Survey of the Angiotensin Converting Enzyme (ACE) inhibitory activity of bioactive peptides from swamp cabbage (Ipomea aquatica), chinese cabbage (Brassica rapa), lettuce (Lactuca sativa)and mustard (Brassica juncea) .

Date

10-2011

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Torio, Mary Ann

Abstract

The crude protein from the samples—swamp cabbage, lettuce, mustard and Chinese cabbage was extracted using the buffer containing 50 mM Tris-HCl (pH 8.0), 5% (w/v) sucrose, 100 mM NaCl and 1mM EDTA. The protein content of the crude extracts was determined using the Bradford method (swamp cabbage: 5.565 μg/mL, lettuce: 4.417μg/mL, mustard: 3.037 μg/mL and Chinese cabbage: 6.435 μg/mL). The protein profile of the crude extracts was determined through SDS-PAGE with 11% denaturing gel. RuBisco is known to be the most abundant protein in leaves that is composed of eight large subunits (~53-55) kDa and small subunits (~12-14 kDa). Densitometric analysis of the electrophoretogram revealed that a prominent band corresponded to the highest peak can be seen at ~55 kDa in all the extracts. Other bands can also be seen at ~37 kDa, ~25 kDa and <20 kDa which implied that proteins other than RuBisco were isolated. The crude extracts were digested for 24 hours using the enzymes chymotrypsin and trypsin to liberate the bioactive peptides. Angiotensin Converting Enzyme (ACE) inhibitory activity was determined using spectrophotometrical analysis. Results showed that the percent inhibition of chymotrypsin digests for swamp cabbage, lettuce, mustard and Chinese cabbage were 80.04%, 56.50%, 23.11% and 23.74%, respectively. On the other hand, tryptic digests of swamp cabbage, lettuce, mustard and Chinese cabbage exhibited percent inhibition of 53.56%, 55.25%, 28.57% and 11.76%, respectively. The IC50 values of the samples were also determined using the software Graphpad prism. It was estimated that the IC50 values of swamp cabbage, lettuce, mustard and Chinese cabbage digested with chymotrypsin were 1.19x10-4, 4.13x10-4, 3.41x10-2 and 5.02 x10-3 μg/mL respectively. Moreover, the IC50 values of swamp cabbage, lettuce, mustard and Chinese cabbage digested with trypsin were estimated to be 1.31x10-3, 3.04x10-4, 6.47x10-3 and 2.08x10-1μg/mL, respectively. A paired t-test was conducted and it was known that there is a significant relationship between percent inhibition and IC50 values.

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

Thesis

Document Type

Thesis

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