Natural antifungals

Syntheses of natural antifungal bis-y-lactone avenaciolide and related bis-lactones 980PP328. 

The Pd-catalyzed cross-coupling reactions of vinyl iodides 63 with alkynylmagnesium halides 64 have been found to produce enynes 65 with retention of configuration (>97%) [Eq. (24)] [36]. Using this procedure, the thienylacetylene 66, which is an intermediate for the synthesis of a natural antifungal and nematicidal agent can be prepared [Eq. (25)] [37]. 

Adults have an acidic, fatty substance in and on the skin called sebum. Sebum functions as a natural antifungal agent, put of the innate immune system. Fatty acids have been iitetl for years with the idea that if a substance similar to sebum could be applied to the infected area, the effect of the sebum would be augmented and fungi could be eradi-caicd. The application of fatty acids or their salts does in fxi have an antifungal effect, albeit a feeble one. 

This change appears to be due to an imbalance of the ecosystem which allowed a pathogenic fungus to invade the natural reef population [135]. Somehow the natural antifungal protection was lost the details of this development are unclear. Perhaps this protection was conferred by an epibiontic bacteria, although this explanation is speculative at this point. Only by preserving these ecosystems and this biodiversity can questions like this one be investigated. 

Table 1. Structural Category of Natural Antifungals and Their Sources...

This technique was recently applied to the synthesis of natural antifungal caerulomycin C (Scheme 22). 

Another structurally related group of natural antifungal substances are the myxothiazols, which also contain an (E)-) -methoxyacrylate moiety, this time 7 -linked. Their discovery, characterization and structure elucidation was first performed in the German groups of H. Reichenbach and G. Hofle [21-23]. Later, the same groups discovered the closely related melithiazols [24]. For a review on the naturally occurring 7 -methoxyacrylates see Ref. [25]. 

Fig. 13.2.1. From natural antifungals to the enol ether stilbene as a new synthetic lead structure.

This chapter will describe some natural antifungal compounds produced by LAB, the factors that influence their production by this group of bacteria, and some practical applications of such antifungal compounds. In addition, the effect that these bacteria have on the production of mycotoxin by toxigenic fungi will be discussed, along with their potential as mycotoxin binders (by adsorption) in Uquid systems. 

Natural antifungal compounds produced by lactic acid bacteria... 

Podobnik B, Stojan J, Lah L, Krasevec N, Seliskar M, Rizner TL, Rozman D, Komel R (2008) CY-P53A15 of Cochliobolus lunatus, a target for natural antifungal compounds. J Med Chem 51 3480-3486... 

Table 163 List of highly influenced herbal natural antifungal extracts on important aquatic fungi...

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