Therapeutic effect of quercetin in collagen-induced arthritis

Anti-inflammatory action of an alkaloid, fraction and extract from Alchornea glandulosa in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Alchornea glandulosa (Euphorbiaceae) has traditionally been used in medicine for treating immune-mediated inflammatory diseases.

AIM OF STUDY

This work aimed to evaluate the anti-inflammatory effects of a methanolic extract of leaves from A. glandulosa (MEAG), as well as the ethyl acetate fraction (EAFAG) and isolated compound guanidine alkaloid N-1, N-2, N-3-triisopentenylguanidine (AG-1), in experimental in vivo models of inflammation in mice. We also investigated this extract's phenols, flavonoids and flavonol compounds.

MATERIALS AND METHODS

MEAG (extracted by maceration with methanol), EAFAG (fraction resulting from the partition of the methanolic extract with ethyl acetate) and AG-1 (alkaloid isolated by chromatographic methods) were analysed. MEAG and EAFAG were analysed by HPLC/DAD. The effects of MEAG (30, 100 and 300 mg/kg), EAFAG (30, 100 and 300 mg/kg) and AG-1 (5 and 30 mg/kg) were studied in the following experimental mouse models: paw oedema and myeloperoxidase (MPO) activity, croton-oil-induced ear oedema, leukocyte migration in a pleurisy model induced by carrageenan and zymosan induction of joint inflammation.

RESULTS

MEAG and EAFAG were analysed by LC/DAD, and phenolic acids (gallic acid and caffeic acid) and flavonoids (myricetin-3-O-α-rhamnopyranoside and quercetin) were detected. MEAG, EAFAG and AG-1 were used in the carrageenan-induced paw oedema model and showed maximum inhibitions of 60.10% (MEAG, 2 h, 300 mg/kg) and 66.21% (EAFAG, 2 h, 300 mg/kg). AG-1 at 5 mg/kg showed significant inhibition, ranging from 60.92% to 63.13%, at all evaluated times, and the 30 mg/kg dose showed inhibition of 42.12% (1 h) and 40.36% (2 h). MEAG (37%, 46.1% and 68.11%) and EAFAG (31%, 42.21% and 48.93%), at doses of 30, 100 and 300 mg/kg, respectively, significantly reduced the increase in MPO activity, and AG-1 (5 and 30 mg/kg) showed inhibition of 64.62% and 65.12%, respectively. In the pleurisy model, MEAG (300 mg/kg), EAFAG (300 mg/kg) and AG-1 (30 mg/kg) significantly reduced the migration of total leukocytes with maximal inhibition of 80.90%, 83.17% and 89.39%, respectively. In the croton oil model, pretreatment with MEAG (0.1, 0.3 and 1 mg/ear) increased the diameter of the right ear (30.32%, 48.87% and 53.09%, respectively). Finally, MEAG (100 and 300 mg/kg; 33.11% and 56.03%) and EAFAG (100 and 300 mg/kg; 36.89% and 50.53%) reduced zymosan-induced oedema formation.

CONCLUSIONS

To the best of our knowledge, these results are the first to demonstrate that A. glandulosa exhibits oral and topical anti-inflammatory activity. This study detected alkaloid and phenol/polyphenolic compounds in A. glandulosa, which may help to explain the ethnobotanical use of this plant in traditional medicine in Brazil to treat immune-mediated inflammatory diseases.

Pharmacological Effect of Quercetin in Hypertension and Its Potential Application in Pregnancy-Induced Hypertension: Review of In Vitro, In Vivo, and Clinical Studies

Since improving maternal and child health is a public health priority worldwide, the main aim of treatment of hypertension in pregnant women is to prevent complications during pregnancy, labor, and postpartum. In consequence, much attention is paid to the use of antihypertensive drugs that can be used safely during pregnancy. Several side effects of methyldopa, which is currently the most commonly used antihypertensive drug in pregnant women, mean that the search for an effective and safe alternative still continues. Flavonoid compounds present in medicinal plants, vegetables, and fruits may be a promising source of new drugs. In this aspect, quercetin, a well-known flavonoid due to its antihypertensive action, may be considered a prototype for safe antihypertensive drugs. This review focuses on the selective activity of quercetin. Based on recent studies, a few problems were discussed, including (1) pathology of pregnancy-induced hypertension; (2) search for new pharmacological treatments of pregnancy-induced hypertension; (3) issues with the use of herbal extracts during pregnancy; (4) flavonoids as natural active chemical compounds; (5) quercetin: its action during pregnancy, in vitro and in vivo pharmacological activities, clinical trials, and meta-analysis; (6) quercetin intake during pregnancy; (7) other natural compounds tested during pregnancy; (8) potential problems with the use of quercetin; (9) safety profile of quercetin. Various studies have shown a beneficial effect of quercetin on vascular endothelial function and its antioxidative and anti-inflammatory activity on cellular and tissue level. It is known that in animal models quercetin affects positively the development of embryo, fetus, and placenta. Because this flavonoid did not have teratogenic and abortive effect, it is generally recognized as safe. For this reason it should be appreciated and studied in the aspect of its potential use in the prevention and treatment of pregnancy-induced hypertension among women in this risk group.

Simultaneous determination of bioactive flavonoids of Hoveniae Semen in rat plasma by LC-MS/MS: Application to a comparative pharmacokinetic study

A selective, sensitive and fully validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of dihydromyricetin, dihydroquercetin, myricetin and quercetin in rat plasma after intragastric administration of Hoveniae Semen total flavonoids. Baicalin was selected as the internal standard. Analytes were extracted from the rat plasma by protein precipitation with acetonitrile and separated on a C18 chromatographic column (Agilent ZORBAX Eclipse Plus, 4.6 mm × 100 mm, 3.5 μm) using the mobile phase containing acetonitrile (A) and 0.1% formic acid-water (B) by gradient elution at 0.5 mL/min flow rate. A tandem mass spectrometer equipped with an electrospray ionization (ESI) source was used to detect analytes. The analytes were measured by multiple reaction monitoring (MRM) in the negative ionization mode. The lower limit of quantification of dihydromyricetin, dihydroquercetin, myricetin and quercetin were 0.70, 8.16, 1.62 and 0.56 ng/mL, respectively. The accuracy, intra-day and inter-day precision and recovery were all satisfactory and the compounds were stable in rat plasma under all tested conditions. The approach was successfully applied to study pharmacokinetic characteristics of the four bioactive flavonoids in plasma after administering Hoveniae Semen total flavonoids intragastrically to rat. Further investigation was carried out to assess pharmacokinetic comparability of the four bioactive flavonoids after intragastric administration of Hoveniae Semen total flavonoids to mixture of flavonoids.

Therapeutic effects of polysaccharides from Anoectochilus roxburghii on type II collagen-induced arthritis in rats

Anoectochilus roxburghii, a famous Chinese herbal medicine, has been commonly used for the treatment of liver disease, diabetes, and rheumatoid arthritis. Our study aimed to investigate the anti-rheumatoid arthritis effects of A. roxburghii polysaccharides (ARP), using the rat's model of type II collagen-induced arthritis (CIA). ARP was prepared by alcohol sedimentation and structurally characterized based on combined chemical, chromatographic and spectroscopic methods. High Performance Size Exclusion Chromatography-Multiangle Laser Light Scattering-Refrative Index (HPSEC-MALLS-RI) analysis revealed that ARP includes two peaks, and the weight-average molecular weight (Mw) of the principal one was estimated as 5.90 kDa with a relative content of 98.2%. Pharmacological results exhibited that ARP significantly decreased the arthritis index and ameliorated the inflammatory cell infiltration and the synovial tissue destruction in CIA rats. Additionally, ARP possessed significant NO production inhibitory effects and antioxidant activity. Further anti-inflammatory mechanism investigations indicated that ARP significantly inhibited the activation of nuclear factor κB (NF-κB) pathway by suppressing the phosphorylation of IκB and p65, which subsequently down-regulated the mRNA expressions of IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. These findings suggested that ARP has great potential in the development of functional foods and dietary supplements for the treatment of rheumatoid arthritis.

Anti-arthritic properties of crude extract from Chenopodium ambrosioides L. leaves

Objectives

To evaluate the effect of hydroalcoholic crude extract (HCE) from Chenopodium ambrosioides leaves on the development of type II collagen-induced arthritis (CIA) and on pro-inflammatory cytokine balance.

Methods

Collagen-induced arthritis was induced in DBA1/J mice. On the 21st day, the mice were treated orally with HCE or methotrexate, daily. Six weeks after beginning the treatment, the following measures were determined: lymphoid organs cell numbers, percentage of blood cells, IL-6, IFN-γ, TNF-α and IL-17 serum concentrations, activity of hepatic and kidney glutathione S-transferase, hepatic 7-ethoxyresorufin-O-deethylase activity, bone density and histopathology.

Key findings

Treatment of CIA mice with HCE 5 mg/kg (HCE5) reduced the percentage of neutrophils and macrophages and the number of bone marrow cells and increased the lymphocyte numbers and the inguinal lymph node cellularity. This treatment inhibited the serum concentration of IL-6 and TNF-α, which may be related to the preservation of bone density and to the slight thickening of periarticular tissues, with minimal fibrosis and fibroblast proliferation in the joints. The CIA group presented advanced articular erosion and synovial hyperplasia. Phytochemical analysis showed mainly flavonols.

Conclusions

HCE5 presented anti-arthritic potential and reduced IL-6 and TNF-α, which participate directly in the development and maintenance of the inflammatory process in rheumatoid arthritis.

Combining a joint health supplement with tibial plateau leveling osteotomy in dogs with cranial cruciate ligament rupture. An exploratory controlled trial

Canine cranial cruciate ligament rupture (CrCLR) is a very common pathology. Surgical stabilization is the first choice treatment, although it does not fully eliminate the increased risk of osteoarthritis. This preliminary study was carried out to explore whether a newly formulated joint health supplement would benefit metabolic, clinical and radiographic changes in dogs with CrCLR surgically treated with tibial plateau leveling osteotomy (TPLO). Besides chondroitin sulfate and glucosamine hydrochloride, the studied supplement contained anti-inflammatory and antioxidant ingredients, the main ones being N-palmitoyl-D-glucosamine (Glupamid®) and quercetin. It was thus intended to target not only chondrodegenerative components of osteoarthritis, but also post-injury inflammatory response and oxidative stress of joint tissues. Thirteen dogs underwent TPLO and were randomly allocated to treatment (n = 6) and control groups (n = 7), the former receiving the joint supplement for 90 days. Lameness and radiographic osteoarthritis changes were scored before (i.e., baseline) and at 30 and 90 days post-surgery. Synovial fluid samples were collected from injured stifles at the same time points. Levels of representative metabolites were measured by proton nuclear magnetic resonance spectroscopy in a blinded fashion. In the metabolomic analysis, special attention was paid to lactate, due to its emerging recognition as a key marker of inflammation. In the last time period (from the 30th to the 90th day), lameness improved by a factor of 2.3 compared to control dogs. No significant difference was observed in the radiographic osteoarthritis score between groups. In the first postoperative month, lactate and creatine levels significantly dropped in treated compared to control dogs. Compared to surgery alone, combining the joint supplement with TPLO resulted in a trend to a better clinical outcome in the later time interval but did not influence osteoarthritis radiographic progression. A significantly better rebalance of joint microenvironment in the early time interval (baseline - 30 days) was shown by metabolomic analysis, thus suggesting that the study supplement could limit ongoing inflammatory responses.

Himatanthus drasticus Leaves: Chemical Characterization and Evaluation of Their Antimicrobial, Antibiofilm, Antiproliferative Activities

Plant-derived products have played a fundamental role in the development of new therapeutic agents. This study aimed to analyze antimicrobial, antibiofilm, cytotoxicity and antiproliferative potentials of the extract and fractions from leaves of Himatanthusdrasticus, a plant from the Apocynaceae family. After harvesting, H. drasticus leaves were macerated and a hydroalcoholic extract (HDHE) and fractions were prepared. Antimicrobial tests, such as agar-diffusion, Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were carried out against several bacterial species. Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes and Klebsiella pneumoniae were inhibited by at least one extract or fraction in the agar-diffusion assay (inhibition halos from 12 mm to 30 mm). However, the lowest MIC value was found for HDHE against K. pneumoniae. In addition, HDHE and its fractions were able to inhibit biofilm formation at sub-inhibitory concentrations (780 µg/mL and 1.56 µg/mL). As the best activities were found for HDHE, we selected it for further assays. HDHE was able to increase ciprofloxacin (CIP) activity against K. pneumoniae, displaying synergistic (initial concentration CIP + HDHE: 2 µg/mL + 600 µg/mL and 2.5 µg/mL + 500 µg/mL) and additive effects (CIP + HDHE: 3 µg/mL + 400 µg/mL). This action seems to be associated with the alteration in bacterial membrane permeability induced by HDHE (as seen by propidium iodide labeling). This extract was non-toxic for red blood cell or human peripheral blood mononuclear cells (PBMCs). Additionally, it inhibited the lipopolysaccharide-induced proliferation of PBMCs. The following compounds were detected in HDHE using HPLC-ESI-MS analysis: plumieride, plumericin or isoplumericin, rutin, quercetin and derivatives, and chlorogenic acid. Based on these results we suggest that compounds from H. drasticus have antimicrobial and antibiofilm activities against K. pneumoniae and display low cytotoxicity and anti-proliferative action in PBMC stimulated with lipopolysaccharide.