The hot water extract of Rabdosia rubescens was traditionally used as an antithrombotic medicine. To explore its antithrombotic utility and mechanism, we carried out a series of in vitro and in vivo assays in this study. In vitro platelet aggregation assay showed that the half maximal inhibitory concentration values of aqueous extract of R. rubescens leaves (AERL) inhibiting platelet aggregation induced by thrombin, arachidonic acid, adenosine diphosphate, and platelet-activating factor ranged from 0.12 mg/mL to 1.43 mg/mL. The minimal effective oral dose of AERL inhibiting the rats from forming thrombus was 25 mg/kg. Both in vitro and in vivo actions were correlated with AERL concentration-dependently inhibiting sP-selectin release. In water, AERL formed nanoparticles, and their size depended on the concentration. Docking the five nucleotides, 21 phenolic acids, and four diterpenoids identified by high-performance liquid chromatography–photodiode array detector/(−)electrospray ionization-tandem mass spectrometry analysis into the active site of P-selectin, rosmarinic acid was predicted to be the antithrombotic ingredient of AERL. In flow cytometry analysis, 1 μM of rosmarinic acid effectively inhibited sP-selectin release in arachidonic acid-activated platelets. In a rat model, 5 mg/kg of oral rosmarinic acid effectively inhibited thrombosis.
Oridonin, one of the active ingredients in Rabdosia rubescens ( R. rubescens ), has been reported to induce cell apoptosis and cell cycle arrest in many cancers. Conventional extraction methods tend to result in unsatisfied enrichment and poor quality of oridonin present in a given biomass. This paper aims to evaluate the performance and separation characteristics of four different macroporous resins to arrive at the most suitable methodology for the isolation and purification of high-quality oridonin. Static absorption kinetics, thermodynamic and dynamic adsorption were evaluated. HP-20 was selected for further study due to its high adsorption capacity of 32 mg·g −1 and desorption ratio with 98.5%. The pseudo-second-order model was considered to be the most suitable for kinetic results, and Langmuir model was chosen to better describe the absorption thermodynamics. Under optimum conditions (flow rate of 4 ml·min −1 , bed depth with 6 cm and initial concentration of 2.15 mg·ml −1 ), the effective content of oridonin increased from 33.9% to 79.1% in the dry extract with a recovery of 81% and the purity of oridonin improved from 76% to 93%. The results confirm that HP-20 provides an efficient method to purify most oridonin from R. rubescens .