Genetic and Environmental Variations in Baicalin, Baicalein and Wogonin Contents in Scutellaria baicalensis

Abstract

Scutellaria baicalensis has long been used to treat fever, cough, diarrhea and infection in Chinese medicine, and flavonoids such as baicalin (BA), baicalein (BE), and wogonin (WO) have been identified. To understand genetic and environment-dependent variations, 15 Scutellaria baicalensis landraces were collected from Korea and China, and cultivated under different nitrogen fertilizer application and planting density conditions, and resultant changes in BA, BE, and WO were evaluated. Tested 15 landraces exhibited BA, BE, and WO contents ranging 4.56 to 13.59%, 0.28 to 5.54%, and 0.50 to 1.63% with an average of 9.66%, 2.09%, and 0.52%, respectively. Among tested 4 levels (0 to 500kg/ha) of nitrogen fertilizer application 300kg/ha resulted in highest BA (10.3%) and BE (1.3%), as well as WO (0.4%) contents, corresponding to about 10% increment compared to 0kg/ha. Six different levels of planting density (2 and 3 Rows x 1, 5, 10cm distance), however, showed no difference in flavonoid contents. Similarly no difference in flavonoid contents could be observed between Scutellaria baicalensis harvested from early June 6th to Aug. 3rd. When flavonoid contents in different plant parts were compared, leaf and stem of Scutellaria baicalensis showed no BE and WO under our experimental conditions, while relatively low BA (0.67% in leaf and 1.56% in stem) could be found in leaf. Higher composition of BA could be observed in top part of the root, while higher WO could be observed in lower root part close to root hair.