Determination of biologically active substances and antioxidant activity of the aerial parts of Baikal aconite Aconitum baicalense Turcz

The qualitative and quantitative content of free and bound carbohydrates was studied, and the total content of pectin, flavonoids, coumarins, and antioxidant activity were determined in Baikal aconite (Aconitum baicalense Turcz). Carbohydrates were isolated from the plant by pre-infusion in water and subsequent extraction with ultrasonic exposure at room temperature. The resulting extract was dried under reduced pressure in a rotary evaporator. Polysaccharides were precipitated by 96% ethanol in the cold (4-6 °C). Bound carbohydrates were isolated from polyphenol complex by hydrolysis. Total carbohydrates were determined photometrically, by the phenol-sulfuric acid method. The separation of mono- and disaccharides was performed on cationite KU-2-8 in the calcium form in a 250*10 mm (ID) column at 55 ± 0.5 °C. The total amount of available carbohydrates in Baikal aconite is 1.7 ± 0.2%. In addition, the content of bound carbohydrates is 2.1 ± 0.2%. The quantity of bound carbohydrates is slightly higher than that of free carbohydrates and they are more diverse. The largest part of free carbohydrate consists of glucose. Glucose and rhamnose are the majority of bound carbohydrates. In addition to carbohydrates, appreciable quantities of the hex-ahydroxy alcohol sorbitol were discovered in the Baikal aconite. Flavonoids were extracted with 70% ethanol under heating. The extracts were washed with chloroform to remove chlorophyll, coumarin, and other interfering substances, and hydrolyzed. Flavonoids were determined photometrically at a wavelength of 400 nm. Coumarins were determined photometrically after reaction with di-azotized sulfanilic acid, with quantification by reference standard solutions of couma-rin. Pectin was determined by a Cu-pectin volumetric method. Baikal aconite contains 1.61 ± 0.02% flavonoids in the form of aglycones and 0.13 ± 0.03% coumarin. The antioxidant activity of the aerial parts of aconite is 4.0 ± 0.6 mg/100 g in terms of gallic acid. Baikal aconite has a pronounced antioxidant activity associated with the presence of flavonoids, coumarins, and free monosaccha-rides. The content of carbohydrates, pectin, and polyphenolic compounds, along with alkaloids, leads to a wide spectrum of biological activity of Aconitum baicalense Turcz.

Keywords

Authors

References