Targeting the Role of PRME in Regulating Bone Remodelling During Postmenopausal Osteoporosis

Kariavattom Campus Postmenopausal osteoporosis (PMO) is an old age disorder associated with estrogen deficiency, which reduces bone mass and makes bones more prone to fracture. The present study was proposed to evaluate the invivo osteogenic efficiency of Pterospermum rubiginosum methanolic bark extract (PRME) in the PMO model. Molecular docking studies on transcription factor NFATC1 showed excellent interactions with phytochemical ligands with the lowest binding energies. Female Sprague Dawley (SD) rats (n=24) were divided into four groups, (n=6 each) sham control (Group I) and osteoporotic control (Group II) groups treated with saline, PRME (50 mg/kg/day) and alendronate (10 mg/kg/day) treated with Group III and Group IV (n=6) respectively. The serum tartrate-resistant acid phosphatase 5b and cathepsin-K also exhibited a significant rise after PRME treatment 12.33±2.30 mU/ml and 427.68±46.97 pg/ml, respectively. DEXA results exhibited a remarkable increase in total bone mineral content and density values in PRME-treated animals (0.175±0.002 g/cm2) and (7.95±0.23 g) when compared to osteoporotic control (0.163±0.004 g/cm2) and (6.83±0.34 g). Long-term toxicity study revealed that PRME is non-toxic, up to 100 mg/kg bodyweight for 6 months. Our findings suggest PRME protects osteoporotic SD rats from PMO damage resulting from estrogen deficiency by regulating bone remodelling markers and upregulating BMD indices.

Protective effect of Pterospermum rubiginosum bark extract on bone mineral density and bone remodelling in estrogen deficient ovariectomized Sprague-Dawley (SD) rats

Osteoporosis is a common metabolic old age disorder characterised by low bone mass content (BMC) and mineral density (BMD) with micro-architectural deterioration of the extracellular matrix, further increasing bone fragility risk. Several traditional remedies, including plant extracts and herbal formulations, are used worldwide by local healers to improve the overall bone health and metabolism as an excellent osteoregenerative agent. Pteropsermum rubiginosum is an underexplored medicinal plant used by tribal peoples of Western Ghats, India, to treat bone fractures and associated inflammation. The proposed study evaluates the elemental profiling and phytochemical characterisation of P. rubiginosum methanolic bark extract (PRME), along with detailed In vitro and In vivo biological investigation in MG-63 cells and Sprague-Dawley (SD) rats. AAS and ICP-MS analysis showed the presence of calcium, phosphorus, and magnesium and exceptional levels of strontium, chromium, and zinc in PRME. The NMR characterisation revealed the presence of vanillic acid, Ergost-4-ene-3-one and catechin. The molecular docking studies revealed the target pockets of isolated compounds and various marker proteins in the bone remodelling cycle. In vitro studies showed a significant hike in ALP and calcium content, along with upregulated mRNA expression of the ALP and COL1, which confirmed the osteoinductive activity of PRME in human osteoblast-like MG-63 cells. The in vivo evaluation in ovariectomised (OVX) rats showed remarkable recovery in ALP, collagen and osteocalcin protein after 3 months of PRME treatment. DEXA scanning reports in OVX rats supported the above in vitro and in vivo results, significantly enhancing the BMD and BMC. The results suggest that PRME can induce osteogenic activity and enhance bone formation with an excellent osteoprotective effect against bone loss in OVX animals due to estrogen deficiency.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03942-7.

An integrated approach to the structural characterization, long-term toxicological and anti-inflammatory evaluation of Pterospermum rubiginosum bark extract

ETHNOPHARMACOLOGICAL RELEVANCE OF STUDY

Pterospermum rubiginosum is an evergreen plant in Western Ghats, India, used by traditional tribal healers due to its excellent biological potential for treating inflammation and pain relief procedures. The bark extract is also consumed to relieve the inflammatory changes at the bone fractured site. The traditional medicinal plant in India have to be characterized for its diverse phytochemical moieties, its interactive multiple target sites, and to reveal the hidden molecular mechanism behind the biological potency.

AIM OF THE STUDY

The study focussed on plant material characterization, computational analysis (prediction study), toxicological screening (In vivo), and anti-inflammatory evaluation of P. rubiginosum methanolic bark extracts (PRME) in LPS-induced RAW 264.7 cells.

MATERIALS AND METHODS

The pure compound isolation of PRME and their biological interactions were used to predict the bioactive components, molecular targets, and molecular pathways of PRME in inhibiting inflammatory mediators. The anti-inflammatory effects of PRME extract were evaluated in the lipopolysaccharide (LPS)-induced RAW264.7 macrophage cell model. The toxicity evaluation of PRME was performed in healthy 30 Sprague-Dawley experimental rats, were randomly divided into five groups for toxicological evaluation for 90 days. The tissue levels of oxidative stress and organ toxicity markers were measured using the ELISA method. Nuclear magnetic resonance spectroscopy (NMR) was performed to characterize the bioactive molecules.

RESULTS

Structural characterization revealed the presence of vanillic acid, 4-O-methyl gallic acid, E-resveratrol, gallocatechin, 4'-O-methyl gallocatechin, and catechin. Molecular docking of NF-kB exhibited significant interactions with vanillic acid and 4-O-methyl gallic acid with binding energy -351.159 Kcal/Mol and -326.5505 Kcal/Mol, respectively. The PRME-treated animals showed an increase in total GPx and antioxidant levels (SOD and catalase). Histopathological examination revealed no variation in the liver, renal and splenic tissue's cellular pattern. PRME inhibited the pro-inflammatory parameters (IL-1β, IL-6, and TNF-α) in LPS-induced RAW 264.7 cells. The protein level of TNF-α and NF-kB protein expression study brought out a notable reduction and exhibited a good correlation with the gene expression study.

CONCLUSION

The current study establishes the therapeutic potential of PRME as an effective inhibitory agent against LPS-activated RAW 264.7 cells induced inflammatory mediators. Long-term toxicity evaluation on SD rats confirmed the non-toxic nature of PRME up to 250mg/body weight for 3 months.

Alcohol induced NLRP3 inflammasome activation in the brain of rats is attenuated by ATRA supplementation

Alcohol abuse affects several neurological pathways and causes significant alterations in the brain. Abstention from alcohol is an effective intervention against alcohol related diseases. But the recovery of the damaged cells to normal presents a major problem in those who have stopped alcohol consumption. Hence therapeutic interventions are needed. Our previous studies have shown that all trans retinoic acid (ATRA) is effective in reducing alcohol induced neuro toxicity. Chronic alcohol administration up-regulates and activates the NLRP3 inflammasome leading to caspase-1 activation and IL-1β production causing neuroinflammation. Hence, we investigated whether ATRA has any impact on NLRP3 inflammasomes activation. Rats were divided into two groups and were maintained for 90 days as control and ethanol group (4 ​g/kg body weight). After 90 days, ethanol administration was stopped and animals in the control group were divided into control and control ​+ ​ATRA (100 ​μg/kg body weight per day) groups; those in the ethanol group as ethanol abstention and ATRA (100 ​μg/kg body weight per day) and maintained for 30 days. Administration of ATRA reduced reactive oxygen species and endotoxins which were elevated in alcoholic rats. There was also reduction in the expression of NLRP3 inflammasome and caspase 1. Our results suggested ATRA down regulated NLRP3 activation with concomitant decrease in the release of caspase -1 and production of IL1β. However, all these parameters were higher in abstention in comparison with ATRA supplemented group. In short therapeutic intervention with ATRA regressed alcohol induced inflammasome activation better than abstention.

All trans retinoic acid modulates TNF-α and CYP2E1 pathways and enhances regression of ethanol-induced fibrosis markers in hepatocytes and HSCs in abstaining rodent model

Context: Our previous studies showed that all trans retinoic acid (ATRA) ameliorates alcohol-induced toxicity. Hence, we evaluated the efficacy of ATRA and abstention in the regression of alcohol-induced hepatotoxicity. Materials and methods: After ethanol administration to rats for 90 days, the regression of alcohol-induced toxicity was studied by supplementing ATRA at a dose of 100 μg/kg body weight for 30 days. It was also compared with animals in abstention. Results and discussion: Ethanol administration enhanced oxidative stress, activated HSCs and increased collagen deposition. All these alterations were reversed to a certain extent by ATRA supplementation. Conclusions: ATRA had better efficacy than just abstention in reducing ethanol-induced toxicity. The mechanism might be downregulation of CYP2E1, leading to reduced oxidative stress in the hepatocytes and thus impeding NFκB activation, cytokine production, activation of HSC and resulting in the reduction of inflammation and remodelling of fibrosis by modulating MMP and TIMP.

Sulfated polysaccharides from the edible marine algae Padina tetrastromatica attenuates isoproterenol-induced oxidative damage via activation of PI3K/Akt/Nrf2 signaling pathway - An in vitro and in vivo approach

The reactive oxygen species (ROS) induced oxidative stress is an inevitable factor for the pathogenesis of cardiovascular diseases. The edible marine algae-derived sulfated polysaccharides gained special attention as novel bioactive compounds having potential pharmacological activities. The present study evaluated in vitro and in vivo cardioprotective properties of sulfated polysaccharides from the edible brown marine algae Padina tetrastromatica (PSPS) against isoproterenol (ISO) induced cardiac damage. The cardioprotective properties of PSPS were first evaluated in H9c2 cardiac myoblasts and the results were confirmed by in vivo studies conducted in male Sprague-Dawley rats. The biochemical parameters, histopathological analysis, mRNA expressions, and ELISA studies indicated that PSPS significantly decreased (p < 0.05) the cardiac damage induced by ISO by reducing lipid peroxidation and improving antioxidant status, both in vitro and in vivo, via modulating PI3k/Akt/Nrf2 signaling pathway. The histopathological evidence further reinforced our findings and highlighted the promising cardioprotective activities offered by PSPS.

Isolation, identification and characterization of apigenin from Justicia gendarussa and its anti-inflammatory activity

Inflammatory responses during chronic diseases such as atherosclerosis, cancer etc., are harmful to host organisms. Generally NSAIDs are used to treat against these severe conditions but due to its adverse effects studies are going on with medicinal plants, since they are rich in bioactive compounds. Justicia gendarussa is one such plant which has been used as a remedial measure for treating inflammatory diseases since ancient time. Thus the present study involved in the isolation, characterization and identification of apigenin (flavonoid) from this plant and to elucidate its molecular mechanism against inflammation via TLR-NF-κB signaling pathway using ox-LDL induced hPBMCs in in vitro model. Methanolic extract was used for the isolation process and results showed that the F6 fraction collected from ethyl acetate through column chromatography showed 89% paw edema inhibition at a dose of 10 mg/kg in carrageenan induced rats. Purification of F6 by TLC with toluene: chloroform: acetone (8:5:7) and further characterization by ¹HNMR indicated the presence of bioactive compound, apigenin. In vitro studies revealed that pretreatment of ox-LDL induced hPBMCs with apigenin (25 μM) significantly (P < 0.05) reduced the levels of TLR4, MyD88, TRIF, TRAF6, NF-κB, COX-2, PGE2, IL-1β and TNF-α responsible for generating inflammation and elevated the level of anti-inflammatory cytokine, IL-10. These results indicate the therapeutic efficacy of bioflavonoid apigenin which was isolated from Justicia gendarussa against ox-LDL induced inflammation. Therefore apigenin can be treated as a suitable therapeutic agent against inflammatory diseases.

Molecular mechanisms of the antiglycative and cardioprotective activities of Psidium guajava leaves in the rat diabetic myocardium

CONTEXT

Antiglycative potential of Psidium guajava L. (Myrtaceae) leaves has been established. However, the molecular basis of its antiglycative potential remains unknown.

OBJECTIVE

The ethyl acetate fraction of P. guajava leaves (PGEt) was evaluated to determine the cardioprotective effect and its mechanism of action compared to quercetin.

MATERIALS AND METHODS

After the induction of diabetes by streptozotocin (55 mg/kg body weight), PGEt and quercetin (50 mg/kg body weight) was administered for 60 days. Rats were grouped as follows: Group C: Control, Group D: Diabetic, Group D + E: Diabetic rats treated with PGEt, Group D + Q: Diabetic rats treated with quercetin. The antiglycative potential was evaluated by assaying glycosylated haemoglobin, serum fructosamine and advanced glycation end product levels. The differential receptor for advanced glycation end products and nuclear factor kappa B (NFκB) protein levels was determined by western blot and the transcript level changes of connective tissue growth factor (CTGF), brain natriuretic peptide (BNP) and TGF-β1 in heart tissue were assessed by RT-PCR analysis.

RESULTS

Glycated haemoglobin and serum fructosamine levels were found to be enhanced in diabetic rats when compared with control. Administration of PGEt significantly reduced the glycated haemoglobin and fructosamine levels to a larger extent than quercetin treated diabetic rats. PGEt reduced the translocation of NFκB from cytosol to nucleus when compared with diabetic rats. Expression of TGF-β1, CTGF and BNP was downregulated in PGEt treated groups compared with diabetic controls.

DISCUSSION AND CONCLUSION

Administration of PGEt ameliorated diabetes associated changes in the myocardium to a greater extent than quercetin.

Role of cardiac isoform of alpha-2 macroglobulin in diabetic myocardium

Earlier studies from one of the investigator's laboratory have demonstrated the presence of a high molecular weight protein (182 kDa) in the blood serum of laboratory animals subjected to pressure-induced cardiac hypertrophy and suggested that this protein may be involved in the development of cardiac hypertrophy. Studies have shown that this protein is also involved in earlier stages of cardiac complications associated with diabetes, but the role of this protein in diabetic heart is less understood. So we aimed to check whether this protein is having any protective role in diabetic heart. The protein was purified from serum of rats induced with cardiac hypertrophy and the purified protein was injected through tail vein of diabetic rats for further studies. The results of various antioxidant enzymes and the TBARS levels have indicated the antioxidant activity of this protein. Real-time PCR analysis of gene expression revealed the upregulation of certain muscle-specific genes like β-MHC, MLC-2, and skeletal α actin in diabetic group and also in presence of 182-kDa protein. The results further showed a down regulation of genes such as cardiac α-actin and α- MHC implicating the role of this protein in the development of cardiac hypertrophy in diabetes. Increased cardiac hypertrophy as revealed by the expression of various genes and improved antioxidant potential in presence of 182 kDa protein in diabetes at the earlier stages is beneficial for counteracting the myocardial damage associated with diabetes.

Antioxidant and antiglycative potential of ethyl acetate fraction of Psidium guajava leaf extract in streptozotocin-induced diabetic rats

Hyperglycemia causes increased protein glycation and the formation of early glycation products and advanced glycation end products (AGEs) which are major factors responsible for the complications associated with diabetes. The aim of the present study was to investigate the antioxidant as well as antiglycative potential of ethyl acetate fraction of guava leaves. Oral administration of the extract at different doses showed a significant decrease in blood glucose level. It also showed an improved antioxidant potential as evidenced by decreased lipid peroxidation and a significant increase in the activity of various antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase. Glycated hemoglobin as well as fructosamine which are indicators of glycation was also reduced significantly in treated groups when compared to diabetic control. In vitro studies also support the antioxidant as well as antiglycative potential of guava leaves.

Modulatory effect of coffee on platelet function

Blood platelets play a major role in cardiovascular disease (CVD) and thrombosis. Conflicting information exists regarding the effect of coffee consumption on the cardiovascular system. We have investigated whether the consumption of moderate amount of coffee affect platelet functions and primary hemostasis in vivo in normal and high fat diet fed rats. Coffee fed group showed significant (P < 0.05) decrease in mean platelet volume, platelet crit and platelet distribution width as compared to high fat diet (HFD) group. The concentration of malondialdehyde in platelets increased in atherosclerotic group indicates the increased thromboxane A2 (TXA2) production from membrane arachidonic acid and it was decreased in coffee treated group. Platelet aggregation studies with ADP, collagen, arachidonic acid and epinephrine showed significant (P < 0.05) decrease in aggregation in coffee fed group. Scanning electron microscopic studies revealed that platelet aggregation tendency increased in HFD group and was reduced in coffee fed group. These results indicate that coffee is active in inhibiting platelet aggregation, a critical step involved in thrombosis.

Pulmonary function studies in rowers

The present study attempts to investigate the pulmonary functions of snake boat rowers before and after rowing. This is made on 12 healthy traditional snake boat rowers ranging from age 16-23 years of Kavanattinkara boat race, Kottayam, Kerala, India. The pulmonary function tests were carried out with vitallograph compact-II spirometer. The results show a decrease in pulmonary functions "lung volumes" and "flow rates" after rowing in comparison to basal condition.