Polyphenols in Naruto Kintoki sweet potato enhanced antiallergic activity after baking and microwave cooking

• Published in: FOOD SCIENCE AND TECHNOLOGY RESEARCH Vol. 28; no. 3; pp. 275 - 283
• Main Authors: Phomkaivon, Naraporn, Amilia, Nia, Tanintaratan, Witwasin, Yonekura, Lina, Tamura, Hirotoshi
• Format: Journal Article
• Language: English; Japanese
• Published: Tsukuba Japanese Society for Food Science and Technology 2022; The Japanese Society for Food Science and Technology; Japan Science and Technology Agency
• Subjects: Aglycones; antiallergic activity; Baking; Cooking; flavonol sulfate; Flavonols; Ipomoea batatas; Naruto Kintoki; Plant extracts; Polyphenols; Potatoes; RBL-2H3 cells; Sulfates; sweet potato peel; Sweet potatoes; Vegetables
• ISSN: 1344-6606; 1881-3984
• DOI: 10.3136/fstr.FSTR-D-21-00268

The antiallergic activity of extracts of Naruto Kintoki sweet potato peel was enhanced after cooking the peel using three conventional methods. Using 400 µg/mL extracts, baking showed the highest suppression of β-hexosaminidase release (36.9%), followed by microwaving (41.9%) and boiling (64.2%). Significant suppression of β-hexosaminidase release from RBL-2H3 cells in response to Naruto Kintoki peel extract was attributed to compounds 9 (r = 0.91, p < 0.01) and 11 (r = 0.76, p < 0.05). UPLC/ESI-Q-TOF-MS analyses of compounds 5 and 8 clarified the existence of two sulfates of flavonol aglycones (3, 5, 3′-trihydroxy-7, 4′-dimethoxyflavone 3-O-sulfate and 3, 5-dihydroxy-7, 4′-dimethoxyflavone 3-O-sulfate). Baking the sweet potato peel changed compounds 5 and 8 to compounds 9 and 11 with enhanced antiallergic activity. Specifically, IC50 values changed from 11.0 µg/mL (5) to 4.1 µg/mL (9) and from 12.1 µg/mL (8) to 4.4 µg/mL (11). We found those four chemicals contributed to the observed antiallergic activity of Naruto Kintoki sweet potato peel extracts.