ABSTRACT
Objective::To investigate the pharmacodynamics of volatile oil in couplet medicines of Moslae Herba and Pogostemonis Herba, to establish a method for simultaneous determination of three essential ingredients (thymol, carvacrol and patchouli alcohol) in volatile oil of the couplet medicines by gas chromatography (GC), to optimize the preparation process of β-cyclodextrin (β-CD) inclusion complex of volatile oil in the couplet medicines and to confirm the formation of the inclusion complex. Method::An in vitro inflammatory response model was established by hyaluronidase activity inhibition test in order to detect the anti-inflammatory activity of the volatile oil. Also, the antioxidant activity of the volatile oil was assessed by 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging method. The inclusion of volatile oil in couplet medicines of Moslae Herba and Pogostemonis Herba was prepared by scaturated aqueous solution method, colloid milling method and grinding method, respectively. GC was used to determine the contents of thymol, carvacrol and patchouli alcohol in volatile oil for optimizing extraction and inclusion processes of volatile oil. Scanning electron microscope, infrared spectroscopy, thermal differential analysis, and X-ray diffraction (XRD) were used to verify the formation of the inclusion complex. Result::The volatile oil not only inhibited hyaluronidase activity to a certain extent, but also eliminated DPPH and increased with the increase of concentration. There was a good linear relationship between the peak area and concentration of thymol, carvacrol and patchouli alcohol at 0.021 3-0.426, 0.020 04-0.400 8, 0.022 6-0.452 g·L-1 (R2>0.999), respectively. Their recoveries were 99.59%(RSD 1.6%), 100.15%(RSD 1.5%), 100.70%(RSD 1.4%), respectively. The colloid milling method was optimized, and the formation of the inclusion complex was verified by the aforementioned methods. Conclusion::The volatile oil in couplet medicines of Moslae Herba and Pogostemonis Herba has certain anti-inflammatory activity and anti-oxidation ability. The colloid milling method was the best inclusion process for the volatile oil. The established GC has the advantages of simple, sensitive, accurate, reliable and reproducible, which can meet the requirements of simultaneous determination of thymol, carvacrol and patchouli alcohol in the inclusion complex.