Comparative metabolites in plasma and urine of normal and type 2 diabetic rats after oral administration of the traditional Chinese scutellaria-coptis herb couple by ultra performance liquid chromatography-tandem mass spectrometry

Benefits of Huang Lian mediated by gut microbiota on HFD/STZ-induced type 2 diabetes mellitus in mice

BACKGROUND

Huang Lian (HL), one of the traditional Chinese medicines (TCMs) that contains multiple active components including berberine (BBR), has been used to treat symptoms associated with diabetes for thousands of years. Compared to the monomer of BBR, HL exerts a better glucose-lowering activity and plays different roles in regulating gut microbiota. However, it remains unclear what role the gut microbiota plays in the anti-diabetic activity of HL.

METHODS

In this study, a type 2 diabetes mellitus (T2DM) mouse model was induced with a six-week high-fat diet (HFD) and a one-time injection of streptozotocin (STZ, 75 mg/kg). One group of these mice was administrated HL (50 mg/kg) through oral gavage two weeks after HFD feeding commenced and continued for four weeks; the other mice were given distilled water as disease control. Comprehensive analyses of physiological indices related to glycolipid metabolism, gut microbiota, untargeted metabolome, and hepatic genes expression, function prediction by PICRUSt2 were performed to identify potential mechanism.

RESULTS

We found that HL, in addition to decreasing body fat accumulation, effectively improved insulin resistance by stimulating the hepatic insulin-mediated signaling pathway. In comparison with the control group, HL treatment constructed a distinct gut microbiota and bile acid (BA) profile. The HL-treated microbiota was dominated by bacteria belonging to Bacteroides and the Clostridium innocuum group, which were associated with BA metabolism. Based on the correlation analysis, the altered BAs were closely correlated with the improvement of T2DM-related markers.

CONCLUSION

These results indicated that the anti-diabetic activity of HL was achieved, at least partly, by regulating the structure of the gut microbiota and the composition of BAs.

Antiviral Properties of Baicalin: a Concise Review

Baicalin is one of the bioactive flavonoid glycosides isolated from the dried root of Scutellaria baicalensis Georgi, Lamiaceae, with antiviral properties. In recent years, the antiviral activity of baicalin has been widely investigated to explore its molecular mechanism of action. In this mini-review, the molecular mechanisms of action of baicalin as an antiviral agent are evaluated, which included three categories: the inhibition or stimulation of JAK/STAT, TLRs, and NF-κB pathways; up or down modulation of the expression levels of IFN, IL, SOCS1/3, PKR protein, Mx1 protein, and AP-1 protein; and inhibition of cell apoptosis caused by virus infection. In addition, clinical studies of baicalin are also discussed. This literature search suggested that baicalin can serve as a potential candidate for the development of a novel broad-spectrum antiviral drug.

Natural Polyphenols in Metabolic Syndrome: Protective Mechanisms and Clinical Applications

Metabolic syndrome (MetS) is a chronic disease, including abdominal obesity, dyslipidemia, hyperglycemia, and hypertension. It should be noted that the occurrence of MetS is closely related to oxidative stress-induced mitochondrial dysfunction, ectopic fat accumulation, and the impairment of the antioxidant system, which in turn further aggravates the intracellular oxidative imbalance and inflammatory response. As enriched anti-inflammatory and antioxidant components in plants, natural polyphenols exhibit beneficial effects, including improving liver fat accumulation and dyslipidemia, reducing blood pressure. Hence, they are expected to be useful in the prevention and management of MetS. At present, epidemiological studies indicate a negative correlation between polyphenol intake and MetS incidence. In this review, we summarized and discussed the most promising natural polyphenols (including flavonoid and non-flavonoid drugs) in the precaution and treatment of MetS, including their anti-inflammatory and antioxidant properties, as well as their regulatory functions involved in glycolipid homeostasis.

Inhibitory effects of Coptidis Rhizoma on the intestinal absorption and metabolism of Scutellariae Radix

ETHNOPHARMACOLOGICAL RELEVANCE

The Scutellariae Radix (SR) and Coptidis Rhizoma (CR) herb couple is widely used in traditional Chinese medicine prescriptions for the treatment of diabetes mellitus due to its interaction and synergistic effect compared to either herb alone, but the underlying mechanism of interaction between these herbs is unclear. This study aimed to investigate the effects of CR on the metabolism and absorption of SR.

MATERIALS AND METHODS

After rats were treated with normal saline (NS group) or the CR extract (CR-treated group) for seven consecutive days, the intestinal flora was extracted from rat faeces for a co-incubation with the SR extract to investigate the metabolism of SR flavonoids, and a non-everted gut sac was prepared in vitro to evaluate the intestinal absorption of the SR extract. The components of the SR extract, the metabolites of the SR extract that was co-incubated with intestinal flora, and the dialysate acquired from non-everted gut sacs were identified and determined by an HPLC-MS/MS method. The absorption rate constant (Ka) and the apparent permeability (Papp) of each compound were calculated, and the effects of CR on the metabolism and absorption of flavonoids in SR were evaluated, by comparison the Ka and Papp between two groups using Student's t-test.

RESULTS

Twenty-nine flavonoids were detected and identified in the SR extract, including 16 glycosides and 13 aglycones. In the co-incubation with the intestinal flora, differences in metabolite classes were not observed between the NS group and CR-treated group; however, the metabolic rates of 17 flavonoids in the CR-treated group were significantly higher than the NS group. The Papp of 11 compounds (4 glycosides and 7 aglycones) across the gut sac were greater than 2 × 10-5 cm/s in both groups, while the Papp values of 7 compounds including wogonoside (WG) and other aglycones were significantly decreased in the CR-treated group.

CONCLUSION

Based on these results, CR decreased the metabolism and absorption of SR flavonoids, and exerted much greater inhibitory effects on aglycones than glycosides, which may be one of the potential mechanisms underlying the therapeutic effects of the combination of SR and CR on diabetes mellitus.

1H NMR-based urinary metabonomic study of the antidiabetic effects of Rubus Suavissimus S. Lee in STZ-induced T1DM rats

Long-term hyperglycemia associated with diabetes mellitus (DM) causes damage to various organs and tissues, including the eyes, kidneys, heart, blood vessels and nerves. Rubus Suavissimus S. Lee (RS), a shrub whose leaves are used in traditional Chinese medicine (TCM), has been shown to exert hypoglycemic effects in DM patients. However, the underlying mechanism is unclear. This was investigated in the present study in a rat model of streptozotocin-induced type 1 diabetes mellitus (T1DM) by ¹H NMR analysis. We identify 9 metabolites whose levels were altered in T1DM rats compared to control rats, namely, lactate, acetate, pyruvate, succinate, 2-oxoglutarate, citrate, creatinine, allantoin, and hippurate, which are mostly related to glycolysis/gluconeogenesis, pyruvate metabolism, TCA cycle, and other metabolism. The observed pathologic changes in the levels of these metabolites in T1DM rats were reversed by treatment with RS. Thus, RS exerts effects in T1DM rats by regulating the three abnormal metabolic pathways synergistically. These findings provide supporting evidence for the therapeutic efficacy of this TCM formulation in the treatment of DM.

Identification of components and metabolites in plasma of type 2 diabetic rat after oral administration of Jiao-Tai-Wan using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

Jiao-Tai-Wan, which is composed of Coptis Rhizoma and Cinnamon Cortex, has been recently used to treat type 2 diabetes. Owing to lack of data on its prototypes and metabolites, elucidation of the pharmacological and clinically safe levels of this formula has been significantly hindered. To screen more potential bioactive components of Jiao-Tai-Wan, we identified its multiple prototypes and metabolites in the plasma of type 2 diabetic rats by ultra high performance liquid chromatography/quadrupole-time-of-flight mass spectrometry. A total of 47 compounds were identified in the plasma of type 2 diabetic rats, including 22 prototypes and 25 metabolites, with alkaloids constituting the majority of the absorbed prototype components. In addition, this is the first study to detect vanillic acid, gallic acid, chlorogenic acid, protocatechuic acid, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, 4-hydroxycinnamic acid, and 2-methoxy cinnamic acid after oral administration of Jiao-Tai-Wan. The prototypes from Jiao-Tai-Wan were extensively metabolized by demethylation, hydroxylation, and reduction in phase Ⅰ metabolic reactions and by methylation or conjugation of glucuronide or sulfate in phase Ⅱ reactions. This is the first systematic study on the components and metabolic profiles of Jiao-Tai-Wan in vivo. This study provides a useful chemical basis for further pharmacological research and clinical application of Jiao-Tai-Wan.

Pharmacokinetics and Bioavailability Enhancement of Baicalin: A Review

Baicalin is one of the major bioactive components of Scutellaria radix, a Chinese herb that has been used since ancient times. Baicalin has various pharmacological activities, including antitumor, antimicrobial, and antioxidant, and has wide clinical applications. Baicalin displays a distinct pharmacokinetic profile including gastrointestinal hydrolysis, enterohepatic recycling, carrier-mediated transport, and complicated metabolism. The in vivo disposition of baicalin is affected by combinations of other herbs and baicalin can interact with other co-administered drugs due to competition between metabolic enzymes and protein binding. Furthermore, baicalin exhibits altered pharmacokinetic properties under different pathological conditions. Due to its low bioavailability, emerging novel baicalin preparations including nano/micro-scale baicalin delivery systems show better absorption and higher bioavailability in preclinical studies, and show promise for future clinical applications. Thus, this current review offers a comprehensive report on the pharmacokinetic behavior of baicalin and strategies to improve its bioavailability.

Comparative analysis of the main active components and hypoglycemic effects after the compatibility of Scutellariae Radix and Coptidis Rhizoma

In this study, a rapid and highly sensitive ultra high performance liquid chromatography with triple quadrupole mass spectrometry method with the mobile phase of acetonitrile and 0.1% aqueous formic acid was established and successfully applied to comparatively analyze main active components after their compatibility. Besides, the effects of Scutellariae Radix, Coptidis Rhizoma and combined extracts on type 2 diabetic rats induced by high-fat diet along with low dose of streptozocin were investigated. Under the optimized chromatographic conditions, good separation of seven target components was achieved within 12 min. All calibration curves exhibited good linearity (R²  ≥ 0.999). The relative standard deviation of precision, repeatability and stability varied from 0.69 to 2.23, 0.98 to 2.56, and 0.92 to 2.57%, respectively. The recovery ranged from 91.11 to 105.35%. The contents of seven active components were notably reduced after compatibility; however, the hypoglycemic effect of combined extracts was stronger than single drug by decreasing the activities of fructose-1,6-bisphosphatase, glucose 6-phosphatase, phosphoenolpyruvate carboxykinase and increasing the activities of glucokinase, phosphofructokinase, pyruvate kinase. Accordingly, the established analytical method was accurate and sensitive enough for quantitative evaluation of seven investigated compounds. Moreover, the combined extract had definite effects on type 2 diabetes through multiple components against multiple targets.

Systematic study on metabolism and activity evaluation of Radix Scutellaria extract in rat plasma using UHPLC with quadrupole time-of-flight mass spectrometry and microdialysis intensity-fading mass spectrometry

Radix Scutellaria is a widely used traditional Chinese medicine in the treatment of various diseases. However, the activities of the absorbed components and metabolites of its main flavones in rat plasma need further investigation. In this study, a systematic method based on ultra-high performance liquid chromatography with quadruple time-of-flight mass spectrometry was developed to speculate the absorbed components and metabolites of the main flavonoids in Radix Scutellaria extract in rat plasma sample after oral administration of the extract. Twelve compounds, including four prototype components and eight metabolites, were confirmed in drug-containing plasma. In these metabolites, five were originally detected in rat plasma. The possible metabolic pathways of these polyhydroxy flavones in vivo were described and clarified. Microdialysis with intensity-fading mass spectrometry was originally employed to investigate the binding affinities of the absorbed components and metabolites with α-glucosidase. The order of their binding affinities was P4 > P3 > P2 > P1≥M5 > M3 > M1. The research result is helpful to deepen the understanding of the absorbed components and metabolic pathways of main flavones from Radix Scutellaria, and provide a new approach to screen potential inhibitors from in vivo components originated from Chinese herb.

Biotransformation of Total Saponins in Siraitia Fructus by Human Intestinal Microbiota of Normal and Type 2 Diabetic Patients: Comprehensive Metabolite Identification and Metabolic Profile Elucidation Using LC-Q-TOF/MS

Siraitia fructus, known as Luo-Han-Guo (LHG) in Chinese, shows good antidiabetic activity. Gut microbiota have emerged as parameter of the pathophysiology of type 2 diabetes (t2D) mellitus. In this study, in vitro biotransformation of LHG extract by t2D and normal human intestinal microbiota was analyzed using ultraperformance liquid chromatography with time-of-flight mass spectrometry. A total of 19 and 12 metabolites were characterized in t2D and normal human intestinal microbiota, respectively. These metabolites were formed by a series of metabolic reactions including deglycosylation, oxidation, isomerization, and/or deoxidation. The metabolite classes of LHG extract in normal and t2D human intestinal microbiota were nearly the same, but oxidation and isomerization reactions were usually present in t2D human intestinal bacteria. This might be due to metabolic activation by pathological human intestinal bacteria. Our study indicates that there are differences in the biotransformation of LHG extract in normal and t2D human intestinal bacteria.

Comparative investigation on the pharmacokinetics of geniposide in type 2 diabetic and normal rats after oral administration of Fructus Gradeniae extract

Fructus Gradeniae, the fruit of Gardenia jasminoides Ellis, was used alone or in combination with other herb medicines in the treatment of type 2 diabetes mellitus in China for a long time. In present investigation, the HPLC method for the determination of geniposide in rat plasma was developed and validated, and the pharmacokinetics of geniposide in type 2 diabetic rats after oral administration of Fructus Gradeniae extract or pure was studied. The results showed that the pharmacokinetic profile (especially the area under the plasma concentration-time curve, AUC) of geniposide in type 2 diabetic rats after orally administered with Fructus Gradeniae extract or pure geniposide was remarkably different from that in normal rats. The results indicated that the increased AUC of geniposide in type 2 diabetic rats did not result from the effects of other components contained in Fructus Gradeniae. It could be speculated that the increased AUC of geniposide might result from the pathological state of type 2 diabetes mellitus which resulted in the pharmacokinetic alterations of geniposide.

Selective separation and identification of metabolite groups of Polygonum cuspidatum extract in rat plasma using dispersion solid-phase extraction by magnetic molecularly imprinted polymers coupled with LC/Q-TOF-MS

In this work, magnetic molecularly imprinted polymers (MMIPs) were successfully prepared for specific recognition and selective enrichment of metabolite groups of Polygonum cuspidatum extract in rat plasma.