Amalesh Samanta

Amberlite-IRA-402 (OH) ion exchange resin mediated synthesis of indolizines, pyrrolo [1,2-a] quinolines and isoquinolines: Antibacterial and antifungal evaluation of the products

A number of indolizines and pyrrolo[1,2-a]quinolines/isoquinolines were prepared from phenacyl pyridinium, quinolinium and isoquinolinium salts derived from the reaction of the heterocycles with 2-bromo acetophenone with alkynes and alkenes using amberlite-IRA-402 (OH) ion exchange resin as the base. Antibacterial and antifungal studies were carried out against thirteen bacterial and four fungal strains, which revealed that three derivatives (4a, 4b, 7a) out of fifteen are effective against all the thirteen strains and one derivative, 10, showed dual antibactericidal and antifungal efficacy.

Evaluation of the wound healing activity of methanol extract of Pedilanthus tithymaloides (L.) Poit leaf and its isolated active constituents in topical formulation

ETHNOPHARMACOLOGICAL RELEVANCE Pedilanthus tithymaloides leaves are widely used in Indian medicine to heal wounds, burn, mouth ulcers. However, systematic evaluation of these activities is lacking. Thus, the present study aimed to assesses the wound healing activity of Pedilanthus leaves and its isolated constituents in topical ointment formulation. MATERIALS AND METHODS Bioassay-guided chromatographic fractionation of the methanol extract of leaves resulted in the isolation of 2-(3,4-dihydroxy-phenyl)-5,7-dihydroxy-chromen-4-one and 1, 2-tetradecanediol, 1-(hydrogen sulfate), sodium salt. The ointment formulation of methanol extract (2.5%, 5% w/w) and isolated compounds (0.25% w/w) was prepared and evaluated on excision, incision and dead space wound models in rats. The effects of formulations on wound healing were assessed by the rate of wound closure, period of epithelialization, tensile strength, granulation tissue weight, hydroxyproline content and histopathology. RESULTS Significant wound healing activity was observed with methanol extract and isolated constituents. Topical application of isolated compound ointments caused faster epithelialization, significant wound contraction (95.41%), and better tensile strength (565.33 g) on 16 post-wounding day, while 5% extract showed wound epithelialization with 95.55% contraction on 18th post-wounding day, better than the control group (76.39% on 22 day). The tensile strength of incision wound was significantly increased in extract and compound treated animals. Moreover, in dead space model the extract significantly increased granuloma tissue weight, tensile strength and hydroxyproline content. The tissue histology of ointment treated groups showed complete epithelialization with increased collagenation, compared to the povidone-iodine group. CONCLUSIONS The results validated the traditional use of Pedilanthus tithymaloides for cutaneous wound management.

Evaluation of the wound healing activity of Shorea robusta, an Indian ethnomedicine, and its isolated constituent(s) in topical formulation.

ETHNOPHARMACOLOGICAL RELEVANCE Different parts of Indian ethnomedicinal plant Shorea robusta is traditionally used for several ailments including wounds and burn by different tribal groups, since ages. Here we have validated, for the first time, the effectiveness and the possible mechanism of action of young leaf extracts of Shorea robusta, used by two distinct tribes of India, and its isolated compounds as a topical formulation in three wound models in rats. MATERIALS AND METHODS Bioactivity-guided study of the active extract resulted in the isolation of two known compounds. The prepared ointment containing extracts (2.5 and 5%, w/w), fractions (5% w/w) and isolated compounds (0.25% w/w) were evaluated on excision, incision and dead space wound models in rats by the rate of wound closure, period of epithelialisation, tensile strength, granulation tissue weight, hydroxyproline content and histopathology. RESULTS The animals treated with the extracts and fractions (5%) showed significant reduction in wound area 96.55 and 96.41% with faster epithelialisation (17.50 and 17.86), while the isolated compounds bergenin and ursolic acid heal the wound faster, but complete epithelialisation with 100% wound contraction was evident with 5% povidone-iodine group on 18th post-wounding day. Moreover, the tensile strength of incision wound, granuloma tissue weight, and hydroxyproline content was significantly increased in both the extract and compound(s) treated animals. Furthermore, the tissue histology of animals treated with the isolated compound(s) showed complete epithelialisation with increased collagenation, similar to povidone-iodine group. CONCLUSION Thus, our results validated the traditional use of Shorea robusta young leaves in wound management.

Prevention of cyclophosphamide-induced hepatotoxicity and genotoxicity: Effect of an L-cysteine based oxovanadium(IV) complex on oxidative stress and DNA damage.

Vanadium has been emerged as a promising agent owing to its ability to prevent several types of cancer. This study was aimed to investigate the protective role of an organovanadium complex, viz., oxovanadium(IV)-L-cysteine methyl ester (VC-IV) against cyclophosphamide (CP)-induced hepatotoxicity and genotoxicity in mice. Oral administration of VC-IV quite effectively ameliorated CP-induced histopathological lesions and reduced levels of alanine transaminase, aspartate transaminase and alkaline phosphatase. In addition, VC-IV significantly attenuated CP-induced oxidative stress in the liver as evident from levels of reactive oxygen species, nitric oxide and lipid peroxidation. Restoration of glutathione level and activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase) were also observed upon VC-IV administration. Moreover, VC-IV significantly mitigated CP-induced chromosomal aberrations, micronuclei formation, DNA fragmentation and apoptosis in bone marrow cells and DNA damage in lymphocytes. The present study showed that VC-IV could provide adequate protection against CP-induced hepatotoxicity and genotoxicity in vivo.

Signal transducer and oxidative stress mediated modulation of phenylpropanoid pathway to enhance rosmarinic acid biosynthesis in fungi elicited whole plant culture of Solenostemon scutellarioides.

This study aimed to improve rosmarinic acid (RA) production in the whole plant culture of Solenostemon scutellarioides through elicitation with phytopathogenic fungi. Amongst selected fungi, Aternaria alternata caused significant elevation (p<0.05-0.01) in RA accumulation (∼1.3-1.6-fold) between 25 and 100 μg l(-1). However, elicitation at the dose of 50 μg l(-1) has been found to be most effective and intracellular RA content reached almost ∼1.6-fold (p<0.01) higher in day 7. Therefore, A. alternata (50 μg l(-1)) was selected for mechanism evaluation. A significant elevation of intercellular jasmonic acid was observed up to day 6 after elicitation with A. alternata (50 μg l(-1)). A significant increase in tissue H2O2 and lipid peroxidation coupled with depletion of antioxidant enzymes superoxide dismutase and catalase indicated augmented oxidative stress associated with biotic interaction. Preceding the elicitor-induced RA accumulation, a notable alteration in the specific activities of biosynthetic enzymes namely PAL and TAT was recorded, while, no significant change in the activities of RAS was observed. HPPR activity was slightly improved in elicited plant. Therefore, it could be concluded that A. alternata elicited the biosynthesis of rosmarinic acid via signal transduction through jasmonic acid coupled with elicitor induced oxidative stress and associated mechanism.

Development and evaluation of intestinal targeted mucoadhesive microspheres of Bacillus coagulans

Background: Intestinal targeted mucoadhesive microsphere of probiotics may provide numerous associated health benefits. Aim: To develop mucoadhesive microspheres that will deliver viable probiotic cells into gut protectively against harsh environmental conditions of stomach for extended period. Materials and methods: Core mucoadhesive microspheres of Bacillus coagulans were prepared using hypromellose, following coacervation and phase separation technique and were then coated with hypromellose phthalate to achieve their site-specific release. Microspheres were evaluated for percent yield, entrapment efficiency, surface morphology, particle size and size distribution, flow property, swelling property, mucoadhesion property by the in vitro wash-off and the ex vivo mucoadhesive strength tests, in vitro release profile and release kinetic, in vivo probiotic activity, and stability. The values for kinetic constant and regression coefficient of model-dependent approaches and the difference factor, the similarity factor, and the Rescigno index of model-independent approaches were determined for accessing and comparing in vitro performance. Results: Microsphere formulation batches have percent yield value between 56.26% and 69.13% and entrapment efficiency value between 66.95% and 77.89%. Microspheres were coarser with spherical shape having mean particle size from 28.03 to 48.31 μm. In vitro B. coagulans release profile follows zero-order kinetics and depends on the grade of hypromellose and the B. coagulans-to-hypromellose ratio. Experimental microspheres rendered adequate stability to B. coagulans at room temperature. Conclusion: Microspheres had delivered B. coagulans in simulated intestinal condition following zero-order kinetics, protectively in simulated gastric condition, exhibiting appreciable mucoadhesion in intestinal condition, which could be useful to achieve site-specific delivery for extended period.

Antiproliferative effect of isolated isoquinoline alkaloid from Mucuna pruriens seeds in hepatic carcinoma cells

The present study was undertaken to investigate the antiproliferative action of isolated M1 (6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) from Mucuna pruriens seeds using human hepatic carcinoma cell line (Huh-7 cells). Initially, docking studies was performed to find out the binding affinities of M1 to caspase-3 and 8 enzymes. Later, cytotoxic action of M1 was measured by cell growth inhibition (MTT), followed by caspase-3 and 8 enzymes assay colorimetrically. Our results collectively suggested that M1 had strong binding affinity to caspase-8 in molecular modelling. M1 possessed antiproliferative activity on Huh-7 cells (EC50 = 13.97 μM) and also inhibited the action of caspase-8 enzyme, signified process of apoptosis. M1 was active against Huh-7 cells that may be useful for future hepatic cancer treatment.

Synthesis, characterization, X-ray crystallography, and antimicrobial activities of Ni(II) and Cu(II) complexes with a salicylaldehyde-based thiosemicarbazone ligand

A new salicylaldehyde-based ‘ONS’ tridentate salicylaldehyde-N(4)-diethylthiosemicarbazone (H2SANEt2) has been synthesized and characterized by elemental analyses, mass, IR, and 1H NMR spectral parameters. The coordination mode of the synthesized ligand is reported by solid state isolation and physico-chemical identification of Ni(II) and Cu(II) complexes, [Ni(SANEt2)]2 (1) and [Cu(SANEt2)]2 (2). Both complexes are neutral and oxygen-bridged dinuclear species. The ligand is bideprotonated ‘ONS’ tridentate in both complexes. IR spectral data indicate that coordination of each metal of the two complexes occurs through phenolic oxygen, azomethine nitrogen, and thiolato sulfur. X-ray crystallographic data of 1 and 2 (both monoclinic, P21/c) show a MONSO (where M=Ni and Cu) square-planar coordination around each metal. Magnetic studies of 2 show that the two Cu(II) centers are strongly antiferromagnetically coupled via the bridging phenoxo O. All the synthesized compounds were tested for their in vitro antimicrobial activities against pathogenic bacteria. The inhibition power of the complexes was greater than the parent ligand.

Anti-inflammatory activity of Odina wodier Roxb, an Indian folk remedy, through inhibition of toll-like receptor 4 signaling pathway.

Inflammation is part of self-limiting non-specific immune response, which occurs during bodily injury. In some disorders the inflammatory process becomes continuous, leading to the development of chronic inflammatory diseases including cardiovascular diseases, diabetes, cancer etc. Several Indian tribes used the bark of Odina wodier (OWB) for treating inflammatory disorders. Thus, we have evaluated the immunotherapeutic potential of OWB methanol extract and its major constituent chlorogenic acid (CA), using three popular in vivo antiinflammatory models: Carrageenan- and Dextran-induced paw edema, Cotton pellet granuloma, and Acetic acid-induced vascular permeability. To elucidate the possible anti-inflammatory mechanism of action we determine the level of major inflammatory mediators (NO, iNOS, COX-2-dependent prostaglandin E2 or PGE2), and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-12). Further, we determine the toll-like receptor 4 (TLR4), Myeloid differentiation primary response gene 88 (MyD88), c-Jun N-terminal kinases (JNK), nuclear factor kappa-B cells (NF-κB), and NF-kB inhibitor alpha (IK-Bα) by protein and mRNA expression, and Western blot analysis in drug treated LPS-induced murine macrophage model. Moreover, we determined the acute and sub-acute toxicity of OWB extract in BALB/c mice. Our study demonstrated a significant anti-inflammatory activity of OWB extract and CA along with the inhibition of TNF-α, IL-1β, IL-6 and IL-12 expressions. Further, the expression of TLR4, NF-κBp65, MyD88, iNOS and COX-2 molecules were reduced in drug-treated groups, but not in the LPS-stimulated untreated or control groups, Thus, our results collectively indicated that the OWB extract and CA can efficiently inhibit inflammation through the down regulation of TLR4/MyD88/NF-kB signaling pathway.

An investigation on in vitro and in vivo antimicrobial properties of the antidepressant: amitriptyline hydrochloride

The antidepressant drug amitriptyline hydrochloride was obtained in a dry powder form and was screened against 253 strains of bacteria which included 72 Gram positive and 181 Gram negative bacteria and against 5 fungal strains. The minimum inhibitory concentration (MIC) was determined by inoculating a loopful of an overnight peptone water culture of the organism on nutrient agar plates containing increasing concentrations of amitriptyline hydrochloride (0, 10 μg/mL, 25 μg/mL, 50 μg/mL, 100 μg/mL, 200 μg/mL). Amitriptyline hydrochloride exhibited significant action against both Gram positive and Gram negative bacteria at 25-200 μg/mL. In the in vivo studies it was seen that amitriptyline hydrochloride at a concentration of 25 μg/g and 30 μg/g body weight of mouse offered significant protection to Swiss strain of white mice when challenged with 50 median lethal dose (MLD) of a virulent strain of Salmonella typhimurium NCTC 74. The in vivo data were highly significant (p<0.001) according to the chi-square test.