Heterocyclic homoprostanoid derivative attenuates monoarthritis in rats: An in vitro and in vivo preclinical paradigm

From our lab, among the nineteen heterocyclic homoprostanoids (HHPs), three derivatives (compounds 3, 3b and 3c) exerted antioxidant and anti-inflammatory activity. Present study is an extension of the earlier work, and, is designed to establish their therapeutic potential in monoarthritis in rats. In addition, their possible mechanism of action would be investigated. A battery of in vitro tests such as lipopolysaccharide (LPS)-induced nitrite (NO)/reactive oxygen species (ROS) and NO/interleukin (IL)-6 generation in murine macrophages and whole blood (WhB), respectively were conducted. Later, in vitro cyclooxygenase (COX) enzyme inhibitory activity was also evaluated. All the tested compounds showed comparable efficacy against ROS and NO in LPS-stimulated murine macrophages. However, compound 3 did not exert inhibitory effect on LPS-induced NO/IL-6 generation in WhB assay. Compounds (3b and 3c) inhibited the NO generation in LPS-stimulated WhB. However, only compound 3b reversed the raised IL-6 levels in this assay. None of the test compounds inhibited COX iso-enzymes in the in vitro assay. All three HHPs showed comparable efficacy against carrageenan-induced paw inflammation. However, none of them exhibited any dose-dependent effect in this model. Based upon previous reports, compound 3c was explored against adjuvant-induced monoarthritis (AIA) in male Sprague-Dawley rats, where it exerted promising therapeutic effect. In addition to radiological and histological examinations of tibio-tarsal joint, various parameters such as chronic inflammation/pain, clinical score, interleukin (IL)-6 levels and complete blood cell profile were evaluated in AIA rats. Chronic treatment with 3c halted the disease progression in rats, improved the overall health of animals, as demonstrated by haematological, clinical scoring and joint examinations (radiological and histopathological). Inhibitory effect on elevated IL-6 in AIA rats suggested the possible mechanism of 3c on cytokine signalling. Overall, the study supports the anti-arthritic potential of compound 3c.

Synthesis, characterization, and preclinical evaluation of new thiazolidin-4-ones substituted with p-chlorophenoxy acetic acid and clofibric acid against insulin resistance and metabolic disorder

We synthesized twenty thiazolidin-4-one derivatives, which were then characterized by standard chromatographic and spectroscopic methods. From the in vitro glucose uptake assay, two compounds behaved as insulin sensitizers, where they enhanced glucose uptake in isolated rat diaphragm. In high-carbohydrate diet-induced insulin resistant mice, these two thiazolidin-4-ones attenuated hyperglycemia, hyperinsulinemia, hypertriglyceridemia, hypercholesterolemia, and glucose intolerance. They raised the plasma leptin but did not reverse the diabetes-induced hypoadiponectinemia. Additionally, compound 3a reduced adiposity. The test compounds were also able to reverse the disturbed liver antioxidant milieu. To conclude, these two novel thiazolidin-4-ones modulated multiple mechanisms involved in metabolic disorders, reversing insulin resistance and thus preventing the development of type-2 diabetes.

Effect of Cissus quadrangularis Linn on the development of osteopenia induced by ovariectomy in rats

OBJECTIVE

The aim of our study was to see the efficacy of petroleum ether extract of Cissus quadrangularis (CQ) on development of osteopenia in ovariectomy induced Wistar rats.

MATERIALS AND METHODS

The female Wistar rats were ovariectomized or Sham operated. The rats were anesthetized with pentobarbital sodium (40 mg/ kg b.w, i.p.), the ovaries were removed bilaterally. Sham-operation was performed in the same manner but only exposing the ovaries (sham operated (SHAM) group). A day later, the ovariectomized rats were randomly divided into four groups of eight animals each. The groups are 1. Sham operated (SHAM), 2. Ovariectomized (OVX), 3. Ovariectomized and treated with 25 mg/kg b.w of raloxifene (OVX+RAL), 4. Ovariectomized and treated with 500 mg/kg b.w of petroleum ether extract of CQ (OVX+CQ). The treatment continued for 30 days. At the end of the treatment, rats in all groups were sacrificed by cervical dislocation. Before sacrifice, blood was collected for the estimation of serum ALP, TRAP, Calcium and hydroxyproline; where as the left femur was used for histomorphometrical analysis.

RESULTS

The findings assessed on the basis of animal weight, morphology of femur, histomorphometry and biochemical analysis. As compared to SHAM group, OVX group animals showed a significant rise in serum ALP, TRAP and hydroxyproline levels at the end of 1 month following ovariectomy while no significant change was seen in the serum calcium levels. ALP and TRAP levels of OVX + RAL and OVX + CQ groups showed a further increase following administration of raloxifene and Cissus quadrangularis. The serum hydroxyproline content was found to be increased in the OVX + CQ compared to SHAM group. CQ significantly increased the thickness of both cortical (p <0.001) and trabecular bone (p <0.001).This action of CQ is comparable to action of Raloxifene. )These data suggest a strong anti-osteoporotic activity of CQ.

CONCLUSION

The results confirm, at least in part, for the use of Cissus quadrangularis in folk medicine to treat osteoporosis.

Evidence-based assessment of antiosteoporotic activity of petroleum-ether extract of Cissus quadrangularis Linn. on ovariectomy-induced osteoporosis

The increasing incidence of postmenopausal osteoporosis and its related fractures have become global health issues in the recent days. Postmenopausal osteoporosis is the most frequent metabolic bone disease; it is characterized by a rapid loss of mineralized bone tissue. Hormone replacement therapy has proven efficacious in preventing bone loss but not desirable to many women due to its side-effects. Therefore we are in need to search the natural compounds for a treatment of postmenopausal symptoms in women with no toxic effects. In the present study, we have evaluated the effect of petroleum-ether extract of Cissus quadrangularis Linn. (CQ), a plant used in folk medicine, on an osteoporotic rat model developed by ovariectomy. In this experiment, healthy female Wistar rats were divided into four groups of six animals each. Group 1 was sham operated. All the remaining groups were ovariectomized. Group 2 was fed with an equivolume of saline and served as ovariectomized control (OVX). Groups 3 and 4 were orally treated with raloxifene (5.4 mg/kg) and petroleum-ether extract of CQ (500 mg/kg), respectively, for 3 months. The findings were assessed on the basis of animal weight, morphology of femur, and histochemical localization of alkaline phosphatase (ALP) (an osteoblastic marker) and tartrate-resistant acid phosphatase (TRAP) (an osteoclastic marker) in upper end of femur. The study revealed for the first time that the petroleum-ether extract of CQ reduced bone loss, as evidenced by the weight gain in femur, and also reduced the osteoclastic activity there by facilitating bone formation when compared to the OVX group. The osteoclastic activity was confirmed by TRAP staining, and the bone formation was assessed by ALP staining in the femur sections. The color intensity of TRAP and ALP enzymes from the images were evaluated by image analysis software developed locally. The effect of CQ was found to be effective on both enzymes, and it might be a potential candidate for prevention and treatment of postmenopausal osteoporosis. The biological activity of CQ on bone may be attributed to the phytogenic steroids present in it.