Protective effect of green tea polyphenols on bone loss in middle-aged female rats

The potential application of fermented tea as a drink for regulating bone mass

Currently, there is evidence to suggest the benefits of drinking fermented tea for people with osteoporosis, and based on this, many studies have been conducted on the dosage, exact ingredients, mechanisms, and industrial applications of fermented tea for protecting against osteoporosis. A summary and analysis of studies on the regulation of bone mass by oolong tea, black tea, and their active ingredients (including 39 known catechin compounds) was conducted. It was found that the regulation of bone mass by fermented tea is backed by evidence from epidemiology, animal experiments, and cell experiments. The main active components of fermented tea are tea polyphenols, tea pigments, and trace amino acids. The specific mechanisms involved include regulating bone marrow mesenchymal stem cell osteogenesis, inhibiting osteoclast activity, promoting calcium and phosphorus absorption, reducing inflammation levels, regulating gut microbiota, regulating endocrine function, and inhibiting oxidative stress. In terms of its application, extraction, precipitation, biosynthesis and membrane separation method are mainly used to separate the active ingredients of anti osteoporosis from fermented tea. In conclusion, fermented tea has sufficient theoretical and practical support for regulating bone mass and preventing osteoporosis, and is suitable for development as a health supplement. At the same time, a large amount of epidemiological evidence is needed to prove the specific dosage of tea consumption.

Nutraceuticals and Functional Foods: A Comprehensive Review of Their Role in Bone Health

Bone health is the result of a tightly regulated balance between bone modeling and bone remodeling, and alterations of these processes have been observed in several diseases both in adult and pediatric populations. The imbalance in bone remodeling can ultimately lead to osteoporosis, which is most often associated with aging, but contributing factors can already act during the developmental age, when over a third of bone mass is accumulated. The maintenance of an adequate bone mass is influenced by genetic and environmental factors, such as physical activity and diet, and particularly by an adequate intake of calcium and vitamin D. In addition, it has been claimed that the integration of specific nutraceuticals such as resveratrol, anthocyanins, isoflavones, lycopene, curcumin, lutein, and β-carotene and the intake of bioactive compounds from the diet such as honey, tea, dried plums, blueberry, and olive oil can be efficient strategies for bone loss prevention. Nutraceuticals and functional foods are largely used to provide medical or health benefits, but there is an urge to determine which products have adequate clinical evidence and a strong safety profile. The aim of this review is to explore the scientific and clinical evidence of the positive role of nutraceuticals and functional food in bone health, focusing both on molecular mechanisms and on real-world studies.

Musculoskeletal crosstalk in chronic obstructive pulmonary disease and comorbidities: Emerging roles and therapeutic potentials

Chronic Obstructive Pulmonary Disease (COPD) is a multifaceted respiratory disorder characterized by progressive airflow limitation and systemic implications. It has become increasingly apparent that COPD exerts its influence far beyond the respiratory system, extending its impact to various organ systems. Among these, the musculoskeletal system emerges as a central player in both the pathogenesis and management of COPD and its associated comorbidities. Muscle dysfunction and osteoporosis are prevalent musculoskeletal disorders in COPD patients, leading to a substantial decline in exercise capacity and overall health. These manifestations are influenced by systemic inflammation, oxidative stress, and hormonal imbalances, all hallmarks of COPD. Recent research has uncovered an intricate interplay between COPD and musculoskeletal comorbidities, suggesting that muscle and bone tissues may cross-communicate through the release of signalling molecules, known as "myokines" and "osteokines". We explored this dynamic relationship, with a particular focus on the role of the immune system in mediating the cross-communication between muscle and bone in COPD. Moreover, we delved into existing and emerging therapeutic strategies for managing musculoskeletal disorders in COPD. It underscores the development of personalized treatment approaches that target both the respiratory and musculoskeletal aspects of COPD, offering the promise of improved well-being and quality of life for individuals grappling with this complex condition. This comprehensive review underscores the significance of recognizing the profound impact of COPD on the musculoskeletal system and its comorbidities. By unravelling the intricate connections between these systems and exploring innovative treatment avenues, we can aspire to enhance the overall care and outcomes for COPD patients, ultimately offering hope for improved health and well-being.

Comparative study of the anti-inflammatory activity of etoricoxib and Matcha green tea against acute kidney injury induced by gamma radiation in rats

PURPOSE

The primary objective of this study was to conduct a comparative analysis of the anti-inflammatory activity between Etoricoxib (ETO) and Matcha green tea (MG) in the context of acute kidney injury (AKI) induced by ionizing gamma radiation (IR) in female rats. Furthermore, the potential impact of whole body IR exposure on the intestinal system and serum estradiol levels was investigated. Additionally, it was acknowledged that the ETO and MG treatments might have exerted favorable effects on the intestinal and hormonal responses.

MATERIALS AND METHODS

Six groups of rats were assigned to different treatments: control, ETO, MG, irradiation (IRR), ETO + IRR, and MG + IRR. The evaluation included measuring the total phenolic and flavonoid contents of ETO and MG, as well as assessing their antioxidant activity, radical scavenging capacity, reducing power, and total antioxidant capacity. Kidney function was assessed through serum creatinine and urea levels. Oxidative stress markers, including superoxide dismutase, glutathione, malondialdehyde, and catalase, were measured to evaluate the antioxidant effects of ETO and MG. The anti-inflammatory potential of the treatments was evaluated by measuring STAT-3 and interleukins (IL-6, IL-23, and IL-17) using an ELISA assay. Prostaglandin E2 receptor (PGE-2) mRNA expression, histopathological examination, and immunohistochemistry for NF-κB inhibitors were performed to investigate the underlying mechanisms in kidney tissue homogenates. Histopathological changes and DNA fragmentation in the intestinal tissues were determined, and the characterization of Matcha green tea was performed using liquid chromatography-mass spectrometry (LC-MS). This allowed for the identification and quantification of various compounds present in Matcha green tea. Furthermore, the study assessed the effect of IR and treatments on estrogen levels in female rats.

RESULTS

Data showed that both ETO and MG had the potential to mitigate the adverse effects of AKI induced by IR. Notably, MG exhibited greater efficacy in attenuating oxidative stress and inflammation associated with renal injury. These findings revealed and compared the effects of ETO and MG in alleviating AKI caused by IR. MG demonstrated greater anti-inflammatory and antioxidant properties, highlighting its potential as a natural therapeutic agent.

CONCLUSIONS

These results contribute to the growing evidence supporting the use of MG in managing IR-induced renal complications. Future studies should focus on elucidating the molecular mechanisms and optimizing the application of MG in clinical settings.

Long-Term Consumption of Green Tea Can Reduce the Degree of Depression in Postmenopausal Women by Increasing Estradiol

Postmenopausal women face a higher risk of depression due to a combination of social and physiological factors. As a beverage rich in a variety of bioactive substances, green tea has significant effects on metabolism, inflammation and endocrine, and may reduce the risk of depression, but few studies have looked at the effects of green tea on postmenopausal women. Therefore, we designed this study to investigate the effects of long-term green tea consumption on inflammation, endocrine and depression levels in postmenopausal women. We investigated a tea-producing village and eventually included 386 postmenopausal women, both in the tea drinking and control groups. The results showed that there were significant differences in the degree of insomnia, degree of depression, BMI, SII and estradiol between the two groups. And, green tea consumption may reduce the risk of depression through the mediating pathway of sleep, SII and estradiol. In summary, long-term green tea consumption can reduce the risk of depression in postmenopausal women by reducing inflammation and increasing estradiol. This kind of living habit deserves further promotion.

Green Tea and Benign Gynecologic Disorders: A New Trick for An Old Beverage?

Green tea is harvested from the tea plant Camellia sinensis and is one of the most widely consumed beverages worldwide. It is richer in antioxidants than other forms of tea and has a uniquely high content of polyphenolic compounds known as catechins. Epigallocatechin-3-gallate (EGCG), the major green tea catechin, has been studied for its potential therapeutic role in many disease contexts, including pathologies of the female reproductive system. As both a prooxidant and antioxidant, EGCG can modulate many cellular pathways important to disease pathogenesis and thus has clinical benefits. This review provides a synopsis of the current knowledge on the beneficial effects of green tea in benign gynecological disorders. Green tea alleviates symptom severity in uterine fibroids and improves endometriosis through anti-fibrotic, anti-angiogenic, and pro-apoptotic mechanisms. Additionally, it can reduce uterine contractility and improve the generalized hyperalgesia associated with dysmenorrhea and adenomyosis. Although its role in infertility is controversial, EGCG can be used as a symptomatic treatment for menopause, where it decreases weight gain and osteoporosis, as well as for polycystic ovary syndrome (PCOS).

Green Tea (Camellia sinensis): A Review of Its Phytochemistry, Pharmacology, and Toxicology

Objectives Green tea (Camellia sinensis) is a kind of unfermented tea that retains the natural substance in fresh leaves to a great extent. It is regarded as the second most popular drink in the world besides water. In this paper, the phytochemistry, pharmacology, and toxicology of green tea are reviewed systematically and comprehensively. Key findings Green tea has been demonstrated to be good for human health. Nowadays, multiple pharmacologically active components have been isolated and identified from green tea, including tea polyphenols, alkaloids, amino acids, polysaccharides, and volatile components. Recent studies have demonstrated that green tea shows versatile pharmacological activities, such as antioxidant, anticancer, hypoglycemic, antibacterial, antiviral, and neuroprotective. Studies on the toxic effects of green tea extract and its main ingredients have also raised concerns including hepatotoxicity and DNA damage. Summary Green tea can be used to assist the treatment of diabetes, Alzheimer’s disease, oral cancer, and dermatitis. Consequently, green tea has shown promising practical prospects in health care and disease prevention.

Non-fermented tea consumption protects against osteoporosis among Chinese male elders using the Taiwan biobank database

Few studies compared the effects of non-fermented and fermented tea among the general population. We aimed to compare the risk of incident osteoporosis (OP) between non-fermented tea and fermented tea drinkers by this retrospective nationwide population-based analysis from the Taiwan Biobank. Participants ≥ 40 years who drink fermented tea (n = 2205) were compared with those who drink non-fermented tea (n = 1034) from 2008 to 2015 with a mean follow-up period of 3.64 years. OP was defined by T-score ≤ − 2.5. Multivariate Cox proportional hazards regression models were performed to estimate the risk of developing OP between the two groups. Separate models were used to determine the relationship between tea consumption and OP stratified by sex and age. There was a significant interaction between sex, age, and type of tea consumed. In men aged ≥ 60 years, the risk of developing OP decreased by 79% for those who drank non-fermented tea (hazard ratio, 0.21; 95% confidence level, 0.05–0.94) than those who drank fermented tea. Additionally, those with a family history of OP had a higher risk of developing osteoporosis. This study suggests that male elderly who consume non-fermented tea have a lower risk of OP. Drinking non-fermented tea, such as green tea, could be suggested, especially for those with a family history of osteoporosis.

Innovative Application of Chicken Eggshell Calcium to Improve the Functional Value of Gingerbread

Food waste, such as eggshell, can be an environmental problem if it is not properly managed. One of the ways to solve this is by using the eggshell as the cheap calcium source in food products. Polish gingerbread fortified with chicken eggshell powder (ESP) calcium was developed to solve the eggshell waste problem and to reduce the risk of osteoporosis. This study focused on the effect of ESP addition on basic composition, sensory evaluation, and antioxidative activity of gingerbread. Two samples of gingerbread without and with 3% (w/w of wheat flour) ESP, with controlled green tea powder (4% w/w of white chocolate) were analyzed. Results of the research showed that the addition of 3% ESP significantly increased the ash and calcium content (p < 0.05) without changing the appearance, aroma, texture, taste profiles, and the hedonic score of gingerbread. The gingerbread samples were then stored for 2 months and were analyzed every month. The hedonic evaluation of the aroma of both gingerbread samples decreased significantly (p < 0.05) during storage. During 2 months of storage, the antioxidative activity of gingerbread fortified with 3% ESP was not significantly different compared to the control (p > 0.05), particularly in ABTS and ORACFL assay. The ABTS, DPPH, and ORACFL assays showed decreasing antioxidative activity during storage, which was also in accordance with decreasing total phenolic content of both gingerbread samples. In PCL assay, the lipid-soluble antioxidant activity in gingerbread with 3% ESP was significantly higher during 2 months of storage, compared to the control (p < 0.05). The developed product might be a potential alternative to improve the calcium (26% daily value (DV) recommendation per 100 g) and antioxidant intake in order to prevent calcium deficiency. Gingerbread enriched with an organic source of calcium may become an innovative product to reduce the risk of developing osteoporosis in the elderly population, having potential health and economic significance, given the incidence of osteoporosis and the costs of treating this disease.

Anti-Osteoporotic Mechanisms of Polyphenols Elucidated Based on In Vivo Studies Using Ovariectomized Animals

Polyphenols are widely known for their antioxidant activity, i.e., they have the ability to suppress oxidative stress, and this behavior is mediated by the autoxidation of their phenolic hydroxyl groups. Postmenopausal osteoporosis is a common health problem that is associated with estrogen deficiency. Since oxidative stress is thought to play a key role in the onset and progression of osteoporosis, it is expected that polyphenols can serve as a safe and suitable treatment in this regard. Therefore, in this review, we aimed to elucidate the anti-osteoporotic mechanisms of polyphenols reported by in vivo studies involving the use of ovariectomized animals. We categorized the polyphenols as resveratrol, purified polyphenols other than resveratrol, or polyphenol-rich substances or extracts. Literature data indicated that resveratrol activates sirtuin 1, and thereafter, suppresses osteoclastogenic pathways, such as the receptor activator of the nuclear factor kappa B (RANK) ligand (RANKL) pathway, and promotes osteoblastogenic pathways, such as the wingless-related MMTV integration site pathway. Further, we noted that purified polyphenols and polyphenol-rich substances or extracts exert anti-inflammatory and/or antioxidative effects, which inhibit RANKL/RANK binding via the NF-κB pathway, resulting in the suppression of osteoclastogenesis. In conclusion, antioxidative and anti-inflammatory polyphenols, including resveratrol, can be safe and effective for the treatment of postmenopausal osteoporosis based on their ability to regulate the imbalance between bone formation and resorption.

Relationship between Regular Green Tea Intake and Osteoporosis in Korean Postmenopausal Women: A Nationwide Study

Mixed results have been reported regarding whether habitual tea intake affects bone health. This study investigated the relationship between green tea intake and bone mineral density (BMD) in postmenopausal Korean women. We used data from the Korean National Health and Nutrition Examination Surveys from 2008 to 2011 and divided the participants into three groups according to their frequency of green tea intake over the past 12 months. BMD of the lumbar spine, total femur, and femur neck was measured using dual-energy X-ray absorptiometry. The odds ratios (ORs) and 95% confidence intervals (CIs) of osteoporosis and osteopenia according to green tea consumption were analyzed. Participants who did not consume green tea or consumed less than one cup per day were more likely to have osteopenia of the lumbar spine or femur than those who consumed it once to three times a day (OR 1.81 and 1.85, 95% CI, 1.20–2.71; and 1.23–2.77). Moreover, ORs for osteoporosis were 1.91 (95% CI 1.13–3.23) and 1.82 (95% CI 1.09–3.05) in non-consumers and consumers who drank less than one cup per day, respectively, compared with the reference group. These results support that green tea consumption may have benefits on bone health.

Modifiable lifestyle factors associated with fragility hip fracture: a systematic review and meta-analysis

INTRODUCTION

Among the various hip fracture predictors explored to date, modifiable risk factors warrant special consideration, since they present promising targets for preventative measures. This systematic review and meta-analysis aims to assess various modifiable risk factors.

MATERIAL AND METHODS

We searched four online databases in September 2017. We included studies that reported on modifiable lifestyle risk factors for sustaining fragility hip fractures. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). The inclusion criteria consisted of (1) adult patients with osteoporotic hip fracture, (2) original study, (3) availability of full text articles in English, and (4) report of a modifiable lifestyle risk factor.

RESULTS

Thirty-five studies, containing 1,508,366 subjects in total, were included in this study. The modifiable risk factors that were significantly associated with an increased risk of hip fracture were the following: weight < 58 kg (128 lbs) (pooled OR 4.01, 95% CI 1.62-9.90), underweight body mass index (BMI) (< 18.5) (pooled OR 2.83, 95% CI 1.82-4.39), consumption of ≥ 3 cups of coffee daily (pooled OR 2.27, 95% CI 1.04-4.97), inactivity (pooled OR 2.14, 95% CI 1.21-3.77), weight loss (pooled OR 1.88, 95% CI 1.32-2.68), consumption of ≥ 27 g (approx. > 2 standard drinks) alcohol per day (pooled OR 1.54, 95% CI 1.12-2.13), and being a current smoker (pooled OR 1.50, 95% CI 1.22-1.85). Conversely, two factors were significantly associated with a decreased risk of hip fracture: obese BMI (> 30) (pooled OR 0.58, 95% CI 0.34-0.99) and habitual tea drinking (pooled OR 0.72, 95% CI 0.66-0.80).

CONCLUSION

Modifiable factors may be utilized clinically to provide more effective lifestyle interventions for at risk populations. We found that low weight and underweight BMI carried the highest risk, followed by high coffee consumption, inactivity, weight loss, and high daily alcohol consumption.

Diphlorethohydroxycamalol isolated from Ishige okamurae prevents H2O2-induced oxidative damage via BMP2/Runx2 signaling in osteoblastic MC3T3-E1 cells

Accumulating evidence has shown an association between osteoporosis and oxidative damage. In the present study, the protective effects of diphlorethohydroxycarmalol (DPHC) isolated from the brown algae Ishige okamurae against H2O2-induced oxidative damage via bone morphogenetic protein 2 (BMP2)/ runt-related transcription factor 2 (Runx2) signaling were investigated using MC3T3-E1 osteoblastic cells. DPHC counteracted the reduction in cell viability caused by H2O2 exposure and protected against H2O2-induced dysfunction, demonstrated by improved cellular alkaline phosphatase (ALP) activity and calcium deposition. In addition, treatment with 0.05-0.2 mM DPHC elevated the protein expression of osteoblast differentiation factors type 1 collagen, ALP, p-Smad1/5, Osterix, BMP2, and Runx2, in response to H2O2-induced oxidative damage. Importantly, DPHC decreased the expression levels of receptor activator of nuclear factor kappa-B ligand, which promotes bone resorption, and inhibited the H2O2-induced generation of reactive oxygen species. Taken together, the results suggest that DPHC counteracts the effects of oxidative stress in osteoblastic cells and has the potential to be effective in preventing and alleviating osteoporosis.

Antiosteoporotic effect of hesperidin against ovariectomy-induced osteoporosis in rats via reduction of oxidative stress and inflammation

Osteoporosis is a serious health problem, especially in geriatric patients. Worldwide, it affects 8.9 million people every year. Oxidative stress and inflammation expand the osteoporosis reaction. Hesperidin supplement helps to decrease inflammation and oxidative stress. In this study, we estimated the antiosteoporotic effect of hesperidin against the ovariectomized (OVX) rat model of osteoporosis. Hesperidin was orally administered at 5, 10, and 20 mg/kg to OVX rats for 10 weeks. Different biochemical parameters, such as alkaline phosphatase (ALP), osteocalcin (OC), phosphorus (P), calcium (Ca), and antioxidant parameters, were also estimated. The three-point bending test, bone mineral density (BMD), and histomorphometric features of the femoral bone were also scrutinized. Hesperidin significantly decreased body weight and increased uterine weight. Hesperidin significantly reduced the ALP, OC, acid phosphatase, and β-isomerized C-terminal telopeptides levels in OVX rats. Hesperidin considerably increased BMD and dose-dependently reduced the pixel density. Hesperidin considerably increased the maximum load, energy, stiffness, maximum stress, and young modulus. Hesperidin significantly (p < 0.001) reduced the levels of thiobarbituric acid reactive substance and increased the level of superoxide dismutase, glutathione, glutathione peroxidase, catalase in OVX-induced rats. Hesperidin significantly diminishes the cytokine levels, such as tumor necrosis factor-α, interleukin-6 (IL-6), and IL-1β, and inflammatory mediators such as nuclear factor-kappa B. It significantly reduced the level of Ca, P, and increased the level of vitamin D in OVX rats. Hesperidin significantly (p < 0.001) reduced the expression of sirtuin 1. Collectively, we can conclude that hesperidin exhibited better protection against osteoporosis by enhancing the bone density and bone mineral content in addition to biomechanical parameters.

Natural medicine delivery from biomedical devices to treat bone disorders: A review

With an increasing life expectancy and aging population, orthopedic defects and bone graft surgeries are increasing in global prevalence. Research to date has advanced the understanding of bone biology and defect repair mechanism, leading to a marked success in the development of synthetic bone substitutes. Yet, the quest for functionalized bone grafts prompted the researchers to find a viable alternative that regulates cellular activity and supports bone regeneration and healing process without causing serious side-effects. Recently, researchers have introduced natural medicinal compounds (NMCs) in bone scaffold that enables them to release at a desirable rate, maintains a sustained release allowing sufficient time for tissue in-growth, and guides bone regeneration process with minimized risk of tissue toxicity. According to World Health Organization (WHO), NMCs are gaining popularity in western countries for the last two decades and are being used by 80% of the population worldwide. Compared to synthetic drugs, NMCs have a broader range of safety window and thus suitable for prolonged localized delivery for bone regeneration. There is limited literature focusing on the integration of bone grafts and natural medicines that provides detailed scientific evidences on NMCs, their toxic limits and particular application in bone tissue engineering, which could guide the researchers to develop functionalized implants for various bone disorders. This review will discuss the emerging trend of NMC delivery from bone grafts, including 3D-printed structures and surface-modified implants, highlighting the significance and potential of NMCs for bone health, guiding future paths toward the development of an ideal bone tissue engineering scaffold. STATEMENT OF SIGNIFICANCE: To date, additive manufacturing technology provids us with many advanced patient specific or defect specific bone constructs exhibiting three-dimensional, well-defined microstructure with interconnected porous networks for defect-repair applications. However, an ideal scaffold should also be able to supply biological signals that actively guide tissue regeneration while simultaneously preventing post-implantation complications. Natural biomolecules are gaining popularity in tissue engineering since they possess a safer, effective approach compared to synthetic drugs. The integration of bone scaffolds and natural biomolecules exploits the advantages of customized, multi-functional bone implants to provide localized delivery of biochemical signals in a controlled manner. This review presents an overview of bone scaffolds as delivery systems for natural biomolecules, which may provide prominent advancement in bone development and improve defect-healing caused by various musculoskeletal disorders.

Functional Food for Elderly High in Antioxidant and Chicken Eggshell Calcium to Reduce the Risk of Osteoporosis-A Narrative Review

The elderly population is increasing globally and is predicted to reach 1.5 billion in 2050. The quality of life of the elderly must be concerned, for example, with developing functional food for the elderly. In this article, the development of functional food to reduce the risk of osteoporosis in the elderly is reviewed. Oxidative stress is one of the factors which accelerates osteoporosis. Various antioxidants, including vitamin C, vitamin E, polyphenols, or lycopene, have been proven by former studies to have antioxidant activity, therefore, could reduce the risk of osteoporosis. Additionally, the application of eggshell powder in various food products has been reported to improve calcium intake, and its usage is environmentally sustainable as this could contribute to reducing food waste. The application of both antioxidants and calcium could be a good combination, but the amount of some antioxidants must be concerned so it would not interfere with the bioavailability of calcium. Therefore, this review aims to explore the functional food for the elderly to reduce the risk of osteoporosis, particularly with antioxidants and calcium from chicken eggshells. The eating preference and dietary pattern of the elderly are also considered to determine the suitable form of functional food for the elderly. The results presented in the study may be the basis for the development of new calcium-enriched food products for the elderly.

Green tea extract synergistically enhances the effectiveness of an antiresorptive drug on management of osteoporosis induced by ovariectomy in a rat model

Antiresorptive drugs are effective for reducing bone loss in postmenopausal women, but their long-term application may be associated with adverse effects. The present study aimed to investigate the potential in vivo synergistic effects of green tea extract (GTE) and alendronate or raloxifene on the management of osteoporosis. Ovariectomized rats were fed orally with GTE, alendronate and raloxifene at different concentrations and various combinations for 4 weeks. Bone mineral density (BMD) at the lumbar spine, femur and tibia was monitored weekly using peripheral quantitative computed tomography. Bone microarchitecture in the left distal femur was analyzed using micro-CT, while serum biochemical levels were measured using ELISA kits at the end of the study. GTE alone effectively mitigated BMD loss and improved bone microarchitecture in rats. The co-administration of GTE and alendronate increased total BMD in the lumbar spine, femur and tibia. Particularly, GTE synergistically enhanced the effect of alendronate at a low dose on bone microarchitecture and decreased serum tartrate-resistant acid phosphatase. These findings imply that the dosage of certain antiresorptive agents could be reduced when they are administrated simultaneously with GTE, so that their adverse effects are minimized. The findings may be used to support the development of a new synergistic intervention between food therapy and pharmacotherapy on the management of osteoporosis in a long-term basis.

Osteoprotective Roles of Green Tea Catechins

Osteoporosis is the second most common disease only secondary to cardiovascular disease, with the risk of fracture increasing with age. Osteoporosis is caused by an imbalance between osteoblastogenesis and osteoclastogenesis processes. Osteoclastogenesis may be enhanced, osteoblastogenesis may be reduced, or both may be evident. Inflammation and high reactive oxygen enhance osteoclastogenesis while reducing osteoblastogenesis by inducing osteoblast apoptosis and suppressing osteoblastic proliferation and differentiation. Catechins, the main polyphenols found in green tea with potent anti-oxidant and anti-inflammatory properties, can counteract the deleterious effects of the imbalance of osteoblastogenesis and osteoclastogenesis caused by osteoporosis. Green tea catechins can attenuate osteoclastogenesis by enhancing apoptosis of osteoclasts, hampering osteoclastogenesis, and prohibiting bone resorption in vitro. Catechin effects can be directly exerted on pre-osteoclasts/osteoclasts or indirectly exerted via the modulation of mesenchymal stem cells (MSCs)/stromal cell regulation of pre-osteoclasts through activation of the nuclear factor kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. Catechins also can enhance osteoblastogenesis by enhancing osteogenic differentiation of MSCs and increasing osteoblastic survival, proliferation, differentiation, and mineralization. The in vitro effects of catechins on osteogenesis have been confirmed in several animal models, as well as in epidemiological observational studies on human subjects. Even though randomized control trials have not shown that catechins provide anti-fracture efficacy, safety data in the trials are promising. A large-scale, placebo-controlled, long-term randomized trial with a tea regimen intervention of optimal duration is required to determine anti-fracture efficacy.

Osteoprotective effect of green tea polyphenols and annatto-extracted tocotrienol in obese mice is associated with enhanced microbiome vitamin K2 biosynthetic pathways

The role of the gut microbiome in bone health has received significant attention in the past decade. We investigated the effects of green tea polyphenols (GTP) and annatto-extracted tocotrienols (AT) on bone properties and gut microbiome in obese mice. Male mice were assigned to a two (no AT vs. 400 mg/kg diet AT) × two (no GTP vs. 0.5% w/v GTP) factorial design, namely control, G, T, and G+T group respectively, for 14 weeks. The 4th lumbar vertebra (LV-4) and femur were harvested for bone microstructural analysis using μ-CT. Microbiome analysis using 16S rRNA gene sequencing of cecal feces was performed. AT increased bone volume at distal femur. GTP increased serum procollagen type 1 N-terminal propeptide concentration, bone volume at the distal femur and the LV-4, and trabecular number at distal femur; whereas GTP decreased trabecular separation at distal femur. Interactions between GTP and AT were observed in serum C-terminal telopeptide of type I collagen level (control>G=T=G+T) as well as the cortical bone area (control<G=T=G+T) and thickness (T≥G+T≥G≥control) at femur mid-diaphysis. Redundancy analysis showed a significant difference in the gut microbiome profile among different groups and the relative abundance of Akkermansia muciniphila, Clostridum saccharogumia, and Subdoligranulum variabile was increased in the GTP- and AT-supplemented groups. Functional profiling of the gut microbiome showed the combination of GTP and AT induced biosynthetic pathways for vitamin K₂. Our results suggest that GTP and AT supplementation benefits bone properties in obese mice through modifying gut microbiome composition and function.

Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals

Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.

White Tea Reduced Bone Loss by Suppressing the TRAP/CTX Pathway in Ovariectomy-Induced Osteoporosis Model Rats

Osteoporosis is an important skeletal disease characterized by bone weakness and high risk of fracture in postmenopausal women. Tea consumption is known to play an important role in the prevention or alleviation of osteoporosis. However, the therapeutic effects of aqueous extracts of white tea (WT) have not been evaluated in osteoporosis rat models. The aim of this study was to investigate the potential anti-osteoporotic role of WT in ovariectomized (OVX) rats. WT was given orally at 0.5% w/v doses for 12 weeks in OVX rats. Biochemical parameters in blood samples, bone tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide of type 1 collagen (CTX) and estradiol levels were evaluated. Bone mineral density and bone mineral content values were measured in the left femur. In addition to histopathological examination, osteolcalcin, osteopontin and TUNEL levels were determined. OVX group data demonstrated that bone loss occurred by thinning of the metaphyseal growth plates of the femur. Similarly, the levels of TRAP and CTX, markers of osteoclastic activity, were found to be high concurrently with a decrease in femoral bone mineral density. In addition, increased osteolcalcin and osteopontin levels were present in the metaphyseal growth zones. On the other hand, while TRAP and CTX levels were suppressed in the OVX-WT group, bone mineral content increased. In ad­dition, TUNEL, osteocalcin and osteopontin positivity decreased in the right femoral metaphysis growth zones, proliferating zone and resting zone cells. These results showed that chronic WT consumption has a protective effect by reducing bone resorption in OVX-induced osteoporotic rats.

Proanthocyanidin-rich grape seed extract improves bone loss, bone healing, and implant osseointegration in ovariectomized animals

The purpose of the present study was to confirm if proanthocyanidin-rich grape seed extract (GSE) had the ability to improve bone health such as bone loss, bone healing, and implant osseointegration (defined as the direct connection between bone tissue and an implant) in ovariectomized (OVX) animals. We demonstrated that daily oral administration of GSE prevented bone loss in the lumbar vertebrae and femur in OVX mice. In addition, osteoclastogenesis in the lumbar spine bone of OVX mice, as assessed by histological and histomorphometric analyses, was accelerated but GSE prevented this dynamization, suggesting that GSE could counteract OVX-induced accelerated osteoclastogenic activity. In rats, OVX clearly impaired the healing of defects created on the calvaria, and GSE overcame this OVX-impaired healing. In the same way, osseointegration of a tibial implant in rats was retarded by OVX, and GSE counteracted the OVX-induced poor osseointegration, likely promoting bone healing by preventing imbalanced bone turnover. These results suggest that orally administered GSE improved implant osseointegration by mitigating the impaired bone health induced by OVX as a model of estrogen deficiency.

Polyphenol-Rich Foods and Osteoporosis

BACKGROUND

Osteoporosis is a metabolic disease affecting the bone mineral density and thus compromise the strength of the bones. Disease prevention through diet is the objective of the study and discussion. Among the several nutrients investigated, the intake of phenols seems to influence bone mineral density by acting as free radical scavengers, preventing oxidation-induced damage to bone cells. In addition, the growing understanding of the bone remodelling process supports the theory that inflammation significantly contributes to the etiopathogenesis of osteoporosis.

METHODS

To provide an overview of current evidence on polyphenol-rich foods and osteoporosis prevention we made a comprehensive review of the literature focusing on the state of art of the topic.

RESULTS

Some polyphenol-rich foods, including olive oil, fruit and vegetable, tea and soy, seem to be beneficial for preventing osteoporosis disease and its progression. The mechanism is still partly unknown and may involve different pathways which include inflammation and other disease reactions.

CONCLUSIONS

However, further research is needed to better understand the mechanisms regulating the molecular interaction between osteoporosis incidence and progression and polyphenol-rich foods. The current evidence suggests that dietary intervention with polyphenol rich foods may be useful to prevent incidence and progression of this condition.

Natural Medicinal Compounds in Bone Tissue Engineering

Recent advances in 3D printing have provided unprecedented opportunities in bone tissue engineering applications for producing a variety of complex patient-specific implants for the treatment of critical-sized bone defects. Natural medicinal compounds (NMCs) with osteogenic potential can be incorporated into these 3D-printed parts to improve bone formation and therefore enhance implant performance. Using NMCs to treat bone-related disorders may prove to be a healthy preventive choice as they are considered safe, have lesser or no side effects, and are more suitable for prolonged use than synthetic drugs. In this review paper, the current challenges of bone tissue engineering are addressed briefly, highlighting the immense potential of NMCs integrated within tissue engineering scaffolds for orthopedic and dental applications.

Polyphenols from grape pomace induce osteogenic differentiation in mesenchymal stem cells

Polyphenols are increasingly investigated for the treatment of periodontitis and research on their use in dental biomaterials is currently being conducted. Grape pomace extracts are a rich source of polyphenols. In the present study, the polyphenols of two different types of grape pomace were characterized and identified by high-performance liquid chromatography-diode array detector, and the effect of polyphenol-rich grape pomace extracts on mesenchymal stem cell (MSC) osteogenic differentiation was investigated. Solid-liquid extraction was used to recover polyphenols from red and white grape pomace. The two extracts have been characterized through the phenolic content and antioxidant power. Human MSCs (hMSCs) from the bone marrow were cultured both with and without given amounts (10 or 20 µg/ml) of the obtained pomace extracts. Their effects on cell differentiation were evaluated by reverse transcription-quantitative polymerase chain reaction, compared with relevant controls. Results showed that both pomace extracts, albeit different in phenolic composition and concentration, induced multiple effects on hMSC gene expression, such as a decreased receptor activator of nuclear factor κ-B ligand/osteoprotegerin ratio and an enhanced expression of genes involved in osteoblast differentiation, thus suggesting a shift of hMSCs towards osteoblast differentiation. The obtained results provided data in favor of the exploitation of polyphenol properties from grape pomace extracts as complementary active molecules for dental materials and devices for bone regeneration in periodontal defects.

Red Rooibos Tea Stimulates Osteoblast Mineralization in a Dose-Dependent Manner

Most studies show a positive association between higher tea intake and bone mineral density (BMD), while associations with fracture are inconclusive. Although a few studies have investigated the potential effects of rooibos tea on the bone cell metabolism, only 1 or 2 doses were tested or specific flavonoids were evaluated in isolation. A dose-response study is needed to comprehensively identify whether a level that modulates bone cell activity is associated with dietary or supplemental levels of red rooibos (RR) tea. We investigated if RR tea stimulates mineralization in a dose-dependent manner. Mineralization was induced in Saos-2 cells in the presence of RR tea (0.1–10 µg/mL of polyphenols) or control (dH2O) for 5 days. Cell activity, mRNA, protein expression and activity of key regulators of mineralization were measured. A positive dose-dependent relationship was observed between RR tea concentration and mineralization accompanied with similar trends in cell activity. With high concentrations of tea, protein expression of enzymes directly regulating mineralization (ALP and NPP1) were unchanged but ALP activity was significantly elevated. Osteopontin (OPN) was significantly downregulated midway through mineralization while sclerostin (SOST) was upregulated in response to higher concentrations of RR tea. In conclusion, RR tea stimulated osteoblast mineralization in a dose-dependent manner and were accompanied with downregulation of OPN, increased ALP activity, and increased cell activity.

Effect of Long-Term Green Tea Polyphenol Supplementation on Bone Architecture, Turnover, and Mechanical Properties in Middle-Aged Ovariectomized Rats

We investigated the effects of 6-month green tea polyphenols (GTP) supplementation on bone architecture, turnover, and mechanical properties in middle-aged ovariectomized (OVX) rats. Female rats were sham-operated (n = 39, 13/group) or OVX (n = 143, 13/group). Sham-control and OVX-control rats (n = 39) receiving no GTP were assigned for sample collection at baseline, 3, or 6 months. The remaining OVX rats (n = 104) were randomized to 0.15%, 0.5%, 1%, and 1.5% (g/dL) GTP for 3 or 6 months. Blood and bone samples were collected. Relative to the OVX-control group, GTP (1% and 1.5%) lowered serum procollagen type 1 N-terminal propeptide at 3 and 6 months, C-terminal telopeptides of type I collagen at 3 months, and insulin-like growth factor-I at 6 months. GTP did not affect bone mineral content and density. At 6 months, no dose of GTP positively affected trabecular bone volume based on microCT, but a higher cortical thickness and improved biomechanical properties of the femur mid-diaphysis was observed in the 1.5% GTP-treated group. At 3 and 6 months, GTP (0.5%, 1%, and 1.5%) had lower rates of trabecular bone formation and resorption than the OVX-control group, but the inhibitory effects of GTP on periosteal and endocortical bone mineralization and formation at the tibial midshaft were only evident at 3 months. GTP at higher doses suppressed bone turnover in the trabecular and cortical bone of OVX rats and resulted in improved cortical bone structural and biomechanical properties, although it was not effective in preventing the ovariectomy-induced dramatic cancellous bone loss.

Effects of the Hydroalcoholic Extract of the Psidium guajava Fruit on Osteoporosis Prevention in Ovariectomized Rats

BACKGROUND

Several plants have been shown to possess antioxidant and estrogenic properties that can be useful in postmenopausal bone-loss prevention. The present study aimed to investigate the anti-osteoporotic effects of the hydroalcoholic extract of the Psidium guajava (PG) fruit in ovariectomized (OVX) rats.

METHODS

Sixty female Sprague-Dawley rats were randomly divided into 6 groups: a control positive group, a sham-operated group, an OVX group given normal saline (OVX-only group), and 3 treatment groups comprising 2 OVX groups treated orally with 500 and 1000 mg/kg/d of the hydroalcoholic extract of the PG fruit respectively and an OVX group treated with an injection of 0.15 mg/kg of estradiol. The study was conducted over a 12-week period. Samples from the animals' blood, femoral bones, and uteri were collected for stereological and biochemical analyses. The data were analyzed using SPSS, version 19. A P value equal to or less than 0.05 was considered statistically significant.

RESULTS

The results revealed a significant decrease in the levels of calcium, total antioxidant capacity, and phosphorus as well as uterus weight, femoral ash density, femoral volume and weight, and numbers of osteocytes and osteoblasts. Moreover, there was an increase in the levels of alkaline phosphatase and urine deoxypyridinoline together with a rise in the number of osteoclasts in the OVX-only group compared to the control and treatment groups (P≤0.05). The hydroalcoholic extract of the PG fruit increased femoral weight and volume, femoral ash density, numbers of osteocytes and osteoblasts, and trabecular volume of the bones in comparison with the OVX-only group in a dose-dependent manner. No significant difference was observed between the groups in the levels of malondialdehyde and interleukin-6.

CONCLUSION

The hydroalcoholic extract of the PG fruit prevented OVX-induced bone loss in the rats, with no proliferative effect on atrophic uteri; it should, therefore, be considered for treatment purposes.

Green tea (Camellia sinensis) aqueous extract alleviates postmenopausal osteoporosis in ovariectomized rats and prevents RANKL-induced osteoclastogenesis in vitro

Background

Green tea (Camelliasinensis [L.] Kuntze) belongs to the plant family Theaceae and is mainly distributed in East Asia, the Indian subcontinent and Southeast Asia. This plant has been proven to be beneficial to human health, and green tea is the second most consumed beverage in the world after water. However, until now, the effect of green tea aqueous extract (GTE) upon postmenopausal osteoporosis has remained unclear. In this study, we investigated the therapeutic effects of GTE on estrogen deficiency-induced osteoporosis and explored the possible mechanisms in vivo and in vitro.

Materials and methods

Ovariectomized (OVX) female rats were orally administered with GTE at doses of 60, 120, and 370 mg kg⁻¹ for 13 consecutive weeks. The biochemical parameters, bone gla protein, alkaline phosphatase, acid phosphatase, estrogen, interleukin-1β, and interleukin-6 in blood samples were detected, and histological change in bones was analyzed by hematoxylin and eosin staining. Meanwhile, the mechanisms of GTE on osteoclast formation were explored in RAW 264.7 cells induced by receptor activation of the nuclear factor kappa B ligand (RANKL).

Results

The results showed that GTE could increase bone mass and inhibit trabecular bone loss in OVX rats. Furthermore, real-time quantitative reverse transcription polymerase chain reaction analysis from in vitro experiments also showed that GTE reduced the mRNA expression of osteoclast-associated genes such as cathepsin K (cath-K), c-Fos, matrix metalloproteinase 9, nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and tartrate-resistant acid phosphatase. In addition, GTE caused a reduction in the protein levels of NFATc1, c-Fos, c-src and cath-K.

Conclusion

Evidence from both animal models and in vitro experiments suggested that GTE might effectively ameliorate the symptoms of osteoporosis in OVX rats and inhibit RANKL-induced osteoclast-specific gene and protein expression.

Repression of IGF-I-induced osteoblast migration by (-)-epigallocatechin gallate through p44/p42 MAP kinase signaling

Polyphenolic compounds in beverages may have benefits in the prevention of osteoporosis. It has been demonstrated previously that insulin-like growth factor-I (IGF-I) could stimulate the migration of osteoblasts. In the present study, it was investigated whether chlorogenic acid, a major polyphenol in coffee, and (-)-epigallocatechin gallate (EGCG), a major polyphenol in green tea, could affect this IGF-I-stimulated migration of osteoblast-like MC3T3-E1 cells. The IGF-I-stimulated osteoblast migration, evaluated by Transwell cell migration and wound-healing assays, was inhibited by EGCG but not chlorogenic acid. IGF-I induced the phosphorylation of p44/p42 mitogen-activated protein (MAP) kinase, p70 S6 kinase and Akt. The IGF-I-induced migration was suppressed by PD98059, a MAP kinase kinase 1/2 inhibitor, and deguelin, an Akt inhibitor, but not rapamycin, an inhibitor of the upstream kinase of p70 S6 kinase (mammalian target of rapamycin). EGCG attenuated the IGF-I-induced phosphorylation of p44/p42 MAP kinase but not Akt. Taken together, the present results suggest that EGCG inhibits IGF-I-induced osteoblast migration via p44/p42 MAP kinase.

Actual solubility (S|real.|), level of hydrophilic-lipophilic balance (HLBRequ., HLBD, HLBG) and partition coefficient (log P) of phytochemicals contained in Ext. Camellia sinensis L. aqu. siccum in the light of general Hildebrand-Scatchard-Fedors theory of solubility

Introduction: Using the general Hildebrand-Scatchard-Fedors theory of solubility, the mole fraction (x2) of solubility of phytochemicals contained in the dry green tea leaves was calculated which determines the profile of pharmacological activity.

Objective: The applicative purpose of the study was to estimate the actual solubility of phytochemicals – S|real.| [mol/dm3] in water and in water-ethanol solutions of diversified polarity (εM) for their selective extraction and optimal formulation of oral solid dosage form.

Methods: The basic physico-chemical and structural quantities of phytochemicals and corresponding mathematical equations of general Hildebrand-Scatchard-Fedors theory of solubility were used to calculate the actual solubility – S|real.| and the level of hydrophilic-lipophilic balance (HLB).

Results: The calculated actual solubility values – S|real.| [mol/dm3] collated with correlation equations enabled the assessment of phytochemical capability for the process of mass exchange on phase boundary. Correlation equations for the dependence log P = f (– log S|real.|) point to the structural preferences of phytochemicals in the kinetics of the mass exchange (diffusion) through the natural phase boundary.

Conclusions: Calculations and correlations between the values characterizing the actual solubility – S|real.|, media polarity (water, ethanol and their solutions) and the partition coefficient (log P) including the level of hydrophilic-lipophilic balance (HLB) show that basing on thermodynamic components of the general Hildebrand-Scatchard-Fedors theory of solubility, the diffusion profile of phytochemicals contained in the green tea extract (Ext. Camellia sinensis L. aqu. siccum) through the biological phase boundary as well as optimal choice of the extraction medium for selective extraction of the class of phytochemicals can be estimated.

The Role of Semipurified Fractions Isolated from Quercus infectoria on Bone Metabolism by Using hFOB 1.19 Human Fetal Osteoblast Cell Model

Background. Quercus infectoria (QI) is a plant used in traditional medicines in Asia. The plant was reported to contain various active phytochemical compounds that have potential to stimulate bone formation. However, the precise mechanism of the stimulation effect of QI on osteoblast has not been elucidated. The present study was carried out to isolate QI semipurified fractions from aqueous QI extract and to delineate the molecular mechanism of QI semipurified fraction that enhanced bone formation by using hFOB1.19 human fetal osteoblast cell model. Methods. Isolation of QI semipurified fractions was established by means of column chromatography and thin layer chromatography. Established QI semipurified fractions were identified using Liquid Chromatography-Mass Spectrometry (LC-MS). Cells were treated with derived QI semipurified fractions and investigated for mineralization deposition and protein expression level of BMP-2, Runx2, and OPN by ELISA followed gene expression analysis of BMP-2 and Runx2 by RT-PCR. Results. Column chromatography isolation and purification yield Fractions A, B, and C. LC-MS analysis reveals the presence of polyphenols in each fraction. Results show that QI semipurified fractions increased the activity and upregulated the gene expression of BMP-2 and Runx2 at day 1, day 3, and day 7. OPN activity increased in cells treated with QI semipurified fractions at day 1 and day 3. Meanwhile, at day 7, expression of OPN decreased in activity. Furthermore, the study showed that combination of Fractions A, B, and C with osteoporotic drug (pamidronate) further increased the activity and upregulated the gene expression of BMP-2 and Runx2. Conclusions. These findings demonstrated that polyphenols from semipurified fractions of QI enhanced bone formation through expression of the investigated bone-related marker that is its potential role when combined with readily available osteoporotic drug.

Long-Term Intake of Green Tea Extract Causes Mal-Conformation of Trabecular Bone Microarchitecture in Growing Rats

The purpose of this study was to examine the effects of green tea extract (GTE) intake on bone structural and physiological properties, such as bone mass, trabecular bone microarchitecture, cortical bone geometry, and bone mechanical strength, in growing rats. Four-week-old male Wistar rats were divided into the following four groups: standard diet feeding for 85 days (S-CON) or 170 days (L-CON), and GTE diet feeding for 85 days (S-GTE) or 170 days (L-GTE). At the end of the experiment, in addition to measurement of circulating bone formation/resorption markers, bone mass, trabecular bone microarchitecture, and cortical bone geometry were analyzed in the left femur, and bone mechanical strength of the right femur was measured. There was no difference in all bone parameters between the S-CON and S-GTE groups. On the other hand, the L-GTE group showed the decrease in some trabecular bone mass/microarchitecture parameters and no change in cortical bone mass/geometry parameters compared with the L-CON group, and consequently the reduction in bone weight corrected by body weight. There was no difference in bone formation/resorption markers and bone mechanical strength between the S-CON and S-GTE groups and also between the L-CON and L-GTE groups. However, serum leptin levels were significantly lower in the L-GTE group than in the L-CON group. Thus, the long-term GTE intake had negative effects on bone, especially trabecular bone loss and microarchitecture mal-conformation, in growing rats.

Association between tea consumption and osteoporosis: A meta-analysis

BACKGROUND

Previous reports have suggested a potential association of tea consumption with the risk of osteoporosis. As such association is controversial, we conducted a meta-analysis to assess the relationship between tea consumption and osteoporosis.

METHODS AND FINDINGS

We systematically searched PubMed, EMBASE and WanFang databases until March 30, 2016, using the keywords "tea and osteoporosis," without limits of language. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were derived by using random-effects models throughout the analyses. We conducted the analysis of the statistical heterogeneity using Cochrane I. The funnel plot was used to speculate the publication bias, while the subgroup analysis and multiround elimination method were employed.

RESULTS

Our study was based on 17 journal articles, including 2 prospective cohort studies, 4 case-control studies, and 11 cross-sectional studies. In the present study, the total OR of osteoporosis for the highest versus the lowest categories of tea consumption was 0.62 (95% CI, 0.46-0.83), with significant heterogeneity among studies (I = 94%, P < .01). There was, however, no publication bias of the meta-analysis about tea consumption and osteoporosis. Subgroup analysis showed that tea consumption could reduce the risk of osteoporosis in all examined subgroups.

CONCLUSION

In the present study, it can be concluded from the results that tea consumption can reduce the risk of osteoporosis.

Safety Evaluation of Green Tea Polyphenols Consumption in Middle-aged Ovariectomized Rat Model

This work evaluates chronic safety in middle-aged ovariectomized rats supplemented with different dosages of green tea polyphenols (GTP) in drinking water. The experiment used 6-mo-old sham (n = 39) and ovariectomized (OVX, n = 143) female rats. All sham (n = 39) and 39 of the OVX animals received no GTP treatment and their samples were collected for outcome measures at baseline, 3 mo, and 6 mo (n = 13 per group for each). The remaining OVX animals were randomized into 4 groups receiving 0.15%, 0.5%, 1%, and 1.5% (n = 26 for each) of GTP (wt/vol), respectively, in drinking water for 3 and 6 mo. No mortality or abnormal treatment-related findings in clinical observations or ophthalmologic examinations were noted. No treatment-related macroscopic or microscopic findings were noted for animals administered 1.5% GTP supplementation. Throughout the study, there was no difference in the body weight among all OVX groups. In all OVX groups, feed intake and water consumption significantly decreased with GTP dose throughout the study period. At 6 mo, GTP intake did not affect hematology, clinical chemistry, and urinalysis, except for phosphorus and blood urea nitrogen (increased), total cholesterol, lactate dehydrogenase, and urine pH (decreased). This study reveals that the no-observed-adverse-effect level (NOAEL) of GTP is 1.5% (wt/vol) in drinking water, the highest dose used in this study.

Protective Effect of Chokeberry (Aronia melanocarpa L.) Extract against Cadmium Impact on the Biomechanical Properties of the Femur: A Study in a Rat Model of Low and Moderate Lifetime Women Exposure to This Heavy Metal

The hypothesis that the consumption of Aronia melanocarpa berries (chokeberries) extract, recently reported by us to improve bone metabolism in female rats at low-level and moderate chronic exposure to cadmium (1 and 5 mg Cd/kg diet for up to 24 months), may increase the bone resistance to fracture was investigated. Biomechanical properties of the neck (bending test with vertical head loading) and diaphysis (three-point bending test) of the femur of rats administered 0.1% aqueous chokeberry extract (65.74% of polyphenols) or/and Cd in the diet (1 and 5 mg Cd/kg) for 3, 10, 17, and 24 months were evaluated. Moreover, procollagen I was assayed in the bone tissue. The low-level and moderate exposure to Cd decreased the procollagen I concentration in the bone tissue and weakened the biomechanical properties of the femoral neck and diaphysis. Chokeberry extract administration under the exposure to Cd improved the bone collagen biosynthesis and femur biomechanical properties. The results allow for the conclusion that the consumption of chokeberry products under exposure to Cd may improve the bone biomechanical properties and protect from fracture. This study provides support for Aronia melanocarpa berries being a promising natural agent for skeletal protection under low-level and moderate chronic exposure to Cd.

Updated association of tea consumption and bone mineral density: A meta-analysis

BACKGROUND

Current studies evaluating the association of tea consumption and bone mineral density (BMD) have yielded inconsistent findings. Therefore, we conducted a meta-analysis to assess the relationship between tea consumption and BMD.

METHODS

The PubMed, Embase, and Cochrane Library databases were comprehensively searched, and a meta-analysis performed of all observational studies assessing the association of tea consumption and BMD. Forest plots were used to illustrate the results graphically. The Q-test and I statistic were employed to evaluate between-study heterogeneity. Potential publication bias was assessed by the funnel plot.

RESULTS

Four cohort, 1 case-control, and 8 cross-sectional studies including a total of 12,635 cases were included. Tea consumption was shown to prevent bone loss [odds ratio (OR): 0.66; 95% confidence interval (CI), 0.47-0.94; P = 0.02], yielding higher mineral densities in several bones, including the lumbar spine [standardized mean difference (SMD): 0.19; 95% CI, 0.08-0.31; P = 0.001], hip (SMD: 0.19; 95% CI, 0.05-0.34; P = 0.01), femoral neck [mean difference (MD): 0.01; 95% CI, 0.00-0.02; P = 0.04], Ward triangle (MD: 0.02; 95% CI, 0.01-0.04; P = 0.001), and greater trochanter (MD: 0.03; 95% CI, 0.02-0.04; P < 0.00001), than the non-tea consumption group.

CONCLUSION

This meta-analysis provided a potential trend that tea consumption might be beneficial for BMD, especially in the lumbar spine, hip, femoral neck, Ward triangle, and greater trochanter, which might help prevent bone loss.

Comparison of black, green and rooibos tea on osteoblast activity

Globally, tea is the second most consumed beverage after water. Habitual tea intake has been associated with higher bone mineral density, particularly in postmenopausal women. This association may be due to its polyphenols and resulting protective antioxidant effects. While in vivo studies have shown improved bone outcomes with a consumption of individual purified tea polyphenols, it is unclear if a particular tea - due to its different profiles of polyphenols - is more beneficial than others. Therefore, we compared three different types of commercially available teas on osteoblasts: green, black and rooibos tea. Tea was normalized to 1 or 10 μg per mL gallic acid equivalents to assess differences in outcomes based on tea profiles rather than the quantity of polyphenol naturally present. The lower level of polyphenols (1 μg per mL gallic acid equivalents) - regardless of tea type and thus polyphenol profile - resulted in greater mineral content as well as cellular and alkaline phosphatase activity in Saos2 cells. Moreover, this was associated with higher markers of differentiation (osteopontin, sclerostin) and reduced cellular toxicity and pro-inflammatory markers (IL6, TNFα). Green, black and rooibos tea improved osteoblast activity at the low level and support epidemiological evidence suggesting tea consumption may benefit bone heath.

Green tea and exercise interventions as nondrug remedies in geriatric patients with rheumatoid arthritis

This study aimed to evaluate the effects of green tea and supervised exercise training interventions on improvement of disease activity and bone metabolism markers in rheumatoid arthritis patients. [Subjects and Methods] One-hundred and twenty subjects who had a mean age of (60.7 ± 2.53 years) and had been diagnosed with rheumatoid arthritis at least ten years previously were randomly included in this study. Patients were treated with infliximab, green tea, or a supervised exercise program for six months. Disease activity markers as well as antioxidant activity of green tea extracts were estimated before supplementation using in vitro assays. [Results] Rheumatoid arthritis patients treated with green tea for 6 months alone or in combination with infliximab or an exercise program showed significant improvement in disease activity parameters, including C-reactive protein, and erythrocyte sedimentation rate, swollen and tender joints counts, and modified Stanford Health Assessment Questionnaire score, along with an increase in serum levels of bone resorption markers, i.e., deoxypyridinoline, amino-terminal telopeptide of type 1 collagen, and bone alkaline phosphatase, at 6 months of after initial treatment. The European League Against Rheumatism and American College of Rheumatology scores revealed more clinical improvement in the disease activity of rheumatoid arthritis patients treated with green tea along with exercise compared with rheumatoid arthritis patients treated with infliximab or exercise combinations. This may have been due to the higher potential antioxidant activity of green tea (89.6% to 96.5%). [Conclusion] Both exercise and green tea interventions appeared to be beneficial as nondrug modulates for rheumatoid arthritis disorders.

Noni leaf and black tea enhance bone regeneration in estrogen-deficient rats

OBJECTIVE

Black tea and Nonileaf are among the dietary compounds that can benefit patients with bone resorption disorders. Their bone regeneration effects and their mechanisms were studied in estrogen-deficient rats.

METHODS

Noni leaves (three doses) and black tea water extracts were fed to ovariectomized rats for 4 mo, and their effects (analyzed via mechanical measurements, micro-computed tomography scan, and reverse transcriptase polymerase chain reaction mRNA) were compared with Remifemin (a commercial phytoestrogen product from black cohosh).

RESULTS

The water extracts (dose-dependently for noni leaves) increased bone regeneration biomarker (runt-related transcription factor 2, bone morphogenetic protein 2, osteoprotegerin, estrogen receptor 1 [ESR1], collagen type I alpha 1A) expressions and reduced the inflammatory biomarkers (interleukin-6, tumor necrosis factor-α, nuclear factor [NF]-κB, and receptor activator of NF-κB ligand) mRNA expressions/levels in the rats. The extracts also improved bone physical and mechanical properties. The extracts demonstrated bone regeneration through improving bone size and structure, bone mechanical properties (strength and flexibility), and bone mineralization and density.

CONCLUSIONS

The catechin-rich extract favored bone regeneration and suppressed bone resorption. The mechanisms involved enhancing osteoblast generation and survival, inhibiting osteoclast growth and activities, suppressing inflammation, improving bone collagen synthesis and upregulating ESR1 expression to augment phytoestrogenic effects. Estrogen deficiency bone loss and all extracts studied (best effect from Morinda leaf at 300 mg/kg body weight) mitigated the loss, indicating benefits for the aged and menopausal women.

Tea flavonoids for bone health: from animals to humans

Osteoporosis is a skeletal disease characterized by a deterioration of bone mass and bone quality that predisposes an individual to a higher risk of fragility fractures. Emerging evidence has shown that the risk for low bone mass and osteoporosis-related fractures can be reduced by nutritional approaches aiming to improve bone microstructure, bone mineral density, and strength. Tea and its flavonoids, especially those of black tea and green tea, have been suggested to protect against bone loss and to reduce risk of fracture, due to tea's antioxidant and anti-inflammatory properties. Based on the results of animal studies, moderate intake of tea has shown to benefit bone health as shown by mitigation of bone loss and microstructural deterioration as well as improvement of bone strength and quality. Epidemiological studies have reported positive, insignificant, and negative impacts on bone mineral density at multiple skeletal sites and risk of fracture in humans with habitual tea consumption. There are limited human clinical trials that objectively and quantitatively assessed tea consumption and bone efficacy using validated outcome measures in a population at high risk for osteoporosis, along with safety monitoring approach. This review summarizes the current state of knowledge of laboratory animal research, epidemiological observational studies, and clinical trials assessing the skeletal effects of tea and its active flavonoids, along with discussion of relevant future directions in translational research.

Evaluation of epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes and concerns on osteoblasts

Collagen membranes have ideal biological and mechanical properties for supporting infiltration and proliferation of osteoblasts and play a vital role in guided bone regeneration (GBR). However, pure collagen can lead to inflammation, resulting in progressive bone resorption. Therefore, a method for regulating the level of inflammatory cytokines at surgical sites is paramount for the healing process. Epigallocatechin-3-gallate (EGCG) is a component extracted from green tea with numerous biological activities including an anti-inflammatory effect. Herein, we present a novel cross-linked collagen membrane containing different concentrations of EGCG (0.0064%, 0.064%, and 0.64%) to regulate the level of inflammatory factors secreted by pre-osteoblast cells; improve cell proliferation; and increase the tensile strength, wettability, and thermal stability of collagen membranes. Scanning electron microscope images show that the surfaces of collagen membranes became smoother and the collagen fiber diameters became larger with EGCG treatment. Measurement of the water contact angle demonstrated that introducing EGCG improved membrane wettability. Fourier transform infrared spectroscopy analyses indicated that the backbone of collagen was intact, and the thermal stability was significant improved in differential scanning calorimetry. The mechanical properties of 0.064% and 0.64% EGCG-treated collagen membranes were 1.5-fold greater than those of the control. The extent of cross-linking was significantly increased, as determined by a 2,4,6-trinitrobenzenesulfonic acid solution assay. The Cell Counting Kit-8 (CCK-8) and live/dead assays revealed that collagen membrane cross-linked by 0.0064% EGCG induced greater cell proliferation than pure collagen membranes. Additionally, real-time polymerase chain reaction and enzyme-linked immunosorbent assay results showed that EGCG significantly affected the production of inflammatory factors secreted by MC3T3-E1 cells. Taken together, our results indicate that treatment of collagen membranes with appropriate concentrations of EGCG has an anti-inflammatory effect and shows promise for GBR applications.

Epigallocatechin-3-gallate Protects against Hydrogen Peroxide-Induced Inhibition of Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells

Oxidative stress induces bone loss and osteoporosis, and epigallocatechin-3-gallate (EGCG) may be used to combat these diseases due to its antioxidative property. Herein, oxidative stress in human bone marrow-derived mesenchymal stem cells (BM-MSCs) was induced by H₂O₂, resulting in an adverse effect on their osteogenic differentiation. However, this H₂O₂-induced adverse effect was nullified when the cells were treated with EGCG. In addition, treatment of BM-MSCs with EGCG alone also resulted in the enhancement of osteogenic differentiation of BM-MSCs. After EGCG treatment, expressions of β-catenin and cyclin D1 were upregulated, suggesting that the Wnt pathway was involved in the effects of EGCG on the osteogenic differentiation of BM-MSCs. This was also confirmed by the fact that the Wnt pathway inhibitor, Dickkopf-1 (DKK-1), can nullify the EGCG-induced enhancement effect on BM-MSC's osteogenic differentiation. Hence, our results suggested that EGCG can reduce the effects of oxidative stress on Wnt pathway in osteogenic cells, which supported a potentially promising therapy of bone disorders induced by oxidative stress. Considering its positive effects on BM-MSCs, EGCG may also be beneficial for stem cell-based bone repair.

Epigallocatechin-3-gallate protects against tumor necrosis factor alpha induced inhibition of osteogenesis of mesenchymal stem cells

Anabolic bone accruement through osteogenic differentiation is important for the maintenance of physiological bone mass and often disrupted in various inflammatory diseases. Epigallocatechin-3-gallate, as an antioxidant and anti-inflammatory agent, has been suggested for potential therapeutic use in this context, possibly by the inhibition of bone resorption as well as the enhancement of bone formation through directly activating osteoblast differentiation. However, the reported effects of epigallocatechin-3-gallate modulating osteoblast differentiation are mixed, and the underlying molecular mechanism is still elusive. Moreover, there is limited information regarding the effects of epigallocatechin-3-gallate on osteogenic potential of mesenchymal stem cell in inflammation. Here, we examined the in vitro osteogenic differentiation of human mesenchymal stem cells. We found that the cell viability and osteoblast differentiation of human bone marrow-derived mesenchymal stem cells are significantly inhibited by inflammatory cytokine TNFα treatment. Epigallocatechin-3-gallate is able to enhance the cell viability and osteoblast differentiation of mesenchymal stem cells and is capable of reversing the TNFα-induced inhibition. Notably, only low doses of epigallocatechin-3-gallate have such benefits, which potentially act through the inhibition of NF-κB signaling that is stimulated by TNFα. These data altogether clarify the controversy on epigallocatechin-3-gallate promoting osteoblast differentiation and further provide molecular basis for the putative clinical use of epigallocatechin-3-gallate in stem cell-based bone regeneration for inflammatory bone loss diseases, such as rheumatoid arthritis and prosthetic osteolysis.

Commercial Honeybush (Cyclopia spp.) Tea Extract Inhibits Osteoclast Formation and Bone Resorption in RAW264.7 Murine Macrophages-An in vitro Study

Honeybush tea, a sweet tasting caffeine-free tea that is indigenous to South Africa, is rich in bioactive compounds that may have beneficial health effects. Bone remodeling is a physiological process that involves the synthesis of bone matrix by osteoblasts and resorption of bone by osteoclasts. When resorption exceeds formation, bone remodeling can be disrupted resulting in bone diseases such as osteoporosis. Osteoclasts are multinucleated cells derived from hematopoietic precursors of monocytic lineage. These precursors fuse and differentiate into mature osteoclasts in the presence of receptor activator of NF-kB ligand (RANKL), produced by osteoblasts. In this study, the in vitro effects of an aqueous extract of fermented honeybush tea were examined on osteoclast formation and bone resorption in RAW264.7 murine macrophages. We found that commercial honeybush tea extract inhibited osteoclast formation and TRAP activity which was accompanied by reduced bone resorption and disruption of characteristic cytoskeletal elements of mature osteoclasts without cytotoxicity. Furthermore, honeybush tea extract decreased expression of key osteoclast specific genes, matrix metalloproteinase-9 (MMP-9), tartrate resistant acid phosphatase (TRAP) and cathepsin K. This study demonstrates for the first time that honeybush tea may have potential anti-osteoclastogenic effects and therefore should be further explored for its beneficial effects on bone.