Magnesium lithospermate B ameliorates cephaloridine-induced renal injury

Pharmacokinetics of depside salts from Salvia miltiorrhiza in healthy Chinese volunteers: A randomized, open-label, single-dose study

BACKGROUND

Depside salts from Salvia miltiorrhiza, with active components of lithospermic acid B (LSB), rosmarinic acid (RA), and lithospermic acid (LA), are a multicomponent drug marketed in China for the treatment of coronary heart disease.

OBJECTIVES

The aims of this study were to determine the concentrations of LSB, RA, and LA in human plasma and urine, and to compare the pharmacokinetic properties of depside salts from S miltiorrhiza in healthy Chinese volunteers.

METHODS

A randomized, open-label, single-dose study was conducted in healthy Chinese volunteers. Participants were randomly assigned to receive a single intravenous infusion of 100 or 200 mg of depside salts from S miltiorrhiza. Blood was collected through a venous cannula prior to study drug administration (0 min) and at 10, 20, 30, 60, 65, 70, 80, and 90 minutes and 2, 3, 4, 6, 8, 12, and 24 hours after study drug administration. Urine samples were taken before study drug administration (0) and at 0 to 12 and 12 to 24 hours after study drug administration. LSB, RA, and LA concentrations in serum and urine were analyzed by an LC-MS/MS method. Tolerability was determined by clinical assessment; vital signs (ie, blood pressure, heart rate, breathing rate, body temperature) monitoring at baseline and at the end of the study, clinical laboratory tests (ie, hematology, blood biochemistry, hepatic function, renal function, urinalysis), 12-lead ECG measurements, and physical examinations at baseline and after completion of the study.

RESULTS

Twelve Chinese volunteers (6 males, 6 females; mean [SD] age, 25.2 [3.8] years; mean height, 165.7 [8.9] cm; mean body mass index, 21.6 [2.5] kg/m(2)) were enrolled in the study. Peak plasma concentrations of LSB, RA and LA were observed at 0.3 to 1 hour following the 1-hour intravenous infusion, with respective mean (SD) Cmax of 4925 (1861), 174 (61), and 361 (101) ng/mL for the 100-mg dose and 10,285 (2259), 308 (77), and 674 (85) ng/mL for the 200-mg dose. The AUClast values for LSB, RA, and LA were 4537 (1265), 129 (28), and 1229 (330) ng/mL/h, respectively, for the 100-mg dose and 10,426 (2589), 260 (53), and 2792 (729) ng/mL/h for the 200-mg dose. No significant difference in pharmacokinetic parameters was observed between male and female subjects. Three metabolites were found in the plasma with low concentrations. The urinary excretion recoveries of LSB, RA, and LA were 0.58% (0.42%), 25.21% (20.61%), and 10.02% (7.72%) for the 100-mg dose and 0.38% (0.18%), 20.11% (10.50%), and 6.34% (3.20%) for the 200-mg dose. No adverse events were reported by the subjects or found by the investigators in the analysis of vital signs, 12-lead ECG measurements, physical examinations, or clinical laboratory tests.

CONCLUSIONS

Following single intravenous infusion of 100 or 200 mg of depside salts from S miltiorrhiza to healthy Chinese subjects, no statistical differences in pharmacokinetic parameters were observed between males and females. The 2 doses of depside salts from S miltiorrhiza were clinically well tolerated during the study.

Polyphenols: skin photoprotection and inhibition of photocarcinogenesis

Polyphenols are a large family of naturally occurring plant products and are widely distributed in plant foods, such as, fruits, vegetables, nuts, flowers, bark and seeds, etc. These polyphenols contribute to the beneficial health effects of dietary products. Clinical and epidemiological studies suggest that exposure of the skin to environmental factors/pollutants, such as solar ultraviolet (UV) radiation induce harmful effects and leads to various skin diseases including the risk of melanoma and non-melanoma skin cancers. The incidence of non-melanoma skin cancer, comprising of squamous cell carcinoma and basal cell carcinoma, is a significant public health concern world-wide. Exposure of the skin to solar UV radiation results in inflammation, oxidative stress, DNA damage, dysregulation of cellular signaling pathways and immunosuppression thereby resulting in skin cancer. The regular intake of natural plant products, especially polyphenols, which are widely present in fruits, vegetables, dry legumes and beverages have gained considerable attention as protective agents against the adverse effects of UV radiation. In this article, we first discussed the impact of polyphenols on human health based on their structure-activity relationship and bioavailability. We then discussed in detail the photoprotective effects of some selected polyphenols on UV-induced skin inflammation, proliferation, immunosuppression, DNA damage and dysregulation of important cellular signaling pathways and their implications in skin cancer management. The selected polyphenols include: green tea polyphenols, pomegranate fruit extract, grape seed proanthocyanidins, resveratrol, silymarin, genistein and delphinidin. The new information on the mechanisms of action of these polyphenols supports their potential use in skin photoprotection and prevention of photocarcinogenesis in humans.

Synthesis of a dual-labeled probe of dimethyl lithospermate B with photochemical and fluorescent properties

Dimethyl lithosermate B (DLB) is a highly potent natural antioxidant and antidiabetic polyphenol with unknown mode of action. To determine its cellular targets, a photochemical and fluorescent dimethyl lithopermate B probe was designed and efficiently synthesized. The dual-labeled chemical probe for biological application was evaluated by UV and fluorescence to determine its electrochemical absorption and emission properties. This probe could be valuable for investigating ligand-protein interactions and subcellular localization.

The mechanisms underlying the anti-aging activity of the Chinese prescription Kangen-karyu in hydrogen peroxide-induced human fibroblasts

Our previous study showed that Kangen-karyu extract protected against cellular senescence by reducing oxidative damage through the inhibition of reactive oxygen species generation and regulation of the antioxidative status. Although these findings suggest that Kangen-karyu could delay the aging process, the mechanisms responsible for protection against aging have rarely been elucidated. Therefore, this study was focussed on the mechanisms responsible for the anti-aging activity of Kangen-karyu extract using hydrogen peroxide (H2O2)-induced human diploid fibroblasts, a well-established experimental model of cellular aging. Kangen-karyu extract exerted a protective effect against the morphological changes induced by H2O2 treatment and inhibited senescence-associated β-galactosidase activity. In addition, the beneficial effects of Kangen-karyu extract on cell viability and lifespan indicated that Kangen-karyu extract could delay the cellular aging process. The observation that Kangen-karyu extract prevented nuclear factor kappa B (NF-κB) translocation in response to oxidative stress suggested that Kangen-karyu exerted its anti-aging effect through NF-κB modulation and prevention of H2O2-induced overexpression of haem oxygenase-1 protein. Moreover, pretreatment with Kangen-karyu extract reduced overexpression of bax protein and prevented the mitochondrial membrane potential decline, suggesting that Kangen-karyu extract may protect mitochondria from mitochondrial oxidative stress and dysfunction. These findings indicate that Kangen-karyu is a promising potential anti-aging agent that may delay, or normalize, the aging process by virtue of its protective activity against oxidative stress-related conditions.

Microwave-assisted extraction with water for fast extraction and simultaneous RP-HPLC determination of phenolic acids in radix Salviae Miltiorrhizae

An optimized microwave-assisted extraction method using water (MAE-W) as the extractant and an efficient HPLC analysis method were first developed for the fast extraction and simultaneous determination of D(+)-(3,4-dihydroxyphenyl) lactic acid (Dla), salvianolic acid B (SaB), and lithospermic acid (La) in radix Salviae Miltiorrhizae. The key parameters of MAE-W were optimized. It was found that the degradation of SaB was inhibited when using the optimized MAE-W and the stable content of Dla, La, and SaB in danshen was obtained. Furthermore, compared to the conventional extraction methods, the proposed MAE-W is a more rapid method with higher yield and lower solvent consumption with a reproducibility (RSD <6%). In addition, using water as extractant is safe and helpful for environment protection, which could be referred to as green extraction. The separation and quantitative determination of the three compounds was carried out by a developed reverse-phase high-performance liquid chromatographic (RP-HPLC) method with UV detection. Highly efficient separation was obtained using gradient solvent system. The optimized HPLC analysis method was validated to have specificity, linearity, precision, and accuracy. The results indicated that MAE-W followed by HPLC-UV determination is an appropriate alternative to previously proposed method for quality control of radix Salviae Miltiorrhizae.

Simultaneous determination of lithospermic acid B and its three metabolites by liquid chromatography/tandem mass spectrometry

A rapid and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the simultaneous determination of lithospermic acid B and its three main O-methylated metabolites in rat serum with silibinin as the internal standard. The calibration curves for LSB, and the three metabolites were linear over the ranges of 16-4096, and 8-2048 ng/ml, respectively, with coefficients of correlation >0.998. For LSB, the intra-assay coefficient of variance (CV) was less than 9.3% and the inter-assay CV was less than 8.9%. The inter-assay mean accuracy was between 92.8% and 104.7%. For the three metabolites, the intra-assay CV was less than 8.7% and the inter-assay CV was less than 9.9%. The inter-assay mean accuracy was between 92.5% and 107.9%. This quantitation method was successfully applied to a pharmacokinetic study of LSB in rats. Also, a total recovery of 5.2% was found in bile after oral administration.

Pharmacokinetics, tissue distribution, metabolism, and excretion of depside salts from Salvia miltiorrhiza in rats

Salviae miltiorrhiza, a traditional Chinese medical herb known as "Danshen," has been widely used in clinics to improve blood circulation, relieve blood stasis, and treat coronary heart disease. Depside salts from S. miltiorrhiza are a novel drug in which magnesium lithospermate B and its analogs are the active components. The pharmacokinetics, tissue distribution, metabolism, and excretion of three of the major components, lithospermic acid B, rosmarinic acid (RA), and lithospermic acid (LA), were studied by liquid chromatography-tandem mass spectrometry following intravenous administration in Sprague-Dawley rats. The elimination half-lives for LSB, RA, and LA were 1.04, 0.75, and 2.0 h, respectively, when 60 mg/kg S. miltiorrhiza depside salts were administrated. The areas under the curve for LSB, RA, and LA were 51.6, 6.6, and 25.2 mg . h/l, respectively, and the values decreased in the individual tissues in the following order: kidney > lung > liver > heart > spleen > brain for LSB; kidney > lung > heart > liver > spleen > brain for RA; and heart > lung > kidney > liver > spleen > brain for LA. After intravenous administration of 60 mg/kg S. miltiorrhiza depside salts, 86% of the LSB was excreted in the bile within 6 h. The main metabolites M1 and M2 were found in the serum. Overall, the results show that depside salts from S. miltiorrhiza are rapidly and widely distributed to tissues after intravenous administration in rats but that they are also rapidly cleared and excreted.

Protective effect of the Chinese prescription Kangen-karyu against high glucose-induced oxidative stress in LLC-PK1 cells

We investigated the effects of Chinese prescription Kangen-karyu on high glucose-induced oxidative stress using LLC-PK(1) cells, renal tubular cells, which are the most vulnerable renal tissue to oxidative stress. High-concentration glucose (30mM) treatment induced LLC-PK(1) cell death, but Kangen-karyu, at a concentration of 5, 10 or 50 microg/ml, significantly inhibited high glucose-induced cytotoxicity. In addition, the intracellular reactive oxygen species level was increased by 30mM glucose treatment, but it was concentration-dependently inhibited by Kangen-karyu treatment. Moreover, 30mM glucose treatment induced high levels of superoxide anion, nitric oxide and peroxynitrite. However, Kangen-karyu treatment significantly reduced the radical overproduction induced by high glucose, suggesting Kangen-karyu has radical-scavenging activity that would protect against oxidative stress induced by high glucose. Kangen-karyu also reduced the overexpression of inducible nitric oxide synthase and cyclooxygenase-2 proteins induced by high glucose. Furthermore, treatment with Kangen-karyu, at a concentration of 50mug/ml, inhibited the nuclear translocation of nuclear factor-kappa B induced by 30mM glucose in LLC-PK(1) cells. These findings indicate that Kangen-karyu is a potential therapeutic agent that will reduce the damage caused by hyperglycemia-induced oxidative stress associated with diabetes.

Magnesium lithospermate B ameliorates renal cortical microperfusion in rats

AIM

To investigate the effects of magnesium lithospermate B (MLB) isolated from Salviae miltiorrhizae on renal microcirculation, and renal and systemic hemodynamics in Sprague-Dawley rats.

METHODS

MLB (10, 30, and 60 mg/kg) was injected intravenously and renal blood flow (RBF), renal cortical microperfusion (RCM), and systemic hemodynamic function parameters including heart rate (HR), mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), and maximal velocity of pressure increase (dp/dt(max)) were measured for 45 min after administration.

RESULTS

Intravenous MLB at doses of 10, 30, and 60 mg/kg increased RCM significantly, but had no obvious effects on RBF or systemic hemodynamics. The effect of MLB on RCM reached its peak 15 min after injection and returned to baseline after 45 min. Up to 60 mg/kg MLB increased RCM by 62.4%+/-20.2% (changes from baseline, P<0.01), whereas RBF (3.7%+/-9.7% vs baseline) and renal vascular resistance (-1.4%+/-9.1% vs baseline) did not obviously change.

CONCLUSION

These results indicate that MLB ameliorates renal microcirculation in a dose-dependent manner, which may be related to the renoprotective effects of MLB.

Pharmacokinetics of lithospermic acid B isolated from Salvia miltiorrhiza in rats

The absorption and pharmacokinetics of an active component of Salvia miltiorrhiza, lithospermic acid B (LSB), was investigated after intravenous and oral administration of doses of 10 or 50 mg LSB/kg to rats. Concentrations of LSB were determined by a validated liquid chromatography/mass spectrometry (LC/MS/MS) assay method. After intravenous administration of 50 mg/kg, dose-normalized (10 mg/kg) area under the curve (AUC) (993 microg.min/ml) was significantly greater than that at 10 mg/kg (702 microg.min/ml). The slower clearance Cl-at 50 mg/kg could be due to saturable metabolism of LSB in rats, and this could be supported by significantly slower Cl(NR) and significantly greater 24-h urinary excretion of LSB at 50 mg/kg than at 10 mg/kg. Following oral administration of LSB, the extent of LSB recovered from the entire gastrointestinal tract at 24 h ranged from 41.2% to 23.3%. Although LSB was not detected (limit of quantitation 10 ng/ml) in plasma after oral dose of 10 mg/kg, the absolute oral bioavailability at 50 mg/kg was 5%. Since LSB was shown to have low permeability through the Caco-2 cell monolayers, the low bioavailability of LSB could be due to poor absorption and metabolism.

Liquid chromatography-tandem mass spectrometry for the determination of lithospermic acid B in rat serum

A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/ MS) method for the determination of lithospermic acid B (LSB) in rat serum was developed. LSB and internal standard, 7-hydroxy-3-phenyl-chromen-4-one (HPC) were extracted from rat serum with methyl-tert-butyl ether at acidic pH and analyzed on a Luna C8 column with the mobile phase of acetonitrile-ammonium formate (10 mM, pH 6.5) (50:50, v/v). The analytes were detected using a negative electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring mode. The standard curve was linear (r2= 0.997) over the concentration range of 10.0-500 ng/mL. The coefficient of variation and relative error for intra- and interassay at three QC levels were 1.1 approximately 6.2% and -10.3 approximately -2.7%, respectively. The recovery of LSB from serum sample ranged from 73.2 to 79.5%, with that of HPC (internal standard) being 75.1 %. The lower limit of quantification for LSB was 10 ng/mL using 50 microL of serum sample.

Lithospermic acid B isolated from Salvia miltiorrhiza ameliorates ischemia/reperfusion-induced renal injury in rats

The present study was designed to examine whether lithospermic acid B (LSB) isolated from Salvia miltiorrhiza has an ameliorative effect on renal functional parameters in association with the expression of aquaporin 2 (AQP 2) and Na,K-ATPase in the ischemia-reperfusion induced acute renal failure (ARF) rats. LSB showed strong antioxidant activity against production of reactive oxygen species (ROS), ROS-induced hemolysis, and production of lipid peroxide in a dose-dependent manner. Polyuria caused by down-regulation of renal AQP 2 in the ischemia-reperfusion induced ARF rats was partially restored by administration of LSB (40 mg/kg, i.p.), restoring expression of AQP 2, in renal inner and outer medulla. The expression of Na,K-ATPase alpha1 subunit in outer medulla of the ARF rats was also restored in the ARF rats by administration of LSB, while beta1 subunit level was not altered. The renal functional parameters including creatinine clearance, urinary sodium excretion, urinary osmolality, and solute-free reabsorption were also partially restored in ischemia-ARF rats by administration of LSB. Histological study also showed that renal damages in the ARF rats were abrogated by administration of LSB. Taken together, these data indicate that LSB ameliorates renal defects in rats with ischemia-reperfusion induced ARF, most likely via scavenging of ROS.

Role of Salviae Miltiorrhizae Radix extract and its compounds in enhancing nitric oxide expression

Excessive production of nitric oxide (NO) and its peroxidant product, peroxynitrite, has been implicated in the pathology of acute and chronic renal failure, and inhibitors of NO production have been shown to exert protective and ameliorative effects against renal epithelial cell damage mediated by enhanced generation of NO. Salviae Miltiorrhizae Radix has exhibited a beneficial effect in the improvement of renal failure. In order to clarify the mechanism responsible, we investigated whether Salviae Miltiorrhizae Radix extract and several of its related compounds, including caffeic acid and its polymers which were isolated by our research group, can regulate the generation and release of NO. The results demonstrated that Salviae Miltiorrhizae Radix extract and these compounds suppressed NO effectively in the systems employing activated macrophages and the arginine-hydrogen peroxide, and that, furthermore, the activity shown by the compounds was higher than that shown by the extract. In addition, direct scavenging of NO was also observed. The present findings suggest that Salviae Miltiorrhizae Radix extract and its compounds are potent NO inhibitors, and that their inhibitory effect on the generation and release of NO may contribute to the previously reported pharmacological effect of Salviae Miltiorrhizae Radix in improving renal function.