Piceatannol stimulates osteoblast differentiation that may be mediated by increased bone morphogenetic protein-2 production

Medicinal plants of Southeast Asia with anti-α-glucosidase activity as potential source for type-2 diabetes mellitus treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus, a widespread chronic illness, affects millions worldwide, and its incidence is increasing alarmingly, especially in developing nations. Current pharmacological treatments can be costly and have undesirable side effects. To address this, medicinal plants with antidiabetic effects, particularly targeting α-glucosidase for controlling hyperglycaemia in type-2 diabetes mellitus (T2DM), hold promise for drug development with reduced toxicity and adverse reactions.

AIM OF THIS REVIEW

This review aims to succinctly collect information about medicinal plant extracts that exhibit antidiabetic potential through α-glucosidase inhibition using acarbose as a standard reference in Southeast Asia. The characteristics of this inhibition are based on in vitro studies.

MATERIALS AND METHODS

Relevant information on medicinal plants in Southeast Asia, along with α-glucosidase inhibition studies using acarbose as a positive control, was gathered from various scientific databases, including Scopus, PubMed, Web of Science, and Google Scholar.

RESULTS

About 49 papers were found from specific counties in Southeast Asia demonstrated notable α-glucosidase inhibitory potential of their medicinal plants, with several plant extracts showcasing activity comparable to or surpassing that of acarbose. Notably, 19 active constituents were identified for their α-glucosidase inhibitory effects.

CONCLUSIONS

The findings underscore the antidiabetic potential of the tested medicinal plant extracts, indicating their promise as alternative treatments for T2DM. This review can aid in the development of potent therapeutic medicines with increased effectiveness and safety for the treatment of T2DM.

Microbiota and Resveratrol: How Are They Linked to Osteoporosis?

Osteoporosis (OP), which is characterized by a decrease in bone density and increased susceptibility to fractures, is closely linked to the gut microbiota (GM). It is increasingly realized that the GM plays a key role in the maintenance of the functioning of multiple organs, including bone, by producing bioactive metabolites such as short-chain fatty acids (SCFA). Consequently, imbalances in the GM, referred to as dysbiosis, have been identified with a significant reduction in beneficial metabolites, such as decreased SCFA associated with increased chronic inflammatory processes, including the activation of NF-κB at the epigenetic level, which is recognized as the main cause of many chronic diseases, including OP. Furthermore, regular or long-term medications such as antibiotics and many non-antibiotics such as proton pump inhibitors, chemotherapy, and NSAIDs, have been found to contribute to the development of dysbiosis, highlighting an urgent need for new treatment approaches. A promising preventive and adjuvant approach is to combat dysbiosis with natural polyphenols such as resveratrol, which have prebiotic functions and ensure an optimal microenvironment for beneficial GM. Resveratrol offers a range of benefits, including anti-inflammatory, anti-oxidant, analgesic, and prebiotic effects. In particular, the GM has been shown to convert resveratrol, into highly metabolically active molecules with even more potent beneficial properties, supporting a synergistic polyphenol-GM axis. This review addresses the question of how the GM can enhance the effects of resveratrol and how resveratrol, as an epigenetic modulator, can promote the growth and diversity of beneficial GM, thus providing important insights for the prevention and co-treatment of OP.

Exploring the therapeutic potential of naturally occurring piceatannol in non-communicable diseases

Piceatannol is a naturally occurring hydroxylated resveratrol analogue that can be found in a variety of fruits and vegetables. It has been documented to have a wide range of beneficial effects, including anti-inflammatory, antioxidant, anti-aging, anti-allergic, antidiabetic, neuroprotective, cardioprotective, and chemopreventive properties. Piceatannol has significantly higher antioxidant activity than resveratrol. Piceatannol has been shown in preclinical studies to have the ability to inhibit or reduce the growth of cancers in various organs such as the brain, breast, lung, colon, cervical, liver, prostate, and skin. However, the bioavailability of Piceatannol is comparatively lower than resveratrol and other stilbenes. Several approaches have been reported in recent years to enhance its bioavailability and biological activity, and clinical trials are required to validate these findings. This review focuses on several aspects of natural stilbene Piceatannol, its chemistry, and its mechanism of action, and its promising therapeutic potential for the prevention and treatment of a wide variety of complex human diseases.

Greater habitual resveratrol intakes were associated with lower risk of hip fracture- a 1:1 matched case-control study in Chinese elderly

The aim of the study was to testify the association of dietary resveratrol (RSV) intakes with hip fracture risk in Chinese elderly. This was a 1:1 age- and gender- matched case-control study. Eligible cases were newly diagnosed patients of hip fracture. Dietary assessment was made by a 79-item validated food frequency questionnaire. Habitual RSV intakes were estimated as the sum of trans- and cis- isomers of resveratrol and piceid according to the available database. Multivariable conditional logistic regression was applied to examine the relationship of dietary RSV and RSV-rich foods with hip fracture risk. A total of 1,070 pairs of hip fracture incident cases and controls were recruited and 1,065 were included for analysis. Compared with the lowest group, total RSV in the highest quartile group had significantly reduced hip fracture risk by 66.3% (OR: 0.337, 0.222 ~ 0.571, p_trend  < 0.001). Similar findings were observed for cis- and trans-RSV, cis- and trans-Piceid, as well as RSV-rich foods (grapes, apples and nuts) respectively. Subgroup analysis suggested more evident findings among female and less obese participants. Our findings demonstrated that higher habitual RSV intakes and RSV-rich foods, even in a relatively low amount, were associated with reduced risk of hip fracture in Chinese elderly.

Piceatannol Suppresses the Proliferation and Induced Apoptosis of Osteosarcoma Cells Through PI3K/AKT/mTOR Pathway

Background

Piceatannol (PIC) is confirmed to inhibit the proliferation of various tumors, but its role in osteosarcoma still remains unknown. This study investigated the function of PIC in osteosarcoma, aiming to provide a research basis for osteosarcoma therapy.

Methods

Human osteosarcoma cells in this study were, respectively, treated with PIC at various concentrations (0, 20, 40, 80 μmol/L), PI3K/AKT/mTOR pathway inhibitor (LY294002), or pathway activator (740Y-P) plus PIC. Osteosarcoma cells were subcutaneously injected into nude mice to establish xenograft models, and PIC was intraperitoneally injected into models. The activity, proliferation, apoptosis and cell cycle of treated cells were determined by MTT test, colony formation assay or a flow cytometry. The expressions of PI3K/AKT/mTOR pathway-related proteins in cells and tumor tissues were measured by Western blot (WB) analysis.

Results

PIC (40 and 80 μmol/L) and LY294002 availably suppressed activity and proliferation and induced apoptosis of osteosarcoma cells. PIC observably increased the number of cells retarded in G2 phase, but decreased the cell percentages in G1 and S phases. Conversely, 740Y-P reversed the effects of PIC on osteosarcoma cells, which promoted cell activity and proliferation and restrained apoptosis. In xenograft models, the volume and weight of the tumors treated by PIC were visibly alleviated than those untreated. The PI3K/AKT/mTOR pathway was prominently inhibited in PIC-treated osteosarcoma cells and tumor tissues.

Conclusion

PIC suppresses the proliferation and induces apoptosis of osteosarcoma cells through regulating PI3K/AKT/mTOR pathway, which is expected to be the therapeutic of osteosarcoma.

MicroRNA-410 participates in the pathological process of postmenopausal osteoporosis by downregulating bone morphogenetic protein-2

The present study aimed to investigate bone morphogenetic protein (BMP)-2 and microRNA (miR)-410 expression and the mechanism of regulation in serum and CD¹⁴⁺ peripheral blood mononuclear cells (PBMCs) from postmenopausal osteoporosis patients and model mice. A total of 26 patients with postmenopausal osteoporosis were included in the experimental group and 29 age-matched healthy subjects were included in the control group. A total of 60 mice were divided into sham and ovariectomized (OVX) groups. Following surgery, 28 mice remained in the sham and 25 mice remained in OVX group. BMP-2 protein expression in serum and CD¹⁴⁺ PBMCs from patients and model mice was determined using ELISA and western blotting, respectively. Reverse transcription-quantitative polymerase chain reaction assays were performed to determine miR-410 and BMP-2 mRNA levels in serum and CD¹⁴⁺ PBMCs from patients and model mice. Dual luciferase reporter assays were used to identify direct interactions between miR-410 and BMP-2 mRNA. Compared with the control group, BMP-2 mRNA and protein expression in serum and CD¹⁴⁺ PBMCs from patients with postmenopausal osteoporosis and model mice were significantly decreased. miR-410 levels in serum and CD¹⁴⁺ PBMCs from patients with postmenopausal osteoporosis and model mice were significantly increased when compared with the control group. Dual luciferase reporter assays revealed that BMP-2 was a target gene of miR-410. The current study demonstrated that decreased BMP-2 expression in serum and CD¹⁴⁺ PBMCs from patients with postmenopausal osteoporosis was associated with the upregulation of miR-410. These results suggest that miR-410 may participate in the pathological process of postmenopausal osteoporosis by downregulating BMP-2.

Effects of resveratrol supplementation on bone biomarkers: a systematic review and meta-analysis

The current study presents a comprehensive systematic review and meta-analysis of randomized controlled trials (RCTs) on resveratrol and bone health biomarkers. PubMed, Scopus, and Web of Science (until September 2018) were searched to identify the potential RCTs with information on resveratrol supplementation and bone metabolism biomarkers. Mean differences (MD) were analyzed using a random-effects model. Pooling six RCTs (eight treatment arms with 264 subjects) together identified no significant reduction of serum Ca, osteocalcin, C-terminal telopeptide of type I collagen, and procollagen I N-terminal propeptide values after resveratrol supplementation over placebo treatment. However, a significant increase in serum alkaline phosphatase (ALP) (MD: 5.69 mg/mL, 95% CI: 3.58-7.80, I²  = 95.7%, P < 0.001) and bone alkaline phosphatase (BAP) (MD: 10.57 mmHg, 95% CI: 5.36-15.78, I²  = 99.2%, P < 0.001) values was observed after resveratrol treatment relative to placebo. The findings of this study indicate that resveratrol supplementation increased some key bone biomarkers, such as ALP and BAP. Further precise clinical trials of the effects of resveratrol supplementation on bone health should be conducted.

Piceatannol is superior to resveratrol in promoting neural stem cell differentiation into astrocytes

Piceatannol (3,3',4',5-trans-tetrahydroxystilbene) is a polyphenolic compound abundant in the seeds of passion fruit (Passiflora edulis). Piceatannol is an analogue of resveratrol (3,4',5-trans-trihydroxystilbene) and shares the structural motif and biological activities such as activation of SIRT1. Several studies have shown that piceatannol is more potent than resveratrol. In this study, we examined the effects of piceatannol on neural stem cell differentiation into astrocytes compared with those of resveratrol. At a concentration of 2.5 μM, piceatannol promoted astrocyte differentiation, while resveratrol had no effect at this concentration. Furthermore, we found that oral administration of piceatannol increased the number of astrocytes in the brains of adult mice, while resveratrol administration showed no effects. These results suggest that piceatannol has a superior effect to resveratrol in promoting astrocyte differentiation.

Molecular signaling mechanisms behind polyphenol-induced bone anabolism

For millennia, in the different cultures all over the world, plants have been extensively used as a source of therapeutic agents with wide-ranging medicinal applications, thus becoming part of a rational clinical and pharmacological investigation over the years. As bioactive molecules, plant-derived polyphenols have been demonstrated to exert many effects on human health by acting on different biological systems, thus their therapeutic potential would represent a novel approach on which natural product-based drug discovery and development could be based in the future. Many reports have provided evidence for the benefits derived from the dietary supplementation of polyphenols in the prevention and treatment of osteoporosis. Polyphenols are able to protect the bone, thanks to their antioxidant properties, as well as their anti-inflammatory actions by involving diverse signaling pathways, thus leading to bone anabolic effects and decreased bone resorption. This review is meant to summarize the research works performed so far, by elucidating the molecular mechanisms of action of polyphenols in a bone regeneration context, aiming at a better understanding of a possible application in the development of medical devices for bone tissue regeneration.

Therapeutic Potential and Molecular Targets of Piceatannol in Chronic Diseases

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene; PIC) is a naturally occurring stilbene present in diverse plant sources. PIC is a hydroxylated analog of resveratrol and produced from resveratrol by microsomal cytochrome P450 1A11/2 and 1B1 activities. Like resveratrol, PIC has a broad spectrum of health beneficial effects, many of which are attributable to its antioxidative and anti-inflammatory activities. PIC exerts anticarcinogenic effects by targeting specific proteins involved in regulating cancer cell proliferation, survival/death, invasion, metastasis, angiogenesis, etc. in tumor microenvironment. PIC also has other health promoting and disease preventing functions, such as anti-obese, antidiabetic, neuroptotective, cardioprotective, anti-allergic, anti-aging properties. This review outlines the principal biological activities of PIC and underlying mechanisms with special focus on intracellular signaling molecules/pathways involved.

A Comprehensive Review on the Chemotherapeutic Potential of Piceatannol for Cancer Treatment, with Mechanistic Insights

Cancer is a diverse class of diseases characterized by uncontrolled cell growth that constitutes the greatest cause of mortality and morbidity worldwide. Despite steady progress, the treatment modalities of cancer are still insufficient. Several new concepts have emerged for therapeutic intervention in malignant diseases with the goal of identifying specific targets and overcoming resistance against current cytotoxic therapies. Many studies have reported the remarkable and significant properties of dietary plant polyphenols such as curcumin, resveratrol, flavopiridol, indirubin, magnolol, piceatannol, parthenolide, epigallocatechin gallate, and cucurbitacin as anticancer agents known for their pleiotropic effects on cancer, immune cells, and inflammation. Piceatannol, an analogue and metabolite of resveratrol, is a natural stilbene commonly found in grape skins and wine. Compared to resveratrol, this molecule exhibits superior bioactivities as an inhibitor of COX-1/2 and the CSN-associated kinase. Piceatannol is thought to be a potent natural compound with many therapeutic effects, such as the prevention of hypercholesterolemia, arrhythmia, atherosclerosis, angiogenesis, and cardiovascular diseases. It also demonstrates vasorelaxation, antioxidant, and anticancer activities. This comprehensive review summarizes the current data regarding the mechanisms of action of piceatannol, its chemopreventive properties, and its possible therapeutic potential against various types of human cancer.

Wine and bone health: a review

A light-to-moderate wine consumption has been shown to provide several beneficial effects on the skeletal system, including reduced risk of bone mass loss and fractures. Wine is rich in phenolic compounds, strong phytoestrogens and natural antioxidants, to which bone protection is mainly attributed. The objective of this review was to give an overview of the exact mechanisms by which wine consumption is involved in bone protection. We found a great variety of in vitro research on the beneficial effects of isolated wine phenolics on the skeletal system, with a significant lack of evidence of their in vivo effects. In addition, we found almost no studies investigating how wine, a mixture of these phenolics dissolved in ethanol, affects the skeletal system. Our results warrant further research on this interesting topic.

Piceatannol: a potential futuristic natural stilbene as fetal haemoglobin inducer

Beta thalassaemia is an autosomal recessive inherited blood disorder which results in abnormal formation of Haemoglobin molecule and ineffective erythropoiesis. Patients need to be dependent on habitual blood transfusion and on unaffordable exorbitant therapies for continued existence. It has been hypothesized that if the level of foetal Haemoglobin increases, it compensates the need of adult Haemoglobin and hence, ameliorates clinical symptoms associated with beta thalassaemia major. Illation from previous studies has proved that reactivation of foetal Haemoglobin with the aid of natural compounds is a better alternative therapy for patients of beta thalassaemia because of its cost effectiveness and occurrence in natural eatables. Piceatannol, a naturally occurring stilbene, is less studied compound in comparison to resveratrol, but it shows a wide range of biological activities. This article has mainly focused on piceatannol and its application as a foetal Haemoglobin inducer in future.

BMP signaling in development and diseases: a pharmacological perspective

Bone morphogenetic protein (BMP) signaling has been implicated in several processes during embryonic development and in adult tissue homeostasis. Maintenance of many organs such as skin, intestinal villi, bones and bone marrow requires continuous regeneration and subsequent differentiation of stem cells in order to maintain organ shape and size necessary for proper functioning. Although BMPs were initially identified as osteogenic factors present in demineralized bone capable of inducing ectopic bone formation, it is now evident that BMPs perform several other functions during embryonic development as well as during the adult life of an organism. Many disorders have been linked to either the BMPs or the molecules functioning downstream of BMP signaling pathway. This review summarizes the existing literature describing the role of BMP signaling during embryonic development and in adult tissue homeostasis to provide a perspective on pharmacological interventions of BMP signaling pathway to mitigate several disease conditions.

The "bone morphogenic proteins" pathways in bone and joint diseases: translational perspectives from physiopathology to therapeutic targets

A large body of evidence supports an important role of bone morphogenic proteins (BMPs) pathways in skeletal development in the embryo. BMPs are also involved in skeletal homeostasis and diseases in the adult. They were first identified as major bone anabolic agents and recent advances indicate that they also regulate osteoclastogenesis and joint components via multiple cross-talks with other signaling pathways. This review attempts to integrate these data in the pathogenesis of bone and joints diseases, such as osteoporosis, fracture healing, osteoarthritis, inflammatory arthritis, or bone metastasis. The use of recombinant BMPs in bone tissue engineering and in the treatment of skeletal diseases, or future therapeutic strategies targeting BMPs signal and its regulators, will be discussed based on these considerations.

Molecular mechanism of hesperetin-7-O-glucuronide, the main circulating metabolite of hesperidin, involved in osteoblast differentiation

Citrus fruit hesperidin is hydrolyzed by gut microflora into aglycone form (hesperetin) and then conjugated mainly into glucuronides. We previously demonstrated that hesperetin enhanced osteoblast differentiation. In this study, we examined the effect of hesperetin-7-O-glucuronide (Hp7G) on primary rat osteoblast proliferation and differentiation. The impact of Hp7G on specific bone signaling pathways was explored. Osteoblasts were exposed to physiological concentrations of 1 (Hp7G1) and 10 (Hp7G10) microM of conjugate. The glucuronide did not affect proliferation but enhanced differentiation by significantly increasing alkaline phosphatase (ALP) activity from day 14 of exposure. Hp7G significantly induced mRNA expression of ALP, Runx2, and Osterix after 48 h of exposure. Moreover, phosphorylation of Smad1/5/8 was enhanced by Hp7G, while ERK1/2 remained unchanged after 48 h. Hp7G decreased RANKL gene expression. These results suggest that Hp7G may regulate osteoblast differentiation through Runx2 and Osterix stimulation, and might be implicated in the regulation of osteoblast/osteoclast communication.

Hesperetin stimulates differentiation of primary rat osteoblasts involving the BMP signalling pathway

Hesperidin found in citrus fruits has been reported to be a promising bioactive compound for maintaining an optimal bone status in ovariectomized rodent models. In this study, we examined the capacity of hesperetin (Hp) to affect the proliferation, differentiation and mineralization of rodent primary osteoblasts. Then, the impact of Hp on signalling pathways known to be implicated in bone formation was explored. We exposed osteoblasts to physiological concentrations of 1 microM Hp (Hp1) and 10 microM Hp (Hp10). Neither proliferation nor mineralization was affected by Hp at either dose during 19 days of exposure. Hp at both doses enhanced differentiation by significantly increasing alkaline phosphatase (ALP) activity from Day 14 of exposure (Day 19: Hp1: +9%, Hp10: +14.8% vs. control; P<.05). However, Hp did not induce an obvious formation of calcium nodules. The effect of Hp10 on ALP was inhibited by addition of noggin protein, suggesting a possible action of this flavanone through the bone morphogenetic protein (BMP) pathway. Indeed, Hp10 significantly induced (1.2- to 1.4-fold) mRNA expression of genes involved in this signalling pathway (i.e., BMP2, BMP4, Runx2 and Osterix) after 48 h of exposure. This was strengthened by enhanced phosphorylation of the complex Smad1/5/8. Osteocalcin mRNA level was up-regulated by Hp only at 10 microM (2.2 fold vs. control). The same dose of Hp significantly decreased osteopontin (OPN) protein level (50% vs. control) after 14 days of culture. Our findings suggest that Hp may regulate osteoblast differentiation through BMP signalling and may influence the mineralization process by modulating OPN expression.

When nutrition interacts with osteoblast function: molecular mechanisms of polyphenols

Recent research has provided insights into dietary components that may optimise bone health and stimulate bone formation. Fruit and vegetable intake, as well as grains and other plant-derived food, have been linked to decreased risk of major chronic diseases including osteoporosis. This effect has been partially attributed to the polyphenols found in these foods. Thus, it has been suggested that these compounds may provide desirable bone health benefits through an action on bone cell metabolism. The present review will focus on how some polyphenols can modulate osteoblast function and reports which cellular signalling pathways are potentially implicated. However, to date, despite numerous investigations, few studies have provided clear evidence that phenolic compounds can act on osteoblasts. Polyphenols cited in the present review seem to be able to modulate the expression of transcription factors such as runt-related transcription factor-2 (Runx2) and Osterix, NF-kappaB and activator protein-1 (AP-1). It appears that polyphenols may act on cellular signalling such as mitogen-activated protein kinase (MAPK), bone morphogenetic protein (BMP), oestrogen receptor and osteoprotegerin/receptor activator of NF-kappaB ligand (OPG/RANKL) and thus may affect osteoblast functions. However, it is also important to take in account the possible interaction of these compounds on osteoclast metabolism to better understand the positive correlation reported between the consumption of fruit and vegetables and bone mass.

Screening of potential a disintegrin and metalloproteinase with thrombospondin motifs-4 inhibitors using a collagen model fluorescence resonance energy transfer substrate

The major components of the cartilage extracellular matrix are type II collagen and aggrecan. Type II collagen provides cartilage with its tensile strength, whereas the water-binding capacity of aggrecan provides compressibility and elasticity. Aggrecan breakdown leads to an increase in proteolytic susceptibility of articular collagen; hence, aggrecan may also have a protective effect on type II collagen. Given their role in aggrecan degradation and differing substrate specificity profiles, the pursuit of inhibitors for both aggrecanase 1 (a disintegrin and metalloproteinase with thrombospondin motifs-4 [ADAMTS-4]) and aggrecanase 2 (ADAMTS-5) is desirable. We previously described collagen model fluorescence resonance energy transfer (FRET) substrates for aggrecan-degrading members of the ADAMTS family. These FRET substrate assays are also fully compatible with multiwell formats. In the current study, a collagen model FRET substrate was examined for inhibitor screening of ADAMTS-4. ADAMTS-4 was screened against a small compound library (n=960) with known pharmacological activity. Five compounds that inhibited ADAMTS-4>60% at a concentration of 1muM were identified. A secondary screen using reversed-phase high-performance liquid chromatography (RP-HPLC) was developed and performed for verification of the five potential inhibitors. Ultimately, piceatannol was confirmed as a novel inhibitor of ADAMTS-4, with an IC(50) value of 1muM. Because the collagen model FRET substrates have distinct conformational features that may interact with protease secondary substrate sites (exosites), nonactive site-binding inhibitors can be identified via this approach. Selective inhibitors for ADAMTS-4 would allow a more definitive evaluation of this protease in osteoarthritis and also represent a potential next generation in metalloproteinase therapeutics.