Screening, fractionation and partial identification antioxidants from gabi (Xanthosoma saggitifolium) tubers

Date

3-1992

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Evelyn Mae T. Mendoza

Abstract

Gabing San Fernando (GSF) exhibited antioxidative activity stronger than butylated hydroxyanisole (BHA) and alpha-tocopherol. Fractionation of GSF crude extract on an Amberlite XAD-2 column followed by antioxidative assay revealed that the active fractions are the 75:25 Me0H-H20 and acetone. Semi-preparative HPLC of the 75:25 Me0H-H20 fraction using an isocratic solvent system of 95:5 Me0H-820: CH3COOH, gave two major peaks (2.71 and 3.77 min) and one minor peak (4.21 min), all of which had strong antioxidative activities .The acetone fraction, subjected to the same conditions, showed four major peaks (3.1, 3.6, 17.07 and 19.74 min) and one minor peak (1.7 min). Antioxidative assay of these peaks showed that the minor peak exhibited the strongest activity. All other peaks showed relatively strong activities.

The subfraction eluting at 3.77 min of the 75:25 Me0H-H20 were found to have two major peaks (2.04 and 3.71 min) and two minor peaks (6.14 and 8.81 min), upon injection on a semipreparative HPLC using isocratic condition. The other subfraction eluting at 4.21 min gave two major peaks (2.0 and 3.6 min) and three minor peaks (5.07, 5.87 and 7.33 min) using the same conditions.

The acetone subfraction eluting at 1.70 min showed two major peaks (2.61 and 3.61 min). On the other hand, the eak that elute at 17.07 gave two major peaks (2.50 and 3.40 in) and two minor peaks (5.34 and 9.60 min). Evaluation of he antioxidative activities and HPLC chromatograms of GSF crude extract, active fractions and subfractions, showed that the activity of GSF could be attributed to two major components ( 2.0 and 3.6 min) and to a minor component at 2.61 min.

Based on the elution patterns of standard phenolics, the m...or component eluting at 2.61 min could correspond to chlorogenic acid. Major peaks did not show any elution pattern similar to the standards used in the study.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 1992 C4 P33

Document Type

Thesis

This document is currently not available here.

Share

COinS