Rhodiosin from Rhodiola crenulata effectively alleviate postprandial hyperglycemia by inhibiting both the activity and production of α­glucosidase.

BACKGROUND: Effective control of postprandial blood glucose (PBG) level is essential for the prevention and treatment of diabetes and its complications. Several flavonoids have attracted much attention due to their significant PBG-lowering effects. However, there is still a certain gap in the in vivo hypoglycemic activity of most flavonoids compared to first-line drugs available on the market, and are still lack of the PBG-lowering effects of 8-hydroxyflavones and their structure-activity relationship. PURPOSE: Evaluate hypoglycemic effects of 8-hydroxyflavones from Rhodiola crenulata in vitro and in vivo, especially comparatively analyze the relationship between hypoglycemic effects and flavonoid configuration and reveal the possible mechanism of 8-hydroxyflavones in lowering hyperglycemia. METHODS: Starch, maltose, sucrose, and glucose tolerance tests in both diabetic and normal mice were used to evaluate and compare the hypoglycemic effects of 8-hydroxyflavones rhodiosin (RHS), rhodionin (RHN), and herbacetin (HBT). Molecular docking, enzyme kinetics, and immunofluorescence analysis were used to research the possible hypoglycemic mechanisms of 8-hydroxyflavones. RESULTS: RHS (5 and 10 mg/kg) could efficiently decrease PBG levels in both normal and diabetes mice. Moreover, RHS, RHN, and HBT all had significant PBG-lowering effects in transgenic diabetes mice, and the effects were equivalent to or stronger than acarbose. Further mechanism research indicated that 8-hydroxyflavones achieved PBG-lowering effects by inhibiting both the activity and production of glycosidase. Notably, we have innovatively discovered that inhibiting the expression of glycosidases rather than just their activities may be a new target for hypoglycemic drugs. CONCLUSION: We have firstly comprehensively and systematically clarified PBG-lowering effects of 8-hydroxyflavones from Rhodiola crenulata, and revealed their structure-activity relationships and hypoglycemic mechanisms. The study demonstrated that the substitution of 8-hydroxy groups in flavonoids could significantly enhance their hypoglycemic effects, which were equivalent to or stronger than commercially available drug acarbose. 8-Hydroxyflavones could be used as therapeutic or health drugs with significant potential to reduce postprandial hyperglycemia.

Bioactive fraction of Rhodiola algida against chronic hypoxia-induced pulmonary arterial hypertension and its anti-proliferation mechanism in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhodiola algida var. tangutica (Maxim.) S.H. Fu is a perennial plant of the Crassulaceae family that grows in the mountainous regions of Asia. The rhizome and roots of this plant have been long used as Tibetan folk medicine for preventing high latitude sickness. AIM OF THE STUDY: The aim of this study was to determine the effect of bioactive fraction from R. algida (ACRT) on chronic hypoxia-induced pulmonary arterial hypertension (HPAH) and to understand the possible mechanism of its pharmacodynamic actions. MATERIALS AND METHODS: Male Sprague-Dawley rats were separated into five groups: control group, hypoxia group, and hypoxia+ACRT groups (62.5, 125, and 250mg/kg/day of ACRT). The chronic hypoxic environment was created in a hypobaric chamber by adjusting the inner pressure and oxygen content for 4 weeks. After 4 weeks, major physiological parameters of pulmonary arterial hypertension such as mPAP, right ventricle index (RV/LV+S, RVHI), hematocrit (Hct) levels and the medial vessel thickness (wt%) were measured. Protein and mRNA expression levels of proliferating cell nuclear antigen (PCNA), cyclin D1, p27Kip1 and cyclin-dependent kinase 4 (CDK4)) were detected by western blotting and real time PCR respectively. Chemical profile of ACRT was revealed by ultra performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UHPLC-Q-TOF-MS/MS). RESULTS: The results showed that a successful HPAH rat model was established in a hypobaric chamber for 4 weeks, as indicated by the significant increase in mPAP, RV/LV+S, RV/BW and wt%. Compared with the normal group, administration of ACRT reduced mPAP, right ventricular hypertrophy, pulmonary small artery wall thickness, and damage in ultrastructure induced by hypoxia in rats. PCNA, cyclin D1, and CDK4 expression was reduced (p<0.05), and p27Kip1 expression increased (p<0.05) in hypoxia+ACRT groups compared to hypoxia. 38 constituents in bioactive fraction were identified by UHPLC-Q-TOF-MS/MS. CONCLUSION: Our results suggest that ACRT could alleviate chronic hypoxia-induced pulmonary arterial hypertension. And its anti-proliferation mechanism in rats based on decreasing PCNA, cyclin D1, CDK4 expression level and inhibiting p27Kip1 degradation.

Quantification of six active ingredients in Rhodiola extract by UPLC-MS/MS / 国际药学研究杂志

Objective To develop and fully validate an UPLC-MS/MS method for simultaneous quantification of six active ingredients in Rhodiola extract including salidroside, rhodiosin, rhodionin, herbacetin, kaempferol and quercetin. Methods The chromatographic separation of the analytes was achieved by using Zorbax Eclipse plus C18 column (2.1 mm×100 mm, 3.5 μm). The mobile phase consisted of 0.2% aqueous formic acid and acetonitrile. Analytes were separated using a linear gradient with a flow rate of 0.4 ml/min. The column temperature was set at 25 °C. The mass spectrometric conditions were electrospray negative ionization (ESI) and the scanning mode was multi reaction monitoring (MRM). Results The calibration curves of the six active ingredients were linear over 1020000, 10-4000, 10-4000, 5-2000, 10-2000, and 5-2000 ng/ml concentration ranges, respectively. The RSD of the instrument precision was within 3.31%. The current assay was stable and reproducible in quantification of all analytes with RSD within 5.07% and 4.05%, respectively. The average recovery of all analytes was in a range from 99.27% to 108.91%, with an acceptable RSD of no more than 4.92%. Conclusion The UPLC-MS/MS method could be successfully applied to simultaneously quantifying six major active ingredients in Rhodiola extract with the acceptable specificity, sensitivity and reproducibility.

Determination of six flavonoids in Rhodiolae Crenulatae Radix et Rhizoma by HPLC-DAD / 中草药

Objective: To establish a determination method for the contents of ternatumoside II, rhodiosin, rhodionin, herbacetin, kaempferol, and rhodiolin in Rhodiolae Crenulatae Radix et Rhizoma and to compare the content differences of the six flavonid compounds in Rhodiolae Crenulatae Radix et Rhizoma from different sources. Methods: Using HPLC-DAD method and Kromasil C18 column (250 mm × 4.6 mm, 5 μm), with acetonitrile and water as mobile phase, gradient elution at flow rate of 1.0 mL/min and column temperature of 35℃. The detection wavelength was 382 nm. Results: Ternatumoside II, rhodiosin, rhodionin, herbacetin, kaempferol, and rhodiolin had good linearity in the ranges of 0.015 08-0.301 6, 0.123 2-2.464, 0.109 5-2.190 8, 0.007 8-0.156, 0.021 46-0.429 2, and 0.006 48-0.129 6 μg, respectively. The average recoveries of the six constituents were 98.17%-100.52% and RSD values were 1.64%-1.98%. Conclusion: The method is simple and accutate. It provides the reference for comprehensive quality control of Rhodiolae Crenulatae Radix et Rhizoma.

Quantification of six active ingredients in Rhodiola extract by UPLC-MS/MS / 国际药学研究杂志

Objective To develop and fully validate an UPLC-MS/MS method for simultaneous quantification of six active in?gredients in Rhodiola extract including salidroside,rhodiosin,rhodionin,herbacetin,kaempferol and quercetin. Methods The chro?matographic separation of the analytes was achieved by using Zorbax Eclipse plus C18 column(2.1 mm×100 mm,3.5μm). The mobile phase consisted of 0.2%aqueous formic acid and acetonitrile. Analytes were separated using a linear gradient with a flow rate of 0.4 ml/min. The column temperature was set at 25℃. The mass spectrometric conditions were electrospray negative ionization(ESI)and the scan?ning mode was multi reaction monitoring(MRM). Results The calibration curves of the six active ingredients were linear over 10-20000,10-4000,10-4000,5-2000,10-2000,and 5-2000 ng/ml concentration ranges,respectively. The RSD of the instrument precision was within 3.31%. The current assay was stable and reproducible in quantification of all analytes with RSD within 5.07%and 4.05%,respectively. The average recovery of all analytes was in a range from 99.27%to 108.91%,with an acceptable RSD of no more than 4.92%. Conclusion The UPLC-MS/MS method could be successfully applied to simultaneously quantifying six major active in?gredients in Rhodiola extract with the acceptable specificity,sensitivity and reproducibility.

Application and recovery of ionic liquids in the preparative separation of four flavonoids from Rhodiola rosea by on-line three-dimensional liquid chromatography.

A novel on-line three-dimensional liquid chromatography method was developed to separate four main flavonoids from Rhodiola rosea. Ethyl acetate/0.5 mol/L ionic liquid 1-butyl-3-methylimidazolium chloride aqueous solution was selected as the solvent system. In the first-dimension separation, the target flavonoids were entrapped and subsequently desorbed into the second-dimension high-speed countercurrent chromatographic column for separation. In the third-dimension chromatography, the residual ionic liquid in the four separated flavonoids was removed and the used ionic liquid was recovered. As a result, 35.1 mg of compound 1, 20.4 mg of compound 2, 8.5 mg of compound 3, and 10.6 mg of compound 4 were obtained from 1.53 g R. rosea extract. They were identified as rhodiosin, rhodionin, herbacetin, and kaempferol, respectively. The recovery of ionic liquid reached 99.1% of the initial amount. The results showed that this method is a powerful technology for the separation of R. rosea flavonoids and that the ionic-liquid-based solvent system has advantages over traditional solvent systems in renewable and environmentally friendly properties.