Abstract

Dipeptide synthesis and evaluation of antidiabetic activity of 4-hydroxyisoleucine from fenugreek seeds

Author(s): Sridevi P, Lakshmi GA, Vunutha K, Akshitha K, Mahesh K & BhagavanRaju M

Fenugreek is one of the oldest medicinal plants, originating in India and Northern Africa. The hypoglycemic effects of fenugreek have been attributed to several mechanisms. Under In vitro conditions, the amino acid 4-hydroxyisoleucine(4-OHIL) in fenugreek seeds increased glucose-induced insulin release in human and rat pancreatic islet cells. It was observed that 4-OHILextracted from fenugreek seeds has insulin tropic activity. This amino acid appeared to act only on pancreatic beta cells, since the levels of somatostatin and glucagon were not altered.

Experimental: In order to separate amino acids from methanol extract of fenugreek seeds, ion exchange chromatography method containing 225H cationic resin was used. Five dipeptides were prepared from 4-OHILnamely; GLY-L-4-OHIL, ALA-L-4-OHIL, SER-L-4-OHIL, VAL-L-4-OHIL, THR-L-4-OHIL using cbZ-Cl in protecting step, DCC in peptide forming step and HBr in acetic acid in deprotection step.

Results: Five dipeptides were confirmed by spectral data like IR, MASS, NMR and evaluated for anti-diabetic activity. The studies showed that only GLY-L-4-OHIL showed improved activity than the other derivatives and it is comparable with 4-OHIL.

Conclusion: Remarkable anti diabetic activity was observed when compared with standard drug and the parent compound 4-OHIL.