Efficacy and Safety of Turmeric Extracts for the Treatment of Knee Osteoarthritis: a Systematic Review and Meta-analysis of Randomised Controlled Trials

Role of Anti-Inflammatory Diet and Fecal Microbiota Transplant in Psoriatic Arthritis

PURPOSE

Psoriatic arthritis (PsA) is a chronic inflammatory condition with complex and heterogenous manifestations. Although a myriad of treatment options including biologic medications are available to alleviate symptoms and slow disease progression, there is currently no cure for this condition. There has been a recent emergence of understanding about the relationship between the gut microbiome and immune-mediated inflammatory diseases. This has generated interest in the potential role of dietary interventions, particularly anti-inflammatory diets, and fecal microbiota transplant (FMT) as novel therapeutic approaches. The purpose of this narrative review is to examine the role of an anti-inflammatory diet and FMT in turn and whether their combination may offer alternate approaches for the management of PsA.

METHODS

Our non-systematic narrative review was informed by a literature search using PubMed and Google Scholar using the terms anti-inflammatory diet, FMT, nutrition supplements, and PsA. Preclinical studies and non-English language articles were excluded when synthesizing the narrative review.

FINDINGS

Current randomized controlled trials (RCTs) and observational evidence suggest that a hypocaloric diet or Mediterranean diet can help achieve weight loss among PsA patients who are overweight or obese, which in turn reduces inflammation and improves disease activity. However, there is no strong data to support the beneficial effects of intermittent fasting, vitamin supplements, turmeric supplements, probiotics, or omega-3 fatty acid supplements in PsA. Current evidence on the use of FMT in PsA is limited as only one small RCT has been conducted which did not demonstrate efficacy for improving clinical symptoms.

IMPLICATIONS

Clinicians can consider recommending hypocaloric or Mediterranean diets as an adjunct to standard management of PsA, possibly under the guidance of a dietician. Further research is needed to explore the beneficial effects of the synergistic role of combining an anti-inflammatory diet with FMT in PsA.

The efficacy of curcumin in relieving osteoarthritis: A meta-analysis of meta-analyses

Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases. Several meta-analyses have shown that curcumin could improve the function of the knee and alleviate pain in OA, while some meta-analyses demonstrate controversial results. Hence, we assessed curcumin's effects on knee OA in an umbrella meta-analysis. PubMed, Scopus, Embase, and Web of Science databases were employed to find English-language meta-analyses of randomized controlled trials investigating the effect of curcumin supplementation on OA outcomes up to September 2023. The visual analog scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, function, and stiffness scales were analyzed. Effect sizes and 95% confidence intervals were utilized to obtain the overall effect size. A random-effects model was applied to perform the meta-analysis. Heterogeneity was determined by I2 statistics and the Cochrane Q-test. The pooled effect of the 11 included meta-analyses showed that curcumin could significantly decrease the VAS score (weighted mean difference [WMD] and standardized mean difference [SMD]), WOMAC-total (SMD and WMD), WOMAC-Function (SMD and WMD), WOMAC-Pain (SMD), and WOMAC-Stiffness scores (SMD) (p ≤ 0.001, ≤0.001, ≤0.001, 0.007, ≤0.001, 0.002, ≤0.001, ≤0.001, respectively). The results strongly support curcuminoid supplementation in relieving pain, improving joint mobility and stiffness, and shortening medication usage of OA patients.

Chemical Composition of Turmeric (Curcuma longa L.) Ethanol Extract and Its Antimicrobial Activities and Free Radical Scavenging Capacities

Turmeric (Curcuma longa L.) is a perennial tuberous plant from the genus Curcuma (Zingiberaceae) and has been widely used in foods for thousands of years. The present study examined the ethanol extract of turmeric for its chemical composition, antimicrobial activity, and free radical scavenging properties. UHPLC-MS/MS analysis tentatively identified eight compounds in the turmeric extract. Potential antimicrobial effects of 0.1, 1.0, and 10 mg turmeric equivalents (TE)/mL were evaluated in vitro against a variety of Gram-negative bacteria (i.e., Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp.) and Gram-positive bacteria (i.e., Enterococcus faecalis, Listeria innocua, and Staphylococcus aureus). Concentrations of 0.1 and 1.0 mg TE/mL inhibited the growth of S. aureus and significantly suppressed that of Pseudomonas sp., E. faecalis, and L. innocua. The growth of all strains, including E. coli, was inhibited by 10 mg TE/mL. Moreover, free radical scavenging capacities were determined using HO●, ABTS●+, and DPPH● (HOSC, ABTS, and RDSC, respectively) radicals. The turmeric ethanol extract had a TPC value of 27.12 mg GAE/g, together with HOSC, RDSC, and ABTS values of 1524.59, 56.38, and 1.70 μmol TE/g, respectively. Our results suggest that turmeric extract has potential applications for use in functional foods to reduce microbial burdens and oxidative stress-related health problems.

Curcumin regulates autophagy through SIRT3-SOD2-ROS signaling pathway to improve quadriceps femoris muscle atrophy in KOA rat model

Knee osteoarthritis (KOA) usually leads to quadriceps femoris atrophy, which in turn can further aggravate the progression of KOA. Curcumin (CUR) has anti-inflammatory and antioxidant effects and has been shown to be a protective agent for skeletal muscle. CUR has been shown to have a protective effect on skeletal muscle. However, there are no studies related to whether CUR improves KOA-induced quadriceps femoris muscle atrophy. We established a model of KOA in rats. Rats in the experimental group were fed CUR for 5 weeks. Changes in autophagy levels, reactive oxygen species (ROS) levels, and changes in the expression of the Sirutin3 (SIRT3)-superoxide dismutase 2 (SOD2) pathway were detected in the quadriceps femoris muscle of rats. KOA led to quadriceps femoris muscle atrophy, in which autophagy was induced and ROS levels were increased. CUR increased SIRT3 expression, decreased SOD2 acetylation and ROS levels, inhibited the over-activation of autophagy, thereby alleviating quadriceps femoris muscle atrophy and improving KOA. CUR has a protective effect against quadriceps femoris muscle atrophy, and KOA is alleviated after improvement of quadriceps femoris muscle atrophy, with the possible mechanism being the reduction of ROS-induced autophagy via the SIRT3-SOD2 pathway.

The mechanistic role of curcumin on matrix metalloproteinases in osteoarthritis

A systematic mechanistic review was performed to determine mechanistic evidence for curcumin on pro-inflammatory matrix metalloproteinases and Osteoarthritis to understand the underlying pathophysiology, and to evaluate available human intervention evidence to inform clinical decision making. The systematic literature search was performed in 3 tranches (reviews, mechanistic, intervention studies) using PubMed, with no date limitations and using specific search terms. 65 out of 393 screened papers were accepted based on detailed inclusion and exclusion criteria. The mechanistic search was divided into three searches and the intervention searches were subdivided into four searches. Curcumin demonstrated significant inhibition of matrix metalloproteinases linked to cartilage degradation in Osteoarthritis through reduced activation of the nuclear factor kappa-B signaling pathway via suppressing phosphorylation of Iκβa and p65 nuclear translocation. Mechanistic evidence implicated matrix metalloproteinases in Osteoarthritis by decreasing Type II collagen, leading to cartilage damage. As a potential nutritional intervention for Osteoarthritis, curcumin could reduce inflammatory markers and improve pain and function scores. The evidence indicates most formulations of turmeric extract and curcumin extract, bio-enhanced and non-bio-enhanced, are effective at improving inflammatory markers and pain and function to a greater or lesser extent. Due to the high heterogeneity of the formulations, dosage, and duration of the studies, further research is needed to fully understand curcumin's potential as a promising non-pharmaceutical intervention for Osteoarthritis. This mechanism review identifies a gap in current research for the mechanism by which Type II collagen is mediated.

Efficacy and safety of curcumin therapy for knee osteoarthritis: A Bayesian network meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Curcumin, a polyphenolic compound extracted from turmeric (Curcuma longa L.), is widely used in traditional Chinese medicine to treat osteoarthritis and rheumatoid arthritis. Clinical and experimental studies show that curcuminoid formulations have considerable clinical application value in the treatment of knee osteoarthritis (KOA).

AIM OF THE STUDY

To evaluate the efficacy and safety of curcumin, both alone and in combination with other drugs, in KOA treatment through a Bayesian network meta-analysis (NMA).

METHODS

We searched PubMed, Embase and Cochrane Library for randomized controlled trials of curcumin for KOA treatment. The time range of the search was from the establishment of each database to April 26, 2023. The NMAs of outcome indicators were all performed using a random-effects model. NMAs were calculated and graphed in R using MetaInsight and Stata 140 software. Measurement data were represented by the mean difference (MD), while count data were represented by the odds ratio (OR); the 95% confidence interval (CI) of each effect size was also calculated.

RESULTS

This study included 23 studies from 7 countries, including 2175 KOA patients and 6 interventions. The NMA results showed that compared with placebo, curcumin significantly reduced the visual analogue scale pain score (MD = -1.63, 95% CI: -2.91 to -0.45) and total WOMAC score (MD = -18.85, 95% CI: -29.53 to -8.76). Compared with placebo, curcumin (OR = 0.17, 95% CI: 0.08 to 0.36), curcumin + NSAIDs (OR = 0.01, 95% CI: 0.00 to 0.13) and NSAIDs (OR = 0.11, 95% CI: 0.02 to 0.47) reduced the use of rescue medication. Compared with NSAIDs, curcumin (OR = 0.51, 95% CI: 0.25 to 0.94) and curcumin + NSAIDs (OR = 0.23, 95% CI: 0.06 to 0.9) had a reduced incidence of adverse reactions. The surface under the cumulative ranking curve results indicated that curcumin monotherapy, curcumin + chondroprotective agents, and curcumin + NSAIDs have good clinical value in KOA treatment.

CONCLUSIONS

Curcumin, either alone or in combination with other treatments, is considered to have good clinical efficacy and safety in KOA treatment. Drug combinations containing curcumin may have the dual effect of enhancing efficacy and reducing adverse reactions, but this possibility still needs to be confirmed by further clinical and basic research.

Bioavailability of Oral Curcumin in Systematic Reviews: A Methodological Study

Curcumin is a natural compound found in turmeric that exhibits diverse biological activities. However, its poor bioavailability limits its therapeutic application, which has led to the development of various bioavailability-improved formulations. In this methodological study, we analyzed whether systematic reviews on curcumin considered the bioavailability of systemic oral curcumin formulations when synthesizing evidence from human clinical trials. A total of 171 systematic reviews published between 2003 and 2022 were included in the study. From the included studies, we extracted data on study characteristics; type of curcumin; methods; and reporting regarding bioavailability, funding, and conflict of interest. Our results show that systematic reviews rarely consider the variable bioavailability of tested curcumin formulations. Relevant statistical subgroup and/or sensitivity analyses were reported in the methods and results of only 3.5% and 6.4% of reviews, respectively. However, more reviews mentioned bioavailability in their discussion (57%) or conclusion (13%). The detailed analysis of the included systematic reviews suggests that there is broad recognition of product bioavailability as a crucial factor affecting the health effects of curcumin, which is not accompanied by adequate evidence synthesis. Therefore, the results of most systematic reviews on orally administered curcumin should be taken with caution.

Theoretical studies on the photo protective mechanism of curcuminoids

In this work, the deactivation pathways of curcuminoids after photoexcitation was studied by employing density functional theory to explore their UVA radiation screening capacity. A comprehensive computational characterization of the excited-state processes of curcumin, demethoxycurcumin, and bis-demethoxycurcumin was done. The molecules exist in diketo and enol forms which are in equilibrium and interconvertible through keto-enol tautomerism. The enolic forms of each of the studied molecules have eight geometric cis-trans isomers as a result of torsion rotation about three different carbon-carbon double bonds across the aliphatic chain. For each geometric isomer, sixteen possible rotamers are found to exist due to rotation about five different carbon-carbon single bond rotations, also across the skeleton of the aliphatic chain. Upon photoexcitation, the studied molecules follow three main pathways of radiationless decay: (a) rotamerism and interconversion between rotamers of comparable energies which are in equilibrium, (b) interconversion between the cis-trans geometrical isomers where an efficient vibrational relaxation path is formed at ∼90° during torsion rotation about carbon-carbon double bond, and (c) excited state intramolecular proton transfer in a single O-H stretching vibration through a cyclic intramolecular hydrogen bonded ring formed at the centre of the molecule giving back the original structure. The absorption and emission spectra of the molecules were also simulated where the theoretically obtained absorption and emission maxima are close to the reported experimental values.

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

Therapeutic effects of combining curcumin and swimming in osteoarthritis using a rat model

Osteoarthritis (OA) is a common debilitating degenerative disease of the elderly. We aimed to study the therapeutic effects of combining curcumin and swimming in monosodium iodoacetate (MIA)-induced OA in a rat model. The rats were divided into 5 groups (n = 9). Group 1 received saline and served as a control group. Groups 2-5 were injected intra-articularly in the right knee with 100 μL MIA. One week later, groups 3 and 5 were started on daily swimming sessions that gradually increased to 20-mins per session, and for groups 4 and 5, oral curcumin was administered at a dose of 200 mg/kg for 4 weeks. The combination therapy (curcumin + swimming) showed the most effective results in alleviating pain and joint stiffness as well as improving histological and radiological osteoarthritis manifestations in the knee joints. The combination modality also reduced serum C-reactive protein and tissue cartilage oligomeric matrix protein levels. Mechanistically, rats received dual treatment exhibited restoration of miR-130a and HDAC3 expression. The dual treatment also upregulated PPAR-γ alongside downregulation of NF-κB and its inflammatory cytokine targets TNF-α and IL-1β. Additionally, there was downregulation of MMP1 and MMP13 in the treated rats. In conclusion, our data showed that there is a therapeutic potential for combining curcumin with swimming in OA, which is attributed, at least in part, to the modulation of miR-130a/HDAC3/PPAR-γ signaling axis.

Prevention and treatment of inflammatory arthritis with traditional Chinese medicine: Underlying mechanisms based on cell and molecular targets

Inflammatory arthritis, primarily including rheumatoid arthritis, osteoarthritis and ankylosing spondylitis, is a group of chronic inflammatory diseases, whose general feature is joint dysfunction with chronic pain and eventually causes disability in older people. To date, both Western medicine and traditional Chinese medicine (TCM) have developed a variety of therapeutic methods for inflammatory arthritis and achieved excellent results. But there is still a long way to totally cure these diseases. TCM has been used to treat various joint diseases for thousands of years in Asia. In this review, we summarize clinical efficacies of TCM in inflammatory arthritis treatment after reviewing the results demonstrated in meta-analyses, systematic reviews, and clinical trials. We pioneered taking inflammatory arthritis-related cell targets of TCM as the entry point and further elaborated the molecular targets inside the cells of TCM, especially the signaling pathways. In addition, we also briefly discussed the relationship between gut microbiota and TCM and described the role of drug delivery systems for using TCM more accurately and safely. We provide updated and comprehensive insights into the clinical application of TCM for inflammatory arthritis treatment. We hope this review can guide and inspire researchers to further explore mechanisms of the anti-arthritis activity of TCM and make a great leap forward in comprehending the science of TCM.

Curcuma as an anti-inflammatory component in treating osteoarthritis

Osteoarthritis (OA) is nowadays the most common musculoskeletal progressive condition. In recent decades, incidence and prevalence of OA have increased significantly. It is estimated that the prevalence of OA among adults older than 60 is 12%, affecting about 240 million people globally. The cause has not been fully elucidated, and therefore, there is no cure at the moment. It is a multifactorial degenerative disease with an inflammatory component mediated by numerous proinflammatory and anti-inflammatory cytokines, chemokines, and growth factors. OA is not yet fully understood; therefore, therapeutic interventions are aimed primarily at reducing symptoms and slowing the progression of joint destruction. Of the therapeutic options available, the most often prescribed are nonsteroidal antirheumatic drugs, which have numerous side effects. Therefore, a need for a safe, effective substance is differentiated, which will be used in adjuvant treatment, but also in disease prevention, and which will comparatively have no or fewer side effects. One such substance is curcumin, a hydrophobic polyphenol that forms the active component of the rhizome of the Curcuma longa plant. Several studies have shown its potent antioxidant and anti-inflammatory effect, non-toxicity, and safety at high daily doses. In addition to blocking chondrocyte apoptosis, curcumin also blocks the expression of cyclooxygenase, prostaglandin E-2 and proinflammatory cytokines in chondrocytes, potentially alleviating symptomatic diseases. Although there are significant variations in quality, methodology, and research results conducted on curcumin efficiency in OA treatment, curcumin is primarily recommended as systematic short-term and medium-term adjuvant therapy that reduces inflammatory biochemical factors. Reducing inflammation leads to better pain regulation and improved joint function, significantly reducing standard prescribed doses of drugs. The most researched daily doses of curcumin intake are 1000-2000 mg/day, which would also be the doses that most of the authors recommend. Further research is needed to determine the preventive role of curcumin in the pathogenesis of OA, the effects of long-term usage of curcumin in preventive purposes and treatment of osteoarthritis, as well as to determine optimal therapeutic dosages.

Effect of Curcuma longa extract on serum inflammatory markers and MRI-based synovitis in knee osteoarthritis: secondary analyses from the CurKOA randomised trial

BACKGROUND

Curcuma longa (CL) extract is modestly effective for relieving knee symptoms in knee osteoarthritis (OA) patients; however, its mechanism of action is unclear.

PURPOSE

We aimed to determine the effects of CL treatment on serum inflammatory markers over 12 weeks and to explore its potential effects on synovitis assessed by contrast-enhanced magnetic resonance imaging (CE-MRI) of the knee.

METHODS

Secondary analyses were conducted on the CL for knee OA (CurKOA) trial, which compared CL (n = 36) and placebo (n = 34) over 12 weeks for the treatment of knee OA. Systemic inflammatory markers (TNFα, IL6, and hsCRP) and a cartilage extracellular matrix degradative enzyme (MMP-3) were measured. A subgroup of participants (CL, n = 7; placebo, n = 5) underwent CE-MRI at baseline and a 12-week follow-up.

RESULTS

Over 12 weeks, there were no between-group differences in change in hsCRP, IL-6, and TNFα levels. MMP-3 levels decreased in both CL (-1.31 ng/ml [95%CI: -1.89 to -0.73]) and placebo (-2.34 ng/ml [95%CI: -2.95 to -1.73]) groups, with the placebo group having a slightly greater decrease (1.03 ng/ml [95%CI: 0.19 to 1.88]). Most (10 of 12) sub-study participants had normal synovial thickness scores at baseline. One participant had mild synovitis in each of the placebo and CL groups. Synovitis status was stable for all except two participants, one each in the CL and placebo group, whose synovitis score increased.

CONCLUSION

This is the first study that explored the effect of CL treatment on local and systemic inflammation using biochemical markers and CE-MRI outcomes on knee OA patients. Secondary analyses from this pilot study suggest that CL is unlikely to have clinically significant effects on systemic (inflammatory and cartilage) or local synovitis (CE-MRI) biomarkers compared to placebo. The mechanism of action for CL effect on pain remains unclear.

Efficacy and safety of colchicine for the treatment of osteoarthritis: a systematic review and meta-analysis of intervention trials

OBJECTIVE

Colchicine, an approved treatment for gout, has been trialed in many diseases including osteoarthritis (OA) due to its anti-inflammatory effects. However, its efficacy and safety remain unclear in OA. This systematic review and meta-analysis evaluated the efficacy and safety of colchicine for the treatment of OA.

METHODS

PubMed, Web of Science, Scopus, and Cochrane Central were searched from inception through September 2022. Two reviewers independently screened for randomized controlled trials (RCTs) comparing colchicine with placebo or other active comparators for the treatment of OA (knee, hand, or hip OA), extracted data, and performed Cochrane risk of bias assessments.

RESULT

Nine RCTs for the knee OA and one for the hand OA were identified, consisting of 847 patients (429 in colchicine arms, 409 in control arms). The studies were conducted between 2002 and 2021 with follow-up periods ranging from 2 to 12 months, in India, Iran, Turkey, Australia, Singapore, and Iraq. Moderate-quality evidence showed no clinically important pain reduction with colchicine compared to control (standardized mean difference [SMD], 0.17; 95% confidence interval [CI], - 0.55, 0.22). Moderate-quality evidence showed no improvement in function with colchicine compared to control in knee OA patients (SMD, - 0.37; 95% CI, - 0.87, 0.13). Colchicine showed an acceptable safety profile with AEs/SAEs comparable to control.

CONCLUSION

Current evidence does not suggest a benefit of colchicine in reducing pain and improving physical function in the overall cohort of hand/knee OA patients. Future trials should focus on the subgroups of OA patients with local or systemic inflammation and/or mineralization who might benefit from colchicine.

Efficacy and safety of curcuminoids alone in alleviating pain and dysfunction for knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials

Background

Curcuminoids (CURs) are the principal ingredients of Curcuma longa L. [Zingiberaceae] (CL)—an herbal plant used in east Asia to alleviate pain and inflammation. Thus far, the therapeutic effects of CURs for knee osteoarthritis (OA) uncovered by multiple reviews remained uncertain due to broadly involving trials with different agents-combined or CURs-free interventions. Therefore, we formed stringent selection criteria and assessment methods to summarize current evidence on the efficacy and safety of CURs alone in the treatment of knee OA.

Methods

A series of databases were searched for randomized controlled trials (RCTs) evaluating the efficacy and safety of CURs for knee OA. Clinical outcomes were evaluated using meta-analysis and the minimum clinically important difference (MCID) for both statistical and clinical significance.

Results

Fifteen studies with 1670 patients were included. CURs were significantly more effective than placebo in the improvements of VAS for pain ( WMD: − 1.77, 95% CI: − 2.44 to − 1.09), WOMAC total score ( WMD: − 7.06, 95% CI: − 12.27 to − 1.84), WOMAC pain score ( WMD: − 1.42, 95% CI: − 2.41 to − 0.43), WOMAC function score ( WMD: − 5.04, 95% CI: − 7.65 to − 2.43), and WOMAC stiffness score ( WMD: − 0.54, 95% CI: − 1.03 to − 0.05). Meanwhile, CURs were not inferior to NSAIDs in the improvements of pain- and function-related outcomes. Additionally, CURs did not significantly increase the incidence of adverse events (AEs) compared with placebo ( RR: 1.03, 95% CI: 0.69 to 1.53, P = 0.899, I² = 23.7%) and NSAIDs (RR: 0.71 0.65, 95% CI: 0.57 0.41 to 0.90 1.03).

Conclusions

CURs alone can be expected to achieve considerable analgesic and functional promotion effects for patients with symptomatic knee OA in short term, without inducing an increase of adverse events. However, considering the low quality and substantial heterogeneity of present studies, a cautious and conservative recommendation for broader clinical use of CURs should still be made. Further high-quality studies are necessary to investigate the impact of different dosages, optimization techniques and administration approaches on long-term safety and efficacy of CURs, so as to strengthen clinical decision making for patients with symptomatic knee OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03740-9.

Potential complementary and/or synergistic effects of curcumin and boswellic acids for management of osteoarthritis

For several thousand years (~4000) Boswellia serrata and Curcuma longa have been used in Aryuvedic medicine for treatment of various illnesses, including asthma, peptic ulcers, and rheumatoid arthritis, all of which are mediated through pathways associated with inflammation and pain. Although the in vivo pharmacology of both these natural ingredients is difficult to study because of poor bioavailability, in vitro data suggest that both influence gene expression mediated through nuclear factor kappa B (NF-κB). Therefore, the activity of pathways associated with inflammation (including NF-κB and lipoxygenase- and cyclooxygenase-mediated reduction in leukotrienes/prostaglandins) and those involved in matrix degradation and apoptosis are reduced, resulting in a reduction in pain. Additive activity of boswellic acids and curcumin was observed in preclinical models and synergism was suggested in clinical trials for the management of osteoarthritis (OA) pain. Overall, studies of these natural ingredients, alone or in combination, revealed that these extracts relieved pain from OA and other inflammatory conditions. This may present an opportunity to improve patient care by offering alternatives for patients and physicians, and potentially reducing nonsteroidal anti-inflammatory or other pharmacologic agent use. Additional research is needed on the effects of curcumin on the microbiome and the influence of intestinal metabolism on the activity of curcuminoids to further enhance formulations to ensure sufficient anti-inflammatory and antinociceptive activity. This narrative review includes evidence from in vitro and preclinical studies, and clinical trials that have evaluated the mechanism of action, pharmacokinetics, efficacy, and safety of curcumin and boswellic acids individually and in combination for the management of OA pain.

Zingiberaceae plants/curcumin consumption and multiple health outcomes: An umbrella review of systematic reviews and meta-analyses of randomized controlled trials in humans

This umbrella review is to recapitulate and grade the available evidence of associations between consumption of Zingiberaceae plants/curcumin (Cur) and multiple health-related outcomes. This study included 161 meta-analyses of randomized controlled trials in 76 articles with 67 unique health outcomes. Data on heterogeneity and publication bias are considered to assess the quality of evidence. Based on the different impact of Zingiberaceae plants/Cur on human health, the advantages outweigh the disadvantages. Zingiberaceae plants/Cur can mainly improve metabolic syndrome, non-alcoholic fatty liver disease, cardiovascular disease, and some chronic inflammatory diseases, likewise, obviously relief the pain of osteoarthritis and related diseases. Ginger supplements have been shown to improve vomiting during pregnancy and to relieve nausea and vomiting caused by chemotherapy and surgery. The surgery is any type of surgery, including laparoscopic surgery, gynecological surgery and mixed surgery. Beneficial associations were found with Cur intervention in gastrointestinal, neurological and oral diseases. Zingiberaceae plants/Cur are generally safe and favorable for multiple health outcomes in humans. High-quality research is further needed to prove the observed associations.

Quality of Evidence Supporting the Role of Curcuma Longa Extract/Curcumin for the Treatment of Osteoarthritis: An Overview of Systematic Reviews

Background

Well known for its good anti-inflammatory effect, curcuma longa extract (CLE)/curcumin (C) has a potential effect on osteoarthritis (OA), and a large number of researchers have completed several systematic reviews/meta-analyses (SRs/MAs) in this research area. However, the methodological and evidentiary quality of these SRs/MAs need to be further evaluated, and whether these findings provide reliable evidence for clinicians remains controversial.

Methods

Two researchers collected data from seven databases for SRs/MAs that are about randomized controlled trials (RCTs) on CLE/C for OA. Assessment was made for the SRs/MAs included in this article by means of the Assessment System for Evaluating Methodological Quality 2 (AMSTAR-2), the Risk of Bias in Systematic (ROBIS) scale, the list of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

Results

Nine published SRs/MAs were included in our study. According to the results of the AMSTAR-2 assessment, only one SR/MA was assessed as high quality. According to the ROBIS evaluation results, only 2 SRs/MAs have a low risk of bias. According to the results of the PRISMA checklist assessment, only 2 SRs/MAs studies fully reported the checklist, while other studies had reporting flaws. According to GRADE, a total of 59 effect sizes extracted from the included SRs/MAs were evaluated, among which no effect size was rated as high.

Conclusions

CLE/C may be an effective and safe complementary treatment for OA. However, further standard SRs/MAs and RCTs are needed to provide an evidence-based medical rationale for this.

The comparison of curcuminoid formulations or its combination with conventional therapies versus conventional therapies alone for knee osteoarthritis

BACKGROUND

Presently, curcuminoid formulations or its combination with conventional therapies has been used for the treatment of knee osteoarthritis (KOA). Nevertheless, evidence is limited due to small-sized clinical trials. This study aims to evaluate the efficacy of curcuminoid formulations or its combination with conventional therapies for KOA.

METHODS

Randomized controlled trials comparing curcuminoid formulations or its combination with conventional therapies versus conventional therapies, such as non-steroidal antiinflammatory drugs (NSAIDs) and chondroitin sulfate/glucosamine, were searched from databases.

RESULTS

In total, 14 studies involving 1533 patients were included. Curcuminoid formulations were comparative to NSAIDs in reducing Visual Analogue Scale (VAS), total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and WOMAC score for pain/stiffness/physical function. No significant difference was seen between the two groups in terms of patients' satisfaction index, patients' global assessment, reduction of several inflammatory factor, rate of drug compliance, and rescue medication. Notably, curcuminoid formulations combined with NSAIDs significantly reduced VAS and WOMAC/Knee injury and OA Outcome Score (KOOS) pain score more than NSAIDs did. In addition, the curcuminoid formulations were superior to chondroitin sulfate/glucosamine in reducing VAS, total WOMAC score, and WOMAC score for stiffness/difficulty in physical function, while no significant difference was seen in reducing WOMAC pain score and Karnofsky Performance Scale score.

CONCLUSIONS

Curcuminoid formulations may be considered a promising alternative for treating KOA. Key points • Curcuminoid formulations are comparative to NSAIDs for KOA. • Curcuminoid formulations are superior to chondroitin sulfate/glucosamine for KOA. • Curcuminoid formulations could provide additional benefits in alleviating pain and some adverse events caused by NSAIDs.

The Role of Medicinal and Aromatic Plants against Obesity and Arthritis: A Review

Obesity is a significant health concern, as it causes a massive cascade of chronic inflammations and multiple morbidities. Rheumatoid arthritis and osteoarthritis are chronic inflammatory conditions and often manifest as comorbidities of obesity. Adipose tissues serve as a reservoir of energy as well as releasing several inflammatory cytokines (including IL-6, IFN-γ, and TNF-α) that stimulate low-grade chronic inflammatory conditions such as rheumatoid arthritis, osteoarthritis, diabetes, hypertension, cardiovascular disorders, fatty liver disease, oxidative stress, and chronic kidney diseases. Dietary intake, low physical activity, unhealthy lifestyle, smoking, alcohol consumption, and genetic and environmental factors can influence obesity and arthritis. Current arthritis management using modern medicines produces various adverse reactions. Medicinal plants have been a significant part of traditional medicine, and various plants and phytochemicals have shown effectiveness against arthritis and obesity; however, scientifically, this traditional plant-based treatment option needs validation through proper clinical trials and toxicity tests. In addition, essential oils obtained from aromatic plants are being widely used as for complementary therapy (e.g., aromatherapy, smelling, spicing, and consumption with food) against arthritis and obesity; scientific evidence is necessary to support their effectiveness. This review is an attempt to understand the pathophysiological connections between obesity and arthritis, and describes treatment options derived from medicinal, spice, and aromatic plants.

Botanical Drug Extracts Combined With Biomaterial Carriers for Osteoarthritis Cartilage Degeneration Treatment: A Review of 10 Years of Research

Osteoarthritis (OA) is a long-term chronic arthrosis disease which is usually characterized by pain, swelling, joint stiffness, reduced range of motion, and other clinical manifestations and even results in disability in severe cases. The main pathological manifestation of OA is the degeneration of cartilage. However, due to the special physiological structure of the cartilage, once damaged, it is unable to repair itself, which is one of the challenges of treating OA clinically. Abundant studies have reported the application of cartilage tissue engineering in OA cartilage repair. Among them, cell combined with biological carrier implantation has unique advantages. However, cell senescence, death and dedifferentiation are some problems when cultured in vitro. Botanical drug remedies for OA have a long history in many countries in Asia. In fact, botanical drug extracts (BDEs) have great potential in anti-inflammatory, antioxidant, antiaging, and other properties, and many studies have confirmed their effects. BDEs combined with cartilage tissue engineering has attracted increasing attention in recent years. In this review, we will explain in detail how cartilage tissue engineering materials and BDEs play a role in cartilage repair, as well as the current research status.

An Investigation into the Effects of a Curcumin Extract (Curcugen®) on Osteoarthritis Pain of the Knee: A Randomised, Double-Blind, Placebo-Controlled Study

Curcumin, a phytochemical from the spice turmeric, has anti-inflammatory properties and has been shown to have pain-relieving effects. In this 8-week, randomised, double-blind, placebo-controlled study, 101 adults with knee osteoarthritis received either 500 mg twice daily of a standardised curcumin extract (Curcugen^®) or placebo. Outcome measures included the Knee Injury and Osteoarthritis Outcome Score (KOOS), knee pain ratings, Japanese Orthopaedic Association Score for Osteoarthritic Knees (JOA), PROMIS-29, and performance-based testing comprising the 40-m fast-paced walk test, 6-min walk test, timed up-and-go test, and 30-s chair stand test. Compared to the placebo, curcumin significantly reduced the KOOS knee pain score (p = 0.009) and numeric knee pain ratings (p = 0.001). Curcumin was also associated with greater improvements (p ≤ 0.05) than the placebo on the timed up-and-go test, 6-min walk test, and the JOA total score; but not the 30-s chair stand test or 40-m fast-paced walk test. Pain-relieving medication was reduced in 37% of participants on curcumin compared to 13% on placebo. The findings support the potential efficacy of curcumin for the treatment of osteoarthritis of the knee but studies of longer duration, varying treatment doses, differing curcumin extracts, and the use of other objective outcome measures will be helpful to expand on these findings.

The efficacy of high- and low-dose curcumin in knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to critically appraise and evaluate effects of low- and high-dose curcuminoids on pain and functional improvement in patients with knee osteoarthritis (OA) and to compare adverse events (AEs) between curcuminoids and non-steroid anti-inflammatory drugs (NSAIDs).

METHODS

We systematically reviewed all randomized controlled trials (RCTs) on curcuminoids in knee osteoarthritis from the PubMed, Embase, Cochrane Library, AMED, Cinahl, ISI Web of Science, Chinese medical database, and Indian Scientific databases from inception to June 21, 2021.

RESULTS

We included eleven studies with a total of 1258 participants with primary knee OA. The meta-analysis results showed that curcuminoids were significantly more effective than comparators regarding visual analogue scale (VAS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scores. However, no significant difference in pain relief or AEs between the high-dose (daily dose ≥1000 mg or total dose ≥42 gm) and low-dose (daily dose <1000 mg or total dose <42 gm) curcuminoid treatments was observed. When comparing curcumininoids versus NSAIDs, a significant difference in VAS pain was found. For AE analysis, three of our included studies used NSAIDs as comparators, with all reporting higher AE rates in the NSAID group, though significance was reached in only one study.

CONCLUSIONS

The results of our meta-analysis suggest that low- and high-dose curcuminoids have similar pain relief effects and AEs in knee OA. Curcuminoids are also associated with better pain relief than NSAIDs; therefore, using curcuminoids as an adjunctive treatment in knee OA is recommended.

Osteoarthritis Progression: Mitigation and Rehabilitation Strategies

Osteoarthritis is the most common form of arthritis and is a substantial burden for patients with the disease. Currently, there is no cure for osteoarthritis, but many emerging therapies have been developed to aid in the mitigation of disease progression. When osteoarthritis reaches the end-stage of disease many patients undergo total joint arthroplasty to improve quality of life, yet some experience persistent pain and mobility limitations for extended periods following surgery. This review highlights recent therapeutic advancements in osteoarthritis treatment consisting of pharmacologics, nutraceuticals, biologics, and exercise while emphasizing the current state of post-arthroplasty rehabilitation.

Considerations to Be Taken When Carrying Out Medicinal Plant Research-What We Learn from an Insight into the IC50 Values, Bioavailability and Clinical Efficacy of Exemplary Anti-Inflammatory Herbal Components

Medicinal plants represent a big reservoir for discovering new drugs against all kinds of diseases including inflammation. In spite the large number of promising anti-inflammatory plant extracts and isolated components, research on medicinal plants proves to be very difficult. Based on that background this review aims to provide a summarized insight into the hitherto known pharmacologically active concentrations, bioavailability, and clinical efficacy of boswellic acids, curcumin, quercetin and resveratrol. These examples have in common that the achieved plasma concentrations were found to be often far below the determined IC50 values in vitro. On the other hand demonstrated therapeutic effects suggest a necessity of rethinking our pharmacokinetic understanding. In this light this review discusses the value of plasma levels as pharmacokinetic surrogates in comparison to the more informative value of tissue concentrations. Furthermore the need for new methodological approaches is addressed like the application of combinatorial approaches for identifying and pharmacokinetic investigations of active multi-components. Also the physiological relevance of exemplary in vitro assays and absorption studies in cell-line based models is discussed. All these topics should be ideally considered to avoid inaccurate predictions for the efficacy of herbal components in vivo and to unlock the "black box" of herbal mixtures.