A strain of Streptomyces sp. isolated from rhizospheric soil of Crataegus oxycantha producing nalidixic acid, a synthetic antibiotic.

AIM: Exploration of microbes isolated from rhizospheric soil of Crataegus oxycantha for bioactive natural products. METHODS AND RESULTS: A strain of Streptomyces sp. (C-7) was isolated from rhizospheric soil of C. oxycantha. The 16S rRNA gene sequence of strain C-7 displayed 99% sequence similarity with different Streptomyces species. The highest score was displayed for Streptomyces sp. strain Chy2-8 followed by Streptomyces violarus strain NBRC13104 and Streptomyces arenae strain ISP5293. The position of C-7 in the phylogenetic tree suggested uniqueness of the strain. Nalidixic acid (1), a quinolone antibiotic, was isolated from Streptomyces sp. strain (C-7) for the first time and characterized by NMR and chemically analysed. Compound 1 exhibited antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa. The production of compound 1 was also validated by repeating fermentation of strain C-7 and compound isolation in a separate natural product laboratory with no prior information. Furthermore, Compound 1 showed a cytotoxic effect against human prostate cancer cell line PC3 with an IC50 11 µg ml-1 . CONCLUSION: To the best of our knowledge, this is the first report showing production of nalidixic acid naturally by a strain of Streptomyces sp. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we isolated a strain of Streptomyces sp. producing nalidixic acid, which was otherwise only obtained through chemical synthesis.

In vitro acaricidal activity of Piper nigrum and Piper longum fruit extracts and their active components against Rhipicephalus (Boophilus) microplus ticks.

In vitro acaricidal activity of Piper nigrum and P. longum fruit extracts and their active components (piperine for P. nigrum and piperine and piperlonguminine for P. longum) was evaluated against adults engorged females of Rhipicephalus (Boophilus) microplus using adult immersion test. Three concentrations of each extract with four replications were used in the bioassay. Extracts significantly affected mortality rates of ticks in dose-dependent manner ranged 12.5-95.8% for P. nigrum and 29.2-87.5% for P. longum, with an additional effect on the reproductive physiology of ticks by inhibiting oviposition (28.1-96.9% by P. nigrum and 36.1-89.3% by P. longum). However, the acaricidal and oviposition limiting properties were decreased significantly when the active component(s) of each extract was tested separately. However, the combination of piperine and piperlonguminine (obtained from P. longum extract) caused 79.2% mortality of ticks which is equivalent to the corresponding concentration (~ 5%) of the extract. It can be concluded that the fruit extracts of P. nigrum and P. longum had both acaricidal and oviposition limiting actions against the adults of R. (B.) microplus which could make it a valuable component of developing sustainable strategy for integrated tick management.

Immunosuppressive effects of Euphorbia hirta in experimental animals.

Euphorbia hirta L. (Euphorbiaceae) (E. hirta) is a tree locally used as a traditional medicine in Africa and Australia to treat numerous diseases such as hypertension, respiratory ailments, tumors, wounds, antipyretic, anti-inflammatory activities, etc. Therefore, we undertook to investigate their immunomodulatory effect on T lymphocytes (CD3+, CD4+ and CD8+ receptors) and Th1 cytokines (IL-2, TNF-α, IFN-γ) in a dose-dependent manner. E. hirta ethanol extract at 25, 50, 100 and 200 mg/kg doses was given orally for 7 days from the day of immunization. E. hirta maximum inhibition at 100 and 200 mg/kg p.o. was found to significantly block the production of the cell-mediated immune response, (CD3+, CD4+ and CD8+ receptors) and (IL-2, TNF-α, IFN-γ) and also prolongs graft rejection. E. hirta also showed a decrease of delayed hypersensitivity (DTH) response and dose-related decrease in the primary antibody response, respectively. Based on the data, it can be suggested that E. hirta is a potent and non-toxic immunosuppressor, which can be further explored for the development of potent immunosuppressor.

Modulation of P-glycoprotein ATPase activity by some phytoconstituents.

In the present investigation 16 phytoconstituents, which are active moieties found in several medicinal herbs, have been evaluated for their P-glycoprotein (P-gp) stimulation/inhibition profiles using a P-gp-dependent ATPase assay in rat jejunal membrane (in vitro). Acteoside, agnuside, catechin, chlorogenic acid, picroside -II and santonin showed an inhibitory effect. Negundoside, picroside -I and oleanolic acid caused a stimulatory effect. Andrographolide, apocyanin, berberine, glycyrrhizin, magniferin and piperine produced a biphasic response (stimulation at low concentration and inhibition at high concentration). The results suggested that a possible interaction of these phytoconstituents at the level of P-gp, could be an important parameter in determining their role in several key pharmacodynamic events.

Datura stramonium essential oil composition and it's immunostimulatory potential against colon cancer cells.

The current study deals with the investigation of the antioxidant, anti-inflammatory and immunomodulatory properties of the essential oil from Datura stramonium leaves (D. oil). The GC-MS analysis showed that the dominant compounds present in the D. oil were neophytadiene (Phytol acetate) (10.76%), ß-damascenone (9.67%), and ß- eudesmol (7.2%). D. oil exhibited in vitro scavenging potential of free radicals by DPPH and ABTS assays (IC50 values 71.35 ±1.06 µg/ml and 61.01 ± 1.07 µg/ml, respectively). We found that D. oil decreased the nitric oxide production in LPS-stimulated J774A.1 cells by 52.43% without affecting their cell viability. D. oil was found to stimulate the proliferation of human peripheral blood mononuclear cells (PBMC) and, also enhanced the secretion of IL-2, IFN-γ and TNF-α. Furthermore, D. oil treatment of PBMC induced the expression of CD3, CD8, and CD56 and intracellular granulysin levels in the immune cells. The treatment of human lymphocytes by D. oil enhanced their ability to kill colon cancer cells HCT-116 (51.09 ± 7.5%) and SW620 (48.57 ± 8.08%) at 20:1 (effector: target ratio). Moreover, these activated lymphocytes cause target cell death by reactive oxygen species and by damaging mitochondrial membrane potential of these cells. Taken together, the current findings showed D. oil as immunotherapeutic agent which can be used for colon cancer treatment.

Immunomodulatory activity of Asparagus racemosus on systemic Th1/Th2 immunity: implications for immunoadjuvant potential.

ETHNOPHARMACOLOGICAL RELEVANCE: Roots of Asparagus racemosus Willd (Shatavari in vernacular) are widely used in Ayurveda as Rasayana for immunostimulation, galactogogue as also in treatment of conditions like ulcers and cancer. Various studies have indicated immunomodulatory properties of Shatavari root extracts and formulations. AIM OF THE STUDY: To study the effect of standardized Asparagus racemosus root aqueous extract (ARE) on systemic Th1/Th2 immunity of SRBC sensitized animals. MATERIALS AND METHODS: We used HPTLC to quantify steroidal saponins (Shatavarin IV, Immunoside) and flow cytometry to study effects of ARE on Th1/Th2 immunity. SRBC specific antibody titres and DTH responses were also monitored as markers of Th2 and Th1 responses, respectively. We also studied lymphocyte proliferation. Cyclosporin, cyclophosphamide and levamisole were used as controls. RESULTS: Treatment with ARE (100mg/(kg b.w.p.o.)) resulted in significant increase of CD3(+) and CD4/CD8(+) percentages suggesting its effect on T cell activation. ARE treated animals showed significant up-regulation of Th1 (IL-2, IFN-g) and Th2 (IL-4) cytokines suggesting its mixed Th1/Th2 adjuvant activity. Consistent to this, ARE also showed higher antibody titres and DTH responses. ARE, in combination with LPS, Con A or SRBC, produced a significant proliferation suggesting effect on activated lymphocytes. CONCLUSION: The study suggests mixed Th1/Th2 activity of ARE supports its immunoadjuvant potential.

Anti-histaminic, anti-inflammatory and bronchorelaxant activities of 2, 7-dimethyl-3-nitro-4H pyrido [1,2-a] pyrimidine-4-one.

An immunopharmacological profile of 2, 7-dimethyl-3-nitro-4H pyrido [1,2-a] pyrimidine-4-one (P-I) has been investigated using in vitro and in vivo models representing various features of Type I allergy. P-I prevented compound 48/80-mediated histamine release from rat peritoneal mast cells. A promising anti-inflammatory activity of P-I was evident in active paw anaphylaxis (mice) and carragenan-induced paw edema (rat). P-I inhibited eosonophil accumulation and eosinophil peroxidase activity in bronchoalveolar lavage fluid from ovalbumin challenged balb/c mice: in these animals blood levels of IL-5, and CD4+ T cells also remained attenuated. A promising bronchorelaxant effect of P-I was observed in histamine-contracted guinea pig tracheal chain via its antagonism to H1 receptor. These findings were compared with some known compounds (ketotifen, cetirizine and promethazine). The anti-histaminic, anti-inflammatory and bronchorelaxant activities of P-I has been discussed in context with its potential profile as an anti-allergic and anti-asthmatic agent.

A new clerodane furano diterpene glycoside from Tinospora cordifolia triggers autophagy and apoptosis in HCT-116 colon cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Tinospora cordifolia is a miraculous ayurvedic herb used in the treatment of innumerable diseases such as diabetes, gonorrhea, secondary syphilis, anaemia, rheumatoid arthritis, dermatological diseases, cancer, gout, jaundice, asthma, leprosy, in the treatment of bone fractures, liver & intestinal disorders, purifies the blood, gives new life to the whole body; (rejuvenating herb) and many more. Recent studies have revealed the anticancer potential of this plant but not much work has been done on the anticancer chemical constituents actually responsible for its amazing anticancer effects. This prompted us to investigate this plant further for new potent anticancer molecules. AIM OF THE STUDY: The present study was designed to isolate and identify new promising anticancer candidates from the aqueous alcoholic extract of T. cordifolia using bioassay-guided fractionation. MATERIALS AND METHODS: The structures of the isolated compounds were determined on the basis of spectroscopic data interpretation and that of new potent anticancer molecule, TC-2 was confirmed by a single-crystal X-ray crystallographic analysis of its corresponding acetate. The in vitro anti-cancer activity of TC-2 was evaluated by SRB assay and the autophagic activity was investigated by immunofluorescence microscopy. Annexin-V FITC and PI dual staining was applied for the detection of apoptosis. The studies on Mitochondrial Membrane potential and ROS (Reactive oxygen species) production were also done. RESULTS: Bioassay guided fractionation and purification of the aqueous alcoholic stem extract of Tinospora cordifolia led to the isolation of a new clerodane furano diterpene glycoside (TC-2) along with five known compounds i.e. cordifolioside A (ß-D-Glucopyranoside,4-(3-hydroxy-1-propenyl)- 2,6-dimethoxyphenyl 3-O-D-apio-ß-D-furanosyl) (TC-1), ß-Sitosterol(TC-3), 2ß,3ß:15,16-Diepoxy- 4α, 6ß-dihydroxy-13(16),14-clerodadiene-17,12:18,1-diolide (TC-4), ecdysterone(TC-5) and tinosporoside(TC-6). TC-2 emerged as a potential candidate for the treatment of colon cancer. CONCLUSION: The overall study on the bioassay guided isolation of T.cordifolia identified and isolated a new clerodane furano diterpenoid that exhibited anticancer activity via induction of mitochondria mediated apoptosis and autophagy in HCT116 cells. We have reported a promising future candidate for treating colon cancer.

Anti-anaphylactic effect of Euphorbia hirta.

The Euphorbia hirta ethanolic extract (EH A001) was found to possess a prominent anti-anaphylactic activity. A preventive effect of EH-A001 given by oral route at dose from 100 to 1000 mg/kg was observed against compound 48/80-induced systemic anaphylaxis. At the same range of dose, EH-A001 inhibited passive cutaneous anaphylaxis (PCA) in rat and active paw anaphylaxis in mice. A suppressive effect of EH-A001 was observed on the release of TNF-alpha and IL-6 from anti-DNP-HSA activated rat peritoneal mast cells.

Regiospecific Synthesis of Ring A Fused Withaferin A Isoxazoline Analogues: Induction of Premature Senescence by W-2b in Proliferating Cancer Cells.

Induction of premature senescence represents a novel functional strategy to curb the uncontrolled proliferation of malignant cancer cells. This study unveils the regiospecific synthesis of novel isoxazoline derivatives condensed to ring A of medicinal plant product Withaferin-A. Intriguingly, the cis fused products with ß-oriented hydrogen exhibited excellent cytotoxic activities against proliferating human breast cancer MCF7 and colorectal cancer HCT-116 cells. The most potent derivative W-2b triggered premature senescence along with increase in senescence-associated ß-galactosidase activity, G2/M cell cycle arrest, and induction of senescence-specific marker p21Waf1/Cip1 at its sub-toxic concentration. W-2b conferred a robust increase in phosphorylation of mammalian checkpoint kinase-2 (Chk2) in cancer cells in a dose-dependent manner. Silencing of endogenous Chk2 by siRNA divulged that the amplification of p21 expression and senescence by W-2b was Chk2-dependent. Chk2 activation (either by ectopic overexpression or through treatment with W-2b) suppressed NM23-H1 signaling axis involved in cancer cell proliferation. Finally, W-2b showed excellent in vivo efficacy with 83.8% inhibition of tumor growth at a dose of 25 mg/kg, b.w. in mouse mammary carcinoma model. Our study claims that W-2b could be a potential candidate to limit aberrant cellular proliferation rendering promising improvement in the treatment regime in cancer patients.

Immunostimulatory activity of plumieride an iridoid in augmenting immune system by targeting Th-1 pathway in balb/c mice.

Plumieride, an iridoid glucoside isolated from Plumieria acutifolia leaves was investigated for its immunostimulatory activity on humoral, cell mediated and intracellular cytokine levels in sensitized and unsensitised balb/c mice. Plumieride restores the suppressed cell mediated, humoral immune response and also enhances the release of TNF- α, IFN-γ, and IL-2 (Th-1) in immune compromised cyclosporine and cyclophosphamide treated balb/c mice. It does not stimulate the IL-4 (Th-2) expression. Plumieride demonstrates significant augmentation of Th-1 response in immunosuppressed balb/c mice. Results of the present study suggested that plumieride can be developed as an immunostimulatory adjuvant to treat the immune suppression in various disease condition(s).

Augmentation and proliferation of T lymphocytes and Th-1 cytokines by Withania somnifera in stressed mice.

Stress has been associated with reports of both greater severity and prolongation of diseases in patients with the infectious origin as well as other immune-mediated diseases. Withania somnifera, an Indian medicinal plant used widely in the treatment of many clinical conditions in India, was investigated for its anti-stress properties using BALB/c mice subjected to chronic stress. The study aimed to investigate chronic stress-induced alterations on Th1 lymphocyte subset distribution and corresponding cytokine secretion patterns. Oral administration of chemically standardized and identified aqueous fraction of W. somnifera root (WS) at the graded doses of 25, 50, 100 and 200 mg/kg p.o. caused significant increase in the stress-induced depleted T-cell population and increased the expression of Th1 cytokines in chronically stressed mice.

Immunomodulatory activity of biopolymeric fraction RLJ-NE-205 from Picrorhiza kurroa.

In the last three decades, numerous biopolymeric fractions have been isolated from medicinal plants and used as a source of therapeutic agents. The most promising biopharmacological activities of these biopolymers are their immunomodulatory effects. The biopolymeric fraction RLJ-NE-205 was isolated and purified from the rhizomes of Picrorhiza kurroa. We evaluated the effects of biopolymeric fraction RLJ-NE-205 from P. kurroa on the in vivo immune function of the mouse. Balb/c mice were treated with the biopolymeric fraction RLJ-NE-205 (12.5, 25 and 50 mg/kg body weight) for 14 days with sheep red blood cells (SRBC) as an antigen. Haemagglutination antibody (HA) titre, plaque forming cell (PFC) assay, delayed type hypersensitivity (DTH) reaction, phagocytic index, proliferation of lymphocytes, analysis of cytokines in serum and CD4/CD8 population in spleen (determined by flowcytometry) were studied. At the dose of 50 mg/kg, significant increases in the proliferation of lymphocytes (p<0.001) and cytokine levels (IL-4 and IFN-gamma) in serum (p<0.001) were observed. A dose dependent increase was demonstrated in HA titre (p<0.05), DTH (p<0.01), PFC (p<0.05), phagocytic index (p<0.05) and CD4/CD8 (p<0.01) population. This suggests that the biopolymeric fraction RLJ-NE-205 improves the immune system and might be regarded as a biological response modifier.

Synthesis and bronchodilator activity of new quinazolin derivative.

Taking lead from a naturally occurring quinazolin vasicine, a number of compounds were developed and evaluated for bronchodilator and anti-allergic activities. One of these compounds was 2,4-diethoxy-6,7,8,9,10,12-hexahydroazepino[2,1-b]quinazolin-12-one, hereinafter named 95-4, exhibited marked bronchodilator activity evaluated on contracted trachea or constricted tracheo-bronchial tree. On intestinal smooth muscle too it showed relaxant effect. Tracheal relaxant effect was not found to be mediated through beta-adrenoceptors. Cumulative dose-response study with acetylcholine and histamine indicated for its non-specific direct effect on smooth muscles. 95-4 was found to be more potent than theophylline and less to that of salbutamol on dose basis. Tested by a number of experimental models, it was found devoid of anti-allergic activity. It was also found to be free from any adverse effect. 95-4 due to its marked bronchial muscle relaxant effect can find use in conditions associated with spasm of bronchial muscles.

Terminalia chebula (fruit) prevents liver toxicity caused by sub-chronic administration of rifampicin, isoniazid and pyrazinamide in combination.

Terminalia chebula Gertn. (Combetraceae) is an important herbal drug in Ayurvedic pharmacopea. In the present study, a 95% ethanolic extract of T. chebula (fruit) (TC extract), which was chemically characterized on the basis of chebuloside II as a marker, was investigated for hepatoprotective activity against anti-tuberculosis (anti-TB) drug-induced toxicity. TC extract was found to prevent the hepatotoxicity caused by the administration of rifampicin (RIF), isoniazid (INH) and pyrazinamide (PZA) (in combination) in a sub-chronic mode (12 weeks). The hepatoprotective effect of TC extract could be attributed to its prominent anti-oxidative and membrane stabilizing activities. The changes in biochemical observations were supported by histological profile.

Immunosuppressive properties of an ethyl acetate fraction from Euphorbia royleana.

The objective of the study was to investigate the activity of the ethyl acetate (EA) fraction of Euphorbia royleana latex on cellular and humoral-mediated immune responses and phagocytic function of the cells of the reticuloendothelial system in mice. Oral administration of EA at doses of 50, 100 and 200 mg/kg p.o. in mice with sheep red blood cells (SRBC) as an antigen-inhibited both the delayed-type hypersensitivity reaction and the production of circulating antibody titre. Reduction of CD4+ T cell counts in the peripheral whole blood and the neutrophil counts in pleural exudates of the animals treated with EA was observed by flowcytometric analysis. Process of phagocytosis was also inhibited in in vivo and in vitro experimental test models. The oral LD50 in both rats and mice was more than 2.5 g/kg body weight.

Anti-inflammatory activity of Euphorbia acaulis Roxb.

From various extracts of Euphorbia acaulis , the n-hexane fraction showed marked anti-inflammatory activity in carrageenan induced oedema in rats and mice as compared to phenylbutazone and was equipotent in adrenal- ectomised rats. In chronic models of formaldehyde and adjuvant arthritis, its anti-arthritic activity was found to be superior to that of phenylbutazone. It had a diuretic effect but did not show any analgesic or antipyretic activity.

Immunomodulatory studies of a bioactive fraction from the fruit of Prunus cerasus in BALB/c mice.

In order to evaluate the role of ethyl acetate fraction (PNRS-EtOAC) obtained from the Prunus cerasus fruit in the modulation of immune responses, detailed studies were carried out using a panel of in vivo assays. Oral administration of PNRS-EtOAC (25-100 mg/kg) stimulated the IgM and IgG titre expressed in the form of hemagglutination antibody (HA) titre. Further, it elicited a dose related increase in the delayed type hypersensitivity reaction (DTH) after 24 and 48 h in BALB/c mice. Besides augmenting the humoral and cell mediated immune response, the concentration of cytokines (IFN-γ, IL-4, and TNF-α) in serum with respect to T cell interactions, i.e. the proliferation of lymphocytes were significantly increased at 50 mg/kg compared with the control. The results in these studies demonstrated the immunostimulatory effect of PNRS-EtOAC in a dose-dependent manner with respect to the macrophage activation possibly expressing the phagocytosis and nitrite production by the enhancement of TNF-α production as a mode of action.

Possible role of macrophages induced by an irridoid glycoside (RLJ-NE-299A) in host defense mechanism.

In order to explore the possible role of macrophages and other necessary immune competent (T and B) cells in the modulation of immune responses, an attempt was made to study the immunomodulatory effect of an irridoid glycoside (RLJ-NE-299A) isolated from the roots of Picrorhiza kurroa. Both in vitro and in vivo studies were used to evaluate the effect of RLJ-NE-299A on humoral, cellular, and phagocytic activity of macrophages. The data obtained in the present study showed that RLJ-NE-299A significantly increased sheep red blood cell (SRBC) and induced antibody (IgM and IgG) titer and delayed type hypersensitivity (DTH) reaction in mice. Besides augmenting the humoral and cell-mediated immune response, it induced macrophage phagocytosis and stimulated cytokine-induced macrophage activation and nitric oxide (NO) production, which resulted in a high degree of protection against Candida albicans and Salmonella typhimurium infections. Flow cytometric analysis indicated the enhanced expression of co-stimulatory surface molecules CD80 and CD86. The ability of RLJ-NE-299A to upregulate these cell surface antigens involved in antigen presentation may provide an explanation for the increased T-cell mediated immunity involving macrophages. Taken together this in vitro and in vivo preclinical data suggests that RLJ-NE-299A acts as an effective immunomodulator specifically to improve macrophage function during infections. The effects of this agent on these cells at concentrations relevant to in vivo therapy support its immunopharmacologic application to modify cellular immunity.

A novel sarsasapogenin glycoside from Asparagus racemosus elicits protective immune responses against HBsAg.

The aim of the present investigation was to evaluate the adjuvant potential of a novel sarsasapogenin glycoside (immunoside) isolated from Asparagus racemosus in combination with hepatitis B surface antigen (HBsAg). Various in vitro and animal derived protocols were used to determine the response of immunoside adjuvanted with HBsAg and the results were compared with alum adjuvanted with HBsAg. Several biomarkers such as antibody titre (IgG, IgG1/IgG2a) were measured in mice sera. Cell proliferation, cytokines (IL-2, IFN-γ and IL-4), and lymphocyte sub-populations (CD4/CD8, CD3 and CD19) were determined in splenocytes from mice administered subcutaneously with test substances. In these cells CD4/CD8 derived IFN-γ release was also determined. Macrophage preparations were used for the determination of IL-12, IFN-γ and nitrite content. Seroconversion potential was compared with a standard vaccine. Acute safety evaluation of immunoside was done in mice. Effect of immunoside on red blood cell haemolysis was determined. The results have suggested that immunoside potentially enhanced anti-HBsAg immune response via augmenting Th1/Th2 response in a dose dependent manner.