Effects of light irradiation on essential oil biosynthesis in the medicinal plant Asarum heterotropoides Fr. Schmidt var. mandshuricum (Maxim) Kitag.

Asarum heterotropoides Fr. var. mandshuricum (Maxim) Kitag (Chinese wild ginger) is an important medicinal herb. Essential oil extracted from its roots is the key ingredient and is mainly composed of phenylpropanoid compounds. As a skiophyte plant, light is a crucial factor for A. heterotropoides var. mandshuricum growth and metabolism. To investigate the effects of light irradiation on the essential oil biosynthesis in A. heterotropoides var. mandshuricum, the plants were cultivated in four light irradiation treatments (100, 50, 24 and 12% full sunlight). The photosynthetic capacity, essential oil content and composition, activities of several enzymes and levels of some secondary metabolites involved in the shikimic acid and cinnamic acid pathways were analyzed. The leaf mass per area, average diurnal net photosynthetic rate, and the essential oil content increased significantly with increasing light intensity. Phenylalanine, cinnamic acid, and p-coumaric acid in the cinnamic acid pathway were at their highest levels in plants cultivated in 100% full sunlight. The highest content of shikimic acid in the shikimic acid pathway was obtained in plants grown in 50% sunlight transmittance. The activity of the enzymes 3-Deoxy-D-arabino-heptulosonate-7-phosphate synthase, phenylalanine ammonia lyase, cinnamate-4-hydroxylase and 4-coumarate:CoA ligase increased proportionally with light intensity. Overall, we conclude that high light irradiation promotes high net photosynthetic rate, high activity of enzymes and high amounts of phenylpropanoid precursor metabolites leading to significant biosynthesis of essential oil in A. heterotropoides var. mandshuricum.

[Effect of light intensity on growth and quality of Asarum heterotropoides var. mandshuricum].

To study the infection rate of leaf spot disease, the drying rate of root and volatile oil content of Asarum heterotropoides var. mandshuricum at the unwrapping stage, blooming stage, the initial fruit stage, fructescence and wither stage during the growth period under the different sunlight intensity of 100% (I), 50% (II), 28% (III), 12% (IV). The volatile oil content was measured according to the method of Chinese Pharmacopoeia and the oil composition was determined by GC-MS. The unwrapping stage, blooming stage and the early fruit stage postponed about 2 days with decrease of the sunlight intensity. The infection rate of leaf was 88.46%, 70.00%, 0.23%, 0.07% under light intensity of I, II, III and IV, respectively, the drying rate was 25.14%, 28.27%, 30.23%, 31.57% under light intensity of I, II, III and IV, respectively, and the volatile oil content was 18.1, 17.6, 16.3, 15.3 mL x kg(-1) under light intensity of I, II, III and IV, respectively. The composition of the oil determined by GC-MS was different between the groups, but the content did not changed significantly with the decrease of the light intensity.

[Systematic study on the authentic and superior medicinal herba and GAP of herba asari].

OBJECTIVE: To investigate the methodology of the systematic study on the Authentic and Superior Medicinal Herba and GAP of Herba Asari. METHOD: The study was made by textual criticism of Herbology, Botany, Palynology, Cytology, Chemistry, Pharmacology, the analytic methods of allozyme and RAPD. Many subjects on the herb were investigated, such as history, botanical origin, routine examination, morphology of pollen, chromosome and karyotype, the content of oil and its pharmacological effects and so on. RESULT AND CONCLUSION: The methodology of systematic study on the Authentic and Superior Medicinal Herba was provided. According to the results of the systematic study, the GAP of the herb can be made.