Isolation, purification and determination of bioactive peptides exhibiting antihypertensive activity from mungbean (Vigna radiata (L.) R. Wilczek) vicilin

Date

10-2011

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Angelia, Mark Rickard N.

Co-adviser

Garcia, Roberta N

Committee Member

Torio, Mary Ann O.

Abstract

The total crude protein of mungbean var. Pag-asa 7 was extracted using 0.40 M NaCl in 35 mM potassium phosphate buffer (pH 7.0). Vicilin (8S globulin), the major storage protein, was purified using ammonium sulfate fractionation, dialysis, and gel chromatography. The vicilin fraction was found to comprise 89% of the total proteins. SDS-PAGE profile of vicilin revealed four bands with estimated molecular weights of 66.4, 54.6, 26.3, and 21.1 kDa. The protein content of the crude extract and vicilin fraction was 10.17 and 3.23 mg/mL, respectively. Vicilin was digested with trypsin and chymotrypsin to release any bioactive peptides present within the protein. Spectrophotometric assay was done to confirm the presence of ACE inhibiting peptides in the digested samples. The ACE inhibitory activities of the 24-hr digested vicilin fractions were determined to be 1.786 x 10-3 U and 1.994 x 10-3 U for trypsin and chymotrypsin, respectively. The tryptic and chymotryptic hydrolysates were subjected to RP-HPLC for further purification. Four major peaks were observed in the elution profile of the chymotryptic digest while three major peaks were present in the tryptic digest. The major peaks of both digests exhibited ACE inhibitory activities. IC50 values of the probable ACE-inhibitory peptides were 0.826, 0.203, 0.286, 0.852, 1.325, 1.151, and 1.367 µg/mL for C1, C2, C3, C4, T1, T2, and T3, respectively. Captopril, a commercial antihypertensive drug, has an estimated IC50 of 0.028 µM. Percent inhibition of ACE activities was found to be inversely proportional with that of IC50 of the digested samples. Therefore, vicilin, the major storage protein of mungbean, contain potential antihypertensive peptides.

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

Thesis

Document Type

Thesis

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