Abstract
Background
Asarum heterotropoides and Asarum sieboldii are commonly used in traditional Chinese medicine. However, less is known about how they differ in terms of essential oil (EO) and ethanol extract (EE) content and composition. Moreover, the impact of various geographical locations on the essential oil (EO), ethanol extract (EE), and asarinin content of different Asarum samples remains unknown. We tested four root drying methods, i.e. soil removal and shade drying (P1), water washing and shade drying (P2), water washing and drying at 30 ℃ (P3) and 40 ℃ (P4). We used LC-MS and GC-MS to investigate these differences. We also investigated the pharmacodynamic effects of EO and EE.
Result
Overall, the EO, EE and asarinin contents of the analysed samples were 19.21–51.53 µL.g-1, 20.00–45.00 µL.g-1 and 1.268–2.591 mg.g-1, respectively. P1 treatment yielded the lowest volatile oil content as compared to the other three treatments. GC-MS analysis revealed 78 EO components. Among the six major EO components, eucarvone, 3,5-dimethoxytoluene and methyl eugenol were higher in A. heterotropoides than in A. sieboldii. However, the latter had a higher myristicin content. LC-MS analysis identified 888 EE components in roots and leaves of A. heterotropoides and A. sieboldii; 317 differentially accumulated metabolites were identified. EO and EE showed a dose-dependent reduction in the degree of swelling and an increase in the inhibition rate of drug concentration on acetic acid writhing in mice. Asarum EO proved to be more effective than EE in the pharmacodynamic study.
Conclusion
We conclude that Asarum species show inter- and intra-specific differences in EO, EE content and composition, which may influence the pharmacodynamics of Asarum root extracts.