An innovative extraction strategy for herbal medicine by adopting p‐sulphonatocalix[6]/[8]arenes

• Published in: Phytochemical analysis 2022-10, Vol.33 (7), p.1068-1085
• Main Authors: Yu, Xuan, Liang, Teng‐hui, Wang, Meng, Ren, Xiao‐liang, Zhou, Zhen‐yu, Jiang, Miao‐miao, Zhang, De‐qin
• Format: Article
• Language: English
• Subjects: Alkalizing; Alkaloids; Aromatic compounds; Calorimetry; Differential scanning calorimetry; Energy conservation; extraction; Fluorescence; Herbal medicine; Herbs; host–guest; Infrared analysis; Infrared spectroscopy; NMR; Nuclear magnetic resonance; Optimization; Particle size; p‐sulphonatocalixarenes; Solubilization; Supramolecular compounds; Tetrandrine; Titration
• ISSN: 0958-0344; 1099-1565
• DOI: 10.1002/pca.3160

Introduction Alkaloids exist in various herbal medicine widely and exhibit diverse biological and pharmacological activities. p‐Sulphonatocalix[6]arenes (SC6A) and p‐sulphonatocalix[8]arenes (SC8A) are water‐soluble supramolecular macrocycles and are applied to the extraction of alkaloids from herbal products. Objective In this study, an innovative method of SC6A/SC8A assisted extraction of the alkaloids from herbs was established. Methods SC6A and SC8A were designed to extract 27 alkaloids from seven herbal medicines. Based on the significant solubilisation and extraction effect, Stephaniae Tetrandrae Radix (Fangji, FJ) was selected to obtain the optimal extraction process by adopting single factor test and orthogonal experiment. Then, the alkaloids and SC6A/SC8A were separated by one‐step alkalisation and SCnA were reused. The host–guest complexes between alkaloids and SCnA were determined by competitive fluorescence titration, differential scanning calorimetry (DSC), Fourier‐transform infrared (FTIR) and proton nuclear magnetic resonance (1H‐NMR) analysis. Results The optimum condition for SC6A assisted extraction was 5:1:80 (g/g/mL) for herbs/SC6A/solution ratio, 355–250 μm particle size and ultrasonicate 0.5 h, whilst 10:1:40 (g/g/mL) for herbs/SC8A/solution ratio, 355–250 μm particle size and ultrasonicate 0.5 h for SC8A assisted extraction. The total yield of alkaloids (fangchinoline and tetrandrine) from FJ was increased by 4.87 times and 5.97 times with SC6A and SC8A. Moreover, a good reusability of SC6A/SC8A was achieved by alkalisation dissociation. Host–guest complexes were determined by competitive fluorescence titration at a molar ratio of 1:1 between most alkaloids (25/27, except evodiamine and rutaecarpine) and SC6A/SC8A. The complex structure was proved by DSC, FTIR and 1H‐NMR analysis. Conclusion The study provided an effective eco‐friendly and energy‐saving extraction method of alkaloids from herbal medicine. In this study, an innovative method of p‐sulphonatocalix[6]arenes (SC6A) and p‐sulphonatocalix[8]arenes (SC8A) assisted extraction alkaloids from herbs was established. Stephaniae Tetrandrae Radix was selected to obtain the optimal extraction processing by adopting single factor test and orthogonal experiment. Alkaloids and SC6A/SC8A were separated by one‐step alkalization and SCnA were reused. Host–guest complexes were determined by competitive fluorescence titration at a molar ratio of 1:1 between most alkaloids and SC6A/SC8A. The