KAJIAN PERBANDINGAN AKTIVITI PEROKSIDAAN LIPID SECARA IN~VITRO BAGI EKSTRAK MIMOSA PIGRA DAN APLIKASI EKSTRAK SEBAGAI ANTIOKSIDA DALAM PEMAKANAN TILAPIA
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Date
2007-04
Authors
JIUN, LEE TZE
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Abstract
The antioxidant activities of 36 samples were evaluated by using ferric thiocyanate
(FTC) and thiobarbituric acid (TBA) assays. FTC result showed that leaves extract
that was soaked in distilled had the best antioxidant activity. Meanwhile stems and
leaves extract that was boiled in ethyl acetate has the best antioxidant activity in TBA
assay. Overall, boiling distilled water extract (of stems and leaves mixture) has the
best antioxidant activity in both assays. The experiment was further proceed by
choosing nine out of 36 samples (extracted out the chlorophylls by using paper
chromatography technique) to run the antioxidant activities test [seven boiled extracts
which were methanol (stems and leaves mixture), 80% methanol (stems and leaves
mixture), 70% ethanol (stems and leaves mixture), ethyl acetate (stems and leaves
mixture), 80% methanol (stems), methanol (leaves), ethanol (leaves); two soaked
extracts which were 70% ethanol (stems) and ethyl acetate (stems)]. In this test,
distilled water extracts were neglected because of the absence of chlorophylls during
extraction. FTC result showed that boiled 80% methanol extract without chlorophylls
(stems and leaves mixture) has the best antioxidant activity. Meanwhile stem extract
soaked with 70% ethanol without chlorophylls has the best antioxidant activity in TBA
assay. Overall, soaked 70% ethanol extract without chlorophylls (stems) proved to
have the best antioxidant activity. A comparison has been made between the boiled
distilled water extract (stems and leaves mixture) and the soaked 70% ethanol
extract without chlorophylls (stems). It is found that boiled distilled water extract
(stems and leaves mixture) had the best antioxidant activity. Therefore, the boiled
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The present study was also designed to estimate total phenolic content of all
the samples including with and without chlorophylls samples. The result has shown
that soaked ethyl acetate extract (leaves) had the highest phenolic content
(211±0.006 mgGAE/g extract). A low correlation between antioxidant assays (FTC
and TBA) and total phenolic for all the samples (with and without chlorophylls) except
for the chlorophylls samples from TBA assay, which showed the increased in
antioxidant activity as total phenolic increases. Phytochemical screening was carried
out on the boiled distilled water extract (stems and leaves mixture) by using thin layer
chr~matography (TLC}, UV-visible spectrometry and liquid chromatography mass
spectrometry (LCMS). Two major compounds (C1 and 81} from flavonoids class
(biflavonoids and isoprenoid-substituted flavonoid) has detected in the boiled distilled
water extract (stems and leaves mixture}.
Five fish diets were formulated which contained 0, 15, 20, 25 and 30
milligrams of the boiling distilled water extracts (stem and leaf mixture) and 4
milligrams of BHT as a control diet. The experiment was conducted for eight weeks.
The results showed that fish fed with diet 3 (20 mg) had the best weight gain, relative
growth rate (RGR), specific growth rate (SGR) and protein efficiency ratio (PER}.
Meanwhile, fish fed with diet 4 (25 mg) had the best food conversion ratio (FCR).
However, there were no significant difference (P>0.05) between hepatosomatic index
(HSI), viserasomatic index (VSI) and intraperitoneal index (IPF) within all tested
samples.
The fatty acid composition results showed that diet with increasing weight of
extract has percentage values of 16 types of fatty acids higher than the control diet
(BHT). TBA results showed that the control diet {BHT) has the highest values
throughout the whole storage period and diet 5 (30 mg) has the lowest TBA values
throughout the whole storage period except at the 2nd and 5th hour. The results from
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electrophoresis {SDS-PAGE) showed that diet 4 (25 mg) had the highest number of
protein bands (185) and on contrary, diet 3 (20 mg) had the lowest number of protein
bands (152)0
The histology result showed that fish fed the increment in the extract weight
can inhibit lipid peroxidation in liver (increased in the cytoplasmic vacuolation),
meanwhile hepatic cells of fish fed with control diet (BHT) may undergo a
physiological change which is called atrophy (decrease in cellular size)o Overall, the
results showed that the antioxidant activity of boiled distilled water extract {stems and
leaves mixture), can inhibit lipid oxidation whether in muscle or tilapia's liver.
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KAJIAN PERBANDINGAN AKTIVITI PEROKSIDAAN LIPID SECARA IN~VITRO BAGI EKSTRAK MIMOSA PIGRA