Phosphoric Acid → Isoquercetin

Participants

Reaction Conditions

Reaction Steps

Rutin (5 g) was dispersed in about 90 ml of water. One of the various edible components (food additives) listed in Table 1 was added thereto in a proportion of 0.05 wt. % or 0.5 wt. %, and dissolved or dispersed. The mixture was heated to 72° C. The pH thereof was adjusted to 4.7 by pH adjustors (sulfuric acid, sodium hydroxide). Water was added to the mixture to a total volume of 100 ml. The reaction was initiated by introducing 1 ml of an aqueous solution of naringinase (manufactured by Amano Enzyme, Inc., trade name: naringinase “Amano”) prepared by mixing 0.02 g of naringinase (specific activity: 3000 U/g) with 10 ml of water. Five hours later, 4 μl of the reaction solution was sampled and dissolved in 50 μl N sodium hydroxide. A mixed solution of 15 volume % acetonitrile and 0.085 w/v % phosphoric acid was added (2 ml in total) thereto to stop the reaction. The reaction solution thus obtained was subjected to HPLC under the conditions described below. The amount of isoquercitrin produced was calculated based on the ratio of the peak area for isoquercitrin relative to the sum of the peak areas for rutin and isoquercitrin. The yield (%) of isoquercitrin was calculated from the amount of isoquercitrin. As a control experiment, a similar reaction was conducted in a system in which none of the edible components was present, and the isoquercitrin yield (%) was obtained in the same manner.

Provenance & Evidence