Research on the quality evaluation of different origins of Chinese herbal medicine Lobelia chinensis Lour. based on HPLC fingerprint and content determination. Lobelia chinensis Lour. is a dried whole plant of the Campanulaceae family, which has the effects of clearing heat and detoxifying, diuresis and reducing swelling. It is mainly produced in Henan, Anhui, Jiangxi, Guizhou and other places, and is a commonly used anti-cancer Chinese medicine in clinical practice. Modern chemical composition and pharmacological studies have shown that half lotus contains various effective ingredients such as flavonoids, phenylpropanoids, alkaloids, etc., which have various pharmacological activities such as anti-cancer, microcirculation improvement, pain relief and anti-inflammatory, antioxidant, prevention and correction of blood system damage, and inhibition of alpha glucosidase. The main quality control indicators of Scutellaria barbata in the 2020 edition of the Chinese Pharmacopoeia are thin-layer identification and extraction determination, indicating that the quality control of Scutellaria barbata is still incomplete, which hinders the further development and utilization of Scutellaria barbata resources. Fingerprint/feature map is a commonly used method for quality control of traditional Chinese medicine, and has been extensively studied. However, there is still limited research on the fingerprint/feature map of half lotus, and there have been no reports on the quality evaluation of half lotus medicinal materials from different production areas. This study combines fingerprint spectrum and content determination, and evaluates the quality of Chinese medicine from different production areas through chemometric analysis, providing reference for quality control and a basis for the selection and further development of Chinese medicine resources.

Establishment of fingerprint spectrum. The establishment of the fingerprint spectrum of Banbianlian medicinal herb was investigated using three mobile phase systems: methanol-0.1% phosphoric acid solution, acetonitrile-0.1% phosphoric acid solution, and acetonitrile-0.1mol/L potassium dihydrogen phosphate solution. The results showed that using acetonitrile-0.1mol/L potassium dihydrogen phosphate solution resulted in more chromatographic peak information and better separation efficiency. Using a diode array detector, full wavelength scanning was performed in the range of 190-400nm, and fingerprint spectra were extracted at different wavelengths for comparison. The results showed that at 340nm, the chromatographic peak information of the fingerprint spectrum was large and the overall peak shape was high. The preparation method of the test solution was investigated using single factor analysis, with the index of “total peak area of common peaks in the fingerprint spectrum/sample weight”. The focus was on the effects of extraction solvent, extraction method, extraction time, and extraction solvent dosage on the fingerprint spectrum, and the optimal sample preparation method was selected. The fingerprint spectrum basically reflects the intrinsic quality information of the Chinese medicinal herb. Using high-resolution mass spectrometry to identify common peaks and mzCloud mass spectrometry database to speculate unknown components, combined with comparison of retention time of reference standards and 3D spectral analysis, the identified compounds were confirmed. Currently, 4 compounds have been confirmed, and there are still 4 components that need further confirmation due to difficulty in obtaining reference standards.
Similarity evaluation and chemometric analysis. The overall similarity of the fingerprint spectra of half lotus medicinal materials from different production areas is relatively high, with similarity values above 0.9. However, there are slight differences in the range of similarity values. HCA and PCA divided 18 batches of samples into two categories, proving that samples from different production areas have both similarity and certain production specificity. OPLS-DA analyzed the differential components and found 7 differential markers, with VIP values ranked as Peak 2>Peak 1 (luteolin 7-diglucoside)>Peak 10 (diosmin)>Peak 11 (magnolol)>Peak 3>Peak 8>Peak 5. Comparing the peak areas of the seven common peaks in the fingerprint spectra of 18 batches of Chinese medicinal herbs, the results showed that the peak areas of the seven common peaks in Chinese medicinal herbs from Henan and Anhui production areas were higher than those from other production areas, indicating that the content of the seven components in Chinese medicinal herbs from Henan and Anhui was relatively high. The quality of whole grass traditional Chinese medicine is greatly affected by different harvesting times and processing methods in different production areas. Therefore, the appropriate harvesting period should be selected based on the changes in the active ingredients of whole grass traditional Chinese medicine in different growth periods, and reasonable production area processing should be carried out according to the properties of the active ingredients to ensure the quality of the medicinal materials.
Selection of content determination indicators. Diosimin, also known as Xiangyemu glycoside and Buju glycoside, has pharmacological effects such as increasing venous tension, improving microcirculation, and reducing edema. Menghua glycoside has antibacterial, anti-inflammatory, and antioxidant activities, which can inhibit the proliferation of various tumor cells and induce their apoptosis. It has a protective effect on organs such as the liver and kidneys. Both of these components are one of the main active ingredients of Banbianlian, with high content in Banbianlian medicinal materials and easy access to reference standards. They have certain specificity and are differential markers for medicinal materials from different production areas. Therefore, selecting the above components as content determination indicators can effectively evaluate the quality of Banbianlian medicinal materials. Based on the research results of Zeng et al., the determination of diosmin and paeoniflorin was carried out, and the chromatographic conditions and preparation methods of the test solution were optimized and screened. Diosmin is easily soluble in dimethyl sulfoxide and strong alkaline solutions, insoluble in water, and slightly soluble in methanol or ethanol. Therefore, after investigating the extraction solvent, the “universal solvent” dimethyl sulfoxide was selected as the extraction solvent to ensure the full extraction of diosmin. Methodologically validated, this method has good specificity, repeatability, and accuracy, and can provide important reference for the improvement of quality standards under the Chinese Pharmacopoeia for half lotus medicinal materials. According to the determination results of 18 batches of medicinal materials, the content of diosmin and paeoniflorin in the medicinal materials of Henan and Anhui provinces is generally higher than that in other production areas, proving that the overall quality of medicinal materials in Henan and Anhui provinces is better than that in other production areas, providing a basis for the selection and further development of medicinal materials resources of Henan and Anhui provinces.