Review on Processing Methods of Toxic Chinese Materia Medica and the Related Mechanisms of Action.

Toxic Chinese materia medica (CMM) has both pharmacological activities and toxic effects. Based on thousands of years of experience in the application of CMMs, people have explored many practical processing methods of CMMs, also known as "Pao Zhi", to reduce/control toxicity and preserve/enhance efficacy. Toxic CMMs have been used throughout China's hospitals. Yet, the production and use of toxic CMM should be carried out in accordance with the Chinese pharmacopoeia (ChP) and the processing regulations formulated by the health administrative departments of provinces, autonomous regions, and municipalities directly under the Central Government. This paper summarizes the current understanding and awareness of toxicity and 45 toxic CMMs, the commonly used processing methods of toxic CMMs recorded in the 2020 edition of ChP, and the changes in the chemical component, toxicity, or efficacy profiles after processing. This review may provide useful information for the processing methods of toxic CMMs worldwide. We believe that with an in-depth study and understanding of toxic CMMs combined with a standardized application, the toxicity of CMMs will be predictable and controllable in the future.

Determination and tissue distribution comparisons of five xanthones after orally administering crude and processed gamboge.

Caged polyprenylated xanthones are the main active ingredients isolated from the resin of Garcinia hanburyi, which has been reported to exhibit potential anticancer and anti-inflammatory activities. This study aimed to develop sensitive and specific ultra-performance liquid chromatography coupled with the triple quadrupole mass spectrometry method for investigating the tissue distribution of five xanthones in rats: ß-morellic acid, isogambogenic acid, gambogenic acid, R-gambogic acid and S-gambogic acid. All tissue samples were prepared using the liquid-liquid extraction method and separated on a C8 column with a gradient system. Detection was performed on a triple quadrupole mass spectrometer in multiple-reaction monitoring using positive ionization. The method established in this assay was successfully applied to the tissue distribution study of the five selected xanthones after orally administering crude and processed gamboge in rat tissues. The results indicated that these five xanthones were distributed to rat tissues rapidly and could be detected in all of the selected tissues after oral administration. After processing, the contents of R-gambogic acid and S-gambogic acid in the gastrointestinal tract were significantly reduced. The findings of this study might be helpful in further understanding the processing mechanism of gamboge and providing references for its reasonable clinical application.

Pharmacokinetic comparison of five xanthones in rat plasma after oral administration of crude and processed Garcinia hanburyi extracts.

Gamboge, a dried resin secreted by Garcinia hanburyi Hook. f. (Guttiferae), possesses remarkable anticancer activity. However, due to toxicity, it must be processed before use in clinics. Xanthones are the main bioactive ingredients in gamboge. In order to elucidate the influence of processing technology on pharmacological properties of gamboge, an efficient, sensitive, and selective ultra-performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-MS/MS) method of five critical xanthones, including ß-morellic acid (ß-MA), isogambogenic acid (IGNA), gambogenic acid (GNA), R-gambogic acid (GA), and S-GA in rat plasma was established for a comparative pharmacokinetics study of these xanthones after oral administration of crude and processed G. hanburyi extracts. The chromatographic separation of these five xanthones along with an internal standard (I.S.) was carried out on a Waters Acquity UPLC BEH C8 column with a gradient elution method using acetonitrile/0.1% formic acid-water as mobile phases. The eluate was detected by multiple-reaction monitoring (MRM) scanning with an electrospray ionization source operating in the positive ionization mode. Sample preparation involved a liquid-liquid extraction of the five analytes with ethyl acetate. Deoxyschizandrin was employed as an internal standard. This assay method was validated for selectivity, linearity, intra-day and inter-day precision, accuracy, recovery, matrix effect, and stability. The results revealed that the calibration curves displayed good linear regression (r > 0.995), and the lower limit of quantification (LLOQ) was <5.52 ng/mL for each analyte. The intra-day and inter-day precision (RSD) of the five xanthones at low, medium, and high levels was <10.58%, and the bias of the accuracy ranged from -8.54 to 10.2%. All other parameters fulfilled the FDA criteria for bioanalytical validation. In addition, the assay was successfully applied to the determination and pharmacokinetic study of these five xanthones after oral administration of crude and processed gamboge. Furthermore, Cmax of GNA and AUC0-t of IGNA were increased significantly (P < 0.05) after processing, while AUC0-t of ß-MA, R-GA, and S-GA decreased remarkably (P < 0.05), which suggested that processing exerted different effects on the absorption of xanthones. The results might be valuable for the clinical reasonable application and understanding the processing mechanism of gamboge.

Endothelium corneum gigeriae galli extract inhibits calcium oxalate formation and exerts anti-urolithic effects.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese Medicine is preferred because of its safety and minimal/reduced side effects. Endothelium Corneum Gigeriae Galli (ECGG) extract, a traditional Chinese drug consisting of the dried gizzard membrane of Gallus gallus domesticus Brisson, was assessed for its effects and mechanism on urolithiasis. AIMS OF STUDY: To evaluate the effects of ECGG extract on calcium oxalate (CaOx) crystal formation in vitro, and assess the anti-urolithic effects of ECGG extract in vivo and explore the underlying mechanism. MATERIALS AND METHODS: In vitro, CaOx crystals were treated with ECGG extract (0.05, 0.2, and 0.8 g/mL), and assessed by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction and electrical conductivity. Then, a rat model of renal calculi was established by ethylene glycol and ammonium chloride treatment, and ECGG extract (5.0, 10.0 and 20.0 g/kg) was administered orally. After treatment, urine, serum and kidney bioindicators were analyzed, as well as kidney's pathological features. RESULTS: In the presence of ECGG extract, calcium oxalate dihydrate (COD) crystals with typical tetragonal bipyramidal morphology were obtained; meanwhile, the formation of calcium oxalate monohydrate (COM), a major urinary stone component, was inhibited; in addition, the equilibration time of the chemical reaction of Ca2+ and C2O42- ions was delayed in a concentration dependent manner. ECGG extract actually showed anti-urolithic effects; the incidence rates of crystal formation in the kidney in the model, low, middle and high dose groups were 100%, 90%, 70% and 60%, respectively, with a dose-dependent alleviation of kidney stone amounts and kidney damage. Treatment with middle and high ECGG extract doses significantly decreased urine uric acid and oxalic acid amounts, serum creatinine, urea nitrogen and uric acid contents, and kidney tissue oxalic acid and calcium levels, while increasing kidney and urinary magnesium and superoxide dismutase levels (P < 0.05). CONCLUSION: ECGG extract has outstanding anti-urolithic effects, potentially with included bioorganic molecules inducing COD crystal nucleation and growth. Therefore, ECGG extract is a promising drug for preventing and treating urolithiasis.

[Effects of Pogostemon cablin on gastrointestinal function of rats with syndrome of damp retention in middle-jiao].

To investigate the effects of Pogostemon cablin(patchouli) on gastrointestinal function of rats with the syndrome of damp retention in middle-jiao, and explore its therapeutic mechanism. In this study, gastrointestinal function of rats with the syndrome of damp retention in middle-jiao was evaluated by multiple assays including gastric remnant rate, small intestine propelling rate, gastric juice quantity, pepsin activity and gastrointestinal tissue morphology. ELISA was used to detect gastrointestinal hormones including MTL, GAS, VIP and cytokines including TNF-α and interleukin 10 in rat serum. Real-time fluorescent quantitative PCR technique was used to detect relative mRNA expression of AQP3, AQP4 and AQP8 in gastric and colonic tissues to explore the mechanism of P. cablin in treatment of gastrointestinal functions. The results showed that middle and high dose of P. cablin (3.24, 6.48 g•kg⁻¹) could obviously decrease the gastric remnant rate, promote gastric emptying, increase the small intestine propelling rate(P<0.05), speed up the propulsive movement of gastrointestinal tract, increase the secretion and acidity of gastric juice, increase the activity of pepsin, and improve the injury of gastrointestinal tissue. All the doses of P. cablin could increase the concentration of MTL and GAS in serum, reduce the concentration of VIP, TNF-α and IL-10 in serum, decrease the mRNA expression of AQP3 in gastric and colonic tissues, and increase the expression levels of AQP4 and AQP8 in colonic tissues. The regulatory effects were better in middle and high dose groups. In conclusion, regulation of the levels of gastrointestinal hormones, inflammatory cytokines and aquaporins may be the paths for P. cablin to maintain normal gastrointestinal function of rats with the syndrome of damp retention in middle-jiao. The results of the study laid a foundation for clarifying the treatment mechanism of aromatic damp-resolving drugs for indications including damp retention in middle-jiao and transformation failure of spleen.

[Attenuation mechanism of gamboges during processing based on inflammatory toxicity and AQP3, AQP4 protein and mRNA expressions in rat gastric and duodenal tissues].

To expand the clinical application of gamboges, it is necessary to study crude gamboges' toxicity after oral administration and attenuation mechanism during processing. In this study, crude gamboges' toxicity was judged by multiple assays, including inflammatory mediums [such as nitric oxide (NO), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6)] released by macrophage RAW264.7, and pathological manifestations of rat stomach and duodenal tissues after oral administration with crude and processed gamboges. The attenuation mechanism during processing was studied by detecting AQP3, AQP4 protein and mRNA expression in rat gastric and duodenal tissues using immunohistochemical assay and real-time fluorescent quantitative PCR technique. According to the results, crude gamboges group showed promotion in release of NO, TNF-α and IL-6 by macrophage RAW264.7 in a dose-dependent manner; Compared with crude gamboges group, processed gamboges group showed reduction in release of NO and IL-6, with increase in TNF-α. Crude gamboges could cause rat diarrhea, white blood cells increase, lymphocytes decrease, hyperemia and edema in rat gastric mucosa, duodenal mucosal necrosis and inflammatory cells infiltration. All of these results proved that gamboges had the inflammatory toxicity in gastric and duodenal tissues after oral administration in a dose-dependent manner, which however reduced after processing. In addition to the inflammatory toxicity, the mRNA and protein expressions of aquaporin 3 (AQP3), aquaporin 4 (AQP4) in gastric and duodenal tissues of high-dose crude gamboges group were increased significantly (P<0.05), while the protein and mRNA expressions of AQP3, AQP4 were weakened in processed gamboges group. The results showed that AQP3, AQP4 protein and mRNA expressions were positively correlated with the inflammatory toxicity. In conclusion, down-regulation of AQP3, AQP4 protein and mRNA expressions may be one of attenuation mechanisms in processing gamboges.

Combinative application of pH-zone-refining and conventional high-speed counter-current chromatography for preparative separation of caged polyprenylated xanthones from gamboge.

An efficient method for the preparative separation of four structurally similar caged xanthones from the crude extracts of gamboge was established, which involves the combination of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography for the first time. pH-zone-refining counter-current chromatography was performed with the solvent system composed of n-hexane/ethyl acetate/methanol/water (7:3:8:2, v/v/v/v), where 0.1% trifluoroacetic acid was added to the upper organic stationary phase as a retainer and 0.03% triethylamine was added to the aqueous mobile phase as an eluter. From 3.157 g of the crude extract, 1.134 g of gambogic acid, 180.5 mg of gambogenic acid and 572.9 mg of a mixture of two other caged polyprenylated xanthones were obtained. The mixture was further separated by conventional high-speed counter-current chromatography with a solvent system composed of n-hexane/ethyl acetate/methanol/water (5:5:10:5, v/v/v/v) and n-hexane/methyl tert-butyl ether/acetonitrile/water (8:2:6:4,v/v/v/v), yielding 11.6 mg of isogambogenic acid and 10.4 mg of ß-morellic acid from 218.0 mg of the mixture, respectively. The purities of all four of the compounds were over 95%, as determined by high-performance liquid chromatography, and the chemical structures of the four compounds were confirmed by electrospray ionization mass spectrometry and NMR spectroscopy. The combinative application of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography shows great advantages in isolating and enriching the caged polyprenylated xanthones.

Xanthine oxidase inhibitors from Garcinia esculenta twigs.

The EtOAc-soluble portion of the 80 % (v/v) EtOH extract from the twigs of Garcinia esculenta exhibited strong xanthine oxidase inhibition in vitro. Bioassay-guided purification led to the isolation of 1,3,6,7-tetrahydroxyxanthone (3) and griffipavixanthone (8) as the main xanthine oxidase inhibitors, along with six additional compounds (1, 2, 4-7), including two new compounds (1 and 2). This enzyme inhibition was dose dependent with an IC50 value of approximately 1.2 µM for 3 and 6.3 µM for 8. The inhibitory activity of 3 was stronger than the control allopurinol (IC50 value: 5.3 µM). To our knowledge, compound 8 is the first bixanthone that demonstrated potent XO inhibitory activity in vitro. The structures of the new compounds were established by spectroscopic analysis, and the optical properties and absolute stereochemistry of racemic (±) esculentin A (2) were further determined by the calculation of the DP4 probability and analysis of its MTPA ester derivatives.

[Determination of amino acids in Galli Gigerii endothelium corneum by HPLC with pre-column derivatization].

Hydrolytic amino acids were extracted by acid hydrolysis method, then derivatized with phenyl isothiocyanate (PITC). And the samples were analysed by HPLC on an Ultimate Prime C18 (4.6 mm x 250 mm, 5 microm) column with gradient elution of 0.1 mol x L(-1) sodium acetate buffer solution (adjusted to pH 6. 5)-acetonitrile (93:7) (A) and acetonitrile-water (8:2) (B) at a flow rate of 1.0 mL x min(-1). Column temperature was 40 degrees C and the detected wavelength was 254 nm. Amino acids derivative solution remained stable in 36 hours. The response was linear for 16 amino acids with a correlation coefficient r > 0.999 5. The average recoveries were 98.01% -101.8%. The method is reliable with good accuracy and repeatability, which is useful for the determination of amino acids in Galli Gigerii Endothelium Corneum.

[Study on tissue distribution of psoraleae fructus decoction in rats].

Advanced technologies are used to clarify the meridian tropism theory of traditional Chinese medicine is an important part of theoretical studies of traditional Chinese medicine. In this article, modern pharmacokinetic method was used to investigate tissue distribution characteristics of psoralen and isopsoralen of Psoraleae Fructus decoction in rats, in order to provide research ideas and experimental basis for the meridian tropism theory. In this study, various tissue samples such as heart, liver, spleen, lung, kidney, brain and spermary were collected at different times after oral administration with FP decoction, in order to determine concentration of psoralen and isopsoralen by HPLC. Pharmacokinetic parameters were calculated by DAS 2.0 software. The study results showed that HPLC indexes of psoralen and isopsoralen in various tissues of rats met the determination requirements of biological samples. Both components were distributed in all of the tissues, with AUC(0-t) order of liver > lung approximately kidney > heart > brain approximately spleen > spermary. There was significant difference between liver, kidney, lung and other tissues (P < 0.05). MRT(0-t) of both psoralen and isopsoralen were about 10 h. Therefore, psoralen and isopsoralen showed stronger targeting selection in liver, kidney and lung.