Fast and automated characterization of major constituents in rat biofluid after oral administration of Abelmoschus manihot extract using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry and MetaboLynx

The bioavailability, absorption, metabolism, and regulation of glucolipid metabolism disorders by quercetin and its important glycosides: A review

Quercetin and its glycosides (QG), vitally natural flavonoid, have been popular for health benefits. However, the absorption and metabolism affect their bioavailability, and the metabolic transformation alters their biological activities. This review systematically summarizes the bioavailability and pathways for the absorption and metabolism of quercetin/QG in vivo and in vitro, the biological activities and mechanism of quercetin/QG and their metabolites in treating glucolipid metabolism are discussed. After oral administration, quercetin/QG are mainly absorbed by the intestine, undergo phase II metabolism in the small intestine and liver to form conjugates and are metabolized into small phenolic acids by intestinal microbiota. Quercetin/QG and their metabolites exert beneficial effects on regulating glucolipid metabolism disorders, including improving insulin resistance, inhibiting lipogenesis, enhancing thermogenesis, modulating intestinal microbiota, relieving oxidative stress, and attenuating inflammation. This review enhances understanding of the mechanism of quercetin/QG regulate glucolipid metabolism and provides scientific support for the development of functional foods.

Identification of the main flavonoids of Abelmoschus manihot (L.) medik and their metabolites in the treatment of diabetic nephropathy

Introduction: Huangkui capsule (HKC) is made from the ethanol extract of Abelmoschus manihot (L.) Medik [Malvaceae; abelmoschi corolla] and received approval from the China Food and Drug Administration (Z19990040) in 1999. Currently, HKC is used for treatment of the patients with diabetic nephropathy (DN) in China. The bioactive chemical constituents in HKC are total flavonoids of A. manihot (L.) Medik (TFA). The present study aims to identify the primary flavonoid metabolites in HKC and TFA and their metabolism fates in db/db mice, the animal model for the study of type 2 diabetes and DN. Methods: HKC (0.84 g/kg/d) and TFA (0.076 g/kg/d) or vehicle were respectively administered daily via oral gavage in db/db mice for 4 weeks. The metabolism fate of the main metabolites of HKC in serum, liver, kidney, heart, jejunum, colon, jejunal contents, colonic contents, and urine of db/db mice were analyzed with a comprehensive metabolite identification strategy. Results and Discussion: In db/db mice administered with HKC and TFA, 7 flavonoid prototypes and 38 metabolites were identified. The related metabolic pathways at Phases I and II reactions included dehydroxylation, deglycosylation, hydrogenation, methylation, glucuronidation, sulphation, and corresponding recombined reactions. Quercetin, isorhamnetin, quercetin sulphate, quercetin monoglucuronide, and isorhamnetin monoglucuronide presented a high exposure in the serum and kidney of db/db mice. Thereby, the present study provides a pharmacodynamic substance basis for better understanding the mechanism of A. manihot (L.) Medik for medication of DN.

Protective Effect of the Abelmoschus manihot Flower Extract on DSS-Induced Ulcerative Colitis in Mice

Background

The flower of Abelmoschus manihot (AM) has been widely used in the treatment of chronic inflammatory diseases, including ulcerative colitis. This paper aimed to confirm the therapeutic effect of AM on ulcerative colitis (UC) and explore its mechanism.

Methods

Mouse models were induced by 2.5% dextran sulfate sodium (DSS) and treated with AM. UC signs, symptoms, colon macroscopic lesion scores, and disease activity index (DAI) scores were observed. Colon levels of interleukin- (IL-) 6, IL-1β, IL-18, IL-17, tumor necrosis factor- (TNF-) α, and IL-10 were quantified by ELISA. The colon protein expression levels of NLRP3, ASC, caspase 1 p10, β-arrestin1, ZO-1, occludin-1, and claudin-1 were examined by immunohistochemistry and western blotting. The mRNA levels of IL-1β, IL-18, NLRP3, ASC, and caspase 1 p10 in the colon were determined by real-time quantitative polymerase chain reaction (qPCR).

Results

After treatment with AM, the mortality of mice, pathological damage to the colon, splenomegaly, and the spleen coefficient were decreased. AM reduced the levels of proinflammatory cytokines (IL-6, IL-1β, IL-18, IL-17, and TNF-α) and increased the level of IL-10. The mRNA expression levels of NLRP3, ASC, and caspase 1 in colon tissue were decreased by AM in a dose-dependent manner. In addition, AM also reduced the protein expression of NLRP3, ASC, caspase 1 p10, IL-1β, IL-18, and β-arrestin1 in the colon tissue of model mice. Western blot analysis confirmed that AM increased the expression of occludin-1, claudin-1, and ZO-1 in a dose-dependent manner.

Conclusion

This study shows that AM has a significant therapeutic effect on mice with UC, and the mechanism may be related to the inhibition of the β-arrestin1/NLRP3 inflammasome signaling pathway and the protection of intestinal barrier function.

Traditional Uses, Chemical Constituents, Biological Properties, Clinical Settings, and Toxicities of Abelmoschus manihot L.: A Comprehensive Review

Abelmoschus manihot, an annual herbal flowering plant, is widely distributed throughout eastern Europe and in temperate and subtropical regions of Asia. Its flowers have been traditionally used for the treatment of chronic kidney disease in China. Currently, more than 128 phytochemical ingredients have been obtained and identified from the flowers, seeds, stems, and leaves of A. manihot. The primary components are flavonoids, amino acids, nucleosides, polysaccharides, organic acids, steroids, and volatile oils. A. manihot and its bioactive constituents possess a plethora of biological properties, including antidiabetic nephropathy, antioxidant, antiadipogenic, anti-inflammatory, analgesic, anticonvulsant, antidepressant, antiviral, antitumor, cardioprotective, antiplatelet, neuroprotective, immunomodulatory, and hepatoprotective activities, and have effects on cerebral infarction, bone loss, etc. However, insufficient utilization and excessive waste have already led to a rapid reduction of resources, meaning that a study on the sustainable use of A. manihot is urgent and necessary. Moreover, the major biologically active constituents and the mechanisms of action of the flowers have yet to be elucidated. The present paper provides an early and comprehensive review of the traditional uses, chemical constituents, pharmacological activities, and pharmaceutical, quality control, toxicological, and clinical settings to emphasize the benefits of this plant and lays a solid foundation for further development of A. manihot.

Bioactive Compounds from Abelmoschus manihot L. Alleviate the Progression of Multiple Myeloma in Mouse Model and Improve Bone Marrow Microenvironment

Purpose

Abelmoschus manihot (L.) Medik. (Malvaceae) derived Huangkui capsules (HKC) represent a traditional Chinese medicine that has been widely applied to the clinical therapy of kidney and inflammatory diseases. The present study aimed to determine the potential therapeutic effects and underlying mechanisms of the ingredients on Multiple Myeloma (MM), an incurable disease that exhibits malignant plasma cell clonal expansion in the bone marrow.

Methods

A 5TMM3VT syngeneic MM-prone model was established and treated with HKC. Murine pre-osteoblast MC3T3-E1 and pre-osteoclast Raw264.7 cells were treated with nine flavonoid compounds extracted from the flowers of Abelmoschus manihot. MC3T3-E1 and Raw264.7 cells were then examined by alizarin red staining and tartrate-resistant acid phosphatase activity staining, respectively. The proliferation of two human MM cells (ARP1, H929) was examined by performing an MTT assay following treatment with flavonoid compounds. Additionally, the cell cycle was analyzed via staining and flow cytometry. The differential expressions of certain proteins were detected via Western blotting, transcriptomic RNA-sequencing as well as RT-qPCR.

Results

The results revealed that MM-prone animals appeared to be protected following HKC treatment, as evidenced by a prolonged survival rate. Furthermore, four of the nine flavonoid compounds [Hyperin/Hyperoside, HK-2; Cannabiscitrin, HK-3; 3-O-kaempferol-3-O-acetyl-6-O-(p-coumaroyl)-β-D-glucopyranoside, HK-11; 8-(2’’-pyrrolidione-5’’-yl)-quercetin, HK-B10] induced the differentiation of murine pre-osteoblast MC3T3-E1 cells. In addition, two compounds [Isomyricitrin, HK-8; quercetin-8-(2’’-pyrrolidione-5”-yl)-3ʹ-O-β-D-glucopyranosid, HK-E3] suppressed osteoclastogenesis in murine Raw264.7 cells. HK-11 directly inhibited MM cells (ARP1 and H929) proliferation and induced G0/G1 cell cycle arrest, which may have involved the suppressing β-catenin protein, increasing expressions of IL-6 and TNF-α, as well as activating mature TGF-β1 and some other metabolic pathways.

Conclusion

These results of the present study indicated that the bio-active ingredients of HKC exerted protective effects on MM mouse survival through promoting osteoblastogenesis and suppressing osteoclastogenesis, thus improving the bone marrow microenvironment to inhibit MM cell proliferation.

Biotransformation of estrone, 17β-estradiol and 17α-ethynylestradiol by four species of microalgae

Natural and synthetic estrogens have been widely detected in wastewater treatment plant (WWTP) influent and effluent as well as in the corresponding receiving aqueous environment and other ecosystems. Microalgae can be used to remove nitrogen and phosphorus in wastewater, but the species-dependent removal of estrogens needs further investigation. In this study we investigated estrone, 17β-estradiol and 17α-ethynylestradiol removals and transformation products by four common microalgae Haematococcus pluvialis, Selenastrum capricornutum, Scenedesmus quadricauda, and Chlorella vulgaris. It was found that H. pluvialis, S. capricornutum and S. quadricauda could more effectively remove all three estrogens in synthetic wastewater effluent. The estrogenic activities i.e. 17β-estradiol equivalency determined by yeast estrogenic screening assay showed substantial estrogenic activity reductions after biotransformation by H. pluvialis, S. capricornutum, and S. quadricauda. Quadrupole Time-of-flight Mass Spectrometry results identified several possible ring-cleavage metabolites as well as their metabolic pathways, which had not been reported yet, confirming the estrogen degradation rather than mere absorption or uptake by microalgae. The findings demonstrate that not only can some specific bacteria degrade estrogens, but also the widely living microalgae are able to degrade these emerging pollutants, suggesting that microalgae could be an advanced treatment of WWTPs to remove nutrients and estrogens.

Total Extracts of Abelmoschus manihot L. Attenuates Adriamycin-Induced Renal Tubule Injury via Suppression of ROS-ERK1/2-Mediated NLRP3 Inflammasome Activation

Abelmoschus manihot (L.) Medik. (Malvaceae) is a herb used in traditional Chinese medicine to treat some kidney diseases. To date, the detailed mechanisms by which A. manihot improves some kinds of renal disease are not fully understood. In this study, we established Adriamycin-induced NRK-52E cells, the normal rat kidney epithelial cell line, injury, and Sprague-Dawley rats with Adriamycin-induced nephropathy to evaluate the role and mechanisms of total extracts of A. manihot flower (TEA) both in vitro and in vivo. We found that TEA ameliorated Adriamycin-induced cellular morphological changes, cell viability, and apoptosis through the suppression of protein oxidation and ERK1/2 signaling. However, this anti-oxidative stress role of TEA was independent of ROS inhibition. Adriamycin activated ERK1/2 signaling followed by activation of NLRP3 inflammasomes. TEA suppressed NLRP3 inflammasomes via inhibition of ERK1/2 signal transduction; decreased proteinuria and attenuated renal tubule lesions; and inhibited the expression of NLRP3 in tubules in rats with Adriamycin nephropathy. Collectively, TEA protects renal tubular cells against Adriamycin-induced tubule injury via inhibition of ROS-ERK1/2-NLRP3 inflammasomes.

Protective effects of dietary kaempferol glycoside components from unripe soybean (Edamame, Glycine max L. Merrill. 'Jindai') leaves and their serous metabolite on carbon tetrachloride-induced liver injury mice

The study investigated the protective effects of kaempferol galactoside (KG) components in mice, which were separated from Jindai soybean leaves (JDL) and mainly composed by two kaempferol galactosides. Further, KG-related metabolites in serum of mice were identified by Tof-MS. Results showed that both JDL and KG prevented the CCl₄-induced increases in serum aspartate aminotransferase and serum alanine aminotransferase. Additionally, mice treated with KG had significantly decreased TBARS and TNF-alpha levels, compared to CCl₄-treated mice. Serous analysis showed that kaempferol, glucuronidated kaempferol and methylated kaempferol with a glucuronic acid moiety were identified in the serum of mice fed unripe soybean leaves or kaempferol galactosides isolated from the leaves. The results indicated that kaempferol 3-O-galactoside connected to other glycosides via galactose might be hydrolyzed in the gastro-intestinal tract and/or epithelium cells to release kaempferol, followed by glucuronidation and/or methylation in the liver to contribute to a reduction in liver injury. The use of raw leaves containing kaempferol galactosides as food materials may contribute to a reduction in oxidation-related diseases.

Renal protective effect and action mechanism of Huangkui capsule and its main five flavonoids

ETHNOPHARMACOLOGICAL RELEVANCE

The flower of Abelmoschus manihot (Linn.) Medicus (A. manihot), as a traditional Chinese Herbal medicine, was used widely in China with efficacy of inducing diuresis for treating strangurtia, and subdhing swelling and detoxicating. It has been reported that Huangkui capsule, prepared by the extract of the flower of A. manihot, can reduce the content of urinary protein, serum creatinine and serum urea nitrogen in nephropathy rats and processes renoprotective activity, while the action mechanism need to illuminate deeply.

AIMS OF THE STUDY

In this study, we investigated the protection effect of Huangkui capsule on tubulointerstitial fibrosis in chronic renal failure (CRF) rats and its mechanism against high glucose-induced epithelial to mesenchymal transition (EMT) in renal tubular epithelial cells (HK-2) of its bioactive components.

MATERIALS AND METHODS

The animals were divided into normal group, CRF model group and Huangkui capsule-treated group. Hematoxylin eosin (HE) staining and Masson staining were applied to observe pathological changes in renal tissue of different groups. Biochemical indicators including serum urea nitrogen (BUN), urine protein (UP) and serum creatinine (Scr) were measured according to the manufacturer's instructions of kits. HK-2 cell damaged model was established to access the protection effect and action mechanism of five main flavonoids from Huangkui capsule. The experimental cells were divided into eight groups: control group, model group, positive drug group and five main flavonoids treated groups. The dichlorodihydrofluorescein diacetate (DCFH-DA) assay was used to determine the reactive oxygen species (ROS) in different groups. Western blot was applied to analyze the expression of pathogenesis-related proteins in different groups.

RESULTS

The results stated that Huangkui capsule significantly inhibited the elevation of Scr, BUN, UP, the expression of α-smooth muscle actin (α-SMA), phosphorylation-extracellular signal-regulated kinase (p-ERK1/2), NADPH Oxidase 1, NADPH Oxidase 2 and NADPH Oxidase 4 in adenine-induced CRF rats. The main bioactive components of quercetin (QT), hyperoside (HY), isoquercitrin (IQT), gossypetin-8-O-β-D-glucuronide (GG) and quercetin-3'-O-glucoside (QG) at the dosage of 100µM, like NADPH oxidase inhibitor diphenyleneiodonium, exhibited a significant effect on inhibiting the expression of α-SMA, p-ERK1/2, NADPH Oxidase 1, NADPH Oxidase 2 and NADPH Oxidase 4 in high glucose-induced HK-2 cells, especially GG.

CONCLUSIONS

These results demonstrated that Huangkui capsule and the flavonoids components prevent tubulointerstitial fibrosis in CRF rat involvement in the action mechanism of inhibiting NADPH oxidase/ROS/ERK pathway.

Treatment of chronic kidney disease using a traditional Chinese medicine, Flos Abelmoschus manihot (Linnaeus) Medicus (Malvaceae)

The flowers of Abelmoschus manihot (Linnaeus) Medicus (Malvaceae; Flos A. manihot) have been used in China for many centuries as a traditional Chinese medicine for the treatment of chronic kidney disease. The Huangkui capsule is a single-plant drug extracted from the dry corolla of Flos A. manihot that has been approved by China's State Food and Drug Administration for the treatment of chronic glomerulonephritis. The purpose of this paper is to review briefly some of the past experiences in rapid filtration and to present more fully a few facts brought out in recent studies. The primary chemical constituents of Flos A. manihot are flavonoids. In vivo, the flavonoids can be transformed into glucuronide-sulphate conjugates, which are the major metabolites of Flos A. manihot and could contribute to the renoprotective effects in vivo. Flos A. manihot can ameliorate proteinuria, podocyte apoptosis, glomerulosclerosis and mesangial proliferation. The renoprotective effects of Flos A. manihot are related to inhibition of caspase-3 and caspase-8 overexpression, reduction of the infiltration of ED1(+) and ED3(+) macrophages, downregulation of oxidative stress, inhibition of the p38 mitogen-activated protein kinase and serine/threonine kinase pathways and suppression of transforming growth factor-β1 and tumour necrosis factor-α expression. Recently, a multicentre randomized controlled trial demonstrated that Flos A. manihot was more effective than the angiotensin-receptor blocker losartan in reducing proteinuria in patients with primary glomerular disease. Because Flos A. manihot is generally preferred by Chinese patients and clinicians, high-quality trials to test the efficacy and safety of Flos A. manihot are urgently needed.

Conjugated metabolites represent the major circulating forms of Abelmoschus manihot in vivo and show an altered pharmacokinetic profile in renal pathology

CONTEXT

The nephron-protective efficacy of Abelmoschus manihot (Linn.) Medicus (Malvaceae) has been proved by randomized controlled clinical trial.

OBJECTIVE

Flavonoids are main active components of A. manihot, which can be transformed into glucuronide/sulfate conjugates in vivo. Exploring the pharmacokinetic profile of these conjugates is necessary to further elucidate the mechanism of action.

MATERIAL AND METHOD

Flavonoid fraction of A. manihot (FFA) was extracted from A. manihot flower with ethanol. FFA (400 mg/kg) was orally given to normal rats and chronic kidney disease (CKD) model rats. Blood samples were collected at 5, 15, 30, 45, 60, 90, 120, 240, 360, and 720 min after administration. The plasma concentrations of quercetin and isorhamnetin glucuronide/sulfate conjugates were analyzed by UPLC-MS/MS.

RESULTS

In normal rats, AUC of quercetin-glucuronide conjugates, isorhamnetin-glucuronide conjugates, quercetin-sulfate conjugates, and isorhamnetin-sulfate conjugates was 459.45 ± 192.70, 1153.01 ± 697.04, 417.81 ± 220.31, and 2475.19 ± 1085.22 μmol h/L, respectively. While AUC of quercetin and isorhamnetin was 5.47 ± 2.54 and 30.73 ± 25.95 μmol h/L. AUC of the glucuronide-sulfate conjugates of quercetin and isorhamnetin is 125-times higher than that of aglycone (quercetin and isorhamnetin), showing that glucuronide/sulfate conjugates represent the major circulating forms of A. manihot flavonoid in vivo. AUC of isorhamnetin-glucuronide conjugates and quercetin-sulfate conjugates was 719.65 ± 619.22 and 275.49 ± 1 60.95 μmol h/L, indicating that less conjugated metabolites were formed in CKD rats compared with normal rats. The ratio of AUCglucuronide/sulfate/AUCaglycone decreased from 125 to 104, which implied the impaired phase II metabolism ability in CKD rat.

DISCUSSION AND CONCLUSION

Glucuronide-sulfate conjugates provide an important clue for further elucidating the activity of conjugated metabolites and their relationship with the nephroprotective efficacy of A. manihot. It is necessary to take caution when extrapolating pharmacokinetics parameters from healthy animals in designing pharmacological studies.

Metabolite identification strategy of non-targeted metabolomics and its application for the identification of components in Chinese multicomponent medicine Abelmoschus manihot L

Identification of multicomponent in traditional Chinese medicine (TCM) is complex and time-consuming. The inspection of the full-scan mass chromatograms was usually performed manually, which is labor-intensive. It is difficult to distinguish low response signals from complex chemical background. Furthermore, this process is typically based on earlier knowledge of the chemical composition of TCM, and those molecules that have not been characterized earlier were thus ignored. In this paper, a strategy using UPLC-MS combined with pattern recognition analysis was developed to simplify and quicken the identification of multicomponent in Abelmoschus manihot (L.) Medik. First, complex signals obtained by UPLC-MS were processed using automated data mining algorithm and further processed with multivariate chemometric methods. Multicomponent in Abelmoschus manihot L. can be clearly displayed in S- and VIP-plot. Using this method, 320 peaks which present in Abelmoschus manihot L. were detected. In the next step, accurate mass spectra of the characteristic markers acquired by QTOF MS were used to estimate their elemental formulae and enable structure identification. By searching in METLIN database, 41 components were tentatively identified in Abelmoschus manihot L. Our results showed that UPLC-MS based-pattern recognition analysis approach can be used to quickly identify TCM multicomponent and for standardization of herbal preparations.

Efficacy and safety of Flos Abelmoschus manihot (Malvaceae) on type 2 diabetic nephropathy: A systematic review

OBJECTIVE

To evaluate the efficacy and safety of Flos Abelmoschus manihot (Malvaceae) on type 2 diabetic nephropathy (DN).

METHODS

The Cochrane Library, PubMed/MEDLINE, Excerpta Medical Database, Chinese electronic literature databases, and the references of relevant articles were searched in March 2012 for randomized controlled trials (RCTs) that reported the effects of Flos A. manihot on type 2 DN patients with overt but subnephrotic-range proteinuria (500-3,500 mg/24 h). The quality of trials was evaluated using the Cochrane-recommended method. The results were summarized as risk ratios (RRs) for dichotomous outcomes or mean differences (MDs) for continuous outcomes.

RESULTS

Seven trials (531 patients) were included. Flos A. manihot significantly decreased proteinuria [MD -317.32 mg/24 h, 95% confidence interval (CI) [-470.48, -164.17],P<0.01]. After excluding a trial that only included patients with well-preserved renal function, Flos A. manihot was associated with a significant decrease in serum creatinine (MD -11.99 μmol/L, 95% CI [-16.95, -7.04],P<0.01). Serious adverse events were not observed. The most common adverse event was mild to moderate gastrointestinal discomfort; however, patients receiving this herb did not have an increased risk for tolerated gastrointestinal discomfort (RR 1.48, 95% CI [0.39, 5.68],P=0.57).

CONCLUSIONS

Flos A. manihot may be considered as an important adjunctive therapy with the first-line and indispensable therapeutic strategies for type 2 DN. High-quality RCTs are urgently needed to confirm the effect of Flos A. manihot on definite endpoints such as end-stage renal disease.

Abelmoschi Corolla non-flavonoid components altered the pharmacokinetic profile of its flavonoids in rat

AIM

Abelmoschi Corolla is a well-known herbal medicine used for the treatment of chronic renal disease. Flavonoids are the major bioactive ingredients of Abelmoschi Corolla, but some non-flavonoid components also exist in this herb. In order to clarify the influences of non-flavonoid components on the pharmacokinetics profile of the flavonoid fraction from Abelmoschi Corolla (FFA), an investigation was carried out to compare the pharmacokinetic parameters of seven flavonoid components after administration of FFA and after administration of FFA combined with different non-flavonoid fractions.

MATERIALS AND METHODS

A selective and sensitive UPLC-MS/MS method was established to determine the plasma concentrations of the seven compounds. Sprague-Dawley rats were allocated to four groups which orally administered FFA, FFA combined with macromolecular fraction (FFA-MF), FFA combined with small molecule fraction (FFA-SF) and FFA combined with MF-SF (FFA-MF-SF) with approximately the same dose of FFA. At different time points, the concentration of rutin (1), hyperoside (2), isoquercitrin (3), hibifolin (4), myricetin (5), quercetin-3'-O-glucose (6), quercetin (7) in rat plasma were determined and main pharmacokinetic parameters including T(1/2), T(max), AUC and C(max) were calculated using the DAS 2.0 software package. The statistical analysis was performed using the Student's t-test with P<0.05 as the level of significance.

RESULTS

Flavonoids almost had similar pharmacokinetics profile that were rapidly absorbed, reached the peak concentration at 30-60 min in group A, but the pharmacokinetic profiles and parameters of these flavonoids changed when co-administered with non-flavonoid components. It was found that AUC of five flavonoids but not hibifolin and quercetin in group FFA-SF and group FFA-MF-SF increased (P<0.05) in comparison with group FFA while the tendency was not observed in group FFA-MF. Moreover, seven flavonoids had varying degrees of differences in the pharmacokinetics parameters such as C(max), T(max) and T(1/2) (P<0.05) in group FFA-MF, FFA-SF and FFA-MF-SF by comparison with group FFA.

CONCLUSION

These results indicate that non-flavonoid components could improve the bioavailability and delay the elimination of some flavonoids in rat.

Investigation of in vivo metabolic profile of Abelmoschus Manihot based on pattern recognition analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Abelmoschus manihot (L.) Medik. var. manihot is one of the most commonly used Chinese medicines and has played an important role in treating chronic glomerulonephritis and diabetic nephropathy.

AIM OF THE STUDY

Metabolites identification of traditional Chinese medicine (TCM) is a complex and time-consuming process due to the complicity of TCM and subsequent large number of detected ions. In this paper, UPLC-MS combined with pattern recognition analysis approach were used to simplify and quicken the identification of the metabolites of Abelmoschus Manihot.

MATERIALS AND METHODS

Rat urine samples were collected before (as control sample) and after Abelmoschus Manihot administration. Pattern recognition analysis method was used to differentiate components between Abelmoschus Manihot-treated group and its controlled comparison. These components could be considered as Abelmoschus Manihot-related metabolites in vivo.

RESULTS

LC-MS based metabolomics could be an advanced tool to help us find metabolites with regards to its capacity of processing large datasets, differentiating and classifying of sample groups, as well as its indiscriminative nature of biomarker and metabolite identification. Using this method, seven metabolites were identified, which are flavonoid aglycone glucuronidation, sulfatation, and methylation metabolites.

CONCLUSION

Our results showed that UPLC-MS based- pattern recognition analysis approach can be used to quickly identify Abelmoschus Manihot related metabolites in biological fluids. Furthermore, this work demonstrates the potential application of combining the UPLC-MS approach with the metabolomics approach in identifying the metabolites of TCM.

A new strategy for the discovery of epimedium metabolites using high-performance liquid chromatography with high resolution mass spectrometry

In this paper, a new strategy of drug metabolite discovery and identification was established using high-performance liquid chromatography with high resolution mass spectrometry (HPLC-HRMS) and a mass spectral trees similarity filter (MTSF) technique. The MTSF technique was developed as a means to rapidly discover comprehensive metabolites from multiple active components in a complicated biological matrix. Using full-scan mass spectra as the stem and data-dependent subsequent stage mass spectra to form branches, the HRMS and multiple-stage mass spectrometric data from detected compounds were converted to mass spectral trees data. Potential metabolites were discovered based on the similarity between their mass spectral trees and that known compounds or metabolites in a mass spectra trees library. The threshold value for match similarity scores was set at above 200, allowing approximately 80% of interference to be filtered out. A total of 115 metabolites of five flavonoid monomers (epimedin A, epimedin B, epimedin C, icariin, and baohuoside I) and herbal extract of epimedium were discovered and identified in rats via this new strategy. As a result, a metabolic profile for epimedium was obtained and a metabolic pathway was proposed. In addition, comparing to the widely used neutral loss filter (NLF), product ion filter (PIF), and mass defect filter (MDF) techniques, the MTSF technique was shown superior efficiency and selectivity for discovering and identifying metabolites in traditional Chinese medicine (TCM).

Application of microdialysis for elucidating the existing form of hyperoside in rat brain: comparison between intragastric and intraperitoneal administration

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum (St. John's wort) is an important anti-depressant herb used in clinic and commonly prescribed for mild depression. Hyperoside is one of the major components of H. perforatum and is also detected in many plant species such as Abelmoschus manihot, Black Currant, Rosa agrestis, Apocynum venetum and Nelumbo nucifera.

AIM OF THE STUDY

As the hyperoside showed CNS (central nervous system) protective activity (e.g. anti-depressant-like effect), the possibility of hyperoside or its metabolites to reach CNS should be investigated. Moreover, the pharmacokinetics profile of hyperoside or its metabolites in rat brain should be studied for further elucidating the mechanism of hyperoside action on CNS.

MATERIAL AND METHODS

A simple method for simultaneous determination of unbound hyperoside and its metabolite 3'-O-methyl-hyperoside in rat brain was developed by using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) and microdialysis technique. This method was applied for pharmacokinetics study of hyperoside and 3'-O-methyl-hyperoside in rat brain after intragastric (i.g.) and intraperitoneally (i.p.) administration of hyperoside in vivo.

RESULTS

Results showed that neither hyperoside nor its metabolites were detected in rat brain after i.g. administration but both compounds could be detected after i.p. administration. Considering the activity of hyperoside through both i.g. and i.p. administration, our results imply that the active components of hyperoside in vivo might be different. Therefore, further studies are needed to identify the active components of hyperoside in vivo through these two different routes. Moreover, non-oral administration route (e.g., i.p.) should be further investigated and be explored to obtain higher bioavailability and better activity for hyperoside. Our results also showed that the real existing form of hyperoside in rat brain were hyperoside and its methylated metabolite with maximum concentration to be 63.78 ng/mL and 24.66 ng/mL after 20mg/kg i.p. administration, respectively. Therefore, a more reasonable concentration of hyperoside should be considered in in vitro assay to reflect the real situation of hyperoside concentration in vivo.

CONCLUSION

Due to the wide use of herbal remedies containing hyperoside, our investigation will contribute to further clarifying the action of this substance. Moreover, this method will be applied for clinical pharmacokinetics study of hyperoside and its metabolite as well as herbs that contain hyperoside.

Applications of HPLC/MS in the analysis of traditional Chinese medicines

In China, traditional Chinese medicines (TCMs) have been used in clinical applications for thousands of years. The successful hyphenation of high-Performance liquid chromatography (HPLC) and mass spectrometry (MS) has been applied widely in TCMs and biological samples analysis. Undoubtedly, HPLC/MS technique has facilitated the understanding of the treatment mechanism of TCMs. We reviewed more than 350 published papers within the last 5 years on HPLC/MS in the analysis of TCMs. The present review focused on the applications of HPLC/MS in the component analysis, metabolites analysis, and pharmacokinetics of TCMs etc. 50% of the literature is related to the component analysis of TCMs, which show that this field is the most populär type of research. In the metabolites analysis, HPLC coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry has been demonstrated to be the powerful tool for the characterization of structural features and fragmentation behavior patterns. This paper presented a brief overview of the applications of HPLC/MS in the analysis of TCMs. HPLC/MS in the fingerprint analysis is reviewed elsewhere.

Systematic screening and characterization of the major bioactive components of Poria cocos and their metabolites in rats by LC-ESI-MS(n)

Poria cocos is a well-known medicinal plant widely used in China and other East Asian countries owing to its various therapeutic effects. However, the bioactive constituents responsible for the pharmacological effects of Poria cocos and their metabolites in vivo are still unclear to date. The aim of the present study was to develop a practical method based on the combined use of the liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry (LC-ESI-MS(n) ) for the comprehensive and systematic separation and characterization of the bioactive constituents of Poria cocos extract and their metabolites in rats. Based on the proposed strategy, a total of 34 compounds were characterized from the extract of Poria cocos. Among them, eight were unambiguously identified by comparing their retention times and mass spectra with those of reference standards, and 26 were tentatively identified on the basis of their MS(n) fragmentation behaviors and molecular weight information from literatures. In vivo, seven compounds were successfully detected in rat urine whereas one was found in rat plasma. This study proposed a series of potential bioactive components and provided helpful chemical information for further research on the action mechanism of traditional Chinese medicine.

Identification of metabolites of geniposide in rat urine using ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Geniposide, an iridoid glycoside, is an important and characteristic compound in the fruits of Gardenia jasminoides Ellis, a commonly used medicinal herb in Chinese traditional and folk medicine for the treatment of inflammation and jaundice. However, few studies have been carried out on the metabolism of geniposide. In this study, we have established a rapid and sensitive method using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/ESI-QTOF-MS) for analysis of the metabolic profile of geniposide in rat urine after oral administration. A total of ten metabolites were detected and identified by comparing their fragmentation patterns with that of geniposide using Metabolynx™ and MassFragment™ software tools. The results revealed that the principal metabolism pathways of geniposide in rat occurred after deglycosylation of the irdoid glycoside take place and this is followed by glucuronidation and the pyran-ring cleavages. The major metabolite, the glucuronic acid conjugate of genipin as observed in vivo, was further confirmed by the in vitro enzymatic study. The results of this work have demonstrated the feasibility of the UPLC/ESI-QTOF-MS approach for rapid and reliable characterization of metabolites from iridoid compounds.

Anticonvulsant, antidepressant-like activity of Abelmoschus manihot ethanol extract and its potential active components in vivo

Depression is the most common psychiatric comorbidity in patients with epilepsy. Searching for antiepileptic (anticonvulsant) and antidepressant-like medicines from natural products is very important for the treatment of this disease. The flower of Abelmoschus manihot (Linn.) Medicus has been reported to have neuroprotective effect against cerebral ischemia injury. In order to further explore the activity of Abelmoschus manihot on the central nervous system, the anticonvulsant and antidepressant-like effects of Abelmoschus manihot ethanol extract (AMEE) as well as its potential active components in vivo was investigated in the present study. It was found that AMEE could protect mice against PTZ-induced clonic convulsions and mortality. AMEE could also decrease immobility time in the FST in mice. Furthermore, the potential active components of AMEE in rat brain were identified by ultra performance liquid chromatography-mass spectrometer (UPLC-MS). Five parent components including isoquercitrin, hyperoside, hibifolin, quercetin-3'-O-glucoside, quercetin and three metabolites were detected in rat brain after administration of AMEE. In conclusion, eight flavonoids were identified in rat brain after administration of AMEE; meanwhile, these flavonoids might represent the potential bioactive components of AMEE and contribute to its anticonvulsant and antidepressant-like activity in vivo.

Inhibitory effects of flavonoids from Abelmoschus manihot flowers on triglyceride accumulation in 3T3-L1 adipocytes

The 95% EtOH extract from the flowers of Abelmoschus manihot (L.) Medic showed inhibitory activity on TG accumulation in 3T3-L1 preadipocyte. Chemical studies on the active fraction led to the isolation of 14 flavonoids (1-14). To clarify the multi-mechanism of the isolates on preadipocyte differentiation, the levels of TG and FFA and the related role transcription factors (PPARγ, CEBP/α, and ap2) expression were evaluated. At the concentration of 30 μM, compounds 1-6 and 10-14 showed inhibitory activity on TG accumulation significantly in mature 3T3-L1 cells. 1, 2, 4-7, 9, 10, 13, and 14 reduced the level of FFA. At the molecular level, the mRNA expressions of PPARγ, CEBP/α, and ap2 were down-regulated by compounds 1, 5, 9, 12, 13; 1-8, 10-14; and 1-4, 6, 8-12, 14, respectively. The structure-activity relationships of the 14 flavonoids were also discussed.