Isolation and characterization of a novel antihyperglycemic protein from the fruits of Momordica cymbalaria

Abstract

Aim of the study: A new antihyperglycemic protein was identified in the aqueous extract of fruits of Momordica cymbalaria by bioassay-guided fractionation. The study was aimed at isolation and characterization of this protein.

Materials and methods: The active principle was purified to homogeneity by ammonium sulphate precipitation, gel filtration column chromatography on Sephadex G-50 followed by reverse phase HPLC. Its N-terminal amino acid sequence was identified and compared in the protein data bank. Optimum dose and route of administration of the active principle was determined in STZ induced diabetic rats.

Results: A 17kDa protein with an isoelectric point of 5.0 was identified as the active principle of antidiabetic action present in the aqueous extract of fruits of MC. It is named as M.Cy protein and found to be a novel protein by comparing its N-terminal amino acid sequence with those in the protein data bank. It did not produce any hypoglycemia in either normal or diabetic rats.

Conclusions: The results suggest that 'M.Cy protein', present in the fruits of Momordica cymbalaria is an effective antihyperglycemic active principle in STZ induced diabetic rats at a dose of 2.5mg/kg b.w.