Comparative analysis of soybean [Glycine max (L.) Merr.) and rice bean [Vigna umbellata (Thunb) Ohwi & Ohashi): phenolic profile, phenolic levels; ferric reducing power, free-radical scavenging and angiogenic activities

Date

10-2008

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Evelyn B. Rodriguez

Abstract

TANYAG, RICO MAYRO PAGTANANAN. College of Arts and Sciences, University of the Philippines Los Banos, October 2008. COMPARATIVE ANALYSIS OF SOYBEAN [Glycine max (L.) MERR.] AND RICE BEAN [Vigna umbellata (THUNB) OHWI & OHASHI]: PHENOLIC PROFILE, PHENOLIC LEVELS; FERRIC REDUCING POWER, FREE-RADICAL SCAVENGING AND ANGIOGENIC ACTIVITIES.

ADVISER. EVELYN B. RODRIGUEZ, PhD.

Isoflavones are one of the well-studied flavonoids because of their ability to prevent degenerative diseases like cancer and cardiovascular diseases. In this study, a comparative analysis of the phenolic profiles and levels, antioxidative and angiogenic activities of soybean [Glycine max (L.) Mem] and rice bean [Vigna umbellate (Thunb) Ohwi & Ohashi] phenolic extracts was conducted.

The phenolic compounds in the legumes were extracted using 60% ethanol. Half of the phenolic extracts were acid-hydrolyzed in 2M HCI-MeOH (1:1). A two-dimensional paper chromatography was employed for the phenolic extracts to determine the phenolic profile. Based from the color changes under various light conditions, retardation factors, comparison with the commercial soybean supplement, UV spectral analyses and comparison with the literature data, genistein was determined to be present in the non-hydrolyzed soybean extract (NHSE). No isoflavones were identified in acid-hydrolyzed soybean extract (AHSEOP), non-hydrolyzed rice bean extract (NHRE) and acid-hydrolyzed rice bean extract (AHREOP). Total phenolic content was determined using the Folin-Ciocalteu reagent. The extract that had the highest phenolic content was AHSEOP (15.49 ± 1.97 mg GAE/g sample) followed by AHREOP (10.77 ± 1.01 mg GAE/g sample). Total flavonoid content was determined using the complex formation of aluminum between two hydroxyl groups of the flavonoids. AHREOP (814.35 ± 108.39 mg QE/g sample) gave the highest flavonoid content followed by AHSEOP (417.26 ± 117.44 mg QE/g sample).

The antioxidative activities of the phenolic extracts were evaluated using the ferric reducing power and free radical scavenging assays. AHSEOP gave the highest ferric reducing power followed by AHREOP. The free radical scavenging activity was done using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. It was determined that AHREOP (306.65 ± 24.33 ppm) gave the lowest concentration needed to scavenge 50% of DPPH (EC50), followed by NHRE (359.58 ± 31.06 ppm) and then by AHSEOP (400.43 ± 31.06 ppm). The angiogenic activity of the extracts was assessed using the duck embryo assay. The phenolic extracts were observed to be antiangiogenic. Antiangiogenic compounds act as angiogenic inhibitors which prevent the formation of blood vessels, thus antiangiogenic compounds are potential inhibitors of angiogenesis-dependent diseases like cancer and other degenerative diseases.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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