Effects of growth years, altitude, and light factors on contents of eight components in Rheum officinale / 中草药

ABSTRACT

Objective: To study the effects of growth factors, altitude, and illumination (shady slope and sunny slope) on anthraquinones and tannins in medicinal rhubarb, and to find the theoretical basis for choosing the optimum growth conditions for rhubarb. Methods: The contents of aloe-emodin, rhein, emodin, chrysophanol, emodin, chrysophanol-1-O-glucoside, emodin-8-O-glucoside and (+)-catechin of different growth years at different altitudes and with different illumination were analyzed by variance analysis. Results: The mean contents of free anthraquinones in 1-, 2-, and 3-year rhubarb were 4.26, 5.18, and 8.10 mg/g, respectively. The mean contents of conjugated anthraquinones were 4.67, 5.62, and 6.76 mg/g, and the contents of (+)-catechin were 3.12, 4.18, and 4.72 mg/g, respectively. There were significant differences among the three altitude ranges of (1 300 ± 50), (1 500 ± 50), and (1 700 ± 50) m. There were significant differences between (1 300 ± 50) m and (1 500 ± 50) m and (1 700 ± 50) m in three different growth years (P 0.05). Conclusion: The contents of anthraquinones and tannins in rhubarb increase significantly with the increase of altitude with the same growth range and in the same growth year. There is significant difference between the growth years. When the illumination (shady slope and sunny slope) was different, there is no significant difference in the anthraquinone and tannin contents, but the average contents of anthraquinone and tannin in the sunny slope are higher than those in the shady slope. Artificial cultivation of medicinal rhubarb should be selected at an altitude of 1 400 m above the growth year of not less than 3 years, direct sunshine environment, which is conducive to improve the total contents of anthraquinone and tannin in medicinal rhubarb.