• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.13-20
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• 2000

This study was designed the antioxidative effect of the ethanol extract obtained Rooibos tea (Aspalathus linearis) on various kinds of oil, and examined the synergistic effect of Rooibos tea extract by addition of citric acid to the antioxidation activity and also investigate to antioxidation effect of the extract in food production and storage peroids. The antioxidative activity of 0.2mg of Rooibos tea extract was showed similar to same doses of $\alpha$-tocopherol, BHA and BHT in linolieic acid-ethanol system. The antioxidative effect of the mixture with 0.1% Rooibos tea extract on lard was more effective than that of the mixture with same doses of $\alpha$-tocopherol, BHA and BHT. The antioxidative effect of Rooibos tea extract was showed slightly effects on lard or soybean oil. Antioxidative effects of Rooiboe tea extract in addition of citric acid as synergist showed more effective in linoleic acid-ethanol system, but did not showed in the other oils. In the application of Rooibos tea extract to food prodctuction and storage period, the antioxidative effect was more effective in biscult, preparation added lard mixed with 0.1% Rooibos tea extract.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.4
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• pp.251-262
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• 2007

In this study, the antioxidative effects, inhibitory effects on elastase, and components of Aspalathus linearis extracts were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}$) of extract/fractions of Aspalathus linearis were in the order: 50 % ethanol extract ($11.50\;{\mu}g/mL$) < deglycosylated flavonoid aglycone fraction ($8.47\;{\mu}g/mL$) < ethylacetate fraction ($4.76\;{\mu}g/mL$). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of some Aspalathus linearis extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The order of ROS scavenging activities were ethylacetate fraction ($OSC_{50},\;4.58\;{\mu}g/mL$) < deglycosylated flavonoid aglycone fraction ($2.20\;{\mu}g/mL$) < 50 % ethanol extract ($1.09\;{\mu}g/mL$). 50 % Ethanol extract showed the most prominent scavenging activity. The protective effects of extract/fractions of Aspalathus linearis on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Aspalathus linearis extracts suppressed photohemolysis in a concentration dependent manner, particularly 50 % ethanol extract exhibited the most prominent celluar protective effect (${\tau}_{50}$, 272.00 min at $50\;{\mu}g/mL$). Aglycone fractions obtained from the deglycosylation reaction of ethylacetate fraction among the Aspalathus linearis extracts, showed 3 bands in TLC and 3 peaks in HPLC experiments (360 nm). Three components were identified as luteolin (composition ratio, 18.24 %), quercetin (58.79), and kaempferol (22.97). TLC chromatogram of ethylacetate fraction of Aspalathus linearis extract revealed 7 bands and HPLC chromatogram showed 9 peaks, which were identified as isoorientin (composition ratio, 14.71 %), orientin (28.84 %), vitexin (5.63 %), rutin and isovitexin (12.73 %), hyperoside (9.24 %), isoquercitrin (5.40 %), luteolin (1.48 %), quercetin (17.61 %) and kaempferol (4.59 %) in the order of elution time. The inhibitory effect of aglycone fraction on elastase ($IC_{50},\;9.08\;{\mu}g/mL$) was very high. These results indicate that extract/fractions of Aspalathus linearis can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Aspalathus linearis extract and inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.307-313
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• 2006

Reactive oxygen species (ROS) and formation of advanced glycation end products (AGEs) play an important role in the pathogenesis of diabetic nephropathy by hyperglycemia. To find natural agents improving diabetic nephropathy, 63 natural resources which used to the treatment of diabetes mellitus in a folk remedy were investigated with an in vitro system employing radical scavenging activity and inhibitory activity of AGEs formation. In results, the extracts of Aspalathus linearis, Rubus coreanus, Rosa rugosa, and Epimedium koreanum significantly inhibited the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical with $IC_{50}$ values less than $10{\mu}g/ml$. The extracts of Zea mays, Cucurbita moschata, Cudrania tricuspidata, and Aspalathus linearis effectively reduced the formation of AGEs compared with the positive control $N-acetyl-_L-cystenine$ (NAC) and aminoguanidine (AG). In addition, the extracts of Aspalathus linearis, Commelina communis, Cornus officinalis, and Lespodeza cuneata showed the all inhibitory activity against DPPH radical and AGEs formation. Also, these resources definitely showed the radical scavenging activity against peroxynitrite $(ONOO^-)$ and hydroxyl radical $({\cdot}OH)$ relating to high glucose-induced ROS production. Thus, these results suggest that some natural resources may regulate the initiation and progression of diabetic nephropathy through inhibition of ROS production and AGEs formation.

• Journal of Life Science
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• v.14 no.2
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• pp.291-295
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• 2004

Rooibos (Aspalathus linearis) (RB) is a leguminous shrub native to the mountainous areas of the northwestern Cape Province in South Africa. RB tea infusions are the fermentation products of its leaves and fine sterns, and known to have a high antioxidative activity due to the presence of flavonoids and phenolic acids. We investigated the effects of RB tea on the alleviation of oxidative stress on cultured rat cortical neurons in a hypoxic model. Measurement of lactate dehydrogenase (LDH) released into culture media revealed that RB increased cell viabilities in both normoxia (6-18%) and hypoxia (2-24%) dose-dependently (10-100 $\mu\textrm{g}$/ml) on 16 days in vitro (3 days after treatment). Visualization of cell morphology by expression of GFP-Hsc70 fusion protein showed that RB (50 $\mu\textrm{g}$/ml) reduced the average vacuolated soma from 55.4$\pm$4.59% (no RB addition) to 40.9$\pm$6.3% (RB addition) on 5 days after hypoxia. Our results proves efficacy of RB in the neuroprotection of hypoxic neurons and extend application for RB into the prevention and/or treatment of neuronal damages.

• Food Science and Preservation
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• v.15 no.4
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• pp.582-586
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• 2008

Total phenolic compounds and antioxidative activities of rooibos tea(Aspalathus linearis) fractions were studied. Three extracts, using hexane, ethyl acetate, and ethanol, were prepared. Total phenolic compounds were 3069.3 mg/100 g extract in the hexane fraction, 18604.4 mg/100 g extract in the ethyl acetate fraction, and 13458.8 mg/100 g extract in the ethanol fraction. Levels of vanillic acid, caffeic acid, syringic acid, 4-coumaric acid, and ferulic acid were analyzed by RP-HPLC, and totals of 3452.6 and 3156.1 mg/100 g of extract were found in the ethanol and ethyl acetate fraction, respectively. In the DPPH assay, the ethanol fraction(82.2% of contol) and the ethyl acetate fraction(78.9%) showed the highest free radical scavenging capacities. The induction period of each tea fraction in the fish oil rancimat assay was measured. When 500 ppm of the ethanol fraction was applied, a 1.19 h induction period was observed. This was 2-fold greater than the induction period of the control.