Anti-stress and Antioxidant Effects of Non-Centrifuged Cane Sugar, Kokuto, in Restraint-Stressed Mice

摘要

Stress is a part of everyday life, but excessive stress can be related to diverse diseases. Recently, oral intake of a non-centrifuged cane sugar, Kokuto, was reported to produce potential anti-stress effects in humans. However, the molecular components associated with the anti-stress property of Kokuto remain mostly unknown. Therefore, we focused on the non-sugar component (NSC) fractions of Kokuto, and investigated how serum corticosterone level (used as a stress marker) and antioxidant activity were affected in restraint-stressed mice treated with NSC fractions obtained from the elusion on HP-20 resin with 25%, 50%, 75%, and 100% aqueous methanol (MeOH) solutions. Among the four NSC fractions, the 50% MeOH fraction showed a high content of phenolic compounds and high antioxidant activity. Moreover, oral administration of the 50% MeOH fraction suppressed both corticosterone secretion into the serum and reduction of antioxidant activity in serum and liver in restraint-stressed mice. Component analysis of the 50% MeOH fraction identified five antioxidative phenolic compounds: P-hydroxybenzaldehyde, p-hydroxyacetophenone, schaftoside, isoschaftoside, and P-coumaric acid. Phenolic compounds detected in the NSC fractions of Kokuto might contribute to the anti-stress property of Kokuto. In addition, this research provides more understanding of potential health benefits offered by the constituents of Kokuto.