Detection of Phorbol esters from Jatropha curcas Linn seeds using diffraction-based sensing assay employing chitosan as the binding element

Date

10-2011

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Milagros M. Peralta

Abstract

Phorbol esters were isolated from Jatropha curcas whole seed cake and seed oil. Isolated phorbol esters were derivatized with hydroxylamine hydrochloride to obtain the oxime derivatives used in the diffraction based assay. Chitosan was used as the capture molecule for the phorbol ester and its oxime. Binding of analyte on the capture molecule increased the height of the patterned surface and caused a phase shift that increased the signal intensity which correlated positively with the concentration of the analyte molecules, making quantification of unknown samples possible. Based on the assay, the concentrations of phorbol esters in the crude extracts from Jatropha seed cake were found to be 442, 749 and 334 mg/mL for ethanol, methanol and isopropanol extracts, respectively. The concentration of phorbol esters from oil extracts were 437 and 268 mg/mL for methanol extracts from the oil and methanol extracts obtained from the petroleum ether solution of the oil, respectively. The limit of detection of the method was found to be 166 mg/mL and the analytical sensitivity of 14.45 mV.mL/mg. Thus, the utility of diffraction-based sensing for the detection of phorbol esters in both Jatropha seed cake and oil was demonstrated. The most efficient process for removal of phorbol esters was found to be sequential Soxhlet extraction of the seed cake with petroleum ether, then methanol. Liquid-liquid extraction of the seed oil (as is, without petroleum ether) with methanol as the extracting solvent gave a higher yield of Phorbol esters since the phorbol esters seemed to partition between the petroleum ether and methanol phases.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2011 C42 /G35

Document Type

Thesis

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