Effects of typheramide and alfrutamide found in Allium species on cyclooxygenases and lipoxygenases.

Typheramide (N-caffeoyltyramine) and alfrutamide (N-feruloyltyramine) are phenylpropenoic acid amides found in plants. In this article, typheramide and alfrutamide were isolated from Allium sativum (garlic) and Allium fistulosum (green onion), their chemical structures were confirmed using nuclear magnetic resonance spectroscopic methods, and the potential effects on cyclooxygenases (COXs) (COX 1 and 2) and lipoxygenases (LOXs) (5- and 15-LOX) were investigated. Typheramide and alfrutamide inhibited COX 1 by 74% (P < .01) and 60% (P < .01), respectively, at the concentration of 0.1 μM; at the same concentration, they also inhibited COX 2 by 68% (P < .02) and 54% (P < .02), respectively. Typheramide was slightly stronger than alfrutamide in inhibiting COX enzymes, and the inhibition patterns of COX 1 and 2 were uncompetitive with K(i) = 0.032 and 0.047 μM, respectively. However, typheramide and alfrutamide were not able to inhibit 5-LOX, and they only moderately inhibited 15-LOX by 27% (P < .02) and 17% (P < .02), respectively, at the relatively high concentration of 25 μM. Altogether, the data suggest that typheramide and alfrutamide from garlic and green onions are likely to be significant inhibitors for COX 1 and 2 rather than 5- and 12-LOX.