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Abstract
The present study was performed to investigate antioxidant, anticancer, and antimicrobial activities of four Korean sweet potato variaties and to identify the changes in these biological activities under different cooking conditions. Total polyphenol content was 3.8-73.6 mg/g in 80% ethanol extracts of sweet potatoes. The polyphenol content was highest Sinjami variety (p < 0.05). Radical scavenging activity against DPPH and ABTS·+ was high in Sinjami (p < 0.05) and the ethanol extract from Sinjami also showed effective superoxide dismutase (SOD)-like activity, which decreased significantly by steaming and roasting (p < 0.05). Ethanol extracts from the four sweet potato variaties did not inhibit cancer cell growth in MCF-7 or HepG2 cells at concentrations of 1, 10, and 100 µg/mL. Of the investigated sweet potato variaties, only Sinjami exhibited strong antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium. The antimicrobial activity of Sinjami against E. coli, St. aureus, and S. typhimurium decreased following steaming and roasting (p < 0.05). These results indicate that the Sinjami Korean sweet potato had higher polyphenol content, radical scavenging activity, SOD-like activity, and antimicrobial activity than those of the other variaties and consuming raw Sinjami might be beneficial for maintenance of biological activities.
Figures and Tables
Fig. 1
SOD-like activity of ethanol extracts from sweet potato, Shinzami. The SOD-like activity of sweet potato extracts and L-ascorbic acid was determined at 10 mg/mL. Data was expressed as Mean ± SD. Values with different alphabet are significantly different at p < 0.05 by Duncan's multiple range test.
Fig. 2
Effects of ethanol extracts from sweet potato, Shinzami on the growth of (A) Escherichia coli, (B) Staphylococcus aureus, and (C) Salmonella typhimurium. Values with different alphabet within the same time are significantly different at p < 0.05 by Duncan's multiple range test.
Table 1
Cooking conditions of sweet potato and yields, polyphenol content of their ethanol (80%) extracts by cooking conditions
1) Data was expressed as Mean ± SD 2) Values with different capital letters within the same column are significantly different at p < 0.05 by Duncan's multiple range test 3) Values with different small letters within a column of the same variety of sweet potato are significantly different at p < 0.05 by Duncan's multiple range test. NS: not significantly different at p < 0.05 4) 121℃, 10 min 5) 200℃, 50 min
Table 2
Radical scavenging activity of ethanol extracts from sweet potato
1) Data was expressed as Mean ± SD 2) Values with different capital letters within the same column are significantly different at p < 0.05 by Duncan's multiple range test 3) Values with different small letters within a column of the same variety of sweet potato are significantly different at p < 0.05 by Duncan's multiple range test. NS: not significantly different at p < 0.05
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