Radiolabeling and pharmacokinetics of Bowman-Byrk inhibitor from Macrotyloma axillare

There are several evidences that dietary factors have a tight correlation with different kinds of cancer development. Among the compounds of the diet related with cancer development prevention, we could mention the Bowman-Birk Inhibitors (BBI). We isolated preparations of BBI from Macrotyloma axillare showing high specific inhibitory activities over bovine trypsin and chymotrypsin enzymes, specially the germinated seeds preparation. These inhibitors had their pharmacokinetics parameters determined and compared with soybeans inhibitors parameters, which are by the way, the most studied inhibitors of this class. Macrotyloma axillare inhibitors are widely distributed over mice organs, but they show an important difference in comparison with soybean inhibitor biodistribution, which is a meaning bigger affinity for the stomach. Macrotyloma axillare inhibitors when injected intravenously have a fast distribution, with distribution volumes of approximately four folds the plasmatic volume, but they are eliminated slowly, with plasmatic half-lives between 7 and 15 hours. When applied in isolated intestinal loops of Swiss mice, soybean inhibitors get to almost 50% of bioavailability, while Macrotyloma axillare inhibitors from seeds and cotyledons get to 30 and 40% respectively. Meanwhile, the biggest potency of cotyledons inhibitors of Macrotyloma makes available a bigger activity (approximately nine folds) then soybean inhibitors do. (author)