Quality assessment of Rheum species cultivated in Japan by focusing on M2 polarization of microglia.

In traditional Japanese medicine, Rhei Rhizoma is used as a purgative, blood stasis-resolving and antipsychotic drug. The latter two properties are possibly related to anti-inflammatory effects. Microglia regulate inflammation in the central nervous system. M1 microglia induce inflammation, while M2 microglia inhibit inflammation and show neurotrophic effects. This study investigated the effects from water extracts of roots of cultivated Rheum species in Nagano Prefecture, Japan (strain C, a related strain to a Japanese cultivar, 'Shinshu-Daio'; and strain 29, a Chinese strain) and 3 kinds of Rhei Rhizoma available in the Japanese market, and also examined their constituents on the polarization of cultured microglia. All extracts significantly decreased M1 microglia, and strains C and 29 significantly increased M2 microglia. Furthermore, the extracts of both strains significantly increased the M2/M1 ratio. Among the constituents of Rhei Rhizoma, ( +)-catechin (2), resveratrol 4'-O-ß-D-(6″-O-galloyl) glucopyranoside (5), isolindleyin (8), and physcion (15) significantly increased the M2/M1 ratio. The contents of the constituents in water extract of each strain were quantified using HPLC. The extracts of strains C and 29 contained relatively large amounts of 2 and 5; and 2, 8, and 15, respectively. This study showed the water extracts of roots of cultivated Rheum strains in Japan had the effects of M2 polarization of microglia, suggesting that these strains become the candidate to develop anti-inflammatory Rhei Rhizoma. Moreover, the suitable chemical composition to possess anti-inflammatory activity in the brain was clarified for the future development of new type of Rhei Rhizoma.

Assessment of the anti-inflammatory effects of three rhubarb anthraquinones in LPS-Stimulated RAW264.7 macrophages using a pharmacodynamic model and evaluation of the structure-activity relationships.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhubarb (Rhei Radix et Rhizoma) is a traditional Chinese medicine, has been used as a strong astringent in China to treat inflammation-related diseases, such as acute pancreatitis, acute cholecystitis, appendicitis and so on. Rhein, emodin and aloe-emodin are the important active anthraquinone in rhubarb, and are considered to be the main ingredients contributing to anti-inflammatory. AIM OF THE STUDY: Rhein, emodin and aloe-emodin, anthraquinones with the same parent structure that are found in rhubarb, have beneficial anti-inflammatory effects in vitro and in vivo. Anthraquinone derivatives also have important clinical roles. However, their pharmacodynamic differences and the structure-activity relationships associated with their anti-inflammatory properties have not been systematically explored. The present study was designed to quantify the effects of three rhubarb anthraquinones on inflammation and to explore the structure-activity relationships of these compounds. MATERIALS AND METHODS: In this study, we detected NF-κB phosphorylation, iNOS protein expression, and IL-6 and NO production in LPS-stimulated RAW264.7 cells and then calculated median effect equations and built a dynamic pharmacodynamic model to quantitatively evaluate the efficacy of these three anthraquinones. Additionally, to determine the structure-activity relationships, we investigated the physicochemical properties and molecular electrostatic potentials of the drug molecules. RESULTS: We found that rhein, emodin, and aloe-emodin exerted at least dual-target (NF-κB, iNOS) inhibition of LPS-induced inflammatory responses. Compared with rhein and emodin, aloe-emodin had a stronger anti-inflammatory effect, and its inhibition of iNOS protein expression was approximately twice that of NF-κB phosphorylation. In addition, aloe-emodin had the strongest hydrophobic effect among the three anthraquinones. CONCLUSIONS: Overall, we concluded that the receptor binding the rhubarb anthraquinones had a hydrophobic pocket. Anthraquinone molecules with stronger hydrophobic effects had higher affinity for the receptor, resulting in greater anti-inflammatory activity. These results suggest that the addition of a hydrophobic group is a potential method for structural modification to design anti-inflammatory anthraquinone derivatives with enhanced potency.

[Study on dosage-toxicity/efficacy relationship of prepared rhubarb on basis of symptom-based prescription theory].

OBJECTIVE: To investigate the dosage-efficacy/toxicity relationship of prepared rhubarb, in order to explore the bidirectional effects in hepatoprotection and hepatotoxicity of prepared rhubarb and the objective authenticity for attenuating toxicity by processing. METHOD: Normal and pathological animals were adopted simultaneous to investigate the effect of total extracts from prepared rhubarb within a high dose range (2.0, 5.4, 14.7, 40.0 g x kg(-1) x d(-1)) on normal state, biochemical index and histopathology of experimental animals. The factor analytic approach was used to analyze the dosage-efficacy/toxicity relationship of prepared rhubarb. RESULT: The factor analytic approach was used to extract two common factors from the nine biochemical indexes. The firs common factor was mainly dominated by HA, LN and TGF-ß1, and could be explained as fibrotic factors. The second common factor was mainly dominated by ALT, AST and ALP, and could be explained as cellular factor. The results of the factor analysis suggested that prepared rhubarb showed significant bidirectional effects in hepatoprotection and hepatotoxicity, which could protect liver in CC14 injured chronic hepatic injury, but had a certain hepatotoxic effect to normal animals. The pathological examination showed consistent results with the factor analysis. Under comparable dosages, prepared rhubarb showed a stronger liver protecting effect than crude rhubarb, with a lower toxicity. CONCLUSION: Although prepared rhubarb has a certain hepatotoxic effect to normal animals, it has also a significant therapeutic effect to animals with liver injury. The results proved the symptom-based prescription theory and the scientificity of the symptom-based medication. The symptom-based prescription theory is important to correctly realize the dosage-efficacy/toxicity relationship of traditional Chinese medicines and guide the symptom-based medication.

Comparative pharmacokinetics of aloe-emodin, rhein and emodin determined by liquid chromatography-mass spectrometry after oral administration of a rhubarb peony decoction and rhubarb extract to rats.

This study aimed to clarify the rationality of herbaceous compatibility of a rhubarb peony decoction (DaHuang-Mu-Dan-Tang, RPD) by comparing the pharmacokinetics of aloe-emodin, rhein and emodin in rats' plasma after oral administration of RPD and rhubarb extract. A rapid, sensitive LC-MS method was developed and validated for the determination of the plasma concentrations of the three analytes after oral administration RPD and rhubarb extract. The developed method was successfully applied to a pharmacokinetic study of aloe-emodin, rhein and emodin in rats' plasma after oral administration. Compared with administration of single rhubarb, the C(max) of rhein in RPD was decreased significantly (p < 0.05). Meanwhile, the T1/2 of aloe-emodin and emodin were increased significantly (p < 0.05) after administration of RPD. In addition, the T(max) of rhein and emodin were also increased significantly (p < 0.05) in RPD. These results indicated that the absorption of rhein in rats was suppressed after oral administration RPD. Moreover, The time for rhein and emodin to reach the peak concentration was delayed and the elimination of aloe-emodin and emodin was also postponed in RPD. This study could provide a meaningful basis for evaluating the clinical application of traditional Chinese medicine in terms of pharmacokinetics.

Assessment of antibacterial properties and the active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch).

BACKGROUND: In this study, the antibacterial properties and active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch) were assessed. RESULTS: The transmission electron microscopy and flow cytometric analysis showed that the antibacterial activity of plant extracts is due to the disruption of the cell membrane and the leakage of cytoplasmic contents. The UPLC-MS/MS analysis showed that the contents of gallic acid, (-)-epigallocatechin, (+)-catechin, (-)-epigallocatechin gallate, (-)-epicatechin gallate, aloe-emodin, rhein, emodin, chrysophanol, and physcion, were 5.27%, 3.30%, 1.08%, 19.32%, 5.46%, 0.23%, 0.56%, 1.28%, 0.75% and 0.39% in plant extracts, respectively. Results of feeding experiment showed that feeding crucian carp with 1.0% and 2.0% plant extracts significantly enhanced specific growth rate, serum total protein, lysozyme, catalase and superoxide dismutase activities, and decreased the feed conversion rate, malondialdehyde contents and the mortality rate (P < 0.05). CONCLUSION: It can be concluded that plant extracts added to fish feed can act as natural antimicrobial and immunostimulants to prevent pathogenic infection, enhance immune response, and promote growth of the fish.

Quantifying four-probe metabolites in a single UPLC-MS/MS run to explore the effects of cooked rhubarb on cytochrome P450 isozymes.

BACKGROUND: Cytochrome P450 (CYP) enzymes primarily account for the oxidation of xenobiotics. A single run UPLC-MS/MS method was developed to simultaneously detect four metabolites from a probe cocktail to investigate four CYP isozymes. Paracetamol was detected to investigate CYP1A2, 4-hydroxytolbutamide for CYP2C6, 6-hydroxychlorzoxazone for CYP2E1 and dehydronifedipine for CYP3A1. 6-hydroxychlorzoxazone was detected in ESI-negative mode, while the other three were detected in ESI-positive mode. RESULTS: The method was rapid (2.5 min) and validated to be specific, accurate and precise. It was successfully applied to evaluate the effects of cooked rhubarb on the activities of the four isozymes in rat microsomes. Cooked rhubarb inhibited the activity of CYP2C6 but induced both CYP2E1 and CYP3A1. CONCLUSION: This convenient UPLC-MS/MS method was applicable. It could improve the efficiency of future studies estimating the influence of herbs, herbal products or drug entities on the activities of CYP1A2, CYP2C6, CYP2E1 and CYP3A1.

Assessment of the renal protection and hepatotoxicity of rhubarb extract in rats.

AIM OF THE STUDY: Rhubarb is well used to treat chronic renal failure (CRF) in China and Japan, but recent studies reported that the anthraquinone derivatives contained in rhubarb had nephrotoxicity. In this investigation an attempt was made to assess the value and toxic potential of rhubarb to treat CRF. MATERIALS AND METHODS: Histopathologic and biochemical tests combined with toxicokinetic analysis were performed to investigate the nephrotoxic potential and protective effect of rhubarb extract. RESULTS: In normal rat groups, no death was observed and no renal lesion was found after repetitive administration of rhubarb for 3 weeks. The survival rate, pathologic conditions and biochemical indexes of CRF rats treated with rhubarb at two dosages were all improved and significant amelioration was found in the low dosage group compared to the untreated CRF group. Rhein was the mainly absorbable anthraquinone derivative into systemic circulation after oral administration and the area under curve of rhein in CRF groups was lower than that in normal groups at same dosage. CONCLUSIONS: After 3 weeks of administration of rhubarb extract, there was evidence of protective effect to CRF rats, while incidences of hepatotoxicity with minimal to mild hyaline droplets were also observed in normal rats.

[Quality assessment of the Chinese traditional medicine rhubarb by chemical pattern recognition].

Traditionally, the identification of Chinese medicines is performed by the morphological method. As chemical constituents play the role of therapeutic action, it is more rational to identify Chinese traditional medicines by analyzing their chemical constituents. Furthermore, the therapeutic action of a Chinese traditional medicine is usually the result of coordination of its chemical constituents. In this paper, the PRIMA method was adopted to classify 29 samples of the Chinese traditional medicine rhubarb, with 16 samples as the training set and 13 samples as the test set. The recognition ability was 100% and the prediction ability was 92% on HPLC data, while both of them were 100% on UV data. As far as this research is concerned, the PRIMA method is superior to the Bayes classification rule, the SIMCA method and nonlinear mapping in its simplicity, rapidity and correctness. Pharmacologic experiments were carried out to confirm the results.