Isolation and partial characterization of allelopathic chemicals from the leaves of wild sunflower Tithonia diversifolia (Hemls.) A. Gray

Date

10-1997

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Evelyn B. Rodriguez

Co-adviser

Cleofe A. Calanasan

Abstract

The crude extract from dried and ground wild sunflower leaves obtained by solvent extraction and base hydrolysis was fractionated into the ester-bound compound, free uncombined acid and insoluble-bound acid fractions. The crude fractions were assayed for their inhibitory effects on radish (Raphanus sativus L) seed germination using the petri dish method. Of the three fractions, the ester-hound compound fraction was found to exhibit the greatest inhibition. Hence, it was further fractionated by flash column chromatography, yielding fractions FCC 1 to FCC 6. These fractions were again submitted to radish seed germination bioassay (vial method). FCC 3, obtained in greatest amount, was found to be one of the two most active fractions. Further fractionation of FCC 3 by preparative radial TLC using the Chromatotron gave a whitish solid labeled RST.

RST has a UV max at 216 nm (absolute ethanol). UR spectral analysis showed characteristic absorption bands at 3380 cm.' (phenolic 0-11 stretch, H-bonded), 1605-1454 cm ' (aromatic C.,' stretch) and 1289 cm"' (CO- stretch). Reaction with diazotized p-nitroaniline and ferric chloride-ferricyanide suggested a phenolic group. Taken all together, RST could be a mononuclear. phenol stilt an alkyl or alkenyl substituent.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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