Curcuminoid Treatment for Knee Osteoarthritis: A Randomized Double-Blind Placebo-Controlled Trial

Curcumin and its nano-formulations combined with exercise: From molecular mechanisms to clinic

Curcumin is a strong substance derived from turmeric, a popular spice, renowned for its antioxidant and anti-inflammatory abilities. The study delved deeply into a thorough examination of various sources to evaluate the impact of both regular curcumin and nano-formulated curcumin on elements that impact physical performance, including muscular strain, discomfort, swelling, and oxidative tension. While engaging in exercise, the body experiences a rise in reactive oxygen species and inflammation. As a result, it is important to ensure a proper balance between internal and external sources of antioxidants to maintain stability in the skeletal muscle. Without this balance, there is a risk of muscle soreness, damage, and ultimately, a decline in exercise performance. Curcumin possesses the ability to enhance physical performance and reduce the symptoms of muscle fatigue and injury by virtue of its antioxidative and anti-inflammatory properties. Including curcumin supplements appears to have advantageous effects on various aspects of exercise, such as enhancing performance, assisting with recovery, lessening muscle damage and discomfort, and lowering levels of inflammation and oxidative stress. However, a thorough assessment is necessary to precisely gauge the healing advantages of curcumin in enhancing exercise ability and reducing recovery time.

Is Curcumin Intake Really Effective for Chronic Inflammatory Metabolic Disease? A Review of Meta-Analyses of Randomized Controlled Trials

This review aimed to examine the effects of curcumin on chronic inflammatory metabolic disease by extensively evaluating meta-analyses of randomized controlled trials (RCTs). We performed a literature search of meta-analyses of RCTs published in English in PubMed®/MEDLINE up to 31 July 2023. We identified 54 meta-analyses of curcumin RCTs for inflammation, antioxidant, glucose control, lipids, anthropometric parameters, blood pressure, endothelial function, depression, and cognitive function. A reduction in C-reactive protein (CRP) levels was observed in seven of ten meta-analyses of RCTs. In five of eight meta-analyses, curcumin intake significantly lowered interleukin 6 (IL-6) levels. In six of nine meta-analyses, curcumin intake significantly lowered tumor necrosis factor α (TNF-α) levels. In five of six meta-analyses, curcumin intake significantly lowered malondialdehyde (MDA) levels. In 14 of 15 meta-analyses, curcumin intake significantly reduced fasting blood glucose (FBG) levels. In 12 of 12 meta-analyses, curcumin intake significantly reduced homeostasis model assessment of insulin resistance (HOMA-IR). In seven of eight meta-analyses, curcumin intake significantly reduced glycated hemoglobin (HbA1c) levels. In eight of ten meta-analyses, curcumin intake significantly reduced insulin levels. In 14 of 19 meta-analyses, curcumin intake significantly reduced total cholesterol (TC) levels. Curcumin intake plays a protective effect on chronic inflammatory metabolic disease, possibly via improved levels of glucose homeostasis, MDA, TC, and inflammation (CRP, IL-6, TNF-α, and adiponectin). The safety and efficacy of curcumin as a natural product support the potential for the prevention and treatment of chronic inflammatory metabolic diseases.

Revolutionizing Knee Osteoarthritis Treatment: Innovative Self-Nano-Emulsifying Polyethylene Glycol Organogel of Curcumin for Effective Topical Delivery

In the current study, self-nano-emulsifying (SNE) physically cross-linked polyethylene glycol (PEG) organogel (SNE-POG) as an innovative hybrid system was fabricated for topical delivery of water-insoluble and unstable bioactive compound curcumin (CUR). Response surface methodology (RSM) based on Optimal Design was utilized to evaluate the formulation factors. Solid fiber mechanism with homogenization was used to prepare formulations. Pharmaceutical evaluation including rheological and texture analysis, their mathematical correlations besides physical and chemical stability experiments, DSC study, in vitro release, skin permeation behavior, and clinical evaluation were carried out to characterize and optimize the SNE-OGs. PEG 4000 as the main organogelator, Poloxamer 188 (Plx188) and Ethyl Cellulose (EC) as co-gelator/nanoemulsifier agents, and PEG 400 and glycerin as solvent/co-emulsifier agents could generate SNE-POGs in PS range of 356 to 1410 nm that indicated organic base percentage and PEG 4000 were the most detrimental variables. The optimized OG maintained CUR stable in room and accelerated temperatures and could release CUR sustainably up to 72 h achieving high flux of CUR through guinea pig skin. A double-blind clinical trial confirmed that pain scores, stiffness, and difficulty with physical function were remarkably diminished at the end of 8 weeks compared to the placebo (71.68% vs. 7.03%, 62.40% vs. 21.44%, and 45.54% vs. 8.66%, respectively) indicating very high efficiency of system for treating knee osteoarthritis. SNE-POGs show great potential as a new topical drug delivery system for water-insoluble and unstable drugs like CUR that could offer a safe and effective alternative to conventional topical drug delivery system.

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.

Natural products in osteoarthritis treatment: bridging basic research to clinical applications

Osteoarthritis (OA) is the most prevalent degenerative musculoskeletal disease, severely impacting the function of patients and potentially leading to disability, especially among the elderly population. Natural products (NPs), obtained from components or metabolites of plants, animals, microorganisms etc., have gained significant attention as important conservative treatments for various diseases. Recently, NPs have been well studied in preclinical and clinical researches, showing promising potential in the treatment of OA. In this review, we summed up the main signaling pathways affected by NPs in OA treatment, including NF-κB, MAPKs, PI3K/AKT, SIRT1, and other pathways, which are related to inflammation, anabolism and catabolism, and cell death. In addition, we described the therapeutic effects of NPs in different OA animal models and the current clinical studies in OA patients. At last, we discussed the potential research directions including in-depth analysis of the mechanisms and new application strategies of NPs for the OA treatment, so as to promote the basic research and clinical transformation in the future. We hope that this review may allow us to get a better understanding about the potential bioeffects and mechanisms of NPs in OA therapy, and ultimately improve the effectiveness of NPs-based clinical conservative treatment for OA patients.

Recent updates on clinical developments of curcumin and its derivatives

Curcumin, a natural polyphenol, derived from Curcuma longa L. is extensively studied by various researchers across the globe and has established its immense potential in the management of several disorders at clinical level. The underlying mechanism of curcumin involves regulation of various molecular targets, namely, inflammatory cytokines, transcription factor, apoptotic genes, growth factors, oxidative stress biomarkers, and protein kinases. In clinical trials, curcumin as an adjuvant has significantly boost-up the efficacy of many proven drugs in the management of arthritis, neurodegenerative disorder, oral infection, and gastrointestinal disorders. Moreover, clinical studies have suggested curcumin as an appropriate candidate for the prevention and/or management of various cancers via regulation of signaling molecules including NF-kB, cytokines, C-reactive protein, prostaglandin E2, Nrf2, HO-1, ALT, AST, kinases, and blood profiles. This article highlights plethora of clinical trials that have been conducted on curcumin and its derivatives in the management of several ailments. Besides, it provides recent updates to the investigators for conducting future research to fulfill the current gaps to expedite the curcumin utility in clinical subjects bearing different pathological states.

Natural anti-inflammatory products for osteoarthritis: From molecular mechanism to drug delivery systems and clinical trials

Osteoarthritis (OA) is a degenerative joint disease that affects millions globally. The present nonsteroidal anti-inflammatory drug treatments have different side effects, leading researchers to focus on natural anti-inflammatory products (NAIPs). To review the effectiveness and mechanisms of NAIPs in the cellular microenvironment, examining their impact on OA cell phenotype and organelles levels. Additionally, we summarize relevant research on drug delivery systems and clinical randomized controlled trials (RCTs), to promote clinical studies and explore natural product delivery options. English-language articles were searched on PubMed using the search terms "natural products," "OA," and so forth. We categorized search results based on PubChem and excluded "natural products" which are mix of ingredients or compounds without the structure message. Then further review was separately conducted for molecular mechanisms, drug delivery systems, and RCTs later. At present, it cannot be considered that NAIPs can thoroughly prevent or cure OA. Further high-quality studies on the anti-inflammatory mechanism and drug delivery systems of NAIPs are needed, to determine the appropriate drug types and regimens for clinical application, and to explore the combined effects of different NAIPs to prevent and treat OA.

The extract of Curcumae Longae Rhizoma suppresses angiogenesis via VEGF-induced PI3K/Akt-eNOS-NO pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Curcumae Longae Rhizoma (CLR) is a safe natural herbal medicine, and which has been widely used for centuries as functional food and health products, but its effects on angiogenesis and related underlying mechanism remain unclear.

AIM OF THE STUDY

The abnormal angiogenesis is closely related with various diseases, and therefore the precise control of angiogenesis is of great importance. The well-known angiogenic factor, vascular endothelial growth factor (VEGF), mediates angiogenesis and induces multiple signalling pathways via binding to VEGF receptor (VEGFR). The attenuation of VEGF-triggered angiogenic-related signalling pathways may relieve various diseases through suppression of angiogenesis. Here, we aimed to elucidate that CLR extract could exert striking anti-angiogenic activities both in vitro and in vivo.

MATERIALS AND METHODS

The viability of human umbilical vascular endothelial cell (HUVEC) was examined by LDH and MTT assays. Migrative and invasive ability of the endothelial cells were independently evaluated by wound healing and transwell assays. The activities of CLR extract on in vitro angiogenesis was tested by tube formation assay. In vivo vascularization was determined by using zebrafish embryo model in the present of CLR extract. Western blotting was applied to determine the phosphorylated levels of VEGFR2, PI3K, AKT and eNOS. Besides, the levels of nitric oxide (NO) and reactive oxygen species (ROS) were separately evaluated by Griess assay and 2'7'-dichlorofluorescein diacetate reaction. In addition, the cell migrative ability of cancer cell was estimated by using cultured human colon carcinoma cells (HT-29 cell line), and immunofluorescence assay was applied to evaluate the effect of CLR extract on nuclear translocation of NF-κB p65 subunit in the VEGF-treated HT-29 cultures.

RESULTS

CLR extract significantly suppressed a series of VEGF-mediated angiogenic responses, including endothelial cell proliferation, migration, invasion, and tube formation. Moreover, CLR extract reduced in vivo sub-intestinal vessel formation in zebrafish embryo model. Mechanistically, the extract of CLR attenuated the VEGF-triggered signalling, as demonstrated by decreased level of phosphorylated VEGFR2 and subsequently inactivated its downstream regulators, e.g. phospho-PI3K, phospho-AKT and phospho-eNOS. The production of NO and formation of ROS were markedly inhibited in HUVECs. Furthermore, CLR extract suppressed cell migration and NF-κB translocation in cultured HT-29 cells.

CONCLUSIONS

These preclinical findings demonstrate that the extract of CLR remarkably attenuates angiogenesis and which has great potential as a natural drug candidate with excellent anti-angiogenic activity.

Role of Turmeric and Curcumin in Prevention and Treatment of Chronic Diseases: Lessons Learned from Clinical Trials

Turmeric (Curcuma longa) has been used for thousands of years for the prevention and treatment of various chronic diseases. Curcumin is just one of >200 ingredients in turmeric. Almost 7000 scientific papers on turmeric and almost 20,000 on curcumin have been published in PubMed. Scientific reports based on cell culture or animal studies are often not reproducible in humans. Therefore, human clinical trials are the best indicators for the prevention and treatment of a disease using a given agent/drug. Herein, we conducted an extensive literature survey on PubMed and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The keywords "turmeric and clinical trials" and "curcumin and clinical trials" were considered for data mining. A total of 148 references were found to be relevant for the key term "turmeric and clinical trials", of which 70 were common in both PubMed and Scopus, 44 were unique to PubMed, and 34 were unique to Scopus. Similarly, for the search term "curcumin and clinical trials", 440 references were found to be relevant, of which 70 were unique to PubMed, 110 were unique to Scopus, and 260 were common to both databases. These studies show that the golden spice has enormous health and medicinal benefits for humans. This Review will extract and summarize the lessons learned about turmeric and curcumin in the prevention and treatment of chronic diseases based on clinical trials.

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.

Curcumin Supplementation and Human Disease: A Scoping Review of Clinical Trials

Medicinal properties of turmeric (Curcuma longa L.), a plant used for centuries as an anti-inflammatory, are attributed to its polyphenolic curcuminoids, where curcumin predominates. Although "curcumin" supplements are a top-selling botanical with promising pre-clinical effects, questions remain regarding biological activity in humans. To address this, a scoping review was conducted to assess human clinical trials reporting oral curcumin effects on disease outcomes. Eight databases were searched using established guidelines, yielding 389 citations (from 9528 initial) that met inclusion criteria. Half focused on obesity-associated metabolic disorders (29%) or musculoskeletal disorders (17%), where inflammation is a key driver, and beneficial effects on clinical outcomes and/or biomarkers were reported for most citations (75%) in studies that were primarily double-blind, randomized, and placebo-controlled trials (77%, D-RCT). Citations for the next most studied disease categories (neurocognitive [11%] or gastrointestinal disorders [10%], or cancer [9%]), were far fewer in number and yielded mixed results depending on study quality and condition studied. Although additional research is needed, including systematic evaluation of diverse curcumin formulations and doses in larger D-RCT studies, the preponderance of current evidence for several highly studied diseases (e.g., metabolic syndrome, osteoarthritis), which are also clinically common, are suggestive of clinical benefits.

Analgesic effect of curcumin topical formulation in knee osteoarthritis patients: a clinical trial

OBJECTIVES

The aim of this study was to recognize the efficacy and safety of curcumin ointment on patients with knee osteoarthritis (OA) compare to diclofenac as standard medication.

METHODS

The topical effects of curcumin (10%) and diclofenac (1%) ointments were assessed through the visual analog scale (VAS) and Western Ontario and McMaster Universities Arthritis (WOMAC) index after three times a day administration for two weeks in 60 patients.

RESULTS

Desirable effects compared to the pre-treatment period were observed after two weeks of continuous treatment. Based on our results, VAS and WOMAC index were altered after treatment significantly (p<0.0001).

CONCLUSIONS

Two-week use of curcumin ointment could ameliorate the pain, stiffness and function disability in patients with OA.

The effects of antioxidants on knee osteoarthritis: A systematic review and meta-analysis

Objective

Knee osteoarthritis (KOA) is one of the growing health problems with a considerable burden. With recent research on the possible effectiveness of antioxidants in the remission of KOA symptoms, a systematic review and meta-analysis was required to confirm this hypothesis.

Design

Literature studies were searched on the most comprehensive databases such as PubMed, International Scientific Indexing, and Scopus, with no language and time restrictions. On 17 July 2021, a search strategy was developed based on the roots of "osteoarthritis (OA)" and "antioxidants," with no time or language limitations. As the primary outcome, pain was evaluated based on all indicators for evaluating pain [e.g., Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scores, the visual analog scale (VAS), and the numerical rating scale (NRS)]. The symptoms and functions of KOA and quality of life (QOL) were also considered as secondary outcomes, each of which was measured and reported by the corresponding instrument in the studies. To measure the changes in pain, symptoms, and functions of participants, we included randomized controlled trials with a placebo control or other medical therapeutic interventions. Publication bias was assessed using Begg's funnel plot and Egger's regression test, which was deemed to be statistically significant at 0.1, and the results were checked by the trim-and-fill test.

Results

After refinement, data were extracted from 31 documents from 7,698 primary searched papers. Using the VAS as a reliable psychometric measuring instrument, the present study revealed that a significant difference in the characteristics of disease-related symptoms of patients with KOA was reached after antioxidant therapy (standardized mean difference (SMD): 0.467, 95% confidence interval (CI): 0.303-0.632, p < 0.0001). The results reported by WOMAC confirmed no significant difference in the combined score, difficulty score, pain score, and stiffness score.

Conclusion

As the first comprehensive systematic review of the association between antioxidant supplementation and KOA, this study showed that antioxidants can decrease disease-related symptoms in patients with KOA. The results can be useful for health policy decisions and future related studies.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022351060, identifier: CRD42022351060.

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.

Efficacy and Safety of Curcumin and Curcuma longa Extract in the Treatment of Arthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trial

Background

Modern pharmacological research found that the chemical components of Curcuma longa L. are mainly curcumin and turmeric volatile oil. Several recent randomized controlled trials (RCT) have shown that curcumin improves symptoms and inflammation in patients with arthritis.

Methods

Pubmed, Cochran Library, CNKI, and other databases were searched to collect the randomized controlled trials (RCTs). Then, the risk of bias of RCTs were assessed and data of RCTs were extracted. Finally, RevMan 5.3 was utilized for meta-analysis.

Results

Twenty-nine (29) RCTs involving 2396 participants and 5 types of arthritis were included. The arthritis included Ankylosing Spondylitis (AS), Rheumatoid Arthritis (RA), Osteoarthritis (OA), Juvenile idiopathic arthritis (JIA) and gout/hyperuricemia. Curcumin and Curcuma longa Extract were administered in doses ranging from 120 mg to 1500 mg for a duration of 4-36 weeks. In general, Curcumin and Curcuma longa Extract showed safety in all studies and improved the severity of inflammation and pain levels in these arthritis patients. However, more RCTs are needed in the future to elucidate the effect of Curcumin and Curcuma longa Extract supplementation in patients with arthritis, including RA, OA, AS and JIA.

Conclusion

Curcumin and Curcuma longa Extract may improve symptoms and inflammation levels in people with arthritis. However, due to the low quality and small quantity of RCTs, the conclusions need to be interpreted carefully.

Cepharanthine Ameliorates Chondrocytic Inflammation and Osteoarthritis via Regulating the MAPK/NF-κB-Autophagy Pathway

Osteoarthritis is a worldwide joint disease caused by abnormal chondrocytic metabolism. However, traditional therapeutic methods aimed at anti-inflammation for early-stage disease are palliative. In the present study, we demonstrated that cepharanthine (CEP), extracted from the plant Stephania cepharantha, exerted protective medicinal efficacy on osteoarthritis for the first time. In our in vitro study, CEP suppressed the elevated expression of matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and inducible nitric oxide synthase (iNOS) stimulated by IL-1β or TNF-α by inhibiting the activation of MAPK and NF-κB signaling pathways, and upregulated the protein expression of aggrecan, collagen II, and Sox9. Also, CEP could reverse the reduced level of cellular autophagy in IL-1β or TNF-α–induced chondrocytes, indicating that the protective effect of CEP on osteoarthritis was achieved by restoring MAPK/NF-κB-mediated autophagy. Furthermore, in a murine OA model, CEP mitigated cartilage degradation and prevented osteoarthritis in the CEP-treated groups versus the OA group. Hence, our results revealed the therapeutic prospect of CEP for anti-osteoarthritic treatment.

Efficacy and Safety of Chinese Herbal Medicine for Knee Osteoarthritis: Systematic Review and Meta-analysis of Randomized Controlled Trials

PURPOSE

This study aims to evaluate the effectiveness and safety of oral Chinese herbal medicine (CHM) in the treatment of knee osteoarthritis (KOA).

STUDY DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

MATERIALS AND METHODS

A computer was used to retrieve all RCTs of CHM in the treatment of KOA from 7 databases (PubMed; Embase; Cochrane Central Register of Controlled Trials; China National Knowledge Infrastructure; Chinese VIP Information Database; Chinese Biomedical Database and Wanfang Med Database) from the establishment to August 2021. The literature was organized using NoteExpress, and literature screening and data extraction were conducted by two researchers independently by the inclusion and exclusion criteria. Quality evaluation was performed using GRADE, and the meta-analysis was performed using RevMan5.4.

RESULTS

A total of 31 RCTs and 3115 cases are included. The following meta-analysis results are observed: (1) WOMAC: CHM vs. placebo (SMD = -0.87, 95% CI: -1.27 to -0.47, P < 0.0001), CHM vs. Western medicine (SMD = -1.64, 95% CI: -2.09 to -1.19, P < 0.00001), and CHM + Western medicine vs. Western medicine (SMD = -2.17, 95% CI: -3.01 to -1.33, P < 0.00001); (2) VAS: CHM vs. Western medicine (SMD = -1.02, 95% CI: -1.63 to -0.41, P < 0.00001) and CHM + Western medicine vs. Western medicine (SMD = -2.68, 95% CI: -4.36 to -1.00, P < 0.00001); (3) Lequesne severity index: CHM vs. Western medicine (SMD = -0.90, 95% CI: -1.40 to -0.39, P = 0.0005) and CHM + Western medicine vs. Western medicine (SMD = -0.94, 95% CI: -1.36 to -0.52, P < 0.0001); (4) Lysholm knee joint function score: CHM vs. Western medicine (MD = 9.10, 95% CI: 4.20 to 14.01, P = 0.0003), and CHM + Western medicine vs. Western medicine in a single trial (MD = 21.15, 95% CI: 19.71 to 22.59, P < 0.00001); (5) SOD: in a single trial, CHM vs. Western medicine (MD = 1.62, 95% CI: 0.9 to 2.30, P < 0.00001) and CHM + Western medicine vs. Western medicine (MD = 17.08, 95% CI: 10.71 to 23.44, P < 0.00001); (6) TNF-α: CHM vs. Western medicine (SMD = -1.90, 95% CI: -2.04 to -0.14, P = 0.02) and CHM + Western medicine vs. Western medicine (SMD = -2.32, 95% CI: -4.33 to -0.30, P = 0.02); (7) IL-1β: CHM vs. Western medicine (SMD = -1.60, 95% CI: -2.36 to -0.84, P < 0.0001); and (8) IL-6: in a single trial, CHM vs. Western medicine (MD = -0.75, 95% CI: -1.20 to -0.30, P = 0.001) and CHM + Western medicine vs. Western medicine (MD = -3.18, 95% CI: -6.24 to -0.12, P = 0.04).

CONCLUSION

The efficacy of CHM in the treatment of KOA is superior to those of placebo and Western medicine. At the same time, the combination of CHM + Western medicine is superior to Western medicine alone in the treatment of KOA. However, due to the existence of certain biases in the included studies, and the need for further study on the effective components of Chinese medicine, a positive conclusion on the efficacy of traditional CHM in the treatment of KOA cannot be drawn and needs to be confirmed by high-quality clinical RCTs.

Curcumin: Useful add-on for Rheumatic Diseases?

Plant-derived nutraceuticals are proposed as new key instruments to represent a profound “back to basics” shift in medical treatment. Data accumulated over the past ten years suggest that curcumin, the major active compound of the turmeric plant, has anti-inflammatory properties. It has yet to be determined whether the anti-inflammatory profile of curcumin is potent enough to justify the application of this substance as a nutritional supplement for patients with rheumatic diseases. To address this question, the most relevant in vitro studies that investigate the mechanism of action of curcumin were reviewed in this article. In addition, a total of 18 animal and human trials were evaluated. The pleiotropic, anti-inflammatory and immunomodulatory effects of curcumin were observed in animal studies. In addition, human trials demonstrated promising findings. In these studies, curcumin was able to reduce the expression of proinflammatory cytokines, lower the level of the C-reactive protein and improve clinical parameters. A limiting factor of the application of curcumin is the inconsistent bioavailability of the substance. Therefore, new formulations have been developed to improve the pharmacodynamic profile of curcumin. The future acceptance of the substance is dependent on new controlled clinical trials with a standardised formulation of curcumin administered as well as standard of care.

The cardioprotective effects of nano-curcumin against doxorubicin-induced cardiotoxicity: A systematic review

Although the chemotherapeutic drug, doxorubicin, is commonly used to treat various malignant tumors, its clinical use is restricted because of its toxicity especially cardiotoxicity. The use of curcumin may alleviate some of the doxorubicin-induced cardiotoxic effects. Especially, using the nano-formulation of curcumin can overcome the poor bioavailability of curcumin and enhance its physicochemical properties regarding its efficacy. In this study, we systematically reviewed the potential cardioprotective effects of nano-curcumin against the doxorubicin-induced cardiotoxicity. A systematic search was accomplished based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for the identification of all relevant articles on "the role of nano-curcumin on doxorubicin-induced cardiotoxicity" in the electronic databases of Scopus, PubMed, and Web of Science up to July 2021. One hundred and sixty-nine articles were screened following a predefined set of inclusion and exclusion criteria. Ten eligible scientific papers were finally included in the present systematic review. The administration of doxorubicin reduced the body and heart weights of mice/rats compared to the control groups. In contrast, the combined treatment of doxorubicin and nano-curcumin increased the body and heart weights of animals compared with the doxorubicin-treated groups alone. Furthermore, doxorubicin could significantly induce the biochemical and histological changes in the cardiac tissue; however, coadministration of nano-curcumin formulation demonstrated a pattern opposite to the doxorubicin-induced changes. The coadministration of nano-curcumin alleviates the doxorubicin-induced cardiotoxicity through various mechanisms including antioxidant, anti-inflammatory, and antiapoptotic effects. Also, the cardioprotective effect of nano-curcumin formulation against doxorubicin-induced cardiotoxicity was higher than free curcumin.

A Meta-Analysis of the Impact of Nutritional Supplementation on Osteoarthritis Symptoms

Conflicting evidence exists concerning the effects of nutrient intake in osteoarthritis (OA). A systematic literature review and meta-analysis were performed using PubMed, EMBASE, and Cochrane Library up to November 2021 to assess the effects of nutrients on pain, stiffness, function, quality of life, and inflammation markers. We obtained 52 references including 50 on knee OA. Twelve studies compared 724 curcumin patients and 714 controls. Using the standardized mean difference, improvement was significant with regard to pain and function in the curcumin group compared to placebo, but not with active treatment (i.e., nonsteroidal anti-inflammatory drugs, chondroitin, or paracetamol). Three studies assessed the effects of ginger on OA symptoms in 166 patients compared to 164 placebo controls. Pain was the only clinical parameter that significantly decreased. Vitamin D supplementation caused a significant decrease in pain and function. Omega-3 and vitamin E caused no changes in OA parameters. Herbal formulations effects were significant only for stiffness compared to placebo, but not with active treatment. A significant decrease in inflammatory markers was found, especially with ginger. Thus, curcumin and ginger supplementation can have a favorable impact on knee OA symptoms. Other studies are needed to better assess the effects of omega-3 and vitamin D.

The Oral Administration of Highly-Bioavailable Curcumin for One Year Has Clinical and Chondro-Protective Effects: A Randomized, Double-Blinded, Placebo-Controlled Prospective Study

Purpose

The purpose of this study was to determine the clinical and chondroprotective efficacy and safety of orally administered Theracurmin in patients who underwent mosaicplasty for knee chondral or osteochondral diseases over 12 months of treatment.

Methods

We enrolled 50 patients, older than 20 years of age, who underwent mosaicplasty for their knee joint diseases. Theracurmin at 180 mg of curcumin per day or placebo was administered orally every day for 12 months. Because 7 patients dropped out of the study, 43 patients were examined; they included 14 men and 29 women and 24 right and 19 left knees. The mean operative age was 59.5 years (range, 24-84 years). We evaluated the Japanese Orthopaedic Association knee osteoarthritis score (JOA), visual analog scale (VAS), and Japanese Knee Osteoarthritis Measure (JKOM) as clinical symptoms; T2 mapping values using magnetic resonance imaging as an indication of the chondroprotective effect; and blood concentration of curcumin at 0, 3, 6, and 12 months after the operations. We performed intraoperative acoustic evaluation of articular cartilage as a measure of chondroprotective effect during the operations and second-look arthroscopy.

Results

The JOA, VAS and JKOM at 3, 6, and 12 months were significantly better than those during the preoperative period. However, the values of JOA, VAS and JKOM and T2 mapping were not significantly different between the Theracurmin and placebo groups. The blood concentration of curcumin in the Theracurmin group was significantly higher than that in the placebo group at 3, 6, and 12 months after the operations. Cartilage stiffness and surface roughness were significantly better in the Theracurmin group than in the placebo group at second-look arthroscopy.

Conclusions

The oral administration of Theracurmin for 1 year demonstrated significantly better chondroprotective effects and no worse clinical effects and adverse events than the placebo.

Level of Evidence

Level I, double-blinded, placebo-controlled, prospective study.

In Vitro and In Vivo Cardioprotective Effects of Curcumin against Doxorubicin-Induced Cardiotoxicity: A Systematic Review

Objective

This study aimed to review the potential chemoprotective effects of curcumin against the doxorubicin-induced cardiotoxicity.

Methods

According to the PRISMA guideline, a comprehensive systematic search was performed in different electronic databases (Web of Science, PubMed, and Scopus) up to July 2021. One hundred and sixty-four studies were screened in accordance with a predefined set of inclusion and exclusion criteria. Eighteen eligible articles were finally included in the current systematic review.

Results

According to the in vitro and in vivo findings, it was found that doxorubicin administration leads to decreased cell survival, increased mortality, decreased bodyweight, heart weight, and heart to the bodyweight ratio compared to the control groups. However, curcumin cotreatment demonstrated an opposite pattern in comparison with the doxorubicin-treated groups alone. Other findings showed that doxorubicin significantly induces biochemical changes in the cardiac cells/tissue. Furthermore, the histological changes on the cardiac tissue were observed following doxorubicin treatment. Nevertheless, for most of the cases, these biochemical and histological changes mediated by doxorubicin were reversed near to control groups following curcumin coadministration.

Conclusion

It can be mentioned that coadministration of curcumin alleviates the doxorubicin-induced cardiotoxicity. Curcumin exerts these cardioprotective effects through different mechanisms of antioxidant, antiapoptosis, and anti-inflammatory. Since the finding presented in this systematic review are based on in vitro and in vivo studies, suggesting the use of curcumin in cancer patients as a cardioprotector agent against cardiotoxicity mediated by doxorubicin requires further clinical studies.

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.

Effects of Polyphenols on Oxidative Stress, Inflammation, and Interconnected Pathways during Spinal Cord Injury

Despite the progression in targeting the complex pathophysiological mechanisms of neurodegenerative diseases (NDDs) and spinal cord injury (SCI), there is a lack of effective treatments. Moreover, conventional therapies suffer from associated side effects and low efficacy, raising the need for finding potential alternative therapies. In this regard, a comprehensive review was done regarding revealing the main neurological dysregulated pathways and providing alternative therapeutic agents following SCI. From the mechanistic point, oxidative stress and inflammatory pathways are major upstream orchestras of cross-linked dysregulated pathways (e.g., apoptosis, autophagy, and extrinsic mechanisms) following SCI. It urges the need for developing multitarget therapies against SCI complications. Polyphenols, as plant-derived secondary metabolites, have the potential of being introduced as alternative therapeutic agents to pave the way for treating SCI. Such secondary metabolites presented modulatory effects on neuronal oxidative stress, neuroinflammatory, and extrinsic axonal dysregulated pathways in the onset and progression of SCI. In the present review, the potential role of phenolic compounds as critical phytochemicals has also been revealed in regulating upstream dysregulated oxidative stress/inflammatory signaling mediators and extrinsic mechanisms of axonal regeneration after SCI in preclinical and clinical studies. Additionally, the coadministration of polyphenols and stem cells has shown a promising strategy for improving post-SCI complications.

Phytochemicals Mediate Autophagy Against Osteoarthritis by Maintaining Cartilage Homeostasis

Osteoarthritis (OA) is a common degenerative joint disease and is a leading cause of disability and reduced quality of life worldwide. There are currently no clinical treatments that can stop or slow down OA. Drugs have pain-relieving effects, but they do not slow down the course of OA and their long-term use can lead to serious side effects. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Autophagy is an intracellular protective mechanism, and targeting autophagy-related pathways has been found to prevent and treat various diseases. Attenuation of the autophagic pathway has now been found to disrupt cartilage homeostasis and plays an important role in the development of OA. Therefore, modulation of autophagic signaling pathways mediating cartilage homeostasis has been considered as a potential therapeutic option for OA. Phytochemicals are active ingredients from plants that have recently been found to reduce inflammatory factor levels in cartilage as well as attenuate chondrocyte apoptosis by modulating autophagy-related signaling pathways, which are not only widely available but also have the potential to alleviate the symptoms of OA. We reviewed preclinical studies and clinical studies of phytochemicals mediating autophagy to regulate cartilage homeostasis for the treatment of OA. The results suggest that phytochemicals derived from plant extracts can target relevant autophagic pathways as complementary and alternative agents for the treatment of OA if subjected to rigorous clinical trials and pharmacological tests.

In patients with osteoarthritis, is curcumin, compared to placebo, effective in reducing pain?

CLINICAL QUESTION

In patients with osteoarthritis, is curcumin, compared to placebo, effective in reducing pain?

ANSWER

Yes. Studies have shown that curcumin extract has benefit in treating osteoarthritic pain, compared to placebo. It is reasonable to use curcumin in addition to traditional osteoarthritis treatments, as studies show it has a low side effect profile. However, a greater number of studies as well as larger studies are needed to definitively recommend curcumin, especially as a replacement for more traditional therapies.

LEVEL OF EVIDENCE OF THE ANSWER

B.

Ingredients of a Natural Oral Nutritional Supplement and Their Role in the Treatment of Osteoarthritis

Osteoarthritis is a prevalent degenerative disease affecting a large portion of the world’s aging population. Currently, nonsteroidal anti-inflammatory drugs and acetaminophen are first-line medications for treating osteoarthritis patients’ pain. However, several studies have noted that while these medications control pain they do not halt progressive degeneration and tend to have an unfavorable side-effect profile with prolonged use. Recently, due to their more favorable side-effect profiles, herbal alternatives for controlling osteoarthritis symptoms and for alleviating the progression of the disease are being increasingly studied. Synogesic is a newly developed herbal supplement blend by renowned orthopedic surgeons and physiatrists consisting of turmeric, rutin, ginger root, vitamin C, vitamin D, and boswellia extracts. A study by Sharkey et al. has commented on the efficacy of the blend on the patients with knee osteoarthritis. So far, a review on the ingredients of the blend has not yet carried outbeen. By exploring prominent literature databases including PubMed and ScienceDirect, our aim is to write a narrative review to explore the individual ingredients of this blend and delve into their characteristics, as well as the most recent literature on their mechanism and efficacy in patients with osteoarthritis. Through this, we hope to inform clinicians and patients alike on relevant up-to-date research on the supplement and provide insight on the potential for this supplement for alleviating the disease course of patients with osteoarthritis.

Intra-Articular Injections of Curcumin Monoglucuronide TBP1901 Suppresses Articular Cartilage Damage and Regulates Subchondral Bone Alteration in an Osteoarthritis Rat Model

OBJECTIVE

Curcumin monoglucuronide (TBP1901) is highly water soluble and can convert to free form curcumin, which has pharmacological effects, on intravenous administration. This study aimed to investigate the effectiveness of TBP1901 intra-articular injections in an osteoarthritis (OA) rat model.

METHODS

Sixty-four male Wistar rats (12 weeks old) who underwent destabilized medial meniscus (DMM) surgery were randomly separated into the TBP1901 injection or saline solution (control) injection group. They were sacrificed at 1, 2, 6, or 10 weeks postoperatively (weeks 1, 2, 6, and 10; n = 8 for each group). TBP1901 (30 mg/mL) or saline solution of 50 μL was injected into the knee joints twice a week during weeks 1 and 2 to investigate the effects in the acute phase of posttraumatic (PT) OA or once a week during weeks 6 and 10 to investigate it in the chronic phase of PTOA. Histology, immunohistochemistry, and micro-computed tomography were performed to evaluate the changes in OA.

RESULTS

TBP1901 injections significantly reduced synovial inflammation at weeks 1 and 2, and tumor necrosis factor-α expression in the articular cartilage at week 6. The TBP1901 injections also significantly suppressed articular cartilage damage, subchondral bone (SB) plate thickening, SB plate perforation, and osteophyte formation at week 10.

CONCLUSIONS

TBP1901 intra-articular injections suppressed synovial inflammation in the acute phase of PTOA in DMM rats. In the chronic phase, TBP1901 suppresses articular cartilage damage and regulates SB plate changes.

Hemp Seeds in Post-Arthroplasty Rehabilitation: A Pilot Clinical Study and an In Vitro Investigation

Osteoarthritis is a type of degenerative joint disease that results from the breakdown of joint cartilage and underlying bone. Due to their antioxidants and anti-inflammatory action, the phytochemical constituents of many vegetable varieties could represent a new frontier for the treatment of patients with Osteoarthritis and are still being explored. The aim of this pilot human study was to investigate the effects of pasta enriched with hemp seed flour on osteoarticular pain and bone formation markers in patients in post-arthroplasty rehabilitation. Another purpose was to evaluate the effect of hemp seed extract on bone metabolism, in vitro. A pilot, controlled, clinical study was conducted to verify the feasibility of pain symptom reduction in patients with Osteoarthritis undergoing arthroplasty surgery. We also investigated the effect of hemp seed extract on the Wnt/β-catenin and ERK1/2 pathways, alkaline phosphatase, RANKL, RUNX-2, osteocalcin, and COL1A on Saos-2. After 6 weeks, the consumption of hemp seed pasta led to greater pain relief compared to the regular pasta control group (−2.9 ± 1.3 cm vs. −1.3 ± 1.3 cm; p = 0.02). A significant reduction in serum BALP was observed in the participants consuming the hemp seed pasta compared to control group (−2.8 ± 3.2 µg/L vs. 1.1 ± 4.3 µg/L; p = 0.04). In the Saos-2 cell line, hemp seed extract also upregulated Wnt/β-catenin and Erk1/2 pathways (p = 0.02 and p = 0.03) and osteoblast differentiation markers (e.g., ALP, OC, RUNX2, and COL1A) and downregulated RANKL (p = 0.02), compared to the control. Our study demonstrated that hemp seed can improve pain symptoms in patients with osteoarthritis undergoing arthroplasty surgery and also improves bone metabolism both in humans and in vitro. However, more clinical studies are needed to confirm our preliminary 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.

Non-drug pain relievers active on non-opioid pain mechanisms

This review is aimed to summarize the pain-relieving effect of non-drug substances, mostly prescribed as integrators in treatment of pain, including especially in chronic postoperative pain (CPSP) and in chronic back pain after acute episodes. Their use reflects the fact that the current treatments for these syndromes continue to pose problems of unsatisfactory responses in a significant portion of patients and/or of an excess of side effects like those noted in the present opioid crisis. As integrators are frequently introduced into the market without adequate clinical testing, this review is aimed to collect the present scientific evidence either preclinical or clinical for their effectiveness. In particular, we reviewed the data on the use of: B vitamins; vitamin C; vitamin D; alpha lipoic acid (ALA); N-acetylcysteine; acetyl L-carnitine; curcumin; boswellia serrata; magnesium; coenzyme Q10, and palmitoylethanolamide. The combination of preclinical findings and clinical observations strongly indicate that these compounds deserve more careful attention, some of them having interesting clinical potentials also in preventing chronic pain after an acute episode. In particular, examining their putative mechanisms of action it emerges that combinations of few of them may exert an extraordinary spectrum of activities on a large variety of pain-associated pathways and may be eventually used in combination with more traditional pain killers in order to extend the duration of the effect and to lower the doses. Convincing examples of effective combinations against pain are vitamin B complex plus gabapentin for CPSP, including neuropathic pain; vitamin B complex plus diclofenac against low back pain and also in association with gabapentin, and ALA for burning mouth syndrome. These as well as other examples need, however, careful controlled independent clinical studies confirming their role in therapy.

Current clinical developments in curcumin-based therapeutics for cancer and chronic diseases

The last decade has seen an unprecedented rise in the prevalence of chronic diseases worldwide. Different mono-targeted approaches have been devised to treat these multigenic diseases, still most of them suffer from limited success due to the off-target debilitating side effects and their inability to target multiple pathways. Hence a safe, efficacious, and multi-targeted approach is the need for the hour to circumvent these challenging chronic diseases. Curcumin, a natural compound extracted from the rhizomes of Curcuma longa, has been under intense scrutiny for its wide medicinal and biological properties. Curcumin is known to manifest antibacterial, antiinflammatory, antioxidant, antifungal, antineoplastic, antifungal, and proapoptotic effects. A plethora of literature has already established the immense promise of curcuminoids in the treatment and clinical management of various chronic diseases like cancer, cardiovascular, metabolic, neurological, inflammatory, and infectious diseases. To date, more than 230 clinical trials have opened investigations to understand the pharmacological aspects of curcumin in human systems. Still, further randomized clinical studies in different ethnic populations warrant its transition to a marketed drug. This review summarizes the results from different clinical trials of curcumin-based therapeutics in the prevention and treatment of various chronic diseases.

Mechanistic Insight into the Effects of Curcumin on Neuroinflammation-Driven Chronic Pain

Chronic pain is a persistent and unremitting condition that has immense effects on patients' quality of life. Studies have shown that neuroinflammation is associated with the induction and progression of chronic pain. The activation of microglia and astrocytes is the major hallmark of spinal neuroinflammation leading to neuronal excitability in the projection neurons. Excessive activation of microglia and astrocytes is one of the major contributing factors to the exacerbation of pain. However, the current chronic pain treatments, mainly by targeting the neuronal cells, remain ineffective and unable to meet the patients' needs. Curcumin, a natural plant product found in the Curcuma genus, improves chronic pain by diminishing the release of inflammatory mediators from the spinal glia. This review details the role of curcumin in microglia and astrocytes both in vitro and in vivo and how it improves pain. We also describe the mechanism of curcumin by highlighting the major glia-mediated cascades in pain. Moreover, the role of curcumin on inflammasome and epigenetic regulation is discussed. Furthermore, we discuss the strategies used to improve the efficacy of curcumin. This review illustrates that curcumin modulating microglia and astrocytes could assure the treatment of chronic pain by suppressing spinal neuroinflammation.

A review of therapeutic potentials of turmeric (Curcuma longa) and its active constituent, curcumin, on inflammatory disorders, pain, and their related patents

Turmeric (Curcuma longa) and its constituent, curcumin, have been used for their therapeutic properties for a long time. Most of the medicinal impacts of turmeric and curcumin might be attributed to their anti-inflammatory, antinociceptive, and antioxidant effects. In the present review, the preventive and therapeutic potentials of turmeric and its active constituent, curcumin, on inflammatory disorders and pain as well as patents related to their analgesic and anti-inflammatory effects, have been summarized to highlight their value on human health. A literature review was accomplished in Google Scholar, PubMed, Scopus, Google Patent, Patentscope, and US Patent. Several documents and patents disclosed the significance of turmeric and curcumin to apply in several therapeutic, medicinal, and pharmaceutical fields. These phytocompounds could be applied as a supplementary therapy in phytotherapy, inflammatory disorders such as arthritis, inflammatory bowel diseases, osteoarthritis, psoriasis, dermatitis, and different types of pain including neuropathic pain. However, because of inadequate clinical trials, further high-quality studies are needed to firmly establish the clinical efficacy of the plant. Consistent with the human tendency to the usage of phytocompounds rather than synthetic drugs, particular consideration must be dedicated to bond the worth of turmeric and curcumin from basic sciences to clinical applications.

Clinical efficacy of curcumin versus chlorhexidine as an adjunct to scaling and root planing for the treatment of periodontitis: A systematic review and meta-analysis

This study aims to evaluate the clinical efficacy of curcumin versus chlorhexidine as adjuncts to scaling and root planing (SRP) for periodontitis treatment. We searched PubMed, EMbase, Cochrane Library, and ClinicalTrials.gov from inception to February 18, 2021 and identified studies with relevant randomized controlled trials (RCTs) using curcumin or chlorhexidine as an adjunct to SRP. Nine RCTs involving 420 patients/sites were included. A meta-analysis with a random-effects model revealed that curcumin and chlorhexidine, as an adjunct to SRP, reduced probing pocket depth (PPD) at similar levels during a 3-, 4-, 6-, and 12-week follow-up. No significant differences were observed in reducing clinical attachment loss (CAL) between curcumin and chlorhexidine as an adjunct to SRP at 4 weeks and 6 weeks. Furthermore, gingival index (GI) and plaque index (PI) were similar using curcumin versus chlorhexidine as an adjunct to SRP at the 4-week-, 6-week-, and 12-week follow-up. Based on the available evidence in RCTs, compared with chlorhexidine as an adjunct to SRP, curcumin has a similar effect on reducing PPD, CAL, GI, and PI. The quality of evidence is low, limited by the number of studies and their limitations. Further studies are needed to firmly establish the clinical efficacy of curcumin.

Effectiveness of Curcuma longa extract versus placebo for the treatment of knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials

The aim of this systematic review was to evaluate the efficacy and safety of all types of Curcuma longa extract versus placebo for knee osteoarthritis (OA) treatment. The research was conducted by using the databases of PubMed, Embase, Scopus, and Cochrane Library through April 2021. Randomized controlled trials (RCTs) that compared the effect of Curcuma longa extract with placebo for patients with knee OA were considered eligible. The pooled results were expressed as mean differences or relative risks with 95% confidence intervals. A total of 10 RCTs with 783 patients were eligible for this meta-analysis. The pooled analysis showed that Curcuma longa extract was associated with significantly better pain relief and functional improvement compared with placebo for knee OA. Moreover, the smallest effect sizes of VAS for pain and WOMAC total score exceeded the minimum clinically important differences (MCIDs). Current evidence indicates that, compared with placebo, Curcuma longa extract has more benefit in pain relief and functional improvement for symptomatic knee OA. However, considering the potential heterogeneity in the included studies, more future high-quality RCTs with large sample sizes are necessary to confirm the benefits of Curcuma longa extract on knee OA.

The efficacy and safety of Curcuma longa extract and curcumin supplements on osteoarthritis: a systematic review and meta-analysis

Objective: To assess the efficacy and safety of Curcuma longa extract and curcumin supplements on osteoarthritis (OA).

Methods: The databases such as Pubmed and Cochrane Library were searched to collect the article about Curcuma longa extract and curcumin in the treatment of OA. Then, randomized controlled trials (RCTs) were selected and their data were extracted. Finally, the RevMan5.3 was utilized for risk of bias assessment and meta-analysis, the STATA15.0 were utilized for publication bias assessment, and GRADE tool were used for the evidence quality assessment of primary outcomes.

Results: A total of 15 RCTs involving 1621 participants were included. (1) Compared with placebo, Curcuma longa extract and curcumin (C.) can decrease the visual analog scale (VAS) and The Western Ontario and McMaster Universities (WOMAC) score-pain, the WOMAC score-function and the WOMAC score-stiffness. In terms of adverse events, Curcuma longa extract and curcumin are comparable with those of placebo. (2) Compared with non-steroidal anti-inflammatory drugs (NSAIDs), Curcuma longa extract and curcumin have similar effects on joint pain, function and stiffness. The incidence of adverse events in Curcuma longa extract and curcumin was lower. (3) Compared with the NSAIDs group, C.+NSAIDs can also decrease the VAS and WOMAC score-pain, the WOMAC score-function and the WOMAC score-stiffness. In terms of adverse events, the addition of Curcuma longa extract and curcumin to NSAIDs did not increase adverse events.

Conclusion:Curcuma longa extract and curcumin may be a safer and effective supplement for OA patients. It is recommended to use Curcuma longa extract and curcumin supplement for OA patients for more than 12 weeks.

Prospective, Multicenter Evaluation of a Polyherbal Supplement alongside Standard-of-Care Treatment for Mild Knee Osteoarthritis

BACKGROUND

This study aimed to provide clinical information on general and joint performance from individuals taking Tregocel® (containing curcuminoid and extracts of the herbs Harpagophytum procumbens, Boswellia serrata, Apium graveolens, and Zingiber officinale) alongside a standard therapy of symptomatic mild knee osteoarthritis (OA).

METHODS

This was a multicenter, open-label, prospective, single-arm study, in which Tregocel® was supplemented for 36 weeks. Participants with symptomatic mild knee OA requiring pharmacologic treatment for pain were enrolled. Physical performance (6-minute walk test, WOMAC-pain and functional domain, and heel-thigh distance flexion test), general performance (WOMAC questionnaire), and VAS (Visual Analogue Scale) assessment of knee pain, as well as anti-inflammatory and analgesic medication consumption, were assessed.

RESULTS

Between January and April 2019, 107 participants were enrolled and analysed in per protocol population. Mean age was 59.7 (SD 10.8) years, and there were 68.2% women. Mean observation time was 291.1 (SD 7.7) days. Mean increase in 6MWT result observed at the end of the study was 26.0 (SD 30.4) m (p < 0.001). Median VAS score decreased from 60.0 (IQR 50-72) mm at the beginning of the study to 21.0 (IQR 14-30) mm after 36 weeks of product administration (p < 0.001). Regular knee OA medications were taken in 99.1% of subjects at baseline decreasing to 55.1% at the end of the Tregocel® supplementation.

CONCLUSIONS

During Tregocel® supplementation, participants observed improved functional capacity confirmed in the distance in 6MWT and in the heel-thigh distance flexion test, decreased level of pain, and improved WOMAC scores for all domains.

Zein Nanoparticles Improve the Oral Bioavailability of Curcumin in Wistar Rats

Curcumin is a natural compound obtained from turmeric root with high antioxidant and anti-inflammatory activities. However, clinical application of curcumin has been limited due to its low solubility and bioavailability and rapid metabolism and degradation. This study was conducted to evaluate the effect of curcumin incorporation in zein nanoparticles on the pharmacokinetic parameters of systemic curcumin in plasma. Wistar rats were administered a single oral dose of 250 mg/kg of standard curcumin (control) or nanocurcumin (zein-based nanoparticles, Nucaps). The proposed new formulation was also compared with two commercially available curcumin complexes. Blood samples were collected at different times, and plasma levels were determined using HPLC-MS/MS. Overall, nanocurcumin (Nucaps) formulation was well tolerated and showed a 9-fold increase in oral bioavailability when compared to the standard curcumin natural extract. In addition, the nanoparticles prepared in this study demonstrated a bioavailability profile superior to that of other bioavailability-enhanced curcumin complexes currently available in the marketplace. Thus, our nanoparticle-based formulation has shown great potential as a nutraceutical for the oral administration of curcumin.

The Effect of Nanocurcumin in Improvement of Knee Osteoarthritis: A Randomized Clinical Trial

OBJECTIVE

Osteoarthritis is a degenerative disease of the joints. Non-steroidal antiinflammatory drugs (NSAIDs) are being used for the treatment of osteoarthritis. However, their use is limited due to complications, such as gastrointestinal bleeding. Therefore, it is necessary to find alternative treatments for osteoarthritis. Recently, nanomicelle curcumin has been developed to increase the oral bioavailability of curcumin. The aim of this study was to evaluate the effect of nano curcumin on the alleviation of the symptoms of knee osteoarthritis patients.

METHODS

In this randomized, double-blind controlled trial, the intervention group was administered 40 mg of nanocurcumin capsule every 12 hours over a period of six weeks, and the control group received the placebo (similar components of nanomicelle curcumin capsules yet without curcumin). In the final analysis, 36 patients in the nanocurcumin group and 35 patients in the placebo group were enrolled. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was filled for patients in their first visit and at the end of six weeks. Differences were statistically significant at P-value < 0.05.

RESULTS

There were no significant differences between the two groups regarding gender, age, Kellgren score, and the duration of the disease before the intervention. A significant decrease was observed in the overall score, along with the scores of pain, stiffness and physical activity subscales of the WOMAC questionnaire in patients of the nano curcumin group compared with the placebo group.

CONCLUSION

Nanocurcumin significantly improves the symptoms of osteoarthritis patients.

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

PURPOSE OF THE REVIEW

Finding appropriate pharmacological options to treat osteoarthritis (OA) remain challenging. We aimed to determine the efficacy and safety of all types of turmeric extracts for the management of knee OA.

RECENT FINDINGS

Sixteen RCTs of up to 16 weeks duration including 1810 adults with knee OA were included. Eleven RCTs compared the efficacy of turmeric extracts with placebo and five with active comparators (NSAIDs). The overall risk bias of included RCTs was moderate. Turmeric extracts significantly reduced knee pain (SMD - 0.82, 95% CI - 1.17 to - 0.47, I² = 86.23%) and improved physical function (SMD - 0.75, 95% CI - 1.18 to - 0.33, I² = 90.05%) compared to placebo but had similar effects compared to NSAIDs. BMI was the major contributor to heterogeneity in the placebo-controlled studies (explained 37.68% and 67.24%, respectively, in the models) and modified the effects of the turmeric on pain and physical function with less improvement with higher BMI (SMD 0.26 95% CI 0.04 to 0.48; SMD 0.48 95% CI 0.21 to 0.74). No significant between-group differences were reported for either biochemical markers or imaging outcomes. Turmeric extracts had 12% fewer adverse events than NSAIDs and similar rates to placebo. Turmeric extract is a safe and effective option for the symptomatic management of knee OA, compared to placebo or NSAIDs. However, current evidence from short-term studies is heterogeneous and has moderate risk of bias leading to some uncertainty about the true effect.

Curcumin ameliorates IL-1β-induced apoptosis by activating autophagy and inhibiting the NF-κB signaling pathway in rat primary articular chondrocytes

Articular cartilage damage and chondrocyte apoptosis are common features of rheumatoid arthritis and osteoarthritis. Recently, curcumin has been reported to exhibit protective effects on degeneration in articular cartilage diseases. However, the effects and mechanisms of curcumin on articular chondrocyte injury remain to be elucidated. The aim of the present study is to investigate the chondroprotective mechanisms of curcumin on interleukin-1β (IL-1β)-induced chondrocyte apoptosis in vitro. The results revealed that IL-1β decreased cell viability and induced apoptosis in primary articular chondrocytes. Curcumin pretreatment reduced IL-1β-induced articular chondrocyte apoptosis. In addition, treatment with curcumin increased autophagy in articular chondrocytes and protected against IL-1β-induced apoptosis. The curcumin-mediated protection against IL-1β induced apoptosis was abolished when cells were treated with the autophagy inhibitor 3-methyladenine or transfected with Beclin-1 small interfering RNA. Furthermore, IL-1β stimulation significantly increased the phosphorylation levels of nuclear factor (NF)-κB p65 and glycogen synthase kinase-3β, and decreased the phosphorylation levels of β-catenin in articular chondrocytes, and these alterations to the phosphorylation levels were partly reversed by treatment with curcumin. Dual-luciferase and electrophoretic mobility shift assays demonstrated that IL-1β increased NF-κB p65 promoter activity in chondrocytes, and this was also reversed by curcumin. Pretreatment with the NF-κB inhibitor pyrrolidine dithiocarbamate enhanced the protective effects of curcumin on chondrocyte apoptosis, but Wnt/β-catenin inhibitor, XAV-939, did not exhibit this effect. Molecular docking and dynamic simulation studies results showed that curcumin could bound to RelA (p65) protein. These results indicate that curcumin may suppress IL-1β-induced chondrocyte apoptosis through activating autophagy and restraining NF-κB signaling pathway.

Miconia albicans and Curcuma longa herbal medicines positively modulate joint pain, function and inflammation in patients with osteoarthritis: a clinical study

This study aims to evaluate the analgesic and modulating effect of Curcuma longa and Miconia albicans herbal medicines in knee's osteoarthritis (OA) treatment. This longitudinal study evaluated 24 patients with OA. The patients were divided into three groups: ibuprofen (1200 mg/day), C. longa (1000 mg/day) and M. albicans (1000 mg/day). The medications were applied orally for 30 days. The synovial fluid of the knee joint was collect at the first (day 0) and the last medical (day 30) consultation. The groups treated with herbal medicines presented the same results when compared to Ibuprofen. The comparison of the means of Total WOMAC for M. albicans before and after treatment presented a statistically significant difference (mean day 0 = 57.19; mean day 30 = 31.02) as well as variation of Total WOMAC for C. longa (mean day 0 = 54.79; mean day 30 = 37.08). The WOMAC Total and the VASP were compared, it was found that there was a significant decrease in the means in the C. longa and M. albicans groups, as well as in the Ibuprofen group after treatment. The study demonstrated that the treatment of knee OA with C. longa or M. albicans positively interferes with patients pain and functionality, decreased WOMAC and VASP scores, leading to functional improvement of these patients. This is the first clinical study demonstrating the analgesic and anti-inflammatory effect on knee osteoarthritis from M. albicans comparable to Ibuprofen drug.

Therapeutic effects of turmeric or curcumin extract on pain and function for individuals with knee osteoarthritis: a systematic review

Purpose

To determine whether supplementation with turmeric or curcumin extract effects pain and physical function in individuals with knee osteoarthritis (OA). Second, we investigated the therapeutic response (pain and function) of turmeric compared with non-steroidal anti-inflammatory drugs (NSAIDs).

Methods

A search was conducted in MEDLINE, Embase, CINAHL and Cochrane Review. Inclusion criteria included randomised controlled trials reporting pain and physical function in humans with knee OA comparing turmeric therapy with NSAIDs or no therapy. Two reviewers screened 5273 abstracts. Risk of bias and quality were assessed via Cochrane Collaboration tool and CONSORT (Consolidated Standards of Reporting Trials) 2010, respectively.

Results

Ten studies were included in the final analysis. Eight had high methodological quality and two were categorised as good with a mean CONSORT quality score of 21.1. Nine studies had adequate sequence generation and six had adequate allocation concealment. Participants and outcome assessors were blinded in eight studies. Three of the studies compared turmeric therapy to NSAIDs. All 10 studies showed improvement in pain and function from baseline with turmeric therapy (p≤0.05). In three studies comparing turmeric to NSAIDs, there were no differences in outcome scores (p>0.05). In all studies there were no significant adverse events in the turmeric therapy group.

Conclusion

Compared with placebo, there appears to be a benefit of turmeric on knee OA pain and function. Based on a small number of studies the effects are similar to that of NSAIDs. Variables such as optimal dosing, frequency and formulation remain unclear at this time.

Curcumin protects radiation-induced liver damage in rats through the NF-κB signaling pathway

BACKGROUND

Curcumin has been demonstrated to exert anti-oxidant, anti-fibrotic, anti-inflammatory, and anti-cancer activities. This study was conducted to observe the effect and inner mechanism of curcumin in rats with radiation-induced liver damage (RILD).

METHODS

Thirty SD rats were classified into Control, Radiation group and Curcumin (Cur) + Radiation group (n = 10 in each group). The changes in body weight of the rats were observed on the 3rd, 7th and 14th days after the treatment with curcumin. On the 14th day post treatment, the heart blood of the rats was drawn for measurement of liver function indices including total protein (TP), alanine aminotransfetase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) as well as aspartate aminotransfetase (AST). Subsequently, the rats were euthanized and liver tissues were taken to observe liver morphological changes using hematoxylin-eosin (HE), and to analyze apoptosis condition using transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assays. Meanwhile, the oxidative stress level in liver tissue homogenate was determined by biochemical analysis. The expression of nuclear factor kappa B (NF-κB) pathway-associated and apoptosis-associated proteins was detected using Western blot analysis, and the expression levels of inflammatory factors were measured by Enzyme-linked immunosorbent assay (ELISA).

RESULTS

The reduced body weight was observed in rats of the Radiation group compared to the Control and Cur + Radiation groups on day 14. In the Radiation group, hepatic cell edema and inflammatory cell infiltration could be visible under the light microscope, and the hepatocytes presented with vacuolar degeneration. In the Cur + Radiation group, the hepatocytes swelled under the microscope, but the pathological changes were alleviated in comparison with the Radiation group. RILD rats with curcumin treatment presented with decreased ALT, AST, ALP, LDH, and maleicdialdehyde (MDA) levels, and elevated TP, superoxide dismutase (SOD), caspase activated DNase (CAD) and glutathione (GSH) levels. Apoptosis and inflammation in rats with RILD were up-regulated, and the NF-κB pathway was activated, but they were reversed after continuously intragastric administration of curcumin for 14 days.

CONCLUSION

Our study highlights that curcumin treatment reduces the liver damage caused by radiation through the inhibition of the NF-κB pathway.