Shanmugam Achiraman

Comparative evaluation of antibacterial activity of silver nanoparticles synthesized using Rhizophora apiculata and glucose.

The focus of the study is to compare the antibacterial efficacy of silver nanoparticles (AgNPs) fabricated by exploiting biological (a mangrove plant, Rhizophora apiculata) and chemical means (Glucose). The synthesized nanoparticles were characterised using UV-visible absorption spectrophotometry (UV-vis), Fourier transform Infra-red Spectroscopy (FTIR) and Transmission electron microscopy (TEM). Biologically synthesized silver nanoparticles (BAgNPs) were observed at 423 nm with particle sizes of 19-42 nm. The chemically synthesized silver nanoparticles (CAgNPs) showed a maximum peak at 422 nm with particle sizes of 13-19 nm. An obvious superiority of the antibacterial potency of BAgNPs compared to the CAgNPs as denoted by the zone of inhibition (ZoI) was noted when the nanoparticles were treated against seven different Microbial Type Culture Collection (MTCC) strains. The current study therefore elucidates that the synthesized AgNPs were efficient against the bacterial strains tested.

Hepatocurative activity of biosynthesized silver nanoparticles fabricated using Andrographis paniculata.

The current investigation was aimed to determine the hepatocurative role of silver nanoparticles (AgNPs) synthesized rapidly using Andrographis paniculata. The nanoparticles fabricated at varying temperatures were characterized by UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), fourier transform infra-red spectroscopy (FTIR), energy dispersive X-ray (EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES) alongside zeta potential measurement. UV-vis spectroscopic readings indicated a prominent peak at 423 nm. TEM analysis indicated that the biosynthesized nanospheres were in the size range of 13-27 nm. EDX spectrum indicated strong signal for AgNPs with 90.1% purity. The total concentration of AgNps was 216.7 mg/L after synthesis as by ICP-OES. Zeta potential was -34.3 mV indicating stable AgNPs. In vitro radical scavenging assay proved strong antioxidant effect of the AgNPs compared to 5% aqueous leaf extract. CCl(4) was used to induce hepatic injury in mice model. The biosynthesized AgNPs at three different doses (25, 50, 100mg/kg BW of the animal) were used for treatment. Silymarin was used as a standard. Low dose (25mg/kg BW) was effective in revival of all biological parameters to near normal in all intoxicated groups indicating the curing effects on CCl(4) induced liver injury.

Mangrove Streptomyces sp. BDUKAS10 as nanofactory for fabrication of bactericidal silver nanoparticles.

Biosynthesis has led to the development of various biomimetic approaches for the fabrication of nanoscale materials. The present study reveals a unique procedure for the biosynthesis of bactericidal silver nanoparticles (AgNPs) using a novel Streptomyces sp. BDUKAS10, an isolate of mangrove sediment. Aqueous silver nitrate (AgNO(3)) solution was treated with cell free supernatant (CFS) of the isolate to synthesize bactericidal silver nanoparticles. Initial characterization was performed by visual observation for color change to intense brown color. UV-visible spectrophotometry (UV-vis) for measuring surface plasmon resonance indicated a maximum absorption peak at 441 nm. Fourier Transform Infrared Spectroscopy (FTIR) analysis provides evidence for proteins as possible reducing, and capping agents. Energy dispersive X-ray (EDAX) spectroscopy analysis showed elemental silver as major signal. Transmission Electron Microscopy (TEM) study indicated spherical silver nanoparticles in the size range of 21-48 nm. Compared to the CFS, the biosynthesized AgNPs exemplified superior bactericidal efficacy towards the tested bacterial strains. Results from this study suggested that Streptomyces sp. BDUKAS10 can be advantageous for the synthesis of AgNPs by extracellular method in the view of sustainable and ecofriendly approach.

γ-Sitosterol from Acacia nilotica L. induces G2/M cell cycle arrest and apoptosis through c-Myc suppression in MCF-7 and A549 cells.

ETHNOPHARMACOLOGICAL RELEVANCE Acacia nilotica is widely distributed in Asia. In India, it occupies an important place in the indigenous system of medicine against anti-inflammatory, antioxidant, cancers, and/or tumors. AIM OF THE STUDY The purpose of this study is to investigate the inhibitory effect of Acacia nilotica leaves extract and γ-Sitosterol on cell proliferation, the apoptotic effect and cell cycle arrest in breast and lung cancer cells. MATERIALS AND METHODS GC-MS and HPLC were used to determine the chemical constituents of this extract and γ-Sitosterol respectively. Human MCF-7 and A549 cell lines were treated with Acacia nilotica extract and γ-Sitosterol. Cell viability was determined by MTT assay. Cell proliferation was determined by BrdU incorporation assay. Apoptosis was detected by cell morphologic observation through AO/EtBr staining, cell cycle analysis, and immunoblot analysis on the expression of protein associated with cell cycle arrest. RESULTS Experimental results of bioactive compound analysis indicate that γ-Sitosterol, bioactive ingredients of Acacia nilotica extract. The IC(50) value of extract on MCF-7 and A549 cancer cells was 493.3±15.2 and 696.6±11.5 μg/ml, respectively. Acacia nilotica extract and γ-Sitosterol were inhibited the cell proliferation by 54.34±1.8 and 42.18±3.9% for MCF-7 and 58.26±1.5 and 44.36±3.05% for A549 cells. The percentage of apoptotic cells observed in the MCF-7 and A549 cell lines were increased to 42.46 and 36.8% of extract; 46.68 and 43.24% for γ-Sitosterol respectively. Flow cytometric analysis results demonstrate that cells were arrested at the G2/M phase and decrease the c-Myc expression. CONCLUSIONS This study demonstrates in vitro results, which support the ethnomedical use of γ-Sitosterol against cancer. Experimental results of this study suggest that γ-Sitosterol exerts potential anticancer activity through the growth inhibition, cell cycle arrest and the apoptosis on cancer cells.

In vivo antitumor activity of biosynthesized silver nanoparticles using Ficus religiosa as a nanofactory in DAL induced mice model

Ficus religiosa leaf extract was chosen as a reducing agent to fabricate silver nanoparticles (AgNPs) by a simple, cost-effective and eco-friendly process with the aim of treating Daltons ascites lymphoma (DAL) in mice model. The formation of synthesized nanoparticles were characterized by UV-visible analysis (UV-vis), Fourier transform infra-red (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and zeta potential analyses. A peak at 431nm indicated the surface plasmon resonance of AgNPs. FTIR studies indicated polyphenols and proteins as possible encapsulates. TEM analysis showed particles size in the range of 5-35nm. Healthy Swiss Albino mice (30-35g) were intraperitoneally induced with DAL cells and treated with F. religiosa derived AgNPs at a dose of 50μg/ml. Blood and liver tissues were collected subsequent to dissection and subjected to hematological, biochemical and anticancer assays. Hematological and biochemical analyses revealed revival after treating with F. religiosa derived AgNPs. Antioxidant activity results further proved supportive evidence. The apoptosis inducing effect of AgNPs was observed through acridine orange staining (AO and EB) and DNA fragmentation assay. Anti- angiogenic activity was confirmed by observing vessel development. All these observations indicate that the AgNPs were effective in treatment of DAL.

Doxorubicin treatment inhibits PPARγ and may induce lipotoxicity by mimicking a type 2 diabetes-like condition in rodent models

Doxorubicin‐treated animals show elevated serum triglyceride and blood glucose levels. Adipocytes play an important role in buffering blood glucose and lipids. A raise in serum lipid level triggers adipogenesis in order to increase the lipid absorption capacity of adipose tissue. Doxorubicin inhibits adipogenesis through the down‐regulation of PPARγ, a crucial component of the lipid metabolic pathway which controls the expression of glucose and fatty acid transporters. Doxorubicin‐mediated down‐regulation of PPARγ inhibits blood glucose and lipid clearance thereby causing hyperglycemia and hyperlipidemia resulting in lipotoxicity, glucotoxicity, inflammation and insulin resistance. Therefore we hypothesize that doxorubicin treatment could mimic a type 2 diabetic condition.

Detection of estrus by male mice: Synergistic role of olfactory–vomeronasal system

In rodents, olfactory pathway comprises two distinct systems viz, the main olfactory and vomeronasal systems, both differing in anatomy, physiology and function. The precise role of the main olfactory/vomeronasal system in estrus detection is yet to be explored. Therefore, the present investigation was planned to elucidate the role of main olfactory and vomeronasal system in the estrus discriminating ability of male mice. Female urine samples of proestrus, estrus, metestrus, diestrus, ovarectomized, ovarectomized plus estrogen treated and prepubertal mice were used for the present study. In addition, the urine from intact, castrated and castrated with testosterone treated mice was also tested for odour preference by male mice. The male responders were categorized into three groups namely (a) normal, (b) ZnSO(4)-irrigated and (c) vomeronasal organ (VNO)-ablated. The behavioural responses such as frequency and duration of visits to urine samples were carried out in a Y-maze apparatus to assess odour preference. The normal mice displayed more frequent visits to estrus urine samples than to non-estrus samples. In contrast, ZnSO(4)-irrigated mice showed significant reduction in the frequency of visits towards estrus urine, whereas, the vomeronasal (VNO)-ablated mice did not show any noticeable preference. With regard to the duration of visits the VNO-ablated mice showed significant reduction in visiting time when compared to ZnSO(4)-irrigated mice. This finding indicated that the main olfactory system (MOS) was involved primarily in the attraction from a distance, while the VNO played a major role in close proximity (pre-copulatory behaviour). The males spent less time with the urine of same-sex; however, the response was higher with castrated male urine which was reduced on testosterone treatment indicating that a specific odour in intact male causes aversive behaviour in male. This study provides support to the fact that volatile compounds could also be perceived by VNO, probably when the main olfactory system is in functional state. The study implies that the olfactory-vomeronasal system plays a synergistic role in the detection of estrus.

Antimicrobial activity of Leucas aspera engineered silver nanoparticles against Aeromonas hydrophila in infected Catla catla.

This research describes green synthesis of silver nanoparticles (AgNPs) utilizing Leucas aspera. The synthesized nanoparticles were characterized by UV-visible spectroscopy (UV-vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infra-red spectroscopy (FTIR) and inductively coupled plasmon optical emission spectroscopy (ICP-OES). UV-vis analysis proved the wavelength of the sample to be 429 nm, resembling the surface resonance peak (SPR) specific for AgNPs. DLS analysis indicated particles with superior stability with an average diameter of 189.3 nm. TEM results showed that the particles were in the size range of 29-45 nm. FTIR prediction indicated the presence of possible polyphenol and protein encapsulates on the AgNPs. Antimicrobial activity of the AgNPs was tested against Aeromonas hydrophila. Catla catla, the model organism used for the experiment was divided into six groups with 15 animals in each group. In vivo analysis of biochemical parameters and histological architecture provided evidence for the antibacterial effect of AgNPs in the fish model.

Laser receptive polyelectrolyte thin films doped with biosynthesized silver nanoparticles for antibacterial coatings and drug delivery applications

We report a simple method to fabricate multifunctional polyelectrolyte thin films to load and deliver the therapeutic drugs. The multilayer thin films were assembled by the electrostatic adsorption of poly (allylamine hydrochloride) (PAH) and dextran sulfate (DS). The silver nanoparticles (Ag NPs) biosynthesized from novel Hybanthus enneaspermus leaf extract as the reducing agent were successfully incorporated into the film. The biosynthesized Ag NPs showed excellent antimicrobial activity against the range of enteropathogens, which could be significantly enhanced when used with commercial antibiotics. The assembled silver nano composite multilayer films showed rupture and deformation when they are exposed to laser. The Ag NPs act as an energy absorption center, locally heat up the film and rupture it under laser treatment. The antibacterial drug, moxifloxacin hydrochloride (MH) was successfully loaded into the multilayer films. The total amount of MH release observed was about 63% which increased to 85% when subjected to laser light exposure. Thus, the polyelectrolyte thin film reported in our study has significant potential in the field of remote activated drug delivery, antibacterial coatings and wound dressings.

Spermidine may decrease ER stress in pancreatic beta cells and may reduce apoptosis via activating AMPK dependent autophagy pathway

The risk for diabetes increases with increasing BMI<25. Insulin resistance is the key factor for type 2 diabetes; studies revealed that endoplasmic reticulum stress is the main factor behind this disease. With increase in ER stress, pancreatic beta cells start to undergo apoptosis, leading to a decline in the pancreatic beta cell population. The ER stress arises due to unfolded protein response. Recently, spermidine get importance for increasing the longevity in most of the eukaryotes including yeast, Caenorhabditis elegans, Drosophila and human peripheral blood mononuclear cells via induction of autophagy pathway. Autophagy is also involved in regulation of scavenging of proteins. One of the major cellular pathways for scavenging the aggregated intracellular protein is autophagy. Hence spermidine can be a candidate for the treatment type 2 diabetes. Autophagy genes are regulated by mTOR (mammalian Target Of Rapamycin) dependent or independent pathway via AMPK. Hence either inhibition of mTOR or activation of AMPK by spermidine will play two crucial roles, first being the activation of autophagy and secondly the reduction of endoplasmic reticulum stress which will reduce beta cell death by apoptosis and thus can be a novel therapeutic candidate in the treatment of insulin resistance in type 2 diabetes and preserving pancreatic beta cell mass.