Onion trypsin

The experiment with 0.5 g/mL of erode extracts of different parts of Allium plants (bulb, green leaf, white stalk) showed the inhibition of acrosin and trypsin activities, mostiy the red onion and garlic extracts. These results demonstrated that spermicidal effect of Allium extracts is determined also by their capacity of protease inhibition. The red onion extract shows the higher antioxidant capacity and a very low cytotoxicity. 

Trypsin inhibition activity was determined by measuring the decrease of trypsin activity in the presence of Allium extracts. The results obtained with different types of extracts (bulb, stalk, green leaf-0.5 g/iuL) are presented in Fig. 41.2. All determinations were carried out in triplicate. The higher inhibition activity was obtained with red onion bulb extract (18.55 0.14 Ul/min or 27.94 0.21 U/g fresh plants). Onion bulb extract shows also a high trypsin inhibition (18.48 0.035 UFmin, 27.83 0.053U/g), and all extracts of garlic (bulb, leaf and stalk) show activities between 11.05 1.615 - 13.185 0.205 Ul/min (16.64 2.42 - 19.86 0.31 U/g). 

Non-toxic lectins are lectins of garlic, onions, leeks, tomatoes and amaranth. Of the common lectins, those of peanuts, lentils, peas, common beans and soya beans are slightly toxic, wheat lectins are moderately toxic, and lectins of some beans (such as Jack beans) are highly toxic, while castor seed lectins are lethal (Table 10.21). Some lectins (such as lectins of garlic) have prebiotic effects and inhibit undesirable intestinal microflora Escherichia coli). Often, lectins are not the only toxic substances of the plant material. For example, lectins of soybean seeds participate in their antinutritional and toxic effects at a level of about 25%, but trypsin inhibitors are about 40% and the rest is covered by saponins and other substances. 

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