This study compared the antioxidant properties of Hibiscus sabdariffa extract (HSE), commercial aged garlic extract (AGE, Kyolic) and garlic tablet (GT). The results indicate that HSE, AGE and GT are effective antioxi...This study compared the antioxidant properties of Hibiscus sabdariffa extract (HSE), commercial aged garlic extract (AGE, Kyolic) and garlic tablet (GT). The results indicate that HSE, AGE and GT are effective antioxidant as xanthine/xanthine oxidase generated superoxide ions are significantly inhibited in the presence of 20% (v/v) diethyl ether extract of HSE, AGE and GT by 100%, 66.39% and 18.61% respectively, while uric acid production is not affected byAGEand GT. However, at 2.5% and 5.0% (v/v) reaction volumes,HSEsignificantly inhibits uric acid production by 9.5% and 33.0% respectively, and this suggests that components ofHSEinhibit xanthine oxidase activity while AGE and GT scavenge superoxide. In addition, it is also found that the three extracts scavenge ABTS radical cations in dose-dependent manner. In all cell free assays, HSE is found to be more effective as an antioxidant when compared with AGE and GT under the same experimental conditions. Chromatographic and colorimetric analyses suggest thatHSEhas numerous different types of phenolic compounds with higher amount of phenolic compounds (14.9 mg/g) when compared withAGE(2.8 mg/g) and GT (3.6 mg/g) catechin equivalent respectively. Therefore, the effectiveness of antioxidant activities of these three extracts may be related to their phenolic content.展开更多
Citrullus lanatus (Watermelon) is a fruit cultivated and consumed in Africa for its essential nutrients which are very beneficial to the human body. The present study was designed to evaluate the nutritive contents, f...Citrullus lanatus (Watermelon) is a fruit cultivated and consumed in Africa for its essential nutrients which are very beneficial to the human body. The present study was designed to evaluate the nutritive contents, free radical scavenging activities and phytochemical components of C. lanatus fruit. The extract of the fruit was subjected to in vitro antioxidant assessment using 1,1-di-phenylpicryl-hydrazyl radical (DPPH) and hydrogen peroxide radical scavenging assays. The proximate and phytochemical analyses were conducted using standard procedures. The results of this study showed that C. lanatus fruit had very high moisture content and its crude protein, crude fat, crude fibre and ash content were all in traceable amounts. The sugar content was considerably high in comparison with other nutritive contents. Lycopene and β-carotene contents of C. lanatus fruit were estimated to be 4537.83 and 308.71 μg/100g respectively. The gross energy evaluation showed a value of 0.335 Kcal/g. The fruit extract exhibited significant (p 50 of 0.10 mg/ml) and hydrogen peroxide radicals scavenging activity (IC50 of 0.62 mg/ml) in comparison with the positive control butylated hydroxytoluene (BTH). This study therefore recommends that C. lanatus fruit could be an excellent source of antioxidants which may prevent diseases whose pathogenesis involves oxidative stress.展开更多
文摘This study compared the antioxidant properties of Hibiscus sabdariffa extract (HSE), commercial aged garlic extract (AGE, Kyolic) and garlic tablet (GT). The results indicate that HSE, AGE and GT are effective antioxidant as xanthine/xanthine oxidase generated superoxide ions are significantly inhibited in the presence of 20% (v/v) diethyl ether extract of HSE, AGE and GT by 100%, 66.39% and 18.61% respectively, while uric acid production is not affected byAGEand GT. However, at 2.5% and 5.0% (v/v) reaction volumes,HSEsignificantly inhibits uric acid production by 9.5% and 33.0% respectively, and this suggests that components ofHSEinhibit xanthine oxidase activity while AGE and GT scavenge superoxide. In addition, it is also found that the three extracts scavenge ABTS radical cations in dose-dependent manner. In all cell free assays, HSE is found to be more effective as an antioxidant when compared with AGE and GT under the same experimental conditions. Chromatographic and colorimetric analyses suggest thatHSEhas numerous different types of phenolic compounds with higher amount of phenolic compounds (14.9 mg/g) when compared withAGE(2.8 mg/g) and GT (3.6 mg/g) catechin equivalent respectively. Therefore, the effectiveness of antioxidant activities of these three extracts may be related to their phenolic content.
文摘Citrullus lanatus (Watermelon) is a fruit cultivated and consumed in Africa for its essential nutrients which are very beneficial to the human body. The present study was designed to evaluate the nutritive contents, free radical scavenging activities and phytochemical components of C. lanatus fruit. The extract of the fruit was subjected to in vitro antioxidant assessment using 1,1-di-phenylpicryl-hydrazyl radical (DPPH) and hydrogen peroxide radical scavenging assays. The proximate and phytochemical analyses were conducted using standard procedures. The results of this study showed that C. lanatus fruit had very high moisture content and its crude protein, crude fat, crude fibre and ash content were all in traceable amounts. The sugar content was considerably high in comparison with other nutritive contents. Lycopene and β-carotene contents of C. lanatus fruit were estimated to be 4537.83 and 308.71 μg/100g respectively. The gross energy evaluation showed a value of 0.335 Kcal/g. The fruit extract exhibited significant (p 50 of 0.10 mg/ml) and hydrogen peroxide radicals scavenging activity (IC50 of 0.62 mg/ml) in comparison with the positive control butylated hydroxytoluene (BTH). This study therefore recommends that C. lanatus fruit could be an excellent source of antioxidants which may prevent diseases whose pathogenesis involves oxidative stress.
