Laura Peter Dabbi, (2007) Antioxidant activities of Metroxylon sagu extract and its therapeutic effects on cigarette smoke exposed mice. Masters thesis, Universiti Malaysia Sabah.
It is known that a vast number of natural compounds in the plant kingdom possess antioxidant properties that can combat the deleterious effects of free radicals and thus prevent a number of diseases. Metroxylon sagu was extracted with water using the Liquid-Solid extraction method. 2.87% yield of sago aqueous extract (SAE) was obtained. Determination of the antioxidant activities of the SAE was carried out by the Ferric Thiocyanate (FTC) method, 2,2' Azinobis-(3-ethylbenzothiazoline-6-sulphonate)(ABTS) assay and Metal Chelating Activity. SAE has been shown to be a potential natural antioxidant source, based on its action in inhibiting the peroxidation of linoleic acid, scavenging the 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulphonate) radicals and its metal chelating properties. Three peaks with retention times of 2.61 min, 4.30 min and 4.70 min, respectively, were detected on separation of SAE by HPLC using C18 reverse phase column. The first peak, SAE (Peak 1) was further investigated using FT-IR and NMR as it was the most stable peak. Based on the FT-IR spectrum, the principal bands identified in SAE (Peak 1) were those belonging to alkanes, alkenes, unsaturated aliphatics, carbohydrates and alcohols. Identification of SAE (Peak 1) using 1H NMR found ten different equivalent protons, which could belong to aliphatic and carbohydrate regions (as the region indicative of these compounds is approximately (5 0.8 to 5 4.2). 13C NMR spectrum of SAE (Peak 1) shows the presence of twelve carbons of which ten carbons were located within the range of 5 60.3 -b 81.5, and the remaining two at b 92.3 and b 103.8, respectively. The possible compound with these structures could be carbohydrates, with ten non-anomeric carbons, and the remaining two probably are signals from C-1 at a reducing terminus and C-1 involved in a glycosidic lingkage. The brine shrimp lethality test shows that SAE is non-toxic when compared to potassium dichromate with relative toxicity of 0.004. For the determination of free radical scavenging enzyme activities (superoxide dismutase, glutathione peroxidase and catalase), the negative control group showed significantly higher glutathione peroxidase activities in the lung tissue compared to the experimental group. In liver and kidney tissues, the experimental group showed a significantly lower catalase activity compared to the negative control group and in brain tissue, higher catalase activities were observed in the experimental group compared to the negative controls. Thus, SAE supplementation has protective effects in reducing those free radicals that are released from sidestream cigarette smoke before causing extensive damage to the tissues. Thus, a lesser amount of glutathione peroxidase and catalase activity is needed to combat the oxidative stress induced from the cigarette smoke in those tissues. Based on these results, SAE supplementation might have a beneficial role in protecting smokers and non-smokers exposed to sidestream cigarette smoke.
|Item Type:||Thesis (Masters)|
|Subjects:||?? QD241-441 ??|
|Divisions:||SCHOOL > School of Medicine|
|Deposited By:||IR Admin|
|Deposited On:||19 Nov 2010 14:49|
|Last Modified:||19 Nov 2010 14:49|
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