Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/15985
Title: Investigation of the antioxidant nature of tropical plants and fruits
Authors: LOW LAN ENG
Keywords: Antioxidants; Rhoeo spathacea; Pereskia bleo; Fructus lycii; Soxhlet extraction; vacuum frying
Issue Date: 25-Aug-2008
Source: LOW LAN ENG (2008-08-25). Investigation of the antioxidant nature of tropical plants and fruits. ScholarBank@NUS Repository.
Abstract: Optimization of the extraction of Rhoeo spathacea (Commelinaceae), Pereskia bleo DC. (Cactaceae) and Fructus lycii (Lycium barbarum) was carried out using different methods and solvents. The extracts were examined for their antioxidant activities by evaluating their radical scavenging ability using the 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The total polyphenolics content was determined using the Folin-Ciocalteu reagent while the reducing power was via the ferric reducing ability (FRAP) assay. Soxhlet extraction using polar solvents generally gave higher antioxidant results. Rhoeo spathacea showed the highest antioxidant activity, followed by Pereskia bleo and Fructus lycii. Significantly high correlation between the 3 different assays was observed. Isolation of antioxidants was focused on the major antioxidant peaks of Rhoeo Spathacea, followed by structural elucidation of the pure compounds using HPLC, MS and NMR. The effect of vacuum frying on the antioxidants profile was investigated by comparing the antioxidants profile between fresh and vacuum fried salak and papaya.
URI: http://scholarbank.nus.edu.sg/handle/10635/15985
Appears in Collections:Master's Theses (Open)

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