Medical Plant Extracts for Treating Knee Osteoarthritis: a Snapshot of Recent Clinical Trials and Their Biological Background

A Multicenter, Randomized, Double-Blinded, Placebo-Controlled Clinical Trial to Evaluate the Efficacy and Safety of a Krill Oil, Astaxanthin, and Oral Hyaluronic Acid Complex on Joint Health in People with Mild Osteoarthritis

Osteoarthritis is a significant global health problem. Many patients seek more effective alternatives to nonsteroidal anti-inflammatory medicines or commercial supplements to manage joint pain and inflammation. FlexPro MD® (FP-MD) combines krill oil, astaxanthin, and lower molecular weight hyaluronic acid to support joint health. A 12-week, randomized, double-blind, placebo-controlled trial compared the efficacy and safety of FP-MD and placebo once daily in participants (n = 100) with mild osteoarthritis of the knee or hip joint. For the primary endpoint of joint pain score, per-protocol participants (n = 75) in the FP-MD group (n = 37) had a statistically significantly greater mean reduction from baseline in the Korean Visual Analog Scale (K-VAS) at week 12 compared with participants in the placebo group (n = 38) (20.8 ± 16.16 mm vs. 10.6 ± 17.58, p = 0.0105). The Korean Western Ontario and McMaster Universities Osteoarthritis Index (K-WOMAC) total score was also significantly improved in the FP-MD group at week 12 compared with placebo (-13.0 ± 13.62 vs. -5.5 ± 18.08, p = 0.0489), especially an improvement in pain score (-2.5 ± 2.92 vs. -1.3 ± 3.94, p = 0.02635). FP-MD group had greater improvement in joint function scoring by investigator assessment (p = 0.0127) and by group participants (p = 0.0070). A statistically significantly greater number of patients reported adverse events in the placebo group compared with the FP-MD group (16% vs. 4%, p = 0.0455), most commonly gastrointestinal disorders in both of the groups. These findings suggest that FP-MD is well tolerated and can be effectively used to address joint pain in patients diagnosed with mild osteoarthritis, the main symptom of this condition.

Medicinal plants and their secondary metabolites in alleviating knee osteoarthritis: A systematic review

BACKGROUND

With the increasing ages of the general population, the incidence of knee osteoarthritis (KOA) is also rising, and KOA has become a major health problem worldwide. Recently, medicinal plants and their secondary metabolites have gained interest due to their activity in treating KOA. In this paper, a comprehensive systematic review of the literature was performed concerning the effects of medicinal plant extracts and natural compounds against KOA in recent years. The related molecular pathways of natural compounds against KOA were summarized, and the possible crosstalk among components in chondrocytes was discussed to propose possible solutions for the current situation of treating KOA.

PURPOSE

This review focused on the molecular mechanisms by which medicinal plants and their secondary metabolites act against KOA.

METHODS

Literature searches were performed in the PUBMED, Embase, Science Direct, and Web of Science databases for a 10-year period from 2011 to 2022 with the search terms "medicinal plants," "bioactive compounds," "natural products," "phytochemical," "knee osteoarthritis," "knee joint osteoarthritis," "knee osteoarthritis," "osteoarthritis of the knee," and "osteoarthritis of knee joint."

RESULTS

According to the results, substantial plant extracts and secondary metabolites show a positive effect in fighting KOA. Plant extracts and their secondary metabolites can affect the diagnostic and prognostic biomarkers of KOA. Natural products inhibit the expression of MMP1, MMP3, MMP19, syndecan IV, ADAMTS-4, ADAMTS-5, iNOS, COX-2, collagenases, IL-6, IL-1β, and TNF-α in vitro and in vivo and . Cytokines also upregulate the expression of collagen II and aggrecan. The main signaling pathways affected by the extracts and isolated compounds include AMPK, SIRT, NLRP3, MAPKs, PI3K/AKT, mTOR, NF-κB, WNT/β-catenin, JAK/STAT3, and NRF2, as well as the cell death modes apoptosis, autophagy, pyroptosis, and ferroptosis.

CONCLUSION

The role of secondary metabolites in different signaling pathways supplies a better understanding of their potential to develop further curative options for KOA.

Protective effect of ethanolic extract of Echinacea purpurea contained nanoparticles on meniscal/ligamentous injury induced osteoarthritis in obese male rats

Osteoarthritis (OA) is a chronic degenerative joint disease associated with age, mechanical stress, and obesity. Echinacea purpurea is a medicinal plant that shows good anti-inflammatory, antioxidant, and immunomodulatory activities. In this study, Echinacea purpurea ethanol extract nanoparticles (Nano-EE) were prepared by encapsulating Echinacea purpurea ethanol extract (EE) in chitosan-silica nanoparticles. Obesity (OB) in Sprague-Dawley (SD) rats was induced by fed 40% high-fat diet and then anterior cruciate ligament and meniscus injury were performed to induce OA. The rats got different doses of samples by oral gavage. The encapsulation efficiency and loading capacity of Nano-EE were 69.1% and 36.1%, respectively. The average size, polydispersity index (PDI), and zeta potential (ZP) of the Nano-EE were 145 ± 11 nm, 0.24 ± 0.01, − 4.57 ± 0.44 mV, respectively. Furthermore, electron microscopic images showed that the particles were spherical and were slightly agglomerated. Moreover, it showed that the leptin content, expression of MMPs, cytokines level, NF-κB level, and iNOS production were decreased whereas collagen II expression was increased after treatment. Besides, Nano-EE ameliorated the pain caused by OA and reduced the proteoglycan loss in cartilage. These results indicated that encapsulated EE (Nano-EE) can ameliorate OA with a low dosage and are more effective than unencapsulated EE.

Dietary Interventions with Polyphenols in Osteoarthritis: A Systematic Review Directed from the Preclinical Data to Randomized Clinical Studies

Osteoarthritis (OA) is the most common form of arthritis and a major cause of limited functionality and thus a decrease in the quality of life of the inflicted. Given the fact that the existing pharmacological treatments lack disease-modifying properties and their use entails significant side effects, nutraceuticals with bioactive compounds constitute an interesting field of research. Polyphenols are plant-derived molecules with established anti-inflammatory and antioxidant properties that have been extensively evaluated in clinical settings and preclinical models in OA. As more knowledge is gained in the research field, an interesting approach in the management of OA is the additive and/or synergistic effects that polyphenols may have in an optimized supplement. Therefore, the aim of this review was to summarize the recent literature regarding the use of combined polyphenols in the management of OA. For that purpose, a PubMed literature survey was conducted with a focus on some preclinical osteoarthritis models and randomized clinical trials on patients with osteoarthritis from 2018 to 2021 which have evaluated the effect of combinations of polyphenol-rich extracts and purified polyphenol constituents. Data indicate that combined polyphenols may be promising for the treatment of osteoarthritis in the future, but more clinical trials with novel approaches in the identification of the in-between relationship of such constituents are needed.

Discrimination of Salvia miltiorrhiza Bunge from Different Geographical Locations Employing High-Performance Liquid Chromatography, Near-Infrared Fingerprinting Combined with Chemometrics

To evaluate the quality of Salvia miltiorrhiza Bunge, high-performance liquid chromatography-diode array detector (HPLC/UV-PAD), near infrared (NIR) spectroscopy, and chemometrics were used to discriminate nine components of samples from four different geographical locations. HPLC was performed with a C18 (5 μm, 4.6 mm × 250 mm) column and 0.1% formic acid aqueous solution-acetonitrile with a gradient elution system. Orthogonal partial least squares discriminant analysis was used to identify the amounts of salvianolic acid B. NIR was used to distinguish rapidly S. miltiorrhiza Bunge samples from different geographical locations. In this assay, discriminant analysis was performed, and the accuracy was found to be 100%. The combination of these two methods can be used to quickly and accurately identify S. miltiorrhiza Bunge from different geographical locations.

Sida tuberculata reduces oxidative stress and pain caused by the knee osteoarthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Knee osteoarthritis (OA) cause pain and edema, as well as unbalance between the production of reactive oxygen species and antioxidant activity. These problems interfere with the articular function, leading to a significant loss of life quality. Sida tuberculata R.E.Fr. is an herbaceous plant belonging to the Malvaceae family found in southern Brazil. This plant has traditionally been consumed as an aqueous extract and popularly used in the treatment of many diseases, with antioxidant and antimicrobial activity, reducing pain and inflammation.

AIM OF THE STUDY

To verify the effects of S. tuberculata extract obtained from leaves on oxidative, toxic and nociceptive parameters induced by knee OA in rats.

MATERIALS AND METHODS

Aqueous extracts of S. tuberculata were evaluated under phytochemical analyses. Knee Osteoarthritis was induced in rats with monosodium iodoacetate (1.5 mg/50 μl) and treated with S. tuberculata extract. The animals were treated orally with 3 doses of S. tuberculata extract (STE): 1.5, 5 and 15 mg/ml, for 14 days. For biochemical analyses, the following tests were performed: lipid peroxidation, carbonylated protein content, superoxide dismutase activity, non-protein thiol levels and myeloperoxidase activity. For the evaluation of pain and edema we verify mechanical and thermal hyperalgesia, spontaneous pain observation and measurement of knee edema with a caliper. For histological evaluations, the animal knee joints were removed. For toxicity evaluation, the levels of aspartate aminotransferase, alanine aminotransferase and urea, as well as the relative weight of the organs were analyzed.

RESULTS

The S. tuberculata phytochemical analyses showed the majority peak corresponding to 20-hydroxyecdysone (20HE). The plant extract decreased damages related to oxidative stress in the blood serum (lipid peroxidation and carbonyl content) Overall, the STE 5 mg Group presented the greater statistical significance, in the blood serum samples, in relation to the other groups, being the most relevant result. The S. tuberculata groups presented pain decrease, lower neutrophil activity in the knee, and increased blood serum activity. The animals of S. tuberculata groups showed a decrease in mechanical hyperalgesia. The animals treated also presented lower scores for spontaneous pain. It was observed that the dose of 5 mg presented, once again, more expressive results, since the animals of this group had a higher frequency (greater number of days) with significant decrease of pain. In the histological analysis, in the STE 5 mg group, the articular cartilage lesions were observed at an intermediate point between the damage found in the MIA and Diclofenac groups. Besides that, the STE did not show significant changes in oxidative stress damage in liver and kidney samples. Blood serum samples did not indicate significant differences in liver and renal function. As well as, there were no differences in mean relative body weights in relation to control groups (Salina and MIA).

CONCLUSION

S. tuberculata reduced the damage due to oxidative stress and pain caused by knee osteoarthritis in rats. In addition, the extract presented no toxicity. Our results suggest that S. tuberculata seems to have a therapeutic potential in the osteoarthritis treatment.

Brazilin blocks catabolic processes in human osteoarthritic chondrocytes via inhibition of NFKB1/p50

This study aimed to evaluate the chondroprotective and anti-inflammatory activity of brazilin in human osteoarthritic (OA) cartilage and chondrocytes with particular focus on the nuclear factor-kappa B (NF-κB) pathway. Therefore, brazilin was isolated from Caesalpinia sappan and identified using high performance liquid chromatography (HPLC). The effect of brazilin was assessed in cartilage explants treated with 10 ng/ml interleukin (IL)-1β and 10 ng/ml tumor necrosis factor (TNF)-α using histological and biochemical glycosaminoglycan (GAG) analyses and in primary chondrocytes treated with 10 ng/ml IL-1β using RT-qPCR, ELISA, and Western blot. The involvement of NF-κB signaling was examined using a human NF-κB signaling array and in silico pathway analysis. Brazilin was found to reduce the GAG loss from cartilage explants stimulated with IL-1β and TNF-α. NF-κB pathway analysis in chondrocytes revealed NFKB1/p50 as a central player regulating the anti-inflammatory activities of brazilin. Brazilin suppressed the IL-1β-mediated up-regulation of OA markers and the induction of NFKB1/p50 in chondrocytes. In conclusion, brazilin effectively attenuates catabolic processes in human OA cartilage and chondrocytes-at least in part due to the inhibition of NFKB1/p50-which indicates a chondroprotective potential of brazilin in OA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2431-2438, 2018.

PROSPECTIVE EFFECT OF RED ALGAE, ACTINOTRICHIA FRAGILIS, AGAINST SOME OSTEOARTHRITIS AETIOLOGY

Background:

Osteoarthritis (OA) is a progressive disease characterized by joints pain and articular cartilage destruction. Most of the current treatment strategies for OA are effective for symptoms relief but are accompanied with adverse side effect. Thus, the present investigation aims to evaluate the potential influence of red algae, Actinotrichia fragilis, in the dry powder form (AFP) or gel form (AFG) on some relevant factors of OA progression as well as assess its safety through in vitro and in vivo experiments.

Materials and Methods:

In vitro, AFP was analyzed for its chemical constituents screening, amino acid, proteinase inhibitory activity, HRBC membrane stabilization activity, free radical scavenging activity, total antioxidant potency, nitric oxide radical scavenging power. In vivo, Organization for Economic Co-operation and Development (OECD) toxicity test was performed to test the safety of AFP on rats.

Results:

The present findings revealed that AFP and AFG can be considered as inflammatory-proteinase-oxidant inhibitor and considered to be safe according to the OECD guideline.

Conclusion:

AFP and AFG may have the potency to become the therapeutic candidate for OA disease as it prevents the key causes of OA initiation.

Effect of a Food Supplement Containing L-Methionine on Urinary Tract Infections in Pregnancy: A Prospective, Multicenter Observational Study

OBJECTIVE

Adjuvants or alternatives to antibiotics in urinary tract infections (UTIs) during pregnancy seem advisable because of possible fetal stress. The present study assessed the effectiveness of a food supplement containing L-methionine and Hibiscus sabdariffa L. and Boswellia serrata Roxb. extracts as a treatment for symptomatic UTIs in pregnancy.

DESIGN

Pregnant patients with symptomatic cystitis were screened for UTIs in three different clinical centers. Those unwilling to take antibiotics were offered two alternative treatments: (A) a 1-week treatment with the food supplement or (B) a week in which they were advised to increase their fluid consumption to more than 1.5 L daily. After 1 week, group B patients who still had positive urine cultures (UCs) or had no UC performed took the food supplement for an additional week. UCs were performed on all patients at the first visit (w0) and on most of them at 7 days (w1). Patients who were still positive at w1 or had no UC performed at w1 had UC performed 14 days (w2) thereafter.

RESULTS

Of 264 pregnant women enrolled, 216 joined group A, while 48 joined group B. At w1, 70.0% of group A patients and 43.2% of those in group B had negative UCs (p = 0.003). The reduction of bacterial load was 42.2% ± 8.0% and 4.5% ± 9.2%, respectively (p < 0.0001). At w1, symptoms disappeared in 135 patients (62.5%) in group A and 22 patients (45.8%) in group B (p = 0.03). At w2, 30 of 32 group B patients who switched to taking the supplement for the second week had negative UCs, including 20 who had been positive at w1. At w2, all group A patients had negative UCs. No side effects were reported.

CONCLUSIONS

The food supplement provided effective treatment and might be an adjuvant or alternative to antibiotic therapy of symptomatic UTI in pregnancy.

New Drug Treatments for Osteoarthritis: What Is on the Horizon?

Osteoarthritis (OA) is the most common form of arthritis, yet has historically lagged far behind rheumatoid arthritis in terms of drug development. Despite the many challenges presented by clinical trials in OA, improvements in our understanding of disease pathogenesis and a move to treat pain, as well as underlying disease process, mean there are now many new pharmacological therapies currently in various stages of clinical trials. The medical need for these therapies and the evidence for recent tissue and molecular targets are reviewed. Current therapeutic examples in each area are discussed, including both novel therapeutics and existing agents which may be repurposed from other disease areas. Some challenges remain, but opportunities for improving symptoms and disease process in OA in the clinic with new pharmacological agents would appear to be on the close horizon.

Efficacy of Elaeagnus Angustifolia extract in the treatment of knee osteoarthritis: a randomized controlled trial

Osteoarthritis (OA) is one of the most common musculoskeletal disorders all over the world. Available anti-arthritic medications have only partial efficacy and their long-term use is associated with adverse events. Elaeagnus Angustifolia (EA) is a medicinal plant with analgesic and anti-inflammatory properties. The present study evaluated the impact of two doses of EA extract compared with ibuprofen on the severity of disease in patients with knee OA. This study was designed as a randomized, double blind, active-controlled and parallel group trial. Patients with OA were randomized to receive 300 mg/day (n=33) or 600 mg/day (n=32) of EA aqueous extract, or 800 mg/day ibuprofen (n=32) for 7 weeks. EA extract contained 0.21 % (w/w) kaempferol according to HPLC. Efficacy of treatment was assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Visual Analogue Scale (VAS) of pain, Lequesne's Pain-Function Index (LPFI), and patient's global assessment (PGA) index. The amount of kaempferol in the extract was determined by HPLC method to be 0.21 % w/w. There were significant reductions in WOMAC, VAS, LPFI and PGA scores by the end of trial with all three interventions. Comparison of the changes in WOMAC, VAS and LPFI scores among the treatment groups did not reveal any significant difference between EA and ibuprofen, and between low and high doses of EA. EA was safe and well tolerated during the course of trial and no adverse event was reported. The present results suggest beneficial effects of aqueous EA extract in reducing the symptoms of OA with an efficacy comparable to that of ibuprofen.