Rakesh Maurya

Anticellular and immunosuppressive properties of ethanolic extract of Acorus calamus rhizome

Modulation of immune response to alleviate disease has been of interest since long. Plant extracts have been widely investigated for possible immunomodulatory properties. We have evaluated the anticellular and immunomodulatory properties of ethanolic extract of Acorus calamus rhizome. This extract inhibited proliferation of mitogen (phytohaemagglutinin; PHA) and antigen (purified protein derivative; PPD)-stimulated human peripheral blood mononuclear cells (PBMCs). In addition, A. calamus extract inhibited growth of several cell lines of mouse and human origin. It also inhibited production of nitric oxide (NO), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha). Intracytoplasmic interferon-gamma (IFN-gamma) and expression of cell surface markers, CD16 and HLA-DR, on human PBMC, were not affected on treatment with A. calamus extract but CD25 expression was down regulated. Our study demonstrates the antiproliferative and immunosuppressive potential of ethanolic extract of A. calamus rhizome in vitro.

Methoxylated isoflavones, cajanin and isoformononetin, have non‐estrogenic bone forming effect via differential mitogen activated protein kinase (MAPK) signaling

Following a lead obtained from stem‐bark extract of Butea monosperma, two structurally related methoxyisoflavones; cajanin and isoformononetin were studied for their effects in osteoblasts. Cajanin had strong mitogenic as well as differentiation‐promoting effects on osteoblasts that involved subsequent activation of MEK‐Erk and Akt pathways. On the other hand, isoformononetin exhibited potent anti‐apoptotic effect in addition to promoting osteoblast differentiation that involved parallel activation of MEK‐Erk and Akt pathways. Unlike genistein or daidzein, none of these two compounds appear to act via estrogen receptors in osteoblast. Once daily oral (by gavage) treatment for 30 consecutive days was given to recently weaned female Sprague–Dawley rats with each of these compounds at 10.0 mg kg−1 day−1 dose. Cajanin increased bone mineral density (BMD) at all skeletal sites studied, bone biomechanical strength, mineral apposition rate (MAR) and bone formation rate (BFR), compared with control. BMD levels at various anatomic positions were also increased with isoformononetin compared with control however, its effect was less potent than cajanin. Isoformononetin had no effect on the parameters of bone biomechanical strength although it enhanced MAR and BFR compared with control. Isoformononetin had very mild uterotrophic effect, whereas cajanin was devoid of any such effect. Our data suggest that cajanin is more potent than isoformononetin in accelerating peak bone mass achievement. To the best of our knowledge, this work represents the first attempt to elucidate structure‐activity relationship between the two methoxylated isoflavones regarding their effects in osteoblasts and bone formation. J. Cell. Biochem. 108: 388–399, 2009.

Immunomodulation by ethanolic extract of Boerhaavia diffusa roots

We have earlier reported that ethanolic extract of Boerhaavia diffusa, a plant used in Indian traditional system of medicine, significantly inhibits the cell proliferation. This led us to evaluate the immunomodulatory properties of this plant extract on various in vitro tests such as human natural killer (NK) cell cytotoxicity, production of nitric oxide (NO) in mouse macrophage cells, RAW 264.7, interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-alpha), intracytoplasmic interferon-gamma (IFN-gamma) and expression of various cell surface markers on human peripheral blood mononuclear cells (PBMCs). Ethanolic extracts of B. diffusa roots inhibited human NK cell cytotoxicity in vitro, production of NO in mouse macrophage cells, IL-2 and TNF-alpha in human PBMCs. Intracytoplasmic IFN-gamma and cell surface markers such as CD16, CD25, and HLA-DR did not get affected on treatment with B. diffusa extract. Our study demonstrates immunosuppressive potential of ethanolic extract of B. diffusa.

Osteogenic activity of constituents from Butea monosperma.

Phytochemical investigation from the stem bark of Butea monosperma, led to the isolation and identification of three new compounds named buteaspermin A (1), buteaspermin B (2) and buteaspermanol (3), along with 19 known compounds. The structure of compounds 1-22 were established on the basis of their spectroscopic data. The isolated compounds 2-17 were evaluated using neonatal (1-3 day old) rat calvaria derived primary osteoblast cultures. Five of these compounds 7, 10-13 showed promising osteogenic activity, attributed to increased osteoblast proliferation, differentiation and mineralization as evidenced by marked increase in expression of alkaline phosphatase, an early phase differentiation marker, and alizarin Red S staining of osteoblasts cultured for 48 h and von Kossa silver staining of nodules formed 15 days after culture with these compounds. Quantification of mineralization by optical density measurement of Alizarin Red S extracted from stained osteoblasts cultured for 7 days in presence of these compounds showed significant (P<0.05, vs corresponding vehicle control group) increase in mineralization. On the basis of biological results, structure-activity relationships are discussed.

Neuroprotective effect of Acorus calamus against middle cerebral artery occlusion-induced ischaemia in rat.

The neuroprotective potential of ethanol:water (1:1) extract of rhizomes of Acorus calamus (AC–002) has been investigated in middle cerebral artery occlusion (MCAO)–induced ischaemia in rats. A significant behavioural impairment in Rota–Rod performance and grid walking was observed in rats, 72 hours after MCAO as compared to sham–operated animals. These rats also exhibited an increase in lipid peroxidation (cortex / 157%, corpus striatum – 58%) and a decrease in glutathione levels (cortex – 59%, corpus striatum – 34%) and superoxide dismutase (SOD) activity (cortex – 64%, corpus striatum – 32%) as compared to sham–operated animals. Ischaemic rats treated with AC–002 (25 mg/kg, p.o.) exhibited a significant improvement in neurobehavioural performance viz. Rota–Rod performance and grid walking as compared to the MCAO group. Interestingly, treatment with AC–002 in MCAO rats significantly decreased malonaldialdehyde levels in cortex as compared to ischaemic rats. A significant increase in reduced glutathione levels and SOD activity was also observed both in cortex and corpus striatum in MCAO rats treated with AC–002 in comparison to MCAO rats. Treatment with AC–002 in MCAO rats also reduced the contralateral cortical infarct area (19%) as compared to MCAO rats (33%). Neurological function score was improved in the AC–002–treated rats as compared to the MCAO group. The results of the present study indicate the neuroprotective efficacy of A. calamus in the rat model of ischaemia.

Coagulanolide, a withanolide from Withania coagulans fruits and antihyperglycemic activity☆

One new withanolide, (17S,20S,22R)-14alpha,15alpha,17beta,20beta-tetrahydroxy-1-oxowitha-2,5,24-trienolide) named coagulanolide (4) along with four known withanolides 1-3 and 5 have been isolated from Withania coagulans fruits and their structures were elucidated by spectroscopic techniques. The compounds 1-5 showed significant inhibition on postprandial rise in hyperglycemia post-sucrose load in normoglycemic rats as well as streptozotocin-induced diabetic rats. The compound 5 also showed significant fall on fasting blood glucose profile and improved the glucose tolerance of db/db mice. Further compound 5 showed antidyslipidemic activity in db/db mice. The median effective dose of the compound 5 was determined to be around 25 mg/kg in streptozotocin-induced diabetic rats, which is comparable to the standard antidiabetic drug metformin. Our results provide further support to explain the traditional use of W. coagulans as antihyperglycemic cum antidyslipidemic agent by the traditional medical practitioners.

Role of Phytochemicals in the Prevention of Menopausal Bone Loss: Evidence from In Vitro and In Vivo, Human Interventional and Pharmacokinetic Studies

Substantial body of data generated from cultured bone cells and rat models of osteoporosis supports a significant bone-conserving effect of phytochemicals. Flavonoids including isoflavones, stilbenes and lignans with variable efficacy have shown promising therapeutic application in osteoporosis. Majority of the phytochemicals assessed for their effects on bone cells revealed multiple beneficial actions such as promoting osteoblast functions, and inhibiting osteoclast and adipocyte functions. A variety of molecular targets mediate multiple effects of phytochemicals in bone cells. In vivo, quite a few phytochemicals have been found to afford bone-sparing effect and in some cases even bone restoring effect. However, important pharmacokinetic and bioavailaibility studies associated with these phytochemicals are mostly lacking. As a result, translating these findings to the clinic has been challenging, and so far only a few clinical studies have attempted to evaluate the effect of phytochemicals in menopausal osteoporosis. Clinical studies so far performed are with dietary supplements rather than pure phytochemicals. Clinical trials with pure molecules necessitate preclinical regulatory and safety studies that are not available with the phytochemicals except ipriflavone with bone-conserving properties. Ipriflavone is the only marketed anti-osteoporosis agent that was obtained following a lead from natural substance. As phytochemicals have multiple beneficial influences on bone cells, making analogues of the most potent molecule for developing synthetic series with rational drug design approach could pay rich dividends in menopausal osteoporosis therapy.

Daidzein Prevents the Increase in CD4+CD28null T Cells and B Lymphopoesis in Ovariectomized Mice: A Key Mechanism for Anti-Osteoclastogenic Effect

Estrogen deficiency leads to an upregulation of TNF-α producing T cells and B-lymphopoesis which augments osteoclastogenesis. Estrogen deficiency also increases the population of premature senescent CD4+CD28null T cells which secrete a higher amount of TNF-α thus leading to enhanced osteoclastogenesis. Isoflavonoids like daidzein and genistein are found mostly in soybeans, legumes, and peas. These share structural similarity with 17β-stradiol (E2) and have osteoprotective role. This study explores the effect of daidzein (Daid) on the proliferation of TNF-α producing T cells, premature senescent T cells and B cell lymphopoesis under estrogen deficient conditions. For this study adult Balb/c mice were treated with Daid at 10 mg/kg body weight dose by oral gavage daily post ovariectomy (Ovx). After six weeks animals were autopsied and bone marrow and spleen cells were collected for FACS analysis. Blood serum was collected for ELISA. It was observed that Ovx mice treated with Daid for six weeks show reduction in Ovx induced expansion of CD4+ T cells in bone marrow and spleen when analysed by flow cytometry. Estrogen deficiency led to increased prevalence of TNF-α secreting CD4+CD28null T cells, however, treatment with Daid increased the percentage of CD4+CD28+ T cells. Co-culture of CD4+CD28null T cells and bone marrow resulted in enhanced osteoclastogenesis as evident by increased tartarate resistant acid phosphatase (TRAP) expression, an osteoclast marker. However, treatment with Daid resulted in reduced osteoclastogenesis in CD4+CD28null T cells and bone marrow cell co-culture. Daid also regulated B lymphopoesis and decreased mRNA levels of RANKL in B220+ cells. Taken together, we propose that one of the mechanisms by which Daid prevents bone loss is by reversing the detrimental immune changes as a result of estrogen deficiency.

Adaptogenic and anti-amnesic properties of Evolvulus alsinoides in rodents.

Evolvulus alsinoides (EA) is well known for its memory enhancement, antiepileptic and immunomodulatory properties in the traditional Indian system of medicine, Ayurveda. In view of the increasing attention towards plants offering non-specific resistance (adaptogens) towards stress, we have evaluated crude ethanolic extract of EA for its adaptogenic and memory enhancing properties in rodents. Adaptogenic activity was assessed in rats subjected to acute and chronic unpredictable stress. Male Sprague-Dawley rats, weighing 180-200 g were immobilized for 150 min once only in acute stress (AS) model, whereas in chronic unpredictable stress (CUS) model rats were subjected to different types of stressors daily for 7 days. Stress exposure has induced gastric ulceration with increase in adrenal gland weight, plasma creatine kinase (CK), and corticosterone level in AS and CUS. However plasma glucose was increased only in AS. Rats were treated with graded doses of crude ethanolic extract of EA (100, 200 and 400 mg/kg p.o.) for 3 days and subjected to AS on 3 day after 45 min of last dose. In CUS, EA at a dose of 200 mg/kg p.o. found effective in acute studies was administered 45 min prior to stress regimen for 7 days. EA reduced the stress induced perturbations similar to Panax quinquefolium (PQ) (100 mg/kg p.o.), a well known adaptogen. EA (100 mg/kg) administered orally for 3 days in adult male Swiss mice, was effective in decreasing scopolamine induced deficit in passive avoidance test. The improvement in the peripheral stress markers and scopolamine induced dementia by EA in the present study indicates the adaptogenic and anti-amnesic properties of EA.

Identification of pongamol and karanjin as lead compounds with antihyperglycemic activity from Pongamia pinnata fruits

AIM OF THE STUDY To identify pongamol and karanjin as lead compounds with antihyperglycemic activity from Pongamia pinnata fruits. MATERIAL AND METHODS Streptozotocin-induced diabetic rats and hyperglycemic, hyperlipidemic and hyperinsulinemic db/db mice were used to investigate the antihyperglycemic activity of pongamol and karangin isolated from the fruits of Pongamia pinnata. RESULTS In streptozotocin-induced diabetic rats, single dose treatment of pongamol and karanjin lowered the blood glucose level by 12.8% (p<0.05) and 11.7% (p<0.05) at 50mg /kg dose and 22.0% (p<0.01) and 20.7% (p<0.01) at 100mg/kg dose, respectively after 6h post-oral administration. The compounds also significantly lowered blood glucose level in db/db mice with percent activity of 35.7 (p<0.01) and 30.6 (p<0.01), respectively at 100mg/kg dose after consecutive treatment for 10 days. The compounds were observed to exert a significant inhibitory effect on enzyme protein tyrosine phosphatase-1B (EC 3.1.3.48). CONCLUSION The results showed that pongamol and karangin isolated from the fruits of Pongamia pinnata possesses significant antihyperglycemic activity in Streptozotocin-induced diabetic rats and type 2 diabetic db/db mice and protein tyrosine phosphatase-1B may be the possible target for their activity.