Avena Avenacins

TROJANOWSKA, M.R., OSBOURN, A.E., DANIELS, M.J., THRELFALL, D.R., Investigation of avenacin-deficient mutants of Avena strigosa, Phytochemistry, 2001, 56, 121-129. 

Maizel JV et al (1964) Avenacin, an antimicrobial substance isolated from Avena saliva. I. Isolation and antimicrobial activity. Biochemistry 3 424... 

Fig. 1A-C. Examples of different classes of saponins A the triterpenoid saponin avenacin A-1 from roots of Avena spp B the steroidal saponin gracillin, from Costus speciosus C the steroidal glycoalkaloid a-tomatine from tomato (Lycopersicon spp.)...

Avenacinase, an enzyme from G. graminis var. avenae, is related to tomatinase from S. lycopersici because is able to deglucosilate tomatine by identical mode of action. However, the activity is very low and corresponds to approximately 2% of its activity towards avenacin A-1 [32]. Tomatinase form S. lycopersici, also can cleave avenacin A-l but has less than 0.01% of activity towards it in comparison to its activity towards tomatine [32]. Therefore, the two enzymes are highly specific for their respective host plant saponins. Purification and characterization of S. lycopersici tomatinase revealed that this enzyme shares many properties (including immunological cross-reactivity) with avenacinase... 

Avenacin A-1 Avena sativa (oats) (Poaceae) Permeabilizes membranes... 

The resistance of oats Avena sativa, Poaceae) to the take-all fungus Ophiobolus graminis is due to a fluorescent wot tip glycoside. This resistance factor, avenacin, has proven to be a mixture of four pentacyclic triterpene glycosides (5-8). Compounds (5 and 7), which possess anthranilic acid residues as a part of the molecule, have the greatest fungicidal properties (Fig. 24.3) (Harbome, 1986). 

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