ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

A protein which inactivates trypsin is found in raw soybeans. This protein causes an
increase in the size of the pancreas (hypertrophy), together with increased secretory
pancreatic activity (Pimeutel et al., (1996). Lyman and co-workers (Green and Lyman,
1972; Lyman et aI., 1974) have shown that levels ofthe proteolytic enzymes trypsin and
chymotrypsin in the small intestine determine the efficacy of the system regulating
negative feedback inhibition, which, in turn, controls pancreatic secretion. Liener (1981)
commeuted that the pancreas is stimulated to produce more enzymes when the level of
trypsin is reduced: that is, when it is combined with the inlnbitor. Cholecystokinin (CCK)
is the major hormone responsible for activating pancreatic enzymes. Iftoo little trypsin is
available, CCK is released from the jejunal eudocrine cells ofthe small intestine (Liddle,
2007). These relationships are illustrated in Figure AI-4.
Trypsinogeu .4-------- CCK
Trypsin
Dietary protein (intestine)
Proteolysis Trypsin-Trypsin Inhibitor
Figure AI-4: Mode ofaction ofsoybean trypsin inhibitors on the pancreas
(Anderson et al.,1979)
Proteinase inhibitors may add to their natural biological functions, the treatment of human
pathologies such as blood clotting and haemorrhage, inflammation and cancer (Neuhof et
aI., 2003; Fook et al. 2005; Meno et aI., 2006).
14