bonded substance. In natural cashew nut shell liquid the phenols and their unsaturated constituents have the values 0.20 (cardol). 

Important antimicrobial effects were observed for eashew eom-pounds. Anacardic acids and (E)-2-hexenal characterized from the cashew Anacardium occidentale L. (Anacardiaceae) apple have been found to exhibit antibacterial activity against Helicobacter pylori, a gram-negative bacterium considered to cause acute gastritis (Kubo et al. 1999). It was also observed that the antibacterial activity of methicil-lin against methicilin resistant Staphylococcus aureus (MRSA) strains can be enhanced when combined with certain anacardic acids (Kubo et al. 2003 Muroi and Kubo 1996). 

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