Honey in traditional Chinese medicine: A guide to future applications of NADES to medicines

Honey has played an important role in traditional medicine for thousands of years. It has been used in different aspects of traditional medicine, as a single medicine, as an additive for paozhi processing, and as an adjuvant for different types of pharmaceutical formulations, such as electuary, honeyed pills, etc. Hundreds of compounds have already been found in honeys from different sources. However, the major compounds in honey are glucose and fructose in about equal molar ratios. This means that the basis of honey is a natural deep eutectic solvent (NADES). The physico-chemical properties of NADES may play an important role in the use of honey in traditional medicine. Clarifying the role of honey in traditional medicines helps to rationalize traditional practices, as shown in the example honey-frying of Astragalus propinquus (Astragali Radix) root material. Moreover, it may lead to the application of NADES in drug delivering systems. The different applications of honey in traditional medicine will be described, and its function and mechanism will be discussed. With the NADES concept we can now explain the various applications of honey as additive or adjuvant. As shown in numerous studies NADES are excellent solvents for medium polar bioactive compound. Besides improving the efficacy of herbal medicine, NADES also stabilize the active compounds. Honey has been used since ancient times for this purpose. The same effect can be achieved by a pure NADES, and the principle of improving solubility and stability can be applied to any poorly water-soluble medicine.