Isolation, purification and partial characterization of two lectins from the leaves of Swietenia macrophylla King.

Date

10-2000

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Marivic S. Lacsamana

Co-adviser

Florinia E Merca

Abstract

ABIGAIL JOY DELGADO RODELAS, University of the Philippines Los Bafios, October, 2000. Isolation, Purification and Partial Characterization of Two Lectins from the Leaves of Swietenia macrophylla King.

Adviser: Dr. Marivic S. Lacsamana

The leaves of twelve Meliaceae species, earlier reported to exhibit insecticidal properties, were surveyed for lectin activity. Ten of these species namely, Aglaia edulis (malasaging), Azadirachta indica (neem/margosa), Chisocheton pentandrus (katong matsing), Dysoxylum cumingianum (tars-tara), Melia azedarach (chinaberry/paraiso), Melia duhia (bagalunga), Sandoricum koetjape (santol), Swietenia macrophylla King (large-leafed mahogany), Swietenia mahogany (small-leafed mahogany) and Poona calantas (kalantas) tested positive for lectin activity. The strongest lectin activity was observed in the crude leaf extract of Swietenia macrophylla King.

The lectins were extracted using 0.02 M phosphate buffer containing 0.15 M NaCI at pH 7.2. These were purified through sequential ammonium sulfate (0-90%) fractionation and gel filtration using Sephadex G-150.

Two lectins were isolated and purified from the mature leaves of Swietenia macrophylla King. Lectin I was observed to be non-blood type specific since it agglutinated all human blood types (A, B, 0 and AB). It could also be non-blood-group specific because it was able to agglutinate blood samples from calf, swine and carabao. Sugars such as L-(+)-arabinose, D-W-mannose. D-(+)-galactose, a-L-rhamnose, methyl-a-D-mannopyranose. D-(-9-glucosamine, sucrose and (3-D-(-)-fructose were able to inhibit the agglutination by Lectin 1 of all types of human erythrocytes. Lectin 2, on the other hand, also agglutinated all types of human erythrocytes but did not agglutinate calf and swine erythrocytes. The agglutination by Lectin 2 of all human blood types was not inhibited by any of the sugars used in this study.

Lectins 1 and 2 were found to be glycoproteins containing 0.50% and 1.57% carbohydrate, respectively. SDS-PAGE gave two protein bands for Lectin 1 with the molecular weights estimated to be 253 and 232 kD. Lectin 2, on the other hand, showed only one protein band after SDS-PAGE with a molecular weight of approximately 81 KD.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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