The aim of this study was to investigate the method validation for the determination of loganin content in Cornus officinalis (CO). This medicinal plant reportedly mainly included loganin. The specificity, linearity, precision, accuracy, limit of detection (LOD), and quantification (LOQ) were measured by HPLC/DAD. Our results showed that high linearity in the coefficient of calibration correlation (R2) for loganin standard was 1. LOD and LOQ for loganin were 0.007 and 0.026 mg/mL, respectively. The recovery rate of loganin was revealed to be in the high range of 95.14-105.45%. The relative standard deviation of intra- and inter-day precision of loganin in CO was 1.8% and 2.3%, respectively. The loganin content of CO from Gurye, Uiseng, Ichoen, and China were 7.81, 3.41, 7.42, and 6.52 mg/g, respectively. In conclusion, these methods were validated for the detection of loganin in CO.

Background: This study aimed to investigate the effect of harvest time on the growth, yield characteristics and loganin content in Dipsacus asperoides Wall. Methods and Results: Dipsacus asperoides seedlings were planted within a nursery environment in early May 2015 and harvested in early, middle and late October 2015, and early November 2015. Harvest time did not result significant differences in the plant height, stem diameter, branch length, leaf width and aboveground dry weight moreover, no significant differences were observed in root length, number of roots and root diameter. However, the diameter of lateral roots was greater in the harvests from the late October and period thereafter. The highest values of root dry weight and yield were recorded in early November. Specifically, the yield significantly increased from 205 ㎏/10 a (index: 100) in early October to 358 ㎏/10 a (index: 175) in early November, in terms of root part weight. Loganin contents of D. asperoides differed significantly among harvest times raging from 0.0766% in early October to 0.1704% in late November, thereby showing an increasing trend in later harvest times. Conclusions: These results suggest that the optimum harvest time for D. asperoides is early November, when the yield is the highest. Harvest time significantly affected loganin contents, which constantly increased from early October until early November.