Isolation and Characterisation of Lipoxygenase Inhibitory Compounds from Chisocheton Polyandrus Merr

Author

Chan. K.Y., Chung, L.Y. and Mohamad, K.
Department of Pharmacy, Faculty of Medicine, University of Malaya
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Language

English

Title

Isolation and Characterisation of Lipoxygenase Inhibitory Compounds from Chisocheton Polyandrus Merr

Proceeding

Medicinal and Aromatic Plants Seminar (MAPS 2010)

Date

3rd August - 4th August 2010

Place Held

Forest Research Institute Malaysia(FRIM)

Abstract

Lipoxygenase (LOX) is an important enzyme as a biological target in developing anti- inflammatory drugs. The products of LOX pathway, hydroperoxides are associated with numerous inflammatory diseases such as atherosclerosis, asthma and inflammatory bowel disease. The ferrous oxidation-xylenol orange (FOX) assay is a rapid and robust assay suitable for measuring the hydroperoxides activity in LOX. In a previous study, Chisocheton polyandrus Merr., was reported to exhibit anti-inflammatory properties. In this study, FOX assay was optimised and applied in the bioassay-guided fractionation of the plant to isolate and identify the active anti-inflammatory compounds. FOX assay was carried out in a 96-well microplate by incubating 50 µl of LOX with 20 µl of plant extract of various concentrations for 5 mm. The reaction was started by the addition of 50 µl of linoleic acid and incubated for 15 min. The assay was terminated by the addition of 100 µl of FOX reagent. The absorbance readings were measured at 560 nm using microplate reader and were used to calculate the percentage inhibition of LOX. The dichloromethane and methanol crude extracts of leaves showed LOX inhibitory activities with IC50 value of 8.16±1.81 and 10.19±1.78 µg/ml, respectively. The leaf crude extract was further fractionated by using silica gel column chromatography (solvent hexane: acetone) to afford 15 fractions. Preliminary screening results of the 15 fractions showed five fractions that exhibited LOX inhibitory activities with percentage inhibition > 50% at concentration 10 µg/ ml. Compounds 1 and 2 were isolated from the five fractions and identified as dammarane triterpenoids. The IC50, value for compound I was 0.29±0.03 µg/ml and for compound 2 was 0.49±0.17 µg/ml. The dichloromethane crude extract showed a higher LOX inhibitory activity and was used for further fractionation. Bioassay-guided fractionation using optimised FOX assay had yielded two active compounds at the moment.

Keywords

Anti-inflammatory; inflammation; lipoxygenase; FOX assay: Chisocheton polyandrus Merr.

Session

Session 2: Oral 7

Topic

Harnessing the Tropical heritage: Recent Advances in R&D and commercialization