Intestinal absorption of forsythoside A in different compositions of Shuang–Huang–Lian

Discovery of human pancreatic lipase inhibitors from root of Rhodiola Crenulata via integrating bioactivity-guided fractionation, chemical profiling and biochemical assay

Although herbal medicines (HMs) are widely used in the prevention and treatment of obesity and obesity-associated disorders, the key constituents exhibiting anti-obesity activity and their molecular mechanisms are poorly understood. Recently, we assessed the inhibitory potentials of several HMs against human pancreatic lipase (hPL, a key therapeutic target for human obesity), among which the root-extract of Rhodiola crenulata (ERC) showed the most potent anti-hPL activity. In this study, we adopted an integrated strategy, involving bioactivity-guided fractionation techniques, chemical profiling, and biochemical assays, to identify the key anti-hPL constituents in ERC. Nine ERC fractions (retention time = 12.5–35 min), obtained using reverse-phase liquid chromatography, showed strong anti-hPL activity, while the major constituents in these bioactive fractions were subsequently identified using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS/MS). Among the identified ERC constituents, 1,2,3,4,6-penta-O-galloyl-β-d-glucopyranose (PGG) and catechin gallate (CG) showed the most potent anti-hPL activity, with pIC₅₀ values of 7.59 ± 0.03 and 7.68 ± 0.23, respectively. Further investigations revealed that PGG and CG potently inhibited hPL in a non-competitive manner, with inhibition constant (K_i) values of 0.012 and 0.082 μM, respectively. Collectively, our integrative analyses enabled us to efficiently identify and characterize the key anti-obesity constituents in ERC, as well as to elucidate their anti-hPL mechanisms. These findings provide convincing evidence in support of the anti-obesity and lipid-lowering properties of ERC.

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The root-extract of Rhodiola crenulata (ERC) potently inhibits hPL.

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The hPL inhibitors in ERC were characterized using an integrated panel of assays.

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Six constituents in ERC were identified as hPL inhibitors.

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PGG and CG are potent non-competitive hPL inhibitors (K_i < 0.1 μM).

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The binding modes of PGG and CG were examined based on docking simulations.

Transcriptomic and Lipidomic Analysis of Lipids in Forsythia suspensa

Forsythiae Fructus (Lianqiao in Chinese) is widely used in traditional Chinese medicine. The lipid components in Forsythiae Fructus are the basis of plant growth and active metabolism. Samples were collected at two growth stages for a comprehensive study. Transcriptome and lipidomics were performed by using the RNA-seq and UPLC-Q-TOF-MS techniques separately. For the first time, it was reported that there were 5802 lipid components in Lianqiao comprised of 31.7% glycerolipids, 16.57% phospholipids, 13.18% sphingolipids, and 10.54% fatty acids. Lipid components such as terpenes and flavonoids have pharmacological activity, but their content was low. Among these lipids which were isolated from Forsythiae Fructus, 139 showed significant differences from the May and July harvest periods. The lipids of natural products are mainly concentrated in pregnenolones and polyvinyl lipids. RNA-Seq analysis revealed 92,294 unigenes, and 1533 of these were differentially expressed. There were 551 differential genes enriched in 119 KEGG pathways. The de novo synthesis pathways of terpenoids and flavonoids were explored. Combined with the results of lipidomics and transcriptomics, it is hypothesized that in the synthesis of abscisic acid, a terpenoid, may be under the dynamic regulation of genes EC: 1.1.1.288, EC: 1.14.14.137 and EC: 1.13.11.51 in balanced state. In the synthesis of gibberellin, GA20-oxidase (GA20ox, EC: 1.14.11.12), and GA3-oxidase (GA3ox, EC: 1.14.11.15) catalyze the production of active GAs, and EC: 1.14.11.13 is the metabolic enzymes of active GAs. In the synthesis of flavonoids, MF (multifunctional), PAL (phenylalanine ammonia-lyase), CHS (chalcone synthase), ANS (anthocyanidin synthase), FLS (flavonol synthase) are all key enzymes. The results of the present study provide valuable reference information for further research on the metabolic pathways of the secondary metabolites of Forsythia suspensa.

A comprehensive review of pharmacokinetic and pharmacodynamic in animals: exploration of interaction with antibiotics of Shuang-Huang-Lian preparations

As a traditional Chinese medicine, Shuang-Huang-Lian (SHL) has been widely used for treating infectious diseases of the respiratory tract such as encephalitis, pneumonia and asthma. During the past few decades, considerable research has focused on the pharmacological action, pharmacokinetic interaction with antibiotics and clinical applications of SHL. A huge and more recent body of pharmacokinetic study supports the combination of SHL and antibiotics has different effects such as antagonism and synergism. SHL has been one of the best-selling traditional Chinese medicine (TCM) products. However, there is no system review of SHL preparations, ranging from protection against respiratory tract infections to interaction with antibiotics. Since their important significance in clinical therapy, the pharmacodynamic, pharmacokinetic, and interactions with antibiotics of SHL were reviewed and discussed. In addition, this review attempts to explore the possible potential mechanism of SHL preparations in prevention and treatment of COVID-19. We are concerned about what is known of the effects of SHL against virus, bacterium, and its interactions with antibiotics, providing a new strategy for expanding the clinical research and medication of SHL preparations.

Mechanism of Shuang-Huang-Lian Oral Liquid for Treatment of Mycoplasmal Pneumonia in Children on Network Pharmacology

BACKGROUND AND OBJECTIVE

Mycoplasmal pneumonia (MP) can lead to inflammation, multiple system immune damage, and mixed infection in children. The pathogenesis is still unclear. Shuang-Huang-Lian (SHL) oral liquid can treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. However, our current understanding of the molecular mechanisms supporting its clinical application still lags behind due to the lack of researches. It is difficult to understand the overall sensitization mechanism of SHL oral liquid. The purpose is to explain the mechanism of action of drugs in this study, which is useful to ensure the safety of medication for children.

METHODS

The therapeutic mechanism of SHL oral liquid was investigated by a system pharmacology approach integrating drug-likeness evaluation, oral bioavailability prediction, ADMET, protein-protein interaction worknet, Gene Ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes database pathway performance, C-T-P network construction and molecular docking.

RESULTS

A total of 18 active ingredients contained in SHL oral liquid and 53 major proteins were screened out as effective players in the treatment of M. pneumoniae disease through some related pathways and molecular docking. The majority of targets, hubs and pathways were highly related to anti-mycoplasma therapy, immunity and inflammation process.

CONCLUSION

This study shows that the anti-bacterial effect of SHL oral liquid has multicomponent, multi-target and multi-pathway phenomena. The proposed approach may provide a feasible tool to clarify the mechanism of traditional Chinese medicines and further develop their therapeutic potentials.

Therapeutic potential of phenylethanoid glycosides: A systematic review

Phenylethanoid glycosides (PhGs) are generally water-soluble phenolic compounds that occur in many medicinal plants. Until June 2020, more than 572 PhGs have been isolated and identified. PhGs possess antibacterial, anticancer, antidiabetic, anti-inflammatory, antiobesity, antioxidant, antiviral, and neuroprotective properties. Despite these promising benefits, PhGs have failed to fulfill their therapeutic applications due to their poor bioavailability. The attempts to understand their metabolic pathways to improve their bioavailability are investigated. In this review article, we will first summarize the number of PhGs compounds which is not accurate in the literature. The latest information on the biological activities, structure-activity relationships, mechanisms, and especially the clinical applications of PhGs will be reviewed. The bioavailability of PhGs will be summarized and factors leading to the low bioavailability will be analyzed. Recent advances in methods such as bioenhancers and nanotechnology to improve the bioavailability of PhGs are also summarized. The existing scientific gaps of PhGs in knowledge are also discussed, highlighting research directions in the future.

Bioanalytical Method Development Using Liquid Chromatography with Amperometric Detection for the Pharmacokinetic Evaluation of Forsythiaside in Rats

An analytical method entailing high-performance liquid chromatography coupled with electrochemical detection was developed for determining forsythiaside (FTS) in rat plasma. Rat plasma samples were prepared through efficient trichloroacetic acid deproteination. FTS and the internal standard were chromatographically separated on a reversed-phase core-shell silica C18 column (100 mm × 2.1 mm, i.d. 2.6 μm), with a mobile phase consisting of an acetonitrile-0.05-M phosphate solution (11.8:88.2, v/v), at a flow rate of 400 μL/min. The calibration curve, with r² > 0.999, was linear in the 20-1000 ng/mL range. The intra- and interday precision were less than 9.0%, and the accuracy ranged from 94.5% to 106.5% for FTS. The results indicated that the newly developed HPLC-EC method is more sensitive than previous reported methods using UV detection, and this new analytical method is applied successfully for the pharmacokinetic study of FTS. The hydrogel delivery system can efficiently improve bioavailability and mean residual time for FTS, as evidenced by the 2.5- and 6.3-fold increase of the area under the curve and the extension of the half-life, respectively.

Shuang-Huang-Lian exerts anti-inflammatory and anti-oxidative activities in lipopolysaccharide-stimulated murine alveolar macrophages

Shuang-Huang-Lian (SHL) is a traditional Chinese compound formula prepared from Lonicerae Japonicae Flos, Scutellariae Radix and Fructus Forsythiae. In this study, we demonstrate the anti-inflammatory and anti-oxidative activities of SHL in lipopolysaccharide (LPS)-stimulated murine alveolar macrophages (MH-S). SHL significantly reduces the transcriptional and translational levels of iNOS and COX-2 as well as the production of NO and prostaglandin E2 (PGE2). It also suppresses the transcription and translation of inflammatory cytokines production, such as TNF-α, IL-1β and IL-6. These inhibitory effects mainly act via ERK1/2- and p38-mediated AP-1 rather than the NF-κB pathway. In parallel with the anti-inflammatory activity, SHL suppresses LPS-induced intracellular total ROS levels by weakening NADPH oxidase activity, enhancing SOD activity and increasing GSH content. In addition, SHL directly scavenges OH and O2(-). Thus, our study elucidates the anti-inflammatory and anti-oxidative mechanisms of SHL in LPS-stimulated MH-S.

HPLC and chemometrics for the quality consistency evaluation of Shuanghuanglian injection

A high-performance liquid chromatography method with diode array detection was developed for simultaneous analysis of organic acids (chlorogenic acid, caffeic acid, 4,5-dicaffeoylquinic acid) and flavonoids (baicalin, baicalein, wogonin) in Shuang-huang-lian injection, a traditional Chinese medicine being prescribed widely for anti-bacterial, anti-viral and immunostimulant activity. All calibration curves showed good linear correlation (r(2) > 0.9997) within the test ranges. Validation proved that the repeatability of the method was good and recovery was satisfactory. The validated method was successfully applied to 24 batches of Shuang-huang-lian injection. The result showed that there was a great variation among different samples. Principal component analysis further proved considerable variations among the samples from eight manufacturers, and suggested that chlorogenic acid and baicalin might have the greatest variations among the 24 batches. In conclusion, these results demonstrated that the method proposed was very useful for the analysis and quality consistency evaluation of Shuang-huang-lian injection.

Concentration-dependent inhibitory effects of baicalin on the metabolism of dextromethorphan, a dual probe of CYP2D and CYP3A, in rats

Baicalin has been shown to possess many pharmacological effects, including antiviral, antioxidant, anti-cancer and anti-inflammatory properties. In the current study, we reveal the inhibitory effects of baicalin on the metabolism of dextromethorphan (DXM), a dual probe substrate of CYP2D and CYP3A, in rats. Lineweaver-Burk plots demonstrated that baicalin inhibited the activities of CYP2D and CYP3A in a non-competitive manner in rat liver microsomes (RLMs). Concomitant administration of baicalin (0.90 g/kg, i.v.) and DXM (10 mg/kg, i.v.) increased the maximum drug concentration (C(max)) (37%) and the area under concentration-time curve (AUC) (42%) and decreased the clearance (CL) (27%) of DXM in a randomised, crossover study in rats (P < 0.01). The change in the AUC of DXM was significantly correlated with the C(max) and AUC of baicalin (P < 0.05). The inhibitory effects of multiple doses of baicalin (0.90 g/kg, i.v., 12 days) on the metabolism of DXM were similar to those observed following a single dose in rats. The activity of CYP3A in excised liver samples from rats following multiple baicalin treatment was significantly decreased compared to that of the control group (P < 0.05), whereas multiple doses of baicalin had no obvious effect on the activity of CYP2D. Taken together, these data demonstrate that baicalin inhibits the metabolism of DXM in a concentration-dependent manner in rats, possibly through inhibiting hepatic CYP2D and CYP3A activities.

Improvement of intestinal absorption of forsythoside A in weeping forsythia extract by various absorption enhancers based on tight junctions

Forsythoside A (FTA), one of the main active ingredients in weeping forsythia extract, possesses strong antibacterial, antioxidant and antiviral effects, and its content was about 8% of totally, higher largely than that of other ingredients, but the absolute bioavailability orally was approximately 0.5%, which is significant low influencing clinical efficacies of its oral preparations. In the present study, in vitro Caco-2 cell, in situ single-pass intestinal perfusion and in vivo pharmacokinetics study were performed to investigate the effects of absorption enhancers based on tight junctions: sodium caprate and water-soluble chitosan on the intestinal absorption of FTA, and the eventual mucosal epithelial damage resulted from absorption enhancers was evaluated by MTT test, measurement of total amount of protein and the activity of LDH and morphology observation, respectively. The pharmacological effects such as antioxidant activity improvement by absorption enhancers were verified by PC12 cell damage inhibition rate after H₂O₂ insults. The observations from in vitro Caco-2 cell showed that the absorption of FTA in weeping forsythia extract could be improved by absorption enhancers. Meanwhile, the absorption enhancing effect of water-soluble chitosan may be almost saturable up to 0.0032% (w/v), and sodium caprate at concentrations up to 0.64 mg/ml was safe for the Caco-2 cells, but water-soluble chitosan at different concentrations was all safe for these cells. The observations from single-pass intestinal perfusion in situ model showed that duodenum, jejunum, ileum and colon showed significantly concentration-dependent increase in P(eff)-value, and that P(eff)-value in the ileum and colon groups, where sodium caprate was added, was higher than that of duodenum and jejunum groups, but P(eff)-value in the jejunum group was higher than that of duodenum, ileum and colon groups where water-soluble chitosan was added. Intestinal mucosal toxicity studies showed no significant toxicity below 800 μg/ml sodium caprate and water-soluble chitosan at different concentrations. In pharmacokinetics study, water-soluble chitosan at dosage of 50mg/kg improved the bioavailability of FTA in weeping forsythia extract to the greatest extent, and was safe for gastrointestine from morphological observation. Besides, treatment with weeping forsythia extract with water-soluble chitosan at dosage of 50 mg/kg prevented PC12 cell damage upon H₂O₂ stimulation better than that of control. All findings above suggested that water-soluble chitosan at dosage of 50 mg/kg might be safe and effective absorption enhancer for improving the bioavailability of FTA and the antioxidant activity in vivo in weeping forsythia extract.

Intestinal absorption of forsythoside A in in situ single-pass intestinal perfusion and in vitro Caco-2 cell models

AIM

To investigate the mechanisms underlying the intestinal absorption of the major bioactive component forsythoside A (FTA) extracted from Forsythiae fructus.

METHODS

An in vitro Caco-2 cell model and a single-pass intestinal perfusion in situ model in SD rats were used.

RESULTS

In the in vitro Caco-2 cell model, the mean apparent permeability value (P(app)-value) was 4.15×10(-7) cm/s in the apical-to-basolateral (AP-BL) direction. At the concentrations of 2.6-10.4 μg/mL, the efflux ratio of FTA in the bi-directional transport experiments was approximately 1.00. After the transport, >96% of the apically loaded FTA was retained on the apical side, while >97% of the basolaterally loaded FTA was retained on the basolateral side. The P(app)-values of FTA were inversely correlated with the transepithelial electrical resistance. The paracellular permeability enhancers sodium caprate and EDTA, the P-gp inhibitor verapamil and the multidrug resistance related protein (MRP) inhibitors cyclosporine and MK571 could concentration-dependently increase the Papp-values, while the uptake (OATP) transporter inhibitors diclofenac sodium and indomethacin could concentration-dependently decrease the P(app)-values. The intake transporter SGLT1 inhibitor mannitol did not cause significant change in the P(app)-values. In the in situ intestinal perfusion model, both the absorption rate constant (K(a)) and the effective permeability (P(eff)-values) following perfusion of FTA 2.6, 5.2 and 10.4 μg/mL via the duodenum, jejunum and ileum had no significant difference, although the values were slightly higher for the duodenum as compared to those in the jejunum and ileum. The low, medium and high concentrations of verapamil caused the largest increase in the P(eff)-values for duodenum, jejunum and ileum, respectively. Sodium caprate, EDTA and cyclosporine resulted in concentration-dependent increase in the P(eff)-values. Diclofenac sodium and indomethacin caused concentration-dependent decrease in the Peff-values. Mannitol did not cause significant change in the P(app)-values for the duodenum, jejunum or ileum.

CONCLUSION

The results suggest that the intestinal absorption of FTA may occur through passive diffusion, and the predominant absorption site may be in the upper part of small intestine. Paracellular transport route is also involved. P-gp, MRPs and OATP may participate in the absorption of FTA in the intestine. The low permeability of FTA contributes to its low oral bioavailability.