The polysaccharide content was determined by the sulfuric acid-phenol method [39 (link)]. Briefly, the glucose standard curve was drawn with the mass concentration of D-anhydrous glucose as the abscissa (x) and the absorbance value as the ordinate (y). The linear regression equation of the standard curve was y = 0.0081x − 0.0039, R2 = 0.999. Referring to the extraction method established by Tian et al. [39 (link)], the sample treatment was slightly modified. Briefly, 1.0 g of each sample was accurately weighed, 100 mL of absolute ethanol was added and soaked overnight, filtered, and the filtrate was evaporated. The final volume of 50 mL was made with distilled water. The extract was shaken well and underwent ultrasonication (180 W, 40 kHz) for 40 min, reflux at 90 °C for 1 h, and centrifuge at 4000 r/min for 10 min. The supernatant was collected, and the absorbance was recorded at 490 nm after dilution.
The total coumarin content was determined by the spectrophotometry method, and the standard curve was drawn with osthole as the standard compound (y = 0.0549x − 0.0029; R2 = 0.9994). For each sample, 1.0 g of powder was accurately weighed, and 30 mL of anhydrous ethanol was added. The mixture was ultrasonicated (180 W, 40 kHz) for 30 min, heated and refluxed in a water bath for 30 min, and filtered. The absorbance was recorded at 320 nm after dilution.
The total polyphenols content was determined by the Folin phenol colorimetric method [40 (link)], and the standard curve was drawn with gallic acid as the reference standard (y = 3.7514x + 0.006, R2 = 0.9991). For each sample, 1.0 g of powder was accurately weighed, add 50 mL of 70% ethanol was added. The mixture was ultrasonicated (180 W, 40 kHz) for 30 min, heated to reflux in a water bath for 30 min, and filtered. The final volume was increased to 50 mL using 70% ethanol. The absorbance was recorded at 760 nm.
The total flavonoid content was determined by the aluminum chloride colorimetric method [40 (link)], and the standard curve was drawn with rutin as the reference substance (y = 10.39x + 0.0014, R2 = 0.9998). Briefly, the sample powder was accurately weighed (1.0 g), and 30 mL of 85% ethanol was added. The mixture was ultrasonicated (180 W, 40 kHz) for 30 min and heated under reflux in a water bath for 30 min. The filtered extract was made up to 50 mL with 85% ethanol. The absorbance was measured at a wavelength of 510 nm after dilution.
The total coumarin content was determined by the spectrophotometry method, and the standard curve was drawn with osthole as the standard compound (y = 0.0549x − 0.0029; R2 = 0.9994). For each sample, 1.0 g of powder was accurately weighed, and 30 mL of anhydrous ethanol was added. The mixture was ultrasonicated (180 W, 40 kHz) for 30 min, heated and refluxed in a water bath for 30 min, and filtered. The absorbance was recorded at 320 nm after dilution.
The total polyphenols content was determined by the Folin phenol colorimetric method [40 (link)], and the standard curve was drawn with gallic acid as the reference standard (y = 3.7514x + 0.006, R2 = 0.9991). For each sample, 1.0 g of powder was accurately weighed, add 50 mL of 70% ethanol was added. The mixture was ultrasonicated (180 W, 40 kHz) for 30 min, heated to reflux in a water bath for 30 min, and filtered. The final volume was increased to 50 mL using 70% ethanol. The absorbance was recorded at 760 nm.
The total flavonoid content was determined by the aluminum chloride colorimetric method [40 (link)], and the standard curve was drawn with rutin as the reference substance (y = 10.39x + 0.0014, R2 = 0.9998). Briefly, the sample powder was accurately weighed (1.0 g), and 30 mL of 85% ethanol was added. The mixture was ultrasonicated (180 W, 40 kHz) for 30 min and heated under reflux in a water bath for 30 min. The filtered extract was made up to 50 mL with 85% ethanol. The absorbance was measured at a wavelength of 510 nm after dilution.
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