Elucidation of production mechanism and functionality of the decolorized compounds from acylated anthocyanins under interstine condition

• Project/Area Number: 12660124
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 食品科学・栄養科学
• Research Institution: MINAMI-KYUSHU UNIVERSITY
• Principal Investigator: TERAHARA Norihiko College of Horticulture, MINAMI-KYUSHU UNIVERSITY, Professor, 園芸学部, 教授 (60155471)
• Co-Investigator(Kenkyū-buntansha): MATSUI Toshiro Faculty of Agriculture, MINAMI-KYUSHU UNIVERSITY, Associate Professor, 農学部, 助教授 (20238942)
• Project Period (FY): 2000 – 2001
• Project Status: Completed (Fiscal Year 2001)
• Budget Amount: ¥2,900,000 (Direct Cost: ¥2,900,000); Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000); Fiscal Year 2000: ¥2,400,000 (Direct Cost: ¥2,400,000)
• Keywords: Red morning glory / Acylated anthocyanins / AGH inhibitory activity / Intestinal fluid solution / Faded molecular species / Pseudobase / Chalcone / Preparative ODS-HPLC system / 紫甘藷 / フラビリウム型色素 / ODS分取HPLCシステム

Research Abstract

Large-scale preparation of pure pigments was able to be comparatively performed from the purple sweet potato storage roots and the red morning glory petals in a short time by combining isolation and purification by column chromatographies such as XAD-2000, PVP and preparative HPLC. These were confirmed to be acylated anthocyanins with 3-sophoroside-5-glucoside as a common frame. As a result of putting the isolated acylated anthocyanins for 24 hours on the intestinal tract environment (pH 6.8, 37℃, darkness), the degree of fading (instability) was the order of YGM-5b > SOA-4 > YGM-3 and 6 > SOA-6. This result differs from the order (SOA-4 > SOA-6 > YGM-6 and 3) of AGH inhibitory activity, and not correlating made instability and AGH inhibitory activity clear.
In this reaction solution, three kinds of components considered to be an anhydrobase (A), a pseudobase (B), and a chalcone (C) were found. The reaction progressed like A→B→C with time and the compositions led to A:B:C≒1:1:2 except f or YGM-5b and SOA-6 after 24 hours. All pigments were holding caffeic acid.
Next, SOA-4 was faded under the intestinal tract environment in large quantities, and isolation and purification of C were tried using preparative HPLC. Consequently, when a neutral phosphate buffer solution system was used as eluent, C and other components could be separated, and C has been isolated with sufficient reproducibility. Moreover, it was strongly suggested as a result of mass analysis that component C is a chalcone which was generated from SOA-4 through hydrationand isomerization. Now, the desalting and the structural analysis by NMR are planned. Moreover, it is under examination also about isolation of the remaining components A and B.
It was thought that its 3-acylateded sugar side-chain structure (6-cafffeoylshophorose moiety) which SOA-4, -6 and YGM-3, and -6 have in common was indispensable to the expression of AGH inhibitory activity since the activity of SOA-4 doesnot change with fading (structural transformation of the aglycon part).