Targeting TRPV1 and TRPA1: A feasible strategy for natural herbal medicines to combat postoperative ileus

Under physiological or pathological conditions, transient receptor potential (TRP) channel vanilloid type 1 (TRPV1) and TRP ankyrin 1 (TRPA1) possess the ability to detect a vast array of stimuli and execute diverse functions. Interestingly, increasing works have reported that activation of TRPV1 and TRPA1 could also be beneficial for ameliorating postoperative ileus (POI). Increasing research has revealed that the gastrointestinal (GI) tract is rich in TRPV1/TRPA1, which can be stimulated by capsaicin, allicin and other compounds. This activation stimulates a variety of neurotransmitters, leading to increased intestinal motility and providing protective effects against GI injury. POI is the most common emergent complication following abdominal and pelvic surgery, and is characterized by postoperative bowel dysfunction, pain, and inflammatory responses. It is noteworthy that natural herbs are gradually gaining recognition as a potential therapeutic option for POI due to the lack of effective pharmacological interventions. Therefore, the focus of this paper is on the TRPV1/TRPA1 channel, and an analysis and summary of the processes and mechanism by which natural herbs activate TRPV1/TRPA1 to enhance GI motility and relieve pain are provided, which will lay the foundation for the development of natural herb treatments for this disease.

The isomers, aloe-emodin and emodin, possess differential inhibitory activities against CYP1B1 enzyme

Aloe-emodin, known as a 3-hydroxymethyl-chrysazin, is one of anthraquinones mainly found in Rheum officinale Baill, Rheum palmatum L and Rheum tanguticum Maxim. Ex BALF. In recent studies, aloe-emodin possesses many pharmacological effects, including antitumor, antibacterial, antiviral, anti-inflammatory, cardiovascular protection, liver protection, immune regulation, estrogenic activity as a phytoestrogen, and so on. Cytochrome P450 (CYP) 1B1 (CYP1B1), as a major estrogen metabolizing enzyme, can metabolize 17β-estradiol (E2) to 4-hydroxy-E2 (4-OH-E2), which cause DNA damage and lead to tumor. Few studies have found that anthraquinones possess inhibitory activity against CYP1B1 enzyme. In this study, compared with emodin (3-Hydroxy-6-methyl-chrysazin, C₁₅H₁₀O₅), the inhibition of aloe-emodin (3-hydroxymethyl-chrysazin, C₁₅H₁₀O₅) on the activity of CYP1B1 was studied. The molecular mechanism of inhibition and the structure-activity relationship were also discussed. Although isomeric, the IC50 values of aloe-emodin and emodin were 0.192 ± 0.015 nM and 0.067 ± 0.003 µM, indicating the inhibition of aloe-emodin was about 350times stronger than that of emodin. Through structure-activity relationship analyses, it revealed the difference of inhibitory activity only due to different hydroxyl positions. When the hydroxyl group is transferred from the chrysazin skeleton to the methyl group, the hydrogen bond formed by this structure with the CYP1B1 protein can change the protein conformation, which may interfere with the binding of the substrate to CYP1B1 protein active site pocket and inhibit the catalytic activity of the CYP1B1 protein. Although the hydroxyl position changed, the inhibition mechanism did not change, all of which were mixed inhibition. This study reveals an anti-tumor mechanism of the anthraquinone compound aloe-emodin.

Qingchangligan formula attenuates the inflammatory response to protect the liver from acute failure induced by d-galactosamine/lipopolysaccharide in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The Qingchangligan formula, a traditional Chinese medicine comprising five herbs, is useful for treatment of patients with liver failure; however, its protective and regulatory mechanisms remain elusive.

AIM OF THE STUDY

To test the hypothesis that the Qingchangligan formula protects mice against acute liver failure by inhibiting liver inflammation.

MATERIALS AND METHODS

Acute liver failure (ALF) was induced by intraperitoneal injection of D-GalN (700mg/kg) plus LPS (10μg/kg). The Qingchangligan formula was administered to mice in three doses of 50mg/kg (on day 1, day 2, and day 3) prior to D-GalN/LPS injection by intragastric administration. The mice in different groups were sacrificed at 6h after D-GalN/LPS injection, and liver samples and blood were collected for analysis.

RESULTS

Administration of the Qingchangligan formula not only ameliorated liver injury, as evidenced by reduced transaminase levels and well-preserved liver architecture, but also decreased the lethality in ALF mice. Moreover, in the ALF model, pretreatment with the Qingchangligan formula alleviated liver inflammation and decreased hepatocyte apoptosis. Further demonstrating the protective effects of the Qingchangligan formula, we found that pretreatment with the Qingchangligan formula reduced the expression of inflammatory cytokines by decreasing the expression of components of the mitogen-activated protein kinase (MAPK) pathway and promoting autophagy in vitro and in vivo.

CONCLUSIONS

Our findings demonstrated that the Qingchangligan formula exerts a protective effect against the pathophysiology of ALF, especially in regulating liver inflammation, and provide a rationale for using the Qingchangligan formula as a potential therapeutic strategy to ameliorate ALF.

Ethnobotanical investigations on plants used in folk medicine in the regions of Constantine and Mila (North-East of Algeria)

ETHNO-PHARMACOLOGICAL RELEVANCE

Constantine and Mila regions have been investigated in an ethnobotanical study for the first time. A total of 102 medicinal plants have been cited to treat human ailments. Twenty-eight new species of 31 common plants with 151 new therapeutic applications and 12 new cited species including one endemic specie Zygophyllum cornutum Coss were found as compared to other Algerian regions. In addition, to the best of our knowledge, 369 new medicinal uses of 75 known plants, were reported for the first time in the Mediterranean basin.

AIM OF THE STUDY

This study is aimed at contributing to safeguard world cultural heritage and document ethnomedicinal uses of plants in Algeria and the Mediterranean basin; data on the national and global uses in the world were obtained to extract new potential species for further phytochemical and clinical investigations.

MATERIALS AND METHODS

The survey was carried out in two cities in the northeast of Algeria: Constantine and Mila. It was based on semi-structured interviews of 79 local informants. Data were analyzed using quantitative indices, namely, informant consensus factor, fidelity level (FL), use value (UV), and relative frequency citation (RFC), to evaluate the reliability and richness of herbal knowledge in the region.

RESULTS

The interviewed persons used 102 plant species belonging to 90 genera and distributed among 53 families, represented mainly by Lamiaceae, Apiaceae, and Asteraceae (30%, 13%, and 10%, respectively), which were used to treat 14 ailment categories. The category of most frequent ailments (16%) was digestive disorders (diarrhea, constipation, and stomach bloating). The highest RFC was found for Origanum glandulosum Desf. With regard to the fidelity level, a higher FL was found for Tilia cordata Mill. (100%), followed by Artemisia herba alba Asso. with an FL of 95.74% and Punica granatum L. with an FL of 93.09%) to treat gastrointestinal system diseases, and Aloe sp. L. with an FL of 96.67% for skin diseases. The highest UV was found for Origanum glandulosum Desf. (2.280). Moreover, new medicinal uses were recorded for the first time in Algeria and Mediterranean regions.

CONCLUSION

The present study has highlighted the rich herbal knowledge about newfound medicinal plants and their new uses in the Mediterranean region, which could be useful not only in facilitating other studies such as phytochemical and pharmacological investigations and upgrading the sources of biomolecules beneficial to people but also in reopening discussion on pharmacovigilance in herbal medicine as an imperative requirement for local authorities.

Phytochemical constituents and in vitro radical scavenging activity of different Aloe species

The phytochemical profile of Aloe barbadensis Mill. and Aloe arborescens Mill. was investigated using colorimetric assays, triple quadrupole and time-of-flight mass spectrometry, focusing on phenolic secondary metabolites in the different leaf portions. Hydroxycinnamic acids, several characteristic anthrones and chromones, the phenolic dimer feralolide and flavonoids such as flavones and isoflavones were identified. The stable radical DPPH test and the ORAC assay were then used to determine the in vitro radical scavenging. The outer green rind was the most active, while the inner parenchyma was much less effective. The 5-methylchromones aloesin, aloeresin A and aloesone were the most active among the pure secondary metabolites tested. The results suggest that several compounds are likely to contribute to the overall radical scavenging activity, and indicate that leaf portion must be taken into account when the plant is used for its antioxidant properties.

Investigation on the spectrum-effect relationships of Da-Huang-Fu-Zi-Tang in rats by UHPLC-ESI-Q-TOF-MS method

ETHNOPHARMACOLOGICAL RELEVANCE

Da-Huang-Fu-Zi-Tang (DHFZT) is a crucial TCM formula commonly used for the treatment of acute pancreatitis in Chinese clinical application. Our previous work found that DHFZT could act against pancreatic injury in rats with severe acute pancreatitis (SAP). The goal of this paper was to study the underlying correlations between the chemical spectra and the protective effect of DHFZT on pancreatic acinar cell to reveal the real bioactive compounds in DHFZT.

MATERIALS AND METHODS

The fingerprint chromatograms of rat serum after oral administration of DHFZT were established by UHPLC-ESI-Q-TOF-MS technique. At the same time, the model of anti-acute pancreatitis on cells was established by adding 10(-7) mol/L cerulein to AR42J cell line, and the protective effects of the serum on pancreatic acinar cell from injury was evaluated by detecting the efficacy of amylase. Then, the spectrum-effect relationships between UHPLC fingerprints and anti-acute pancreatitis activities were evaluated using canonical correlation analysis (CCA) statistical method. The chromatogram separation was performed on a C18 reversed phase UHPLC column (2.1 mm × 100 mm, 3.5 μm, Agilent), the column temperature was set at 35°C. The mobile phase consisted of 0.1% formic acid and acetonitrile with gradient elution. The serum samples were analyzed both in negative and positive ion mode. The mother and productive ions were scanned within the mass range of m/z 100-1200 and 50-1200, respectively. A thorough analysis of a great deal of information of the constituents in the rat serum was undertaken. The structure identification of the detected compounds was achieved by using high resolution MS values as well as the MS/MS fragments.

RESULTS

Eighteen peaks in rat serum after oral administration of DHFZT were detected within only 30 min recorded chromatograms. The structure of the 18 compounds were then given out, of which 10 were the original form of compounds absorbed from DHFZT, 8 were the metabolites of the compounds existed in rat serum. According to the CCA results, talatisamine, rhein glucoside, rhein isomer methylation, hypaconine, hydroxyl-chrysophanol, emodin glucuronide conjugation, and chrysophanol glucuronide conjugation were finally found to be the main anti-acute pancreatitis components in DHFZT.

CONCLUSIONS

The model presented in this paper successfully discovered the spectrum-effect relationships of DHFZT, which showed a representative way to discover the primary active ingredients from the complicated herbal drugs.

Aloe-emodin from rhubarb (Rheum rhabarbarum) inhibits lipopolysaccharide-induced inflammatory responses in RAW264.7 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Rheum rhabarbarum (rhubarb) has long been used for the treatment of inflammation in China and other Asian countries. However, the mechanism underlying the anti-inflammatory activity of this medicinal plant is not fully understood. The present study was designed to investigate the anti-inflammatory effects of anthraquinones, the major constituents in rhubarb, and the molecular mechanism involved in their anti-inflammatory effects.

MATERIALS AND METHODS

RAW264.7 cells were stimulated by lipopolysaccharide (LPS) in the presence or absence of the compounds examined. The proliferation of RAW264.7 cells was assayed by the Alamar-Blue method. The quantity of nitric oxide (NO) was determined by Griess assay. The expression of pro-inflammatory cytokines was determined by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR. Inducible nitric oxide synthase (iNOS), inhibitor of nuclear factor κBα (IκBα), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), c-Jun NH2-terminal kinase (JNK), and Akt/phosphoinositide 3-kinase (PI3K) protein expression levels were determined by Western blotting.

RESULTS

Aloe-emodin markedly suppressed the production of NO, interleukin-6 (IL-6), and interleukin-1β (IL-1β) in LPS-stimulated RAW264.7 cells with no apparent cytotoxicity. The mRNA expression levels of iNOS, IL-6, and IL-1β genes were also significantly inhibited by aloe-emodin. Western blot analysis showed that aloe-emodin suppressed LPS-induced iNOS protein expression, IκBα degradation, and the phosphorylation of ERK, p38, JNK, and Akt.

CONCLUSIONS

These results demonstrate that aloe-emodin is the bioactive component of rhubarb that confers an anti-inflammatory effect through a likely mechanism involving a decrease in pro-inflammatory cytokine production in LPS-induced RAW264.7 macrophages via inhibition of NF-κB, MAPK, and PI3K pathways.

Interaction of five anthraquinones from rhubarb with human organic anion transporter 1 (SLC22A6) and 3 (SLC22A8) and drug-drug interaction in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb is a well-known traditional Chinese medicine and has been used in China for thousands of years. Anthraquinone derivatives including rhein, emodin, aloe-emodin, chrysophanol and physcion are the important components in rhubarb.

MATERIALS AND METHODS

Here we studied the interaction of five anthraquinone derivatives with human renal organic anion transporter 1 (hOAT1) and hOAT3 stably expressed in cells, and interaction of rhein or rhubarb extract (RE) with furosemide (FS, substrate of OATs) in rats.

RESULTS

Uptake of 6-carboxyl fluorescein via hOAT1 and fluorescein via hOAT3 were markedly inhibited by rhein, emodin and aloe-emodin, and slightly inhibited by chrysophanol and physcion. The estimated IC₅₀ values for rhein, emodin, aloe-emodin and probenecid (typical inhibitor of hOAT1 and hOAT3) were 0.23, 0.61, 2.29 and 18.34 μM for hOAT1, and 0.08, 1.22, 5.37 and 5.83 μM for hOAT3, respectively. Furthermore, the data from the cellular accumulation assay indicated that these five compounds were not substrates of hOAT1 or hOAT3. Pharmacokinetic interaction between rhein and FS in rats showed that area under the curve (AUC₀-t) for FS was increased by 65% when coadministrated with rhein. RE was also used to interact with FS in rats and results showed that AUC₀-t of FS was increased by 32% and by 52% when coadministrated with single-dose or multiple-dose of RE, respectively.

CONCLUSIONS

These findings suggested that five anthraquinones inhibited hOAT1 and hOAT3, but these compounds were not transported by hOAT1 or hOAT3. Furthermore, rhein or RE, might cause drug-drug interaction when coadministrated with substrates of OAT1 or OAT3 in vivo.

Purgative components in rhubarbs: adrenergic receptor inhibitors linked with glucose carriers

Rhubarbs and their extractives have been used as cathartic for many years. There have been numerous breakthroughs in the pharmacological research of the drug. However, as the key point of the mechanism, the targets of the effective components still remain unclear. In this paper, with an in vitro system of isolated intestine, we found that both the rhubarb extractives and the anthraquinone derivatives can antagonize the adrenaline effectively. Furthermore, computer based docking provided the binding model of the anthraquinone derivatives and adrenergic receptor. Then, based on the results of the small intestinal promotion and purgative effect experiments in vivo, we built an "inhibitor-carrier" hypothesis to elucidate the mechanism of rhubarb. This work provided key massages for the pharmacological research of rhubarb, such a common and active medicinal plant, and might be of help for the development of new purgative drugs.