Mechanisms of olive leaf extract-ameliorated rat arthritis caused by kaolin and carrageenan

Plant-derived bioactive compounds as key players in the modulation of immune-related conditions

The immune system is a complex and fundamental network for organism protection. A minimal unbalance in the host defense system homeostasis can originate severe repercussions in human health. Fundamentally, immune-related diseases can arise from its compromise (immunodeficiency diseases), overactivation against itself (autoimmune diseases) or harmless substances (allergies), and failure of eliminating the harmful agent (chronic inflammation). The notable advances and achievements in the immune system diseases pathophysiology have been allowing for a dramatic improvement of the available treatments. Nevertheless, they present some drawbacks, including the inappropriate benefit/risk ratio. Therefore, there is a strong and urgent need to develop effective therapeutic strategies. Nature is a valuable source of bioactive compounds that can be explored for the development of new drugs. Particularly, plants produce a broad spectrum of secondary metabolites that can be potential prototypes for innovative therapeutic agents. This review describes the immune system and the inflammatory response and examines the current knowledge of eight plants traditionally used as immunomodulatory medicines (Boswellia serrata, Echinacea purpurea, Laurus nobilis, Lavandula angustifolia, Olea europaea, Salvia officinalis, Salvia rosmarinus, and Taraxacum officinale). Moreover, the issues responsible for possible biologic readout inconsistencies (plant species, age, selected organ, developmental stage, growth conditions, geographical location, drying methods, storage conditions, solvent of extraction, and extraction method) will also be discussed. Furthermore, a detailed list of the chemical composition and the immunomodulatory mechanism of action of the bioactive compounds of the selected plant extracts are presented. This review also includes future perspectives and proposes potential new avenues for further investigation.

Phenolic Extract from Olive Leaves as a Promising Endotherapeutic Treatment against Xylella fastidiosa in Naturally Infected Olea europaea (var. europaea) Trees

(1) Background: Since 2013, the pathogenic bacterium Xylella fastidiosa has been severely affecting olive production in Apulia, Italy, with consequences for the economy, local culture, landscape and biodiversity. The production of a phenolic extract from fresh olive leaves was employed for endotherapeutic injection into naturally infected olive trees by Xylella fastidiosa in Apulia region, Italy. (2) Methods: The effectiveness of the extract was tested in vitro and in planta in comparison with analogous treatments based on garlic powder and potassium phosphite. (3) Results: The uptake of phenolic compounds from olive leaves through a trunk injection system device resulted in a statistically significant increase in leaf area index and leaf area density, as well as in the growth of newly formed healthy shoots. Plant growth-promoting effects were also observed for potassium phosphite. Moreover, the bacteriostatic activities of the phenolic extract and of the garlic-powder-based solution have been demonstrated in in vitro tests. (4) Conclusions: The results obtained and the contained costs of extraction make the endotherapeutic treatment with phenolic compounds a promising strategy for controlling X fastidiosa to be tested on a larger scale, although the experiments conducted in this study proved not to be suitable for centenary trees.

Anti-arthritic effects of Schisandra chinensis extract in monosodium iodoacetate-induced osteoarthritis rats

The present study aimed to investigate the therapeutic effects of Schisandra chinensis (SC) extract on clinical symptoms of osteoarthritis and the modulating effect on the mechanisms associated with the progression of osteoarthritis in a rat model of monosodium iodoacetate (MIA)-induced osteoarthritis. Osteoarthritis-induced rats were randomized into four groups: MIA injection control (MC), MIA injection with celecoxib (PC), MIA injection with SC extract 100 mg/kg (SC100), and MIA injection with SC extract 200 mg/kg (SC200). Another healthy group received a saline injection as a negative control (NC). During the treatment, weight-bearing measurements were performed once a week for 4 weeks. Histopathological and biochemical analyses of the joints, blood, and chondrocyte tissue were performed following the completion of treatment. Compared with MC rats, SC rats demonstrated significantly alleviated pain behavior, bone erosion, and cartilage degradation. SC reduced serum levels of matrix metalloproteinases and pro-inflammatory cytokines. SC treatment also reversed the levels of biomarkers such as Collagen II and ADAMTS4 in the cartilage tissue. Moreover, SC administration inhibited the phosphorylation levels of nuclear factor kappa B (NF-κB) and NF-κB Inhibitor alpha. This study demonstrates that SC ameliorated osteoarthritis at in vivo level. Our results suggest that SC might be a potential therapeutic agent for osteoarthritis.

Olive Leaf Waste Management

Olive trees are the oldest known cultivated trees in the world and present-day cultivation is widespread, with an estimated magnitude of 9 million hectares worldwide. As the olive oil industry has continued to grow, so has the environmental impact of olive oil production, such as the energy and water consumption, gas emissions and waste generation. The largest contributor to waste generation are the olive leaves, an abundant and unavoidable byproduct of olive-oil production due to the necessity of tree-pruning. It is estimated that an annual 1.25 million tons of olive leaf waste are generated in Spain alone, around 50% of the total world production. The leaves are currently used for biomass production or animal feed. However, because of their polyphenolic composition, olive leaves have potential in numerous other applications. In this review we analyze the chemical composition of olive leaves, and discuss current processing methods of the olive leaf waste, including thermochemical, biochemical, drying, extraction and condensation methods. We also examine current applications of the treated olive leaves in sectors relating to cattle feed, fertilizers, novel materials, energy generation, and food and pharmaceutical products. The aim of this review is to provide a resource for producers, policy makers, innovators and industry in shaping environmentally sustainable decisions for how olive leaf waste can be utilized and optimized.

Olive leaf extract supplementation improves the vascular and metabolic alterations associated with aging in Wistar rats

Olive leaves are rich in bioactive substances which exert anti-inflammatory, antioxidant, insulin-sensitizing and antihypertensive effects. The aim of this study was to analyze the possible beneficial effects of an olive leaf extract (OLE) rich in secoiridoids and phenolic compounds on the aging-induced metabolic and vascular alterations. Three experimental groups of rats were used: 3-month-old rats, 24-month-old rats and 24-month-old rats supplemented 21 days with OLE (100 mg/kg). Administration of OLE to aged rats decreased the weight of adrenal glands and prevented the aging-induced loss of body weight and muscle mass. In the serum, OLE reduced the circulating levels of LDL-cholesterol and IL-6 and increased the concentrations of leptin and adiponectin. In the liver OLE attenuated the decreased gene expression of SOD-1, GSR, GCK and GSK-3β and reduced the aging-induced overexpression of NOX-4, Alox-5, iNOS and TNF-α. In aorta segments, OLE prevented endothelial dysfunction and vascular insulin resistance and improved vasoconstriction in response to KCl and NA. Improvement in vascular function was associated with the attenuation of the alterations in the gene expression of COX-2, IL-6, GPx, NOX-1 and IL-10. In conclusion, OLE exerts anti-inflammatory and antioxidant effects in aged rats and attenuates the alterations in vascular function associated with aging.

Tunisian Olea europaea L. leaf extract suppresses Freund's complete adjuvant-induced rheumatoid arthritis and lipopolysaccharide-induced inflammatory responses

ETHNOPHARMACOLOGICAL RELEVANCE

Olea europaea L. (olive) is traditionally used as a folk remedy and functional food in Europe and Mediterranean countries to treat inflammatory diseases. O. europaea contains phenolic compounds and have been reported to prevent cartilage degradation. However, the function and mechanism of O. europaea in rheumatoid arthritis are not known.

AIM OF THE STUDY

In this study, we aimed to examine anti-inflammatory and anti-arthritic effects of Tunisian O. europaea L. leaf ethanol extract (Oe-EE).

MATERIALS AND METHODS

To do this, we employed an in vitro macrophage-like cell line and an in vivo Freund's complete adjuvant (AIA)-induced arthritis model. Levels of inflammatory genes and mediators were determined from in vivo samples.

RESULTS

The Oe-EE clearly reduced the production of the lipopolysaccharide-mediated inflammatory mediators, nitric oxide (NO) and prostaglandin E₂ (PGE₂), in RAW264.7 cells. The results of HPLC showed that Oe-EE contained many active compounds such as oleuropein and flavonoids. In AIA-treated rats, swelling of paws, pain, and cartilage degeneration were alleviated by oral Oe-EE administration. Correlating with in vitro data, PGE₂ production was significantly reduced in paw samples. Furthermore, the molecular mechanism of Oe-EE was dissected, and Oe-EE regulated the gene expression of interleukin (IL)-6, inducible NO synthase (iNOS), and MMPs and inflammatory signaling activation.

CONCLUSION

Consequently, Oe-EE possesses anti-inflammatory and anti-rheumatic effects and is a potential effective treatment for rheumatoid arthritis.

TLR4, RAGE, and p-JNK/JNK mediated inflammatory aggression in osteoathritic human chondrocytes are counteracted by redox-sensitive phenolic olive compounds: Comparison with ibuprofen

Osteoarthritic chondrocytes show an over-activity of inflammatory catabolic mediators, and olive products have attracted attention because they were discovered to have some benefits on osteoarthritis patients. We investigated the mechanisms of action of olive leaf polyphenolic compounds in osteoarthritic chondrocytes (OACs) using a standardized leaf extract, ZeyEX, and its main phenolic component, oleuropein, also compared with anti-inflammatory drug ibuprofen. OACs, isolated from joint-cartilages of Grade 4 OA patients, were found to express COMP and MMP-9 throughout their culture period. ZeyEX, oleuropein, and ibuprofen increased cell viability at concentrations of 1-100 nM, did not change at 500 nM-50 μM, but inhibited at ≥100 μM. The adherence profile of OACs increased with 1 μM of ibuprofen or ZeyEX and 10 nM-1 μM oleuropein. Although the markers for oxidative and nitrosative stresses (ROS and 3-NT) generally inhibited by three agents, the inhibitory effect of ZeyEX on 3-NT emerged dramatically (1 nM-10 μM). Lipid-hydroperoxides and HNE-adducts were also inhibited by each agent, but AGE-adducts unchanged by oleuropein while reduced by ZeyEX and ibuprofen. Inflammatory biomarkers, IL-1β, IL-6, Casp-1/ICE, and TNF-α, were inhibited by three agents, however osteopontin and GM-CSF by only ZeyEX and ibuprofen. A decreased COMP, TLR4, and RAGE expression levels were observed by three agents, but only the effects of ZeyEX was concentration-dependent. In particular, ZeyEX and oleuropein improved COL2, inhibited p-JNK/JNK, and increased GPx. COX2 was only inhibited by ibuprofen. The results indicate that polyphenolic-olive compounds counteract redox-sensitive inflammatory aggressions in osteoarthritic chondrocytes that may stop the progression of pathology and allow regeneration.

Laquinimod Mitigated IL-1β-Induced Impairment of the Cartilage Extracellular Matrix in Human ATDC5 Chondrocytes

To date, a safe and reliable treatment of osteoarthritis (OA) has not yet been announced. Inflammatory response and degradation of the articular extracellular matrix (ECM) induced by IL-1β are important pathological characteristics of OA. Laquinimod is a quinoline-3-carboxamide and a novel oral immunomodulatory compound in clinical use. However, whether laquinimod has a beneficial effect in OA is not known. In our research, we found that laquinimod could ameliorate IL-1β-induced generation of ROS and improve mitochondrial function by increasing mitochondrial membrane potential (ΔΨm). Furthermore, treatment with laquinimod suppressed IL-1β-induced production of TNF-α and IL-6. Notably, laquinimod prevented the degradation of type II collagen by inhibiting MMP-3 and MMP-13. Meanwhile, the presence of laquinimod attenuated the reduction in aggrecan by mediating ADAMTS-4 and ADAMTS-5. Mechanistically, laquinimod ameliorated IL-1β-induced inflammation and degeneration of ECM by suppressing the activation of NF-κB. Taken together, our findings reveal that laquinimod possesses a beneficial effect against IL-1β insults in human chondrocytes, implying an important role of laquinimod in OA.

Anti-inflammatory and anti-osteoarthritis effect of Mollugo pentaphylla extract

CONTEXT

Mollugo pentaphylla L. (Molluginaceae) extract (MPE) has been reported to have anti-inflammatory effect on MSU-induced gouty arthritis in a mouse model.

OBJECTIVE

This study examined the anti-inflammatory activities of an MPE in vitro and anti-osteoarthritis effects on monosodium iodoacetate (MIA)-induced osteoarthritis (OA) in vivo.

MATERIALS AND METHODS

The dried whole plants of M. pentaphylla were extracted with 70% ethanol under reflux. The anti-inflammatory effect of MPE was evaluated in vitro in lipopolysaccharide (LPS)-treated RAW264.7 cells. The anti-osteoarthritic effect of MPE was investigated in a Sprague-Dawley rat model of MIA-induced OA. Each seven male rats were orally administered MPE (75, 150 or 300 mg/kg) or the positive control drug indomethacin (1 mg/kg) 3 days before MIA injection and once daily for 11 days thereafter. After the treatment with MPE, no evidence of systemic adverse effects was observed in any study group.

RESULTS

MPE exhibited anti-inflammatory activity via inhibition of the production of NO (57.8%), PGE2 (97.1%) and IL-6 (93.2%) in LPS-treated RAW264.7 cells at 200 μg/mL. In addition, MPE suppressed IL-1β (60.9%), TNF-α (37.9%) and IL- 6 (40.9%) production and suppressed the synthesis of MMP-2, MMP-9 and COX-2 in the MIA-induced OA rat model.

CONCLUSIONS

These results demonstrate that MPE exerts potent anti-inflammatory activities and protects cartilage in an OA rat model. This might be a potential candidate for therapeutic OA treatment.

Physical activity and Mediterranean diet based on olive tree phenolic compounds from two different geographical areas have protective effects on early osteoarthritis, muscle atrophy and hepatic steatosis

PURPOSE

Osteoarthitis (OA) leads to progressive loss of articular cartilage, pain and joint disability. An acute injury constitutes an important risk factor for early OA, determining an inflammatory process responsible of cartilage degeneration and muscle atrophy, due to the joint pain and immobility. The study aims to assess the effects of conjugation of physical activity and diet enriched by olive tree compounds [extra virgin olive oil (EVOO) and olive leaf extract (OLE)], on the musculoskeletal system in OA rat model.

METHODS

OA was induced by anterior cruciate ligament transection and confirmed by Mankin and OARSI scores. Rats were subjected to physical activity on treadmill 5 days a week for 10 min daily and fed with experimental diets (standard diet enriched with Sicilian EVOO, Tunisian EVOO and Tunisian EVOO-OLE) for 12 weeks. Immunohistochemistry was used to evaluate IL-6 and lubricin expression in cartilage tissue and ELISA was used to quantify these proteins in serum at different time points. Histology and histomorphometry analysis were done to valuate liver steatosis, muscle atrophy and cartilage pathological changes.

RESULTS

Compared to the OA group, the experimental groups showed general increased lubricin and decreased IL-6 expression, significant muscle hypertrophy and no signs of liver steatosis, suggesting the beneficial effects of physical activity coupled with EVOO-enriched diets on rat articular cartilage. Interestingly, the best result was shown for Sicilian EVOO-enriched diet.

CONCLUSION

In conclusion, the conjugation of physical activity and EVOO-enriched diet determines a significant articular cartilage recovery process in early OA.

RETRACTED: Polar and apolar extra virgin olive oil and leaf extracts as a promising anti-inflammatory natural treatment for osteoarthritis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Authors. An anonymous reader made the authors aware of potential errors in the presentation and the experimental design for the Western blot data in Figure 3. Upon thorough investigation the authors concluded that in fact, in addition to an honest error (wrong image selected for inclusion into the article), the experimental design was not state-of-the-art in that the loading controls were run on parallel gels rather than on the gels to be probed for iNOS and collagen II. Therefore, in order to avoid any potentially wrong conclusions, the authors decided to retract the article, to confirm the data in a separate series of experiments and to submit the manuscript again after proper confirmation of the results and conclusions. The authors thank the anonymous reader, who spotted this error, and apologize for any inconvenience caused.

Twelve-month consumption of a polyphenol extract from olive (Olea europaea) in a double blind, randomized trial increases serum total osteocalcin levels and improves serum lipid profiles in postmenopausal women with osteopenia

OBJECTIVES

Osteoporosis is a skeletal disorder characterized by impaired bone turnover and compromised bone strength, thereby predisposing to increased risk of fracture. Preclinical research has shown that compounds produced by the olive tree (Olea europaea), may protect from bone loss, by increasing osteoblast activity at the expense of adipocyte formation. The aim of this exploratory study was to obtain a first insight on the effect of intake of an olive extract on bone turnover in postmenopausal women with decreased bone mass (osteopenia).

DESIGN AND SETTING

For that, a double blind, placebo-controlled study was performed in which participants were randomly allocated to either treatment or placebo groups.

PARTICIPANTS

64 osteopenic patients, with a mean bone mineral density (BMD) T-score between -1.5 and -2.5 in the lumbar spine (L2-L4) were included in the study.

INTERVENTION AND MEASUREMENTS

PARTICIPANTS received for 12 months daily either 250 mg/day of olive extract and 1000 mg Ca (treatment) or 1000 mg Ca alone (placebo). Primary endpoints consisted of evaluation of bone turnover markers. Secondary endpoints included BMD measurements and blood lipid profiles.

RESULTS

After 12 months, the levels of the pro-osteoblastic marker osteocalcin were found to significantly increase in the treatment group as compared to placebo. Simultaneously, BMD decreased in the placebo group, while remaining stable in the treatment group. In addition, improved lipid profiles were observed, with significant decrease in total- and LDL-cholesterol in the treatment group.

CONCLUSION

This exploratory study supports preclinical observations and warrants further research by showing that a specific olive polyphenol extract (Bonolive®) affects serum osteocalcin levels and may stabilize lumbar spine BMD. Moreover, the improved blood lipid profiles suggest additional health benefits associated to the intake of the olive polyphenol extract.

Mouse models of osteoarthritis: modelling risk factors and assessing outcomes

Osteoarthritis (OA) is a prevalent musculoskeletal disease that results in pain and low quality of life for patients, as well as enormous medical and socioeconomic burdens. The molecular mechanisms responsible for the initiation and progression of OA are still poorly understood. As such, mouse models of the disease are having increasingly important roles in OA research owing to the advancements of microsurgical techniques and the use of genetically modified mice, as well as the development of novel assessment tools. In this Review, we discuss available mouse models of OA and applicable assessment tools in studies of experimental OA.

Naturally derived anti-inflammatory compounds from Chinese medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Though inflammatory response is beneficial to body damage repair, if it is out of control, it can produce adverse effects on the body. Although purely western anti-inflammatory drugs, orthodox medicines, can control inflammation occurrence and development, it is not enough. The clinical efficacy of anti-inflammation therapies is unsatisfactory, thus the search for new anti-inflammation continues. Chinese Material Medica (CMM) remains a promising source of new therapeutic agents. CMM and herbal formulae from Traditional Chinese Medicine (TCM), unorthodox medicines, play an improtant anti-inflammatory role in multi-targets, multi-levels, and multi-ways in treating inflammation diseases in a long history in China, based on their multi-active ingredient characteristics. Due to these reasons, recently, CMM has been commercialized as an anti-inflammation agent which has become increasingly popular in the world health drug markets. Major research contributions in ethnopharmacology have generated vast amount of data associated with CMM in anti-inflammtion aspect. Therefore, a systematic introduction of CMM anti-inflammatory research progress is of great importance and necessity.

AIM OF THE STUDY

This paper strives to describe the progress of CMM in the treatment of inflammatory diseases from different aspects, and provide the essential theoretical support and scientific evidence for the further development and utilization of CMM resources as a potential anti-inflammation drug through a variety of databases.

MATERIAL AND METHODS

Literature survey was performed via electronic search (SciFinder®, Pubmed®, Google Scholar and Web of Science) on papers and patents and by systematic research in ethnopharmacological literature at various university libraries.

RESULTS

This review mainly introduced the current research on the anti-inflammatory active ingredient, anti-inflammatory effects of CMM, their mechanism, anti-inflammatory drug development of CMM, and toxicological information.

CONCLUSION

CMM is used clinically to treat inflammation symptoms in TCM, and its effect is mediated by multiple targets through multiple active ingredients. Although scholars around the world have made studies on the anti-inflammatory studies of CMM from different pathways and aspects and have made substantial progress, further studies are warranted to delineate the inflammation actions in more cogency models, establish the toxicological profiles and quality standards, assess the potentials of CMM in clinical applications, and make more convenient preparations easy to administrate for patients. Development of the clinically anti-inflammatory drugs are also warranted.