New Research Methods for Analyzing Traditional Chinese Medicine Revealed

A recent joint study from the Harbin University of Commerce and Northeast Forestry University, both in Harbin, China, highlighted advancements made in analyzing active components in traditional Chinese medicine (TCM). Their research was published in the Journal of Chromatography A (1).

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TCM has been practiced for thousands of years for preventing and treating various ailments. Including various physical and psychological approaches, herbal TCM products have been noted for having outstanding medicinal value, moderate treatment effects, and few side effects (2). TCM can play a central role during clinical courses, providing a valuable and easily accessible resource for medical and epidemiological research; further, TCM is commercially available in some western countries as dietary supplements or natural health foods with high medicinal values.

However, the active components of TCM are typically complex, with clinical efficacy often depending on the comprehensive effects of multiple ingredients. It is important, then, to create a simple, rapid, and reliable method for extracting active ingredients from TCM. Various sample pretreatment technologies have been increasingly utilized to address these challenges, including liquid-phase microextraction (LPME), molecularly imprinted solid-phase extraction, magnetic solid-phase extraction (MSPE), and solid-phase microextraction. While these are all effective, environmentally friendly technologies are rising in popularity to meet green chemistry standards. As a result, green solvents-based LPME techniques are becoming the preferred choice for TCM researchers extracting active components.

In this review, the scientists presented a summary of various LPME techniques, novel green solvents, and their applications in analyzing active ingredients within complex TCM samples. LPME methods, such as single-drop microextraction (SDME), hollow-fiber liquid-phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME), and electro-membrane extraction (EME), have proven successful in extracting active TCM ingredients, in addition to their determination by various chromatography or spectral techniques. SDME was the simplest and most effective method for enriching volatile compounds in TCM, while the HP-LPME technique was most notable for its purification functions. Meanwhile, the EME and DLLME methods can significantly shorten extracting times, with DLLME being the most used method for extracting active components in TCM samples, thus showing DLLME’s simplicity, quickness, and easy-to-automate nature.

Novel green solvents are also gaining considerable attention in recent decades, namely deep eutectic solvents (DESs), ionic liquids (ILs), magnetic ionic liquids (MILs), supramolecular solvents (SUPRAS), and switchable solvents (SSs). DESs and ILs have been widely applied to extract bioactive TCM ingredients, showing good solubility, low volatility, and low toxicity. The active ingredients of TCM are the material basis for their ability to play therapeutic roles; as such, LPME techniques based on green solvents are vital in extracting active TCM ingredients due to the complex nature of TCM samples.

While these findings are notable, there are still challenges faced by researchers that extract active compounds from TCM, such as simultaneous extraction of multi-component features, since TCM exerts its pharmacological effects through a multi-component, multi-target mechanism. It is therefore important to synthesize suitable green solvents that ensure the isolation of multiple active TCM compounds while minimizing contaminant presence. Various biomaterials, such as enzymes, cells, and polymer materials, should also be considered to allow for discovery of various active TCM ingredients. The researchers also pushed for the combination of LPME techniques and analysis approaches to be explored further. Their future research efforts will focus on studying miniaturized extraction techniques, seeking for green solvents, and promoting LPME application in targeted and untargeted metabolomics, contributing to their advancements in TCM and human health quality.

References

(1) Zhao, L-Z.; Cao, H-L.; He, Z-Q.; et al. Recent Advances in Green Solvents-Based Liquid-Phase Microextraction Techniques for Chromatographic Analysis of Active Components in Traditional Chinese Medicine. J. Chromatogr. A 2025, 1741, 465604. DOI:10.1016/j.chroma.2024.465604

(2) Traditional Chinese Medicine: What You Need to Know. National Center for Complementary and Integrative Health 2019. https://www.nccih.nih.gov/health/traditional-chinese-medicine-what-you-need-to-know (accessed 2025-1-8)