Dynamic changes of the main active constituents in valerian rhizome and root /Valeriana amurensis Smir. ex Kom.) during different harvest periods

Valeriana amurensis Smir. ex Kom. widely distributed in the northeast region of China and some region in Russia and Korea, and its underground parts (roots and rhizomes) being used to cure nervous system diseases such as insomnia. The active components including the essential oil and iridoids of underground parts were investigated in different harvest periods in order to evaluate the quality for the roots and rhizomes of V. amurensis. The content of the essential oil was obtained by hydrodistillation and bornyl acetate in the oil was quantitated by GC-EI. The iridoids, valepotriates were determined by potentiometric titration and the main component, valtrate was quantitated by HPLC-UV. The factors of biomass were considered in the determination of collection period. Statistical analysis of results showed that, the highest content of the essential oil per plant was 22.69 μl in withering period and then 21.58 μl in fruit ripening period, while the highest contents of bornyl acetate, valepotriates and valtrate per plant were 2.82 mg, 31.90 mg and 0.98 mg in fruit ripening period separately. Fruit ripening period was decided as the best harvest period for the content of active constituents and output of drug, and it would provide scientific basis for the artificial cultivation of V. amurensis.