Serum concentrations of anthraquinones after intake of Folium Sennae and potential modulation on P-glycoprotein.

Folium Sennae (leaves of Cassia angustifolia or senna) is a laxative and a component in diets for weight control. It contains a variety of anthranoids such as sennosides, aloe-emodin, and rhein. In order to measure the serum concentrations of senna anthranoids, Sprague-Dawley rats were orally administered with single dose and multiple doses of Folium Sennae. The concentrations of anthranoids in serum were determined by HPLC method before and after hydrolysis with sulfatase and ß-glucuronidase. The results showed that in the serum, aloe-emodin glucuronides and rhein glucuronides were the major metabolites. Traces of rhein free form were present transiently during the early phase, whereas the free form of aloe-emodin was not detected. We also evaluated the modulation effect of Folium Sennae on P-glycoprotein by using the LS 180 cell model which showed that it significantly inhibited P-glycoprotein by 16-46 %. In conclusion, senna anthranoids were rapidly and extensively metabolized to rhein glucuronides and aloe-emodin glucuronides in rats. Folium Sennae ingestion inhibited the efflux function of P-glycoprotein in the intestine.

Enhancing the bioavailability of magnolol in rabbits using melting solid dispersion with polyvinylpyrrolidone.

OBJECTIVE: Preparation of magnolol-loaded amorphous solid dispersion was investigated for improving the bioavailability. MATERIALS AND METHODS: A solid dispersion of magnolol was prepared with polyvinylpyrrolidone K-30 (PVP) by melting method, and the physical properties were characterized by using differential scanning calorimetry, powder X-ray diffractometry, Fourier transformation-infrared spectroscopy and scanning electron microscope. In addition, dissolution test was also performed. Subsequently, the bioavailability of magnolol pure compound, its physical mixture and solid dispersion were compared in rabbits. The blood samples withdrawn via marginal ear vein at specific time points were assayed by HPLC method. RESULTS: Oral administration of the solid dispersion of magnolol with PVP significantly increased the systemic exposures of magnolol and magnolol sulfates/glucuronides by 80.1% and 142.8%, respectively, compared to those given with magnolol pure compound. CONCLUSION: Magnolol-loaded amorphous solid dispersion with PVP has demonstrated enhanced bioavailability of magnolol in rabbits.

Interaction of rhubarb and methotrexate in rats: in vivo and ex vivo approaches.

Rhubarb, the rhizome of Rheum palmatum L. (RP), is a popular herb used in Chinese medicine prescriptions. RP contains a variety of polyphenolic anthraquinones, such as aloe-emodin, rhein, emodin and chrysophanol. Our previous study found that the anthraquinones in RP existed predominantly as glucuronides/sulfates in the bloodstream, which were putative substrates of MRPs. Methotrexate (MTX) is a widely used immunosuppressant and anticancer agent, but it has a narrow therapeutic index. The transcellular transport of MTX is mediated by multidrug resistance associated proteins (MRPs). This study investigated the effects of coadministration of RP on MTX pharmacokinetics in rats. The possible involvement of MRP 2 was verified by using cell models and various typical MRP 2 substrates. The results showed that coadministration of 0.5 mg/kg of RP significantly increased the AUC 0-t and MRT of MTX by 307% and 364%, and 1.0 g/kg of RP significantly increased the AUC 0-t and MRT of MTX by 602% and 419%, respectively. Cell line studies indicated that the activity of MRP 2 was inhibited by the metabolites of RP and rhein. In conclusion, concomitant administration of RP markedly increased the systemic exposure of MTX via inhibiting MRP 2-mediated excretion.

Pharmacokinetics and tissue distribution of resveratrol, emodin and their metabolites after intake of Polygonum cuspidatum in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The rhizome of Polygonum cuspidatum SIEB. et ZUCC. (Polygonaceae, PC), a widely used Chinese medicine, is commonly prescribed for the treatments of amenorrhea, arthralgia, jaundice, abscess, scald and bruises. AIM OF THE STUDY: PC contains various polyphenols including stilbenes, anthraquinones and flavonoids. This study investigated the pharmacokinetics and tissue distribution of emodin and resveratrol in PC. MATERIAL AND METHODS: Male Sprague-Dawley rats were orally administered PC (2 and 4 g/kg) and blood samples were withdrawn at the designed time points via cardiopuncture. Moreover, after 7-dose administrations of PC (4 g/kg), brain, liver, lung, kidney and heart were collected. The concentrations of resveratrol and emodin in the plasma and tissues were assayed by HPLC before and after hydrolysis with ß-glucuronidase and sulfatase. RESULTS: The glucuronides/sulfates of emodin and resveratrol were exclusively present in the plasma. In liver, kidney, lung and heart, the glucuronides/sulfates of resveratrol were the major forms. For emodin, its glucuronides/sulfates were the major forms in kidney and lung, whereas considerable concentration of emodin free form was found in liver. Neither free forms nor conjugated metabolites of resveratrol and emodin were detected in brain. CONCLUSION: The sulfates/glucuronides of resveratrol and emodin were the major forms in circulation and most assayed organs after oral intake of PC. However, the free form of emodin was predominant in liver.

Ixora parviflora Protects against UVB-Induced Photoaging by Inhibiting the Expression of MMPs, MAP Kinases, and COX-2 and by Promoting Type I Procollagen Synthesis.

Ixora parviflora with high polyphenol content exhibited antioxidant activity and reducing UVB-induced intracellular reactive oxygen species production. In this study, results of the photoaging screening experiments revealed that IPE at 1000 µg/mL reduced the activity of bacterial collagenase by 92.7 ± 4.2% and reduced the activity of elastase by 32.6 ± 1.4%. Therefore, we investigated the mechanisms by which IPE exerts its anti-photoaging activity. IPE at 1 µg/mL led to an increase in type I procollagen expression and increased total collagen synthesis in fibroblasts at 5 µg/mL. We found that IPE inhibited MMP-1, MMP-3, and MMP-9 expression at doses of 1, 5, and 10 µg/mL, respectively, in fibroblasts exposed to UV irradiation (40 mJ/cm(2)). Gelatin zymography assay showed that IPE at 50 µg/mL inhibited MMP-9 secretion/activity in cultured fibroblasts after UVB exposure. In addition, IPE inhibited the phosphorylation of p38, ERK, and JNK induced by UVB. Furthermore, IPE inhibited the UVB-induced expression of Smad7. In addition, IPE at 1 µg/mL inhibited NO production and COX-2 expression in UV-exposed fibroblasts. These findings show that IPE exhibits anti-inflammatory and anti-photoaging activities, indicating that IPE could be a potential anti-aging agent.

Antioxidant and anti-inflammatory potential of hesperetin metabolites obtained from hesperetin-administered rat serum: an ex vivo approach.

In recent years much attention has been focused on the pharmaceutical relevance of bioflavonoids, especially hesperidin and its aglycon hesperetin in terms of their antioxidant and anti-inflammatory actions. However, the bioactivity of their metabolites, the real molecules in vivo hesperetin glucuronides/sulfates produced after ingestion, has been poorly understood. Thus, the study using an ex vivo approach is aimed to compare the antioxidant and anti-inflammatory activities of hesperidin/hesperetin or hesperetin metabolites derived from hesperetin-administered rat serum. We found that hesperetin metabolites (2.5-20 µM) showed higher antioxidant activity against various oxidative systems, including superoxide anion scavenging, reducing power, and metal chelating effects, than that of hesperidin or hesperetin. The data also showed that pretreatment of hesperetin metabolites (1-10 µM) within the range of physiological concentrations, compared to hesperetin, significantly inhibited nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production, as evidenced by the inhibition of their precursors, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein levels without appreciable cytotoxicity on LPS-activated RAW264.7 macrophages or A7r5 smooth muscle cells. Concomitantly, hesperetin metabolites dose-dependently inhibited LPS-induced intracellular reactive oxygen species (ROS). Furthermore, hesperetin metabolites significantly downregulate LPS-induced nuclear factor-κB (NF-κB) activation followed by the suppression of inhibitor-κB (I-κB) degradation and phosphorylation of c-Jun N-terminal kinase1/2 (JNK1/2) and p38 MAPKs after challenge with LPS. Hesperetin metabolites ex vivo showed potent antioxidant and anti-inflammatory activity in comparison with hesperidin/hesperetin.

Steady-state pharmacokinetics and tissue distribution of anthraquinones of Rhei Rhizoma in rats.

AIM OF THE STUDY: Rhei Rhizoma, the rhizome of Rheum palmatum L. (RP), is a popular herb in clinical Chinese medicine. RP is abundant in polyphenolic anthraquinones, which have been reported to show various beneficial bioactivities. This study investigated the pharmacokinetics and tissue distribution of anthraquinones following seven-dose administration of RP decoction to rats. MATERIALS AND METHODS: Six Sprague-Dawley rats were given 2.0 g/kg of RP twice daily for seven doses and blood samples were collected at designated time after the 7th dose. Another six rats were sacrificed at 30 min after the 7th dose and organs including liver, kidney, lung and brain were collected. Serum and tissue specimens were assayed by HPLC before and after hydrolysis with ß-glucuronidase and sulfatase, respectively. RESULTS: Pharmacokinetic analysis indicated that the anthraquinones in serum mainly presented as glucuronides/sulfates and contained higher ratio of sulfates when compared with single-dose administration of RP. Contrary to the finding in serum, tissue analysis discovered mainly free form of anthraquinone in most organs assayed, such as aloe-emodin and rhein in kidney, liver, lung; emodin in liver, lung; trace of chrysophanol in kidney and liver. In all brains, neither free forms nor their glucuronides/sulfates have been detected. CONCLUSIONS: The glucuronides/sulfates of anthraquinones were the major forms in bloodstream, whereas the free forms of most anthraquinones were predominant in kidney and liver.

Pharmacokinetics, bioavailability, and tissue distribution of magnolol following single and repeated dosing of magnolol to rats.

Magnolol (M) is a polyphenol antioxidant abundant in the bark of Magnolia officinalis Rehder & E. Wilson, a popular Chinese herb. To understand the pharmacokinetics and bioavailability of M, Sprague-Dawley rats were intravenously injected with a bolus of M (20 mg/kg) and orally given a single dose and seven doses of M (50 mg/kg). Blood samples were withdrawn via cardiopuncture at specific times. Organs including the liver, kidney, brain, lung, and heart were collected at 30 min after the 7th oral dose. The serum and tissue specimens were assayed by HPLC before and after hydrolysis with ß-glucuronidase and sulfatase. The results showed that after intravenous bolus, the systemic exposure of magnolol glucuronides (MG) was comparable with that of M while after oral administration, magnolol sulfates/glucuronides (M S/G) were predominant in the bloodstream. Conversely, M was predominant in the liver, kidney, brain, lung, and heart. Among the studied organs, the liver contained the highest concentrations of M and MG. In conclusion, M S/G was the major form in circulation, whereas M was predominant in the liver, kidney, brain, lung, and heart after oral administration of M; among these organs, the liver contained the highest concentrations of M and MG.

Quercetin and rutin reduced the bioavailability of cyclosporine from Neoral, an immunosuppressant, through activating P-glycoprotein and CYP 3A4.

Quercetin and rutin are popular flavonoids in plant foods, herbs, and dietary supplements. Cyclosporine (CSP), an immunosuppressant with a narrow therapeutic window, is a substrate of P-glycoprotein (P-gp) and cytochrome P-450 3A4 (CYP3A4). This study investigated the effects of quercetin and rutin on CSP pharmacokinetics from Neoral and relevant mechanisms. Rats were orally administered Neoral with and without quercetin or rutin. The blood CSP concentration was assayed by a specific monoclonal fluorescence polarization immunoassay. The results showed that quercetin and rutin significantly decreased the C(max) of CSP by 67.8 and 63.2% and reduced the AUC(0-540) by 43.3 and 57.2%, respectively. The in vitro studies indicated that the quercetin and rutin induced the functions of P-gp and CYP3A4. In conclusion, quercetin and rutin decreased the bioavailability of CSP through activating P-gp and CYP3A. Transplant patients treated with Neoral should avoid concurrent consumption of quercetin or rutin to minimize the risk of allograft rejection.

Hydrolysates of citrus plants stimulate melanogenesis protecting against UV-induced dermal damage.

The sun-tanning process occurs as a spontaneous response to ultraviolet (UV) irradiation. UV will induce tanning and DNA damage, processes that can lead to photoaging and skin disorders such as hyperpigmentation and cancer. The pigment melanin protects skin from UV damage; therefore, an efficient melanin-promoting suntan lotion could be highly beneficial. In this study, a process was developed to increase the content of naringenin in citrus extracts and to determine whether a higher naringenin content of citrus would induce melanogenesis. Melanin content and tyrosinase expression in mouse B16 melanoma cells were assayed after treatment with citrus plant extracts and their hydrolysates. The results indicate that hydrolysis increased the naringenin content in citrus extracts and that citrus preparations stimulated cellular melanogenesis and tyrosinase expression. It is suggested that this method is applicable to the industrial production of melanin-promoting suntan lotions with antiphotocarcinogenic properties derived from citrus rind and citrus products.

Metabolism and pharmacokinetics of san-huang-xie-xin-tang, a polyphenol-rich chinese medicine formula, in rats and ex-vivo antioxidant activity.

San-Huang-Xie-Xin-Tang (SHXXT), a widely used Chinese herbal formula, consists of rhizomes of Rheum officinale, roots of Scutellaria baicalensis and rhizomes of Coptis chinesis. This study investigated the metabolism and pharmacokinetics of polyphenols in SHXXT, including baicalin, baicalein, wogonin, emodin, aloe-emodin, rhein and chrysophanol. The quantitation methods of SHXXT decoction and rat serum using high performance liquid chromatography were developed and validated in this study. After oral administration of SHXXT decoction to rats, the parent forms of various constituents and their conjugated metabolites in serum were determined before and after hydrolysis with ß-glucuronidase and sulfatase. The results showed that only free form of rhein can be quantitated, whereas the parent forms of coptisine, palmatine, berberine, baicalein, wogonin, emodin, aloe-emodin and chrysophanol were not detected in serum. The glucuronides of baicalein, wogonin, emodin, aloe-emodin, rhein and chrysophanol were the predominant forms in bloodstream. In order to evaluate the in vivo antioxidant activity of SHXXT, the serum metabolite of SHXXT was prepared, characterized and followed by evaluation of the effect on AAPH-induced hemolysis. The results indicated that metabolites of SHXXT exhibited significant free radical scavenging activity. We suggest that biologists redirect their focus to the bioactivity of the conjugated metabolites of these polyphenols.

Differences in pharmacokinetics and ex vivo antioxidant activity following intravenous and oral administrations of emodin to rats.

Emodin, a natural anthraquinone polyphenol, has been reported to possess promising in vitro antioxidation, anticancer and anti-inflammatory activities. Whether the in vitro bioactivities can predict in vivo effects remained an unanswered question without understanding emodin pharmacokinetics in animals. To fill this blank, this study investigated the biological fate of emodin in rats. Emodin was intravenously (5.0 mg/kg) and orally (20.0 and 40.0 mg/kg) administered to rats. Blood samples were assayed by HPLC before and after hydrolysis with sulfatase and beta-glucuronidase. It is observed that after intravenous bolus of emodin, the parent form of emodin declined rapidly, and emodin glucuronides, omega-hydroxyemodin (omega-OHE) and omega-OHE sulfates/glucuronides all emerged instantaneously. In contrast, when emodin was given orally, emodin glucuronides were exclusively present in serum, whereas emodin, omega-OHE and omega-OHE sulfates/glucuronides were not detected. In order to evaluate the in vivo antioxidation activity, the serum metabolites of emodin following intravenous and oral administrations were prepared from rats and characterized, followed by investigating the effects on 2,2'-azobis(2-amidinopropane hydrochloride)-induced hemolysis. The results suggested that the serum metabolites of oral emodin exhibited more promising free radical scavenging activity than those of intravenous emodin and emodin parent form. We suggest biologists to redirect their targets to emodin glucuronide.

Metabolism and pharmacokinetics of anthraquinones in Rheum palmatum in rats and ex vivo antioxidant activity.

Anthraquinones are a major group of polyphenols in the rhizome of Rheum palmatum L. (RP). This study investigated the metabolism and pharmacokinetics of anthraqinones in RP decoction in rats. The concentrations of four anthraquinones including aloe-emodin, rhein, emodin, chrysophanol, and their glycosides in the decoction were quantitated by HPLC before and after acid hydrolysis with the results indicating that the anthraquinones mainly existed as the glycoside form except for rhein. Rats were orally administered RP decoction and blood samples were assayed by HPLC before and after treatments with sulfatase and beta-glucuronidase. It was found that the glucuronides of aloe-emodin, rhein, emodin and chrysophanol were predominant in the blood, whereas their aglycones were not detected except for rhein. In conclusion, the anthraquinones were subject to a rapid and extensive conjugation metabolism in rats and the serum metabolites of RP exhibited a potential free radical scavenging effect on AAPH-induced hemolysis at pharmacologically relevant concentrations.

Biotransformation and pharmacokinetics of 4-(3,4-dihydroxybenzoyloxymethyl)phenyl-O-beta-D-glucopyranoside, an antioxidant isolated from Origanum vulgare.

4-(3,4-Dihydroxybenzoyloxymethyl)phenyl- O-beta-D-glucopyranoside (OV-16) is a polyphenolic glycoside isolated from oregano (Origanum vulgare L.), which is a popular Chinese herb and a common spice in Western diet. To understand the biotransformation and pharmacokinetics of OV-16, rats were orally administered OV-16 and oregano decoction. Blood samples were withdrawn at specific time points. The presence of OV-16 and its metabolites protocatechuic acid (PCA) and p-hydroxybenzyl alcohol (HBA) in serum were determined by HPLC method, whereas their conjugated metabolites were assayed indirectly through hydrolysis with beta-glucuronidase and sulfatase. Our results showed that when OV-16 was orally administered, free forms of OV-16, PCA, and HBA were not present in blood and the major metabolites were the glucuronides/sulfates of PCA and HBA sulfate. The serum metabolites of OV-16 exhibited free radical scavenging activity. When oregano decoction was given, the glucuronides and sulfates of PCA were the major metabolites in blood.

Enhanced biodegradation of mixed phenol and sodium salicylate by Pseudomonas putida in membrane contactors.

A polypropylene (PP) hollow fiber membrane contactor was used as a reactor to enhance the biodegradation of equimolar phenol and sodium salicylate (SA) by Pseudomonas putida CCRC 14365 at 30 degrees C and pH 7. Experiments were performed at a fixed initial cell density of 0.025 g/L and in the total substrate level range 5.32-63.8 mM. The degradation experiments by free cells were also studied for comparison. With pristine hydrophobic fibers, the degradation of SA was started only after phenol was completely consumed. Substrate inhibitory effect was avoided due to sufficiently low substrate levels in the cell medium; however, the biodegradation was time consuming. With ethanol-wetted fibers, both substrates were completely degraded much faster than the use of pristine fibers. Although the wetted fibers were unable to prevent movement of substrates through the pores, biofilm formed on the outer surfaces of the fibers could enhance the tolerance limit of substrate toxicity. This greatly extended the treatment range to high-level substrate mixtures, as long as the water was nearly neutral and free of concentrated inorganic salts.