基于蜂蜜“NADES”特征研究黄芪蜜炙增效的炮制原理

Honey is one of the most commonly used excipients for processing Chinese medicine. The raw and honey-fried Radix Astragali are differentiated, but there is no conclusive evidence from the view of chemical composition. The previous researches focuses on the pieces, ignoring the synergistic effect of the excipients on the ingredients of the pieces in the process of "Honey processing- - Decoction - Absorption". Our study have confirmed that honey is a natural deep eutectic solvents (NADES) mainly composed of fructose and glucose. It forms intermolecular force with the molecules of solutes and plays the role of protecting the stability of solutes, improving extraction rate of ingredients, promoting the absorption of drugs. Those effects of NADES will be played in the honey-processed pieces. In this project, Astragali Radix (Huangqi) will be selected as an example and different processed products will be made. Firstly, the decoctions of different products will be compared on an animal model to evaluate their different effects on immune system, analyzed with metabolomics and synthetic chemistry to compared their chemical composition and find the changing tendency of chemical components, evaluated their difference in bioavailability in rat to evaluate the absorption-promoting effect of honey-frying. Then, NADES and compound monomers were used to verify the role of honey in “processing--decocting--absorbing” from the perspective of biological activity and chemical composition, so as to reveal the overall effect of accumulated effect of honey on the chemical components of Astragali Radix, reveal the mechanism of honey-processing. The results of the study will provide new ideas for the research of processing of Chinese medicine, and provide a reference for enterprises to improve the quality of the pieces.

蜂蜜是最常用中药炮制辅料之一。传统中医将炙品与生品异用，但蜜炙原理研究很少从化学层面找到确凿证据。已有研究重点关注饮片，忽略辅料在“蜜炙-煎煮-吸收”全程中对饮片成分的协同作用。我们研究证实蜂蜜是一种主要由葡萄糖和果糖组成的天然共熔混合物(NADES)，能与溶质形成分子间作用力，具有保护成分稳定、提高提取率、促进药物吸收的作用，因此推断NADES的作用也会体现在蜜炙饮片中。本项目以黄芪为例，制备不同炮制品，采用升白动物模型，结合肠道菌群分析，确认蜜炙增效作用；采用代谢组学和综合化学分析，比较其化学成分变化规律；通过多元统计分析，找出与蜜炙增效相关成分；通过药代实验，找出蜜炙促进吸收的成分。然后从生物活性和化学组成角度，分段验证蜂蜜在“蜜炙-煎煮-吸收”中的作用，厘清蜂蜜对黄芪成分的叠加作用，揭示蜜炙机理。研究结果将为中药炮制的研究提供新思路，也为企业提高饮片质量提供参考。

传统中医将蜜炙品与生品异用，但蜜炙原理研究很少从饮片化学物质层面找到确凿证据，与蜜炙是温和的炮制方式，没有引起主要化学成分的显著变化有关。本项目从蜂蜜的理化性质，从“辅料作用”角度进行整体研究。整体动物实验和细胞实验均证实蜜炙饮片的生物活性优于炒制饮片和生饮片，蜜炙饮片的生物活性的提升主要由蜂蜜对饮片成分的协同作用引起。蜂蜜在蜜炙饮片“炮制—煎煮—体内吸收”各个环节均发挥作用： ① 炮制过程，蜂蜜具有防止加热引起的饮片化学成分结构转化的作用，从而保持成分组成的稳定性的作用；② 煎煮过程中，蜂蜜具有促进成分溶出，显著提高汤剂中有效成分如总黄酮和总皂苷成分含量的作用；③ 体内吸收过程中，蜂蜜显著提升了活性成分的生物利用度。虽然单个环节作用很有限，但在上述过程的叠加作用下，最终结果表现出蜜炙显著提升饮片生物活性的作用。深入研究显示蜂蜜是一种具有超分子结构的天然共熔混合物(NADES)，能与溶质分子产生相互作用，从而发挥保护成分稳定、提高提取率、促进药物吸收的作用，最终表现出提升饮片生物活性的作用。该作用在蜜炙黄芪和蜜炙甘草饮片中均得到证实。该项目研究成果为完善黄芪蜜炙增效的炮制机理提供了科学实证；为完善已有的“辅料作用”论的科学内涵提供科学实证和理论基础；为蜂蜜及NADES的广泛应用提供了理论基础；为中药炮制理论的传承、创新和发展提供了示范性研究。