BACKGROUND Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactivities. However, the physicochemical properties of DMY related to its bioavailability, especially the stability, were unclear yet. RESULTS The effects of pH, temperature, metal ions and ascorbic acid (AA) on the stability of DMY were studied by HPLC. The bioavailability of DMY in the absence and presence of AA was compared. DMY was unstable in weak alkaline solutions, and the degradation was significantly accelerated with the presence of Cu2+ and Fe3+ . The degradation process followed the first-order kinetic model. The degradation rate constant (k) increased with the rise of pH and temperature. The remaining DMY was only 49% after 4 h in simulated intestinal fluid (SIF) at 37 °C. However, by supplementing with AA, DMY remained almost 100% within 6 h. The solubility of DMY at pH 3-5 was about 750 μg mL-1 with slightly increased to 853 μg mL-1 at pH 6. Pharmacokinetic studies showed that the bioavailability of DMY was increased from 0.122% to 0.341% by supplementing with AA (10% of DMY). CONCLUSION The degradation of DMY is one reason for its poor bioavailability. The presence of AA could significantly improve the stability of DMY, and further improve its bioavailability in rats. This article is protected by copyright. All rights reserved.

中文翻译：

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二氢杨梅素的理化性质及抗坏血酸对其稳定性和生物利用度的影响

背景二氢杨梅素（DMY）是一种具有多种生物活性的天然二氢黄酮醇。然而，DMY 与其生物利用度相关的理化性质，尤其是稳定性尚不清楚。结果采用高效液相色谱法研究了pH、温度、金属离子和抗坏血酸(AA)对DMY稳定性的影响。比较了不存在和存在 AA 时 DMY 的生物利用度。DMY在弱碱性溶液中不稳定，Cu2+和Fe3+的存在显着加速降解。降解过程遵循一级动力学模型。降解速率常数 (k) 随着 pH 值和温度的升高而增加。在 37°C 的模拟肠液 (SIF) 中，4 小时后剩余的 DMY 仅为 49%。然而，通过补充 AA，DMY 在 6 小时内几乎保持 100%。DMY在pH 3-5时的溶解度约为750 μg mL-1，在pH 6时略增至853 μg mL-1。药代动力学研究表明，添加AA后DMY的生物利用度从0.122%提高到0.341%（ DMY 的 10%）。结论 DMY 的降解是其生物利用度差的原因之一。AA的存在可以显着提高DMY的稳定性，进一步提高其在大鼠体内的生物利用度。本文受版权保护。版权所有。AA的存在可以显着提高DMY的稳定性，进一步提高其在大鼠体内的生物利用度。本文受版权保护。版权所有。AA的存在可以显着提高DMY的稳定性，进一步提高其在大鼠体内的生物利用度。本文受版权保护。版权所有。