Of anacardic acids

The structures of anacardic acid, cardol, cardanol, and 2-methyl cardol are given in Fig. 9. Each component... 

Several small molecule modulators (SMM) of p300 and PCAF have been developed (Varier et al, 2004). Recently, the first naturally occurring HAT inhibitor anacardic acid was isolated from cashew nut shell liquid, which inhibits the HAT activity of both p300 and PCAF very effectively (Balasubramanyam et al, 2003). By using anacardic acid as a synthon, an amide derivative of anacardic acid, CTPB, has been synthesized, which is the only known small molecule activator of any histone acetyltransferase, in this case, p300. However, cells are impermeable or... 

Castillo-Juarez 1, Rivero-Cruz F, Celis H. (2007) Anti-Helicobacter pylori activity of anacardic acids from Amphipterygium adstringens. J Ethnopharmacol 114 12-11. 

Contradictory results were obtained from studies with berKamide analogs of anacardic acid. While CTPB 4 (Figure 11.2) was reported to be an activator of p300 [13], the related cyano-benzamides S and 6 (Figure 11.2) aded as cell-permeable inhibitors of p300, exhibiting a similar profile to anacardic acid [15]. 

Yamagiwa, Y. Ohashi, K., Sakamoto, Y, Hirakawa, S., Kamikawa, T., and Kubo, L, Syntheses of anacardic acids and ginkgoic acid. Tetrahedron, 43, 3387, 1987. 

The initial application to the synthesis of anacardic acid-8Z,l lZ-diene, used the synthons, ArCi — ArC7 - ArCio — ArCis [114,236]. 

Scheme 3. Synthesis of anacardic acid 8(Z),1 l(Z)-diene and C14 reactant stereoisomers...

Anacardic acid 8Z,11Z,14-triene Scheme 4. Synthesis of Anacardic acid 8Z),1 l(Z),14-triene... 

Antimicrobial base materials formulated with metal and amine salts of anacardic acid, said to be non-irritative, have been proposed for cosmetic use [270]. It is of interest that anacardic acid and 2(E)-hexenal isolated from the cashew apple to which the pendant kernel (the external seed) is attached have been found to exhibit antibacterial activity against the Gram-negative bacterium, Helicobacter pylori, which is considered to cause acute gastritis [271]. The same compounds also inhibit the enzyme urease. 

Molluscicidal activity of anacardic acids, notably of the 8Z,1 lZ,14-triene has been reported [276] and the mechanism of its action has been studied by examining its role in initiating the action of prostacyclin (PGI2) in human blood platelets through competition for receptor sites although the connectioin between the two systems may be hypothetical. More recently the molluscicidal of anacardic acids and its complexes with copper II and lead has been investigated [277]. 

The most significant developments in biological uses of anacardic acids have been in studies of specific inhibitive action towards enzymes. Thus for example, the action of P-lactamase which cleaves the four-membered ring in penicillins, was specifically inhibited by (15 3)-anacardic acid obtained from Spondias mombin [45,278][68,69]. This botanical source is a little known member of the Anacardiaceae [279]. 

A series of 6-oxa isosteres of anacardic acids was synthesised and several members found to be among the most potent inhibitors (IC50 values < 5pM) of the bacterial two component regulatory systems, KinA/SpoOF and NRII/NRI reported [286]. 

Regiospecific hydroperoxidation of (15 2)-anacardic acid has been effected with soy bean lipogenase to form 2-hydroxy-6-[12-hydroperoxy-(8Z,10E)-pentadecadienyl]-benzoic acid [288] but the (15 l)-monoene exhibited inhibitory action, (IC50, 50pM) [289]. Related work on the inhibitory properties of anacardic acids towards soybean 5-lipogenase and ovine prostaglandin endoperoxide synthase has been carried out [39], These authors reported that 8Z-(15 l)-anacardic acid and the 10Z-(15 1)-... 

Allergenic properties of anacardic acids and allergic contact dermatitis... 

Biological activities of anacardic acids and related compounds... 

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. 

A full biosynthetic pathway has to account for the simultaneous formation of cardol, 2-methylcardol, anacardic acid, some cardanol and for the different unsaturation pattern of anacardic acid and cardanol which are similar with a relatively low 40% of triene compared with cardol and 2-methylcardol where the the triene constituent is more than 75%. Scheme 1 summarises known ring formation stages and speculative ones. 

Although the mechanism of formation of unsaturation may well proceed as for the polyethenoid fatty acids, it is of interest that palmitoleic acid was not found to be incorporated (ref. 83). The conclusion was drawn that in the biosynthesis of anacardic acid, the side chain was in a different state of activation and/or site than in the case of the triacylglycerol lipids. Some of these of course are found in the oil in the cashew kernel. 

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