3.3. Assay of DPPH radical scavenging activity
The complete reduction of the DPPH radical is related to the high scavenging activity shown by a particular sample. A high level of antioxidants in the extract would indicate greater radical scavenging activity. Other studies on tea extracts showed that the levels of catechin affect the antioxidant capacity. Green and black teas were efficient in reducing DPPH due to their high catechin levels . The results of our study showed that white tea effectively reduces the oxidant free radical, DPPH. This could be due to the presence of high levels of EGCG (epigallocatechin gallate), a tea polyphenol in white tea . Hot water extract of tea showed IC50 values of 99.9 } 4.9 lg/ml . White tea extract was able to reduce the stable radical DPPH to the yellow coloured diphenylpicrylhydrazine. The scavenging effect increased with increasing concentrations of the extract. The results showed that the scavenging activity of catechin, a known antioxidant, was higher than extracts of C. sinensis. The IC50 value of catechin, quercetin and rutin was 39.3 } 4.6, 35.5 } 3.6 and 44.4 } 5.8 lg/ml, respectively. Other studies showed the relationship between tea TPC and scavenging of DPPH radical. An increase in TPC resulted in an increase of DPPH radical scavenging activity . In the present study, the tea with high TPC exhibited high potential DPPH radical scavenging activity.
3.3. Assay of DPPH radical scavenging activity
The complete reduction of the DPPH radical is related to the high scavenging activity shown by a particular sample. A high level of antioxidants in the extract would indicate greater radical scavenging activity. Other studies on tea extracts showed that the levels of catechin affect the antioxidant capacity. Green and black teas were efficient in reducing DPPH due to their high catechin levels . The results of our study showed that white tea effectively reduces the oxidant free radical, DPPH. This could be due to the presence of high levels of EGCG (epigallocatechin gallate), a tea polyphenol in white tea . Hot water extract of tea showed IC50 values of 99.9 } 4.9 lg/ml . White tea extract was able to reduce the stable radical DPPH to the yellow coloured diphenylpicrylhydrazine. The scavenging effect increased with increasing concentrations of the extract. The results showed that the scavenging activity of catechin, a known antioxidant, was higher than extracts of C. sinensis. The IC50 value of catechin, quercetin and rutin was 39.3 } 4.6, 35.5 } 3.6 and 44.4 } 5.8 lg/ml, respectively. Other studies showed the relationship between tea TPC and scavenging of DPPH radical. An increase in TPC resulted in an increase of DPPH radical scavenging activity . In the present study, the tea with high TPC exhibited high potential DPPH radical scavenging activity.
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