Urginea indica attenuated rheumatoid arthritis and inflammatory paw edema in diverse animal models of acute and chronic inflammation

Opuntia monacantha: Validation of the anti-inflammatory and anti-arthritic activity of its polyphenolic rich extract in silico and in vivo via assessment of pro- and anti-inflammatory cytokines

ETHNOPHARMACOLOGICAL RELEVANCE

Opuntia monacantha belongs to the cactus family Cactaceae and is also known by cochineal prickly pear, Barbary fig or drooping prickly pear. It was traditionally used to treat pain and inflammation. O. monacantha cladodes showed pharmacological effects such as antioxidant potential owing to the presence of certain polysaccharides, flavonoids, and phenols.

AIM OF THE STUDY

This research aimed to evaluate the anti-inflammatory as well as the anti-arthritic potential of ethanol extract of Opuntia monacantha (E-OM).

MATERIALS AND METHODS

In vivo edema in rat paw was triggered by carrageenan and used to evaluate anti-inflammatory activity, while induction of arthritis by Complete Freund's Adjuvant (CFA) rat model was done to measure anti-arthritic potential. In silico studies of the previously High performance liquid chromatography (HPLC) characterized metabolites of ethanol extract was performed by using Discovery Studio 4.5 (Accelrys Inc., San Diego, CA, USA) within active pocket of glutaminase 1 (GLS1) (PDB code: 3VP1; 2.30 Å).

RESULTS

EOM, particularly at 750 mg/kg, caused a reduction in the paw edema significantly and decreased arthritic score by 80.58% compared to the diseased group. It revealed significant results when histopathology of ankle joint was examined at 28th day as it reduced inflammation by 18.06%, bone erosion by 15.50%, and pannus formation by 24.65% with respect to the diseased group. It restored the altered blood parameters by 7.56%, 18.47%, and 3.37% for hemoglobin (Hb), white blood count (WBC), and platelets, respectively. It also reduced rheumatoid factor RF by 13.70% with concomitant amelioration in catalase (CAT) and superoxide dismutase (SOD) levels by 19%, and 34.16%, respectively, in comparison to the diseased group. It notably decreased mRNA expression levels of COX-2, IL-6, TNF-α, IL-1, NF-κβ and augmented the levels of IL-4 and IL-10 in real time PCR with respect to the diseased group and piroxicam. HPLC analysis previously performed showed that phenolic acids and flavonoids are present in E-OM. Molecular docking studies displayed pronounced inhibitory potential of these compounds towards glutaminase 1 (GLS1), approaching and even exceeding piroxicam.

CONCLUSIONS

Thus, Opuntia monacantha could be a promising agent to manage inflammation and arthritis and could be incorporated into pharmaceuticals.

Launaea fragilis extract attenuated arthritis in rats through modulation of IL-1β, TNF-α, IL-6, NF-κB, COX-2, IL-4, and IL-10

Launaea fragilis (Asso) Pau is a Cholistan desert medicinal plant. Launaea species are used as traditional remedies against various inflammatory conditions. The current research was designed to evaluate the anti-nociceptive, anti-inflammatory, and anti-arthritic potential of ethanolic extract of L. fragilis (Et-LF). The plant extract was prepared by triple maceration. GC-MS screening explored the presence of various bioactive phytoconstituents including n-tetracosanol-1, 1-heptacosanol, and n-hexadecanoic acid. DPPH assay demonstrated the antioxidant potential of Et-LF. Safety profile data indicated that Et-LF was safe up to the oral dose of 5000 mg/kg in female rats. Anti-nociceptive activity of Et-LF was assessed in hot plate method and acetic acid-induced writhing model and the results suggested that Et-LF had significant analgesic effects in both animal models. Carrageenan, histamine, and serotonin-induced edema models were used to estimate the anti-inflammatory effects of Et-LF and were found to prevent paw edema development dose dependently. The anti-arthritic effect of Et-LF was estimated in CFA-induced arthritic rat model. Treatment with Et-LF 125, 250, 500 and flurbiprofen (FP) 10 mg/kg/day significantly attenuated the paw edema, reversed the reduced body weight, and restored the altered hematological parameters in arthritic rats. Gene expression studies revealed the significant downregulation of IL-1β, TNF-α, IL-6, NF‑κB, and COX-2, and upregulation of IL-4 and IL-10 in arthritic rats treated with various doses of plant extract. Histological evaluation of ankle joints showed that Et-LF mitigated pannus formation, infiltration of inflammatory cells, and fibrous connective tissue formation in the diseased rats. Thereof, it may be concluded that the recent study demonstrated the anti-nociceptive, anti-inflammatory, and anti-arthritic effects ascribed to the signifying presence of phytoconstituents in L. fragilis.

Assessment of antiarthritic potential of Asparagus dumosus using formaldehyde and CFA-induced arthritic models in rats via modulation of oxidative stress biomarkers and mRNA expression of IL-1b, IL-6, RANKL, OPG, TNF-α and COX-2

Medicinal plants play a pivotal role in the prevention of chronic non-communicable diseases including arthritis. Despite the traditional use of Asparagus dumosus in arthritis, it has not been studied yet for its effectiveness in arthritis. This study was aimed to explore the antiarthritic potential of A. dumosus in formaldehyde and complete Freund's adjuvant (CFA)-induced arthritic rats. Body weight, arthritic index, hepatic oxidative stress, hematological, biochemical and inflammatory markers were assessed using ELISA, whilst qRT-PCR studies were carried out for the mRNA expression of IL-1b, IL-6, RANKL, OPG, TNF-α and COX-2 genes. GCMS and HPLC analysis were performed to identify the secondary metabolites of A. dumosus. From day 8 to 28 post-administration of formaldehyde and CFA, oral administration of A. dumosus (600, 300 and 150 mg/kg) showed a noteworthy improvement (p < 0.001) in the body weights, immune organ weights, serum levels of rheumatoid (RA) factor, C-reactive protein, TNF-α and IL-6 levels in arthritic rats similar to the effect of piroxicam and methotrexate. Subsequently, the administration of A. dumosus to formaldehyde and CFA-challenged rats, caused a marked decrease (p < 0.001) in the mRNA expression of IL-1b, IL-6, OPG, RANKL, TNF-α and COX-2 genes in treated rats. Likewise, when assessed for antioxidant potential, A. dumosus produced a pronounced (p < 0.001) reduction in malondialdehyde (MDA) levels and hydrogen peroxide (H2O2) production, whilst a dose-dependent (p < 0.001) increase in catalase (CAT) and superoxide dismutase (SOD) activities was recorded. GCMS profiling of A. dumosus presented benzaldehyde, 3-hydroxy-4-methoxy-, 1-decanol and undecane as plant compositions, whereas HPLC fingerprinting displayed quercetin, benzaldehyde, 3-hydroxy-4-methoxy-, gallic acid and cinnamic acid as plants constituents. These results depict that A. dumosus possesses anti-arthritic effect mediated possibly through attenuation of arthritic indices, chronic inflammatory and oxidative stress biomarkers along with down-regulation in the mRNA expression of arthritic candid genes.

Phytochemical and biological studies of Panicum antidotale aerial parts ethanol extract supported by molecular docking study

Panicum antidotale has traditionally been used as a poultice to alleviate local inflammation and painful diseases. This study aimed to evaluate the anti-inflammatory, wound-healing, analgesic, and antipyretic potential of its ethanol extract (PAAPEE) in vivo for the first time. In vitro antioxidant assays of Panicum antidotale using a 2,2-diphenyl-1-picrylhydrazyl assay revealed that it showed IC50 of 62.50 ± 6.85 μg/mL in contrast to standard, ascorbic acid, that showed IC50 of 85.51 ± 0.38 μg/mL. Administration of PAAPEE at a dose of 500 mg/kg (PAAPEE-500) displayed 78.44% and 75.13% inhibition of paw edema in carrageenen and histamine-induced edema models. respectively, 6 h post-treatment compared to that of the untreated group. Furthermore, it showed 68.78% inhibition of Freund's complete adjuvant-induced edema 21 days after treatment. It reduced the animal's rectal temperature in the yeast-induced fever model to 99.45 during the fourth h post-treatment. It significantly inhibited abnormal writhing by 44% in the acetic acid-induced pain model. PAE-500 also showed enhancement in wound closure by 72.52% with respect to that of the untreated group on the 10th day post-treatment using the excision healing of wound model. Histopathological examination of skin samples confirmed this improvement, showing enhanced tissue architecture with minimal infiltration of inflammatory cells. High-performance liquid chromatography (HPLC) of PAAPEE revealed the presence of quercetin, gallic, p-coumaric, benzoic, chlorogenic, syringic, ferulic, cinnamic, and sinapic acids. Molecular docking of 5-lipoxygenase and glycogen synthase kinase-3 β protein indicated their potential interaction within the active sites of both enzymes. Thus, P. antidotale serves as an effective natural wound-healing, anti-inflammatory, analgesic, and antipyretic agent.

Phytochemical characterization and anti-arthritic potential of Croton bonplandianus leaves extract: In-vivo and in-silico approach

Croton bonplandianus, a natural source traditionally used for treating various illnesses, including rheumatoid arthritis, was evaluated in this study. The effects of ethanolic extracts (CBEE) and aqueous fractions (CBAF) of C. bonplandianus leaves on arthritis-induced inflammation were studied using an albino rat model of inflammation induced by Freund's complete adjuvant. Eight test groups (n = 5 per group) and one vehicle control were used to evaluate the antiarthritic effects of different doses of CBEE and CBAF (125 mg.kg-1, 250 mg.kg-1, and 500 mg.kg-1) on days 5, 10, 15, and 20 compared to arthritic and vehicle controls. Arthritis severity was assessed using macroscopic arthritis grading, histological analysis, body weights, and paw thickness. CBEE and CBAF were found to reduce the prevalence of arthritis, increase body weight, and decrease paw inflammation compared to the vehicle control group by the 23rd day. In addition, they showed no effect on biochemical parameters, but a significant difference (p < 0.05) in hematological parameters compared to the arthritic control group. The study identified Hentriacontane compound as a potential contributor to the anti-inflammatory effect of C. bonplandianus, as it showed the lowest dock score for IL-1β and IL-6. Palmitoylethanol amide was identified as a potential contributor to the anti-inflammatory effect of TNF-α. Gene expression of IL-6, IL-1β, and TNF-α was down-regulated significantly (p < 0.05) in a dose-dependent manner in all treatment groups compared to the arthritic control group. In conclusion, this study validated the anti-arthritic and anti-inflammatory properties of CBEE and CBAF in a time and dose-dependent manner.

Investigating antiarthritic potential of polyherbal emulgel

BACKGROUND

Rheumatoid arthritis (RA) is an inflammation of joints with increased cellularity of synovial tissue. Allopathic drugs possess several adverse effects, which have led to increase in the utilization of herbal medicines. Polyherbal emulgel resolves the bioavailability issue associated with hydrophobic drugs and can be used effectively in the treatment of RA.

OBJECTIVES

The present study aimed at the formulation of polyherbal emulgel, and evaluation of in vitro anti-inflammatory activity and in vivo antiarthritic activity.

METHODS

Seven emulgels F-1 to F-7 were optimally formulated. In vitro anti-inflammatory activity was determined using protein denaturation method employing Diclofenac sodium as the standard. In antiarthritic study Complete Freund's Adjuvant (CFA) model was used. The various parameters were assessed, like paw volume, body weight, hematological parameters, antioxidant parameters, Rheumatic factor (RF), and histopathological study of ankle joint.

RESULTS

F-4 and F-7 were found to be optimized formulations as compared to other formulations. The in vitro anti-inflammatory activity was found to be highest in F-4 with IC50 7.74 and F-7 with IC50 8.87 in comparison with Diclofenac sodium having IC50 57.0. Both formulations F-7 and F-4 showed a significant reduction in paw volume and normalization of body weights. The formulation F-7 even showed more potent antiarthritic activity than F-4 by decreasing white blood cells (WBC), lymphocytes, increasing packed cell volume (PCV), neutrophils, superoxide dismutase (SOD), catalase and decreasing malondialdehyde (MDA) levels in serum. This was further confirmed by histopathological study.

CONCLUSION

As an anti-inflammatory agent, this newly developed emulgel was found to possess more therapeutic efficacy than commercially available diclofenac sodium.

Evaluation of anti-inflammatory and immunomodulatory potential of Lawsone (2-hydroxy-1,4-naphthoquinone) using pre-clinical rodent model of rheumatoid arthritis

Background: Lawsone (2-hydroxy-1,4-naphthoquinone) is naturally present in Lawsonia Inermis and flowers of Eicchornia crassipes. This study assessed the anti-arthritic potential of Lawsone, using FCA-induced Sprague-Dawley rats. Methods: Arthritic progress was analyzed through a macroscopic scoring scale, measurement of paw edema, and histopathological changes. Effects of Lawsone on mRNA expression levels of inflammatory markers were examined using the reverse transcription PCR technique. ELISA technique was used to evaluate the PGE2 levels. Moreover, levels of biochemical and hematological parameters were also analyzed. Results: The research elucidated that Lawsone showed an inhibitory potential towards arthritic progress and ameliorated the paw edema. The histopathological analysis also validated the inhibition in arthritic development. Treatment with Lawosne reduced the expression levels of inflammatory markers in rats i.e., VEGF, TNF-α, MMP-2, MMP-3, NF-κB, IL-1β, and IL-6. PGE2 levels (all p < 0.001) were also found reduced in treatment groups. Lab investigations showed improved results of hematological and hepatic parameters in the treated groups as compared to the positive control. This study found no hepatotoxic or nephrotoxic effects of Lawsone in the test doses. Conclusion: Lawsone possesses an anti-arthritic property which could be ascribed to its immunomodulatory and anti-inflammatory effects.

Eichhornia crassipes Ameliorated Rheumatoid Arthritis by Modulating Inflammatory Cytokines and Metalloproteinase Enzymes in a Rat Model

Background and Objectives: This study was planned to investigate the anti-arthritic property of flowers of E. crassipes in a Sprague-Dawley rat model by administering Freund's Complete Adjuvant (FCA). Materials and Methods: Arthritis was induced at day 0 in all rats except negative controls, while arthritic progress and paw edema were analyzed on specific days (8th, 13th, 18th, and 23rd) via the macroscopic arthritic scale and a digital Vernier caliper, respectively. Histopathological parameters were examined using a Hematoxylin and Eosin (H&E) staining method. Blood samples were withdrawn from rats to investigate the effects of the E. crassipes flower on the mRNA expression values of inflammatory markers, via a reverse transcription PCR technique. Serum samples were used to determine prostaglandin E2 (PGE2) levels using enzyme-linked immunosorbent assay (ELISA). Values of alanine transaminase (ALT), aspartate aminotransferase (AST), creatinine, and urea, besides hematological parameters, i.e., the hemoglobin (Hb) content and complete blood count (CBC), were investigated. Results: The data showed that E. crassipes inhibited the arthritic progress and ameliorated the paw edema. The amelioration of parameters assessed via the histopathological analysis of ankle joints, as well as via hematological analysis, confirmed the diminution of rheumatoid arthritis (RA) in the plant-treated groups. Treatment with E. crassipes inhibited the expression levels of tumor necrosis factor-α (TNF-α), interleukins (IL-1β and IL-6), nuclear factor KappaB (NF-κB), matrix metalloproteinase (MMP-2 and MMP-3), and vascular endothelial growth factor (VEGF). Serum PGE2 levels were also found to be reduced in treatment groups. A biochemical investigation revealed the improvements in hepatic markers in plant-treated groups. The data indicated that the plant has no hepatotoxic or nephrotoxic effects at the studied dose. GC-MS (Gas Chromatography-Mass Spectrometry) analysis displayed the presence of phytochemicals having known anti-inflammatory and antioxidant properties. Conclusions: Therefore, it may be concluded that E. crassipes possesses anti-arthritic characteristics that could be attributed to the modulation of pro-inflammatory cytokines, MMPs, and PGE2 levels.

Anti-inflammatory and antinociceptive activities of Daniellia oliveri (Fabaceace) stem bark extract

ETHNOPHARMACOLOGICAL RELEVANCE

Daniellia oliveri (Rolfe) Hutch. & Dalziel (Fabaceae) is used for the treatment of inflammatory diseases and pains (chest pain, toothache and lumbago) and rheumatism.

AIM OF THE STUDY

The study investigates the anti-inflammatory and antinociceptive properties of D. oliveri and possible mechanism of antiinflammatory action.

MATERIALS AND METHODS

Acute toxicity of the extract was evaluated in mice using the limit test. The anti-inflammatory activity was assessed in xylene-induced paw oedema and carrageenan-induced air-pouch models at doses of 50, 100 and 200 mg/kg, p.o. Volume of exudate, total protein, leukocyte counts, myeloperoxidase (MPO) and concentration of cytokines (TNF-α and IL-6) were measured in the exudate of rats in the carrageenan-induced air-pouch model. Other parameters include lipid peroxidation (LPO), nitric oxide (NO) and antioxidant indices (SOD, CAT and GSH). Histopathology of the air pouch tissue was also carried out. The antinociceptive effect was assessed using acetic acid-induced writhing, tail flick and formalin tests. Locomotor activity was done in the open field test. The extract was analysed with HPLC-DAD-UV technique.

RESULTS

The extract showed significant anti-inflammatory effect (73.68 and 75.79%, inhibition) in xylene-induced ear oedema test at the dose of 100 and 200 mg/kg, respectively. In carrageenan air pouch model, the extract significantly reduced exudate volume, protein concentration, the migration of leukocytes and MPO production in the exudate. The concentrations of cytokines TNF-α (12.25 ± 1.80 pg/mL) and IL-6 (21.12 pg/mL) in the exudate at the dose of 200 mg/kg were reduced compared to carrageenan alone group (48.15 ± 4.50 pg/mL; 82.62 pg/mL) respectively. The extract showed significant increase in the activities of CAT and SOD and GSH concentration. The histopathological assessment of the pouch lining revealed reduction of immuno-inflammatory cell influx. Nociception was significantly inhibited by the extract in acetic acid-induced writhing model and the second phase of formalin test indicating a peripheral mechanism of action. The open field test showed that D. oliveri did not alter locomotor activity. The acute toxicity study did not cause mortality or signs of toxicity at 2000 mg/kg, p.o. We identified and quantified caffeic acid, p-coumaric acid, ferulic acid, rutin, apigenin-7-glucoside, quercetin and kaempferol in the extract.

CONCLUSION

The results of our study showed that the stem bark extract of D. oliveri possesses anti-inflammatory and antinociceptive activities thereby supporting its traditional use in the treatment of some inflammatory and painful disorders.

Chrysin, a 5,7-dihydroxyflavone restrains inflammatory arthritis in rats via subsiding oxidative stress biomarkers and inflammatory cytokines

This study was intended to appraise the anti-inflammatory and anti-arthritic potential of Chrysin (CR), a natural dietary flavone found in several plant genera, including Passiflora and Propalis, and honey. The in vitro anti-arthritic potential was assessed by protein denaturation and membrane stabilization assays. The acute anti-inflammatory action was assessed by Carrageenan and Xylene induced oedema models in Wistar rats. For determining anti-arthritic potential, 0.1 ml Complete Freund's adjuvant was injected into the left hind paw of rats to induce adjuvant-induced arthritis, followed by initiation of treatment with individual CR at 25, 50, 100 mg/kg and in combination with methotrexate (MTX) by oral gavage for 21 days. The standard treatment group was given MTX (1 mg/kg). Treatment with MTX, chrysin and their combination exhibited a notable inhibition of paw oedema and pain, restoration of body weight and immune organ weight as evident by the histology of ankle joints. Treatment with chrysin alone and in combination significantly (p < 0.0001) restored altered blood parameters (CRP, RF, Hb, WBC, and platelets) with notable (p < 0.0001) down-regulation of interleukin (IL)-6,-1β, tumor necrosis factor-α, NF-κβ, and cyclooxygenase-2 and up-regulation (p < 0.0001) of IL-4, 10, and I-κβ in contrast to disease control rats. The treatment with the combination noticeably improved the superoxide dismutase, and catalase activities while reduced the peroxidation level in liver homogenate. It can be concluded from the findings that chrysin especially in combination with MTX ameliorated CFA-induced arthritis owing to its profound anti-oxidant, analgesic and anti-inflammatory actions.

Nimbolide attenuates complete Freund's adjuvant induced arthritis through expression regulation of toll-like receptors signaling pathway

Nimbolide is an active constituent of Azadirachta indica and is known for its anti-inflammatory, anti-oxidant, immune-modulatory, and anti-cancer effects. Few studies suggest that nimbolide treatment influences the responses to rheumatoid arthritis, but the underlying molecular mechanisms involved are not yet well established. Therefore, the present study was designed to determine the effect of nimbolide on expression regulation of toll-like receptors to attenuate rheumatoid arthritis. The rheumatoid arthritis model was established by injecting complete Freund's adjuvant (CFA) intra-dermally into the sub-plantar region of the left hind paw of rats. Nimbolide (20 mg/kg) and piroxicam (10 mg/kg) were given to arthritic rats. Rats treated with nimbolide showed a significant reduction in inflammatory cells, rheumatoid factor, ESR, and improved the body weight. The results indicated that nimbolide possesses the capacity to attenuate rheumatoid arthritis by downregulating toll-like receptors, IL-17, IL-23, HSP70, and IFN-γ expression levels. Nimbolide treatment showed significant reduction in the severity of inflammation and destruction of joints and showed comparable effects to piroxicam, which is a standard non-steroidal anti-inflammatory drug used for the treatment of rheumatoid arthritis. It can be concluded that nimbolide can be considered as a potential candidate for therapeutic targeting of the toll-like receptors pathway in rheumatoid arthritis.

Thymoquinone counteracts oxidative and inflammatory machinery in carrageenan-induced murine paw edema model

Thymoquinone (TQ) is an active constituent in Nigella sativa (black cumin) and is extensively reported for its distinguished antioxidant and anti-inflammatory bioactivities. Despite the local protective response of acute inflammation, it contributes to the development of various disease conditions such as cell death, organ damage, or carcinogenesis. Hence, in this study, the effects of orally administered TQ (50 mg/kg and 100 mg/kg) for 14 days against edema development, oxidative stress, and inflammation were investigated in paw edema induced by carrageenan in mice. Indomethacin (10 mg/kg) was used as a reference drug. The results revealed that TQ reduced the paw edema volume in a time-dependent manner, attenuated acetic acid-provoked writhing movements, and reduced xylene-triggered ear edema. Hematological findings revealed marked normalization of altered counts of WBCs, and platelets. Furthermore, paw tissue levels of malondialdehyde and nitric oxide showed marked decreases together with increases in nuclear factor erythroid 2-related factor 2, glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase after TQ administration. Additionally, TQ decreased pro-inflammatory mediators, such as interleukin-1 beta, tumor necrosis factor-alpha, interleukin-6, monocyte chemoattractant protein-1, C-reactive protein, myeloperoxidase, and nuclear factor kappa-B in the inflamed paw tissue. Moreover, appreciable decreases were recorded in cyclooxygenase-2 and its product prostaglandin E2 and the immune reaction of tumor necrosis factor-alpha in TQ-treated mice. Histopathological findings further validated the potential antiedematous, anti-inflammatory power of TQ in inflamed tissues. Conclusively, the results encourage the potent application of TQ to subside acute inflammatory events because of its striking antioxidant and anti-inflammatory properties in inflamed paw tissue.

Inhibition of sPLA2 enzyme activity by cell-permeable antioxidant EUK-8 and downregulation of p38, Akt, and p65 signals induced by sPLA2 in inflammatory mouse paw edema model

The arachidonic acid (AA) metabolic pathway, plays a vital role in the production of eicosanoids by the action of pro-inflammatory secretory phospholipase A₂ (PLA₂ ). Release of eicosanoids is known to be involved in many inflammatory diseases. Identification of the inhibitory molecules of this AA pathway enzyme along with the regulation of intracellular signaling cascades may be a finer choice to develop as a powerful anti-inflammatory drug. In this regard, we have screened few cell-permeable antioxidant molecules Tempo, Mito-TEMPO, N,N'-Bis(salicylideneamino)ethane-manganese(II) (EUK)-134, and EUK-8 against pro-inflammatory sPLA₂ s. Among these, we found EUK-8 is a potent inhibitor with its IC₅₀ value ranges 0.7-2.0 µM for sPLA₂ s isolated from different sources. Furthermore, docking studies confirm the strong binding of EUK-8 towards sPLA₂ . In vivo effect of EUK-8 was studied in HSF-sPLA₂ -induced edema in mouse paw model. In addition to neutralizing the edema, EUK-8 significantly reduces the phosphorylation level of inflammatory proteins such as p38 member of MAPK pathway, Akt, and p65 along with the suppression of pro-inflammatory cytokine (interleukin-6) and chemokine (CXCL1) in edematous tissue. This shows that EUK-8 not only inhibits the sPLA₂ activity, it also plays an important role in the regulation of sPLA₂ -induced cell signaling cascades. Apart from the sPLA₂ inhibition, we also examine the regulatory actions of EUK-8 with other downstream enzymes of AA pathway such as 5-LOX assay in human polymorphonuclear leukocytes (PMNs) and COX-2 expression in carrageenan-λ induced paw edema. Here EUK-8 significantly inhibits 5-LOX enzyme activity and downregulates COX-2 expression. These data indicate that EUK-8 found to be a promising multitargeted inhibitory molecule toward inflammatory pathway. In conclusion, mitochondrial targeted antioxidant EUK-8 is not only the powerful antioxidant, also a potent anti-inflammatory molecule and may be a choice of molecule for pharmacological applications.

Preclinical Rodent Models of Arthritis and Acute Inflammation Indicate Immunomodulatory and Anti-Inflammatory Properties of Juglans regia Extracts

Juglans regia has been used to treat inflammatory and arthritic disorders in traditional medicine. The present study aimed to investigate the antiarthritic and anti-inflammatory potential of ethanolic leaves extract of J. regia. Arthritis was induced in rodents with Freund’s complete adjuvant. J. regia treatment was started on 8th day of arthritis induction and sustained for 20 days. Acute inflammatory models were developed using carrageenan, histamine, serotonin, and dextran. Qualitative and GC-MS analyses were also performed. Arthritis was determined using an arthritis scoring index and histopathological examination of ankle joints. RT-PCR was performed to determine the expression of pro-inflammatory markers (TNF-α, NF-κB, IL-6, IL-1β, and COX-2) and anti-inflammatory IL-4. PGE2 levels were evaluated using an ELISA. Blood and biochemical parameters were also determined. Paw edema was measured using a digital plethysmometer. Treatment with extracts inhibited arthritic development and attenuated paw edema along with all histopathological parameters. The expression levels of pro-inflammatory cytokines and COX-2 were downregulated, while IL-4 was upregulated. PGE2 levels were also reduced in extract-treated groups. Blood and biochemical parameters were nearly normalized in the treatment groups. Both extracts significantly inhibited carrageenan, histamine, serotonin, and dextran-induced paw edema. Qualitative phytochemical screening and GC-MS analysis confirmed that extracts possessed potential medicinal compounds. In conclusion, ethanol and n-hexane extracts of J. regia leaves have immunomodulatory and anti-inflammatory effects that ameliorate experimentally induced arthritis and edema. The inhibition of autacoids may also be one of the mechanisms inducing the immunomodulatory effect.

Tetrandrine Ameliorates Rheumatoid Arthritis in Mice by Alleviating Neutrophil Activities

Rheumatoid arthritis (RA) is a common autoimmune disease worldwide. Neutrophils play critical roles in the onset and development of RA and are the promising target for RA treatment. Tetrandrine is a bis-benzyl isoquinoline alkaloid derived from the traditional Chinese herbal Stephania tetrandra S. Moore. Tetrandrine is effective in alleviating RA by inhibiting macrophage inflammatory response, fibroblast overproliferation, and pannus formation. However, whether tetrandrine regulates the activities of neutrophils in RA is largely unknown. In this study, we adopted adjuvant-induced arthritis (AA) murine model to explore the effect of tetrandrine on RA and neutrophils. Twenty-eight mice were divided into four groups. The control group was injected with PBS in the limbs and treated with PBS by intraperitoneal injection (i.p.) from Day 10 to Day 37. The arthritis murine model was induced by injecting FCA into the ankle joints of hind limbs. The AA group, the AA + TET group, and the AA + DEX group mice were treated with PBS, tetrandrine (6 mg/kg), or dexamethasone (1 mg/kg) i.p. daily, respectively. Arthritic scores were evaluated, and the joint diameter was measured every three days. A cytometric bead assay was performed to measure the concentrations of IFN-γ, TNF-α, and IL-6 in the serum. H&E staining and Safranin O-fast staining were adopted to monitor the tissue changes in the joint. Immunohistochemistry assays were applied to detect the MPO, NE, CitH3, and PAD4 expression levels. To assess the effect of tetrandrine on neutrophil activities in vitro, CCK8 tests were applied to determine cell viability. The qPCR and ELISA were performed to determine IL-1β and IL-6 expression levels. Immunofluorescence assays were performed to measure the formation of NETs. The results indicated that tetrandrine significantly alleviated the symptoms of RA in terms of the ankle diameter (from 4.629 ± 2.729 to 3.957 ± 0.257; P < 0.01) and ankle score (from 4.000 ± 0.000 to 3.286 ± 0.756; P < 0.05). Tetrandrine treatment significantly increased the cartilage areas and decreased serum IL-6 significantly (from 5.954 ± 2.127 to 2.882 ± 2.013; P < 0.01). The immunohistochemistry assays also showed decreased expression levels of NE, MPO, PAD4, and CitH3 induced by tetrandrine in comparison with the AA group (P < 0.01). The qPCR assays and ELISAs showed that tetrandrine had an anti-inflammatory effect in vitro by significantly inhibiting IL-6 (P < 0.01). The immunofluorescence assays showed that NET formation induced by PMA could be reduced by tetrandrine (P < 0.01). In conclusion, tetrandrine has good efficacy in treating RA by regulating neutrophil-involved inflammation and NET formation.

Optimization for ultrasonic-microwave synergetic extraction of total iridoid glycosides and screening of analgesic and anti-inflammatory active fractions from patrinia scabra Bunge (Valerianaceae)

Background

Patrinia scabra Bunge is a well-known herbal medicine for its favorable treatment on inflammatory diseases owing to its effective ingredients, in which iridoid glycoside plays an extremely significant role. This article aimed to improve the content of total iridoid glycosides in crude extract through a series optimization of extraction procedure. Moreover, considering that both pain and inflammation are two correlated responses triggered in response to injury, irritants or pathogen, the article investigated the anti-inflammatory and analgesic activities of P. scabra to screen out the active fraction.

Method

P. scabra was extracted by ultrasonic-microwave synergistic extraction (UMSE) to obtain total iridoid glycosides (PSI), during which a series of conditions were investigated based on single-factor experiments. The extraction process was further optimized by a reliable statistical method of response surface methodology (RSM). The elution fractions of P. scabra extract were prepared by macroporous resin column chromatography. Through the various animal experiment including acetic acid-induced writhing test, formalin induced licking and flinching, carrageenan-induced mice paw oedema test and xylene-induced ear edema in mice, the active fractions with favorable analgesic and anti-inflammatory effect were reasonably screen out.

Results

The content of PSI could reach up to 81.42 ± 0.31 mg/g under the optimum conditions as follows: ethanol concentration of 52%, material-to-liquid ratio of 1:18 g/mL, microwave power at 610 W and extraction time of 45 min. After gradient elution by the macroporous resin, the content of PSI increased significantly. Compared with other concentrations of elution liquid, the content of PSI in 30 and 50% ethanol eluate was increased to reach 497.65 and 506.90 mg/g, respectively. Owing to the pharmacology experiment, it was reasonably revealed that 30 and 50% ethanol elution fractions of P. scabra could relieve pain centrally and peripherally, exhibiting good analgesic and anti-inflammatory activities.

Conclusion

Patrinia scabra possessed rich iridoids and exhibited significant analgesic and anti-inflammatory activities.

Bulbous Plants Drimia: "A Thin Line between Poisonous and Healing Compounds" with Biological Activities

Drimia (synonym Urginea) plants are bulbous plants belonging to the family Asparagaceae (formerly the family Hyacinthaceae) and are distinctive, powerful medicinal plants. Just some species are indigenous to South Africa and have been traditionally utilized for centuries to cure various diseases and/or ailments. They have been recognized among the most famous and used medicinal plants in South Africa. Traditionally, the plants are used for various illnesses such as dropsy, respiratory disease, bone and joint complications, skin disorders, epilepsy and cancer. A number of studies have reported biological properties such as antiviral, antibacterial, antioxidant and anti-inflammatory, immunomodulatory, and anticancer activities. Their bulbs are a popular treatment for colds, measles, pneumonia, coughs, fever and headaches. However, some plant species are regarded as one of the six most common poisonous plants in Southern Africa that are toxic to livestock and humans. Due to the therapeutic effects of the Drimia plant bulb, research has focused on the phytochemicals of Drimia species. The principal constituents isolated from this genus are cardiac glycosides. In addition, phenolic compounds, phytosterols and other phytochemical constituents were identified. This study constitutes a critical review of Drimia species' bioactive compounds, toxicology, biological properties and phytochemistry, advocating it as an important source for effective therapeutic medicine. For this purpose, various scientific electronic databases such as ScienceDirect, Scopus, Google Scholar, PubMed and Web of Science were researched and reviewed to conduct this study. Despite well-studied biological investigations, there is limited research on the toxic properties and the toxic compounds of certain Drimia species. Searching from 2017 to 2021, Google Scholar search tools retrieved 462 publications; however, only 3 investigated the toxicity and safety aspects of Drimia. The aim was to identify the current scientific research gap on Drimia species, hence highlighting a thin line between poisonous and healing compounds, dotted across numerous publications, in this review paper.

Validating potent anti-inflammatory and anti-rheumatoid properties of Drynaria quercifolia rhizome methanolic extract through in vitro, in vivo, in silico and GC-MS-based profiling

Background

The fronds of Drynaria quercifolia have traditionally been used in rheumatic pain management. The goal of the present study was to validate the potent anti-inflammatory and anti-rheumatoid properties of the methanolic-extract of its rhizome using in vitro, in vivo and in silico strategies.

Methods

The plant was collected and the methanolic extract was prepared from its rhizome. Protein denaturation test, hypotonicity and heat-induced haemolysis assays were performed in vitro. The in vivo anti-rheumatoid potential was assessed in Freund’s complete adjuvant (FCA)-induced Wistar rat model through inflammatory paw-edema, haematological, biochemical, radiological and histopathological measurements. Moreover, metabolites of methanolic extract were screened by gas chromatography-mass spectrometry (GC-MS) and 3D molecular structures of active components were utilized for in silico docking study using AutoDock.

Results

In vitro results evinced a significant (p < 0.05) anti-inflammatory activity of the rhizome methanolic extract in a dose-linear response. Further, Drynaria quercifolia rhizome methanolic extract (DME) significantly ameliorated rheumatoid arthritis as indicated by the inhibition of arthritic paw-edema (in millimeter) in the rat rheumatoid arthritis models in both the low (57.71 ± 0.99, p < 0.01) and high dose groups (54.45 ± 1.30, p < 0.001) when compared to arthritic control. Treatment with DME also normalized the haematological (RBC, WBC, platelet counts and hemoglobin contents) and biochemical parameters (total protein, albumin, creatinine and ceruloplasmin) significantly (p < 0.05), which were further supported by histopathological and radiological analyses. Furthermore, GC-MS analysis of DME demonstrated the presence of 47 phytochemical compounds. Compounds like Squalene, Gamma Tocopherol, n-Hexadecanoic acid showed potent inhibition of cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukin (IL-6) in the docking analysis.

Conclusion

Results from in vivo and in vitro studies indicated that DME possesses a potent anti-inflammatory and anti-arthritic activity. In silico studies delineated the emergent potent inhibitory effects of several bio-active components on the target inflammatory markers (COX-2, TNF-α and IL-6).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03265-7.

Evaluation of Immunomodulatory and Antiarthritic Potential of Trigonella gharuensis Extracts

The genus of Trigonella has long been used for the treatment of arthritis and inflammatory disorders. This study was aimed to investigate the immunomodulatory activities of ethanol and n-hexane extracts of T. gharuensis in the rat model of rheumatoid arthritis. Freund's complete adjuvant (FCA) model was used to induce arthritis in rats. Arthritis was induced on day 0, while treatment which was started on day 8 continued for twenty days. Arthritic development and paw edema were determined using an arthritic scoring index and plethysmometer, respectively. Histopathology was evaluated using H&E staining. RNA extraction, reverse transcription, and polymerase chain reaction (RT-PCR) were performed to determine expression levels of proinflammatory markers such as TNF-α, NF-ĸB, IL-6, IL-1β, COX2, and anti-inflammatory cytokine IL-4. Prostaglandin E2 level (PGE2) was evaluated using ELISA. Blood analysis and biochemical parameters were also determined. The significance level was set as P < 0.05. Treatment with extracts reduced paw edema, arthritic progression, and histopathological parameters. Expression levels of abovementioned proinflammatory cytokines and COX2 were downregulated, while IL-4 was upregulated. PGE2 levels were found reduced with extract treatment. Blood parameters were nearly normalized in treatment groups. Extract treatment did not alter biochemical parameters. Both extracts had effects comparable with piroxicam. In conclusion, extracts of T. gharuensis ameliorated experimentally induced arthritis that may be ascribed to its immunomodulatory effects.

Amelioration of Rheumatoid Arthritis by Anacardium occidentale via Inhibition of Collagenase and Lysosomal Enzymes

Anacardium occidentale (cashew) has been used in the traditional system of medicine for curing many inflammatory disorders. The present study investigates the antiarthritic effects of cashew leaves extract using the rat model of FCA-induced rheumatoid arthritis. Arthritic rats were treated with 100 and 200 mg/kg b.w. ethanolic extract of cashew leaves. Animals were sacrificed at day 23, and before sacrificing the animals, gross pathological changes were observed. Histopathology of ankle joint was evaluated with hematoxylin and eosin staining, whereas the serum levels of C-reactive protein (CRP) were evaluated by the agglutination method. Inflammatory cells and other hematological parameters were assessed by employing an automated hemocytometer and chemistry analyzer. Rheumatoid factor (Rf) and lysosomal enzymes levels were determined in blood. Results indicated that A. occidentale significantly decreased the CPR levels, macroscopic arthritic score, and rheumatoid factor as compared to the diseased group. Histopathological evaluation showed significant attenuation in bone erosion, joint inflammation, and pannus formation by plant extract. Treatment with A. occidentale significantly suppressed the levels of acid phosphatase, β-galactosidase, β-glucuronidase, N-acetylglucosaminidase, and collagenase. Moreover, A. occidentale significantly raised the HB levels and RBCs counts which were found depleted in the diseased group. The raised counts of total leukocytes, platelets, neutrophils, lymphocytes, and monocytes were also significantly decreased by treatment with plant extract. Comparative analysis showed that higher dose of A. occidentale demonstrated superior amelioration of rheumatoid arthritis as compared to low dose. In conclusion, A. occidentale possesses significant antiarthritic potential, which may be attributed to the suppression of lysosomal enzymes and collagenase levels.

Iridoid glycosides from Morinda officinalis How. exert anti-inflammatory and anti-arthritic effects through inactivating MAPK and NF-κB signaling pathways

Background

The root of Morinda officinalis How. (MO, the family of Rubiaceae) has long been used to treat inflammatory diseases in China and other eastern Asian countries, and iridoid glycosides extracted from MO (MOIG) are believed to contribute to this anti-inflammatory effect. However, the mechanism underlying the anti-inflammatory and anti-arthritic activities of MOIG has not been elucidated. The aim of the present study was to determine how MOIG exerted anti-inflammatory and anti-arthritic effects in vivo and in RAW 264.7 macrophages.

Methods

MOIG were enriched by XDA-1 macroporous resin. The maximum feasible dose method was adopted to evaluate its acute toxicity. The analgesic effect of MOIG was evaluated by acetic acid writhing test and the anti-inflammatory effect was evaluated by cotton-pellet granuloma test in rats and air pouch granuloma test in mice. The anti-arthritic effect was evaluated by establishing an adjuvant arthritis model induced by Complete Freund’s Adjuvant (CFA). The viability of the cultured RAW 264.7 macrophages was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The anti-inflammatory activity was evaluated by measuring NO, IL-1β, IL-6 and TNF-α levels in LPS-stimulated RAW 264.7 cells. The protein level of inflammatory responsive genes was evaluated by Western blot analysis.

Results

MOIG had no significant toxicity at maximum feasible dose of 22.5 g/kg. MO extracts and MOIG (50,100 and 200 mg/kg) all evoked a significantly inhibitory effects on the frequency of twisting induced by acetic acid in mice compared with the model control group. Administration of MO extracts and MOIG markedly decreased the dry and wet weight of cotton pellet granuloma in rats and air pouch granuloma in mice. MOIG significantly attenuated the paw swelling and decreased the arthritic score, weight loss, spleen index, and the serum level of inflammatory factors IL-1β, IL-6 and IL-17a in CFA-induced arthritic rats. MOIG inhibited the production of inflammatory cytokines in LPS-stimulated RAW264.7 cells, and the expressions of iNOS, COX-2 and proteins related to MAPK and NF-κB signaling pathways in LPS-stimulated RAW 264.7 macrophages.

Conclusion

MOIG exerted anti-inflammatory and anti-arthritic activities through inactivating MAPK and NF-κB signaling pathways, and this finding may provide a sound experimental basis for the clinical treatment of rheumatoid arthritis with MOIG.

N-Butanol Extract of Gastrodia elata Suppresses Inflammatory Responses in Lipopolysaccharide-Stimulated Macrophages and Complete Freund's Adjuvant- (CFA-) Induced Arthritis Rats via Inhibition of MAPK Signaling Pathway

Gastrodia elata is a traditional herbal medicine that has been used for centuries to treat rheumatism. Previous studies have confirmed that ethanol extracts of Gastrodia elata have anti-inflammatory and antioxidant activities, and the n-butanol fraction exerts a higher inhibitory effect. However, the in vivo anti-inflammatory effects of Gastrodia elata have not been evaluated. Thus, we assessed the therapeutic effect of the n-butanol extract of Gastrodia elata (BGE) on complete Freund's adjuvant- (CFA-) induced arthritis rats which were separated into six groups (NOR; MODEL; CFA + dexamethasone (DEX); CFA + 25, 50, 100 mg/kg BGE). The paw swelling, joint radiology, and histology were used to analyze the effect of BGE on delaying the progression of rheumatoid arthritis. Furthermore, serum levels of inflammatory cytokines were analyzed via ELISA. In addition, the effect of BGE on nitric oxide (NO) production, expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2(COX-2), and inflammatory cytokines were detected in lipopolysaccharide- (LPS-) stimulated RAW264.7 macrophage cells. Lastly, the impacts of BGE on the activation of the mitogen-activated protein kinases (MAPK) pathway in CFA rats and LPS-stimulated RAW264.7 macrophage were examined by western blot analysis. The results show that BGE can significantly reduce paw swelling without losing the body weight of rats. Imaging assessment confirms that BGE can protect cartilage from destruction, as well as reducing inflammatory cell infiltration and synovial proliferation. Moreover, BGE suppresses the production of inflammatory cytokines in serum and inhibits the activation of the phosphorylation of p38 and ERK in CFA rats. BGE was also demonstrated to decrease the production of NO and inflammatory cytokines in LPS-stimulated RAW264.7 cells. The effect of BGE in LPS-induced expression leads to reduced p38 and ERK phosphorylation and also downregulates the protein expression of iNOS and COX-2. Taken together, BGE exhibits a potential therapeutic effect on CFA rats, and its anti-inflammatory and antioxidant effects were possibly exerted by regulation of ERK/p38MAPK.