Efficacy of various naturally occurring caffeic acid derivatives in preventing post-harvest protein losses in forages.

摘要: BACKGROUND: In red clover, oxidation of endogenous o-diphenols by polyphenol oxidase (PPO) inhibits post-harvest proteolyis. This system is transferable to alfalfa providing PPO (via a transgene) and o-diphenol substrates exogenous application). To exploit the for protein protection, it would be advantageous produce in alfalfa, which lacks them. We assessed extent PPO-mediated proteolytic inhibition phenolic compounds, especially those whose biosynthesis could engineered into alfalfa. RESULTS: Tested compounds included (caffeic acid, phaselic chlorogenic clovamide) monophenols (p-coumaric p-coumaroyl-malic acid). presence PPO, 2 mmol g−1 reduced 24 h proteolysis 68–87% (P < 0.001) as little 0.25 still decreased 43–60% 0.001). At high concentrations, clovamide inhibited 50% absence likely due non-PPO oxidation. Monophenol p-coumaric acid did not inhibit proteolyis, although levels its malate ester exhibit PPO- oxygen-independent (37%, P 0.001). CONCLUSIONS: For inhibition, pathways both may good targets engineering alfalfa. Clovamide useful inhibiting without PPO. Published 2012 John Wiley & Sons, Ltd.