Synthesis, Characterization and Study of Antimicrobial Activities of Mannich Bases Incorporating 1,2,4-Triazole Nucleus

Heterocyclic compounds containing triazole moiety have great importance in the field of medicine, pharmaceuticals, biochemistry, biology, therapeutics, environmental science, and industry. Triazoles and their derivatives have been extensively used in the development of new drugs. Biological activities of Schiff bases are highly investigated, but Mannich bases are on the verge of their development, and they are being synthesized in large number nowadays. In this work, Mannich bases are synthesized by incorporation 1,2,4-triazole moiety through Schiff base using different amines. Mannich bases are found to exhibit highly effective antibacterial and antifungal activities. The formation of synthesized compounds - 1,2,4-triazole-5-thione, Schiff base (4) and Mannich bases (5a and 5b) - are confirmed and characterized by spectroscopic techniques like UV, FTIR 1H-NMR and 13C-NMR. The activity of the synthesized compounds was tested against bacterial and fungal strain.

Recent Advances in Biomass-Based Waste Materials for the Removal of Chromium (VI) from Wastewater: A Review

Hexavalent chromium (Cr(VI)) is a critical pollutant with high toxicity, even at trace concentrations. Cr(VI) is possibly carcinogenic and mutagenic and can produce serious health issues. Hence, it is necessary to remove Cr(VI) from the water before releasing it into the environment. Currently, numerous removal techniques were used. Adsorption is the best method compared to others because it is simple, cheap, highly efficient, and can be used in water having trace concentrations of contaminants. Biomass-based waste materials (BMWs) are found as far better adsorbents than commercially and other available adsorbents. In this study, the existing Cr(VI) removal techniques are reviewed and, a broad range of current research studies of Cr(VI) removal from water by using BMWs are evaluated. This review can be helpful to develop a more efficient, cheap, reliable, and environmentally benign bio-adsorbent. It is obvious after the literature review given herein that BMWs exhibited potential adsorbents for the removal of Cr(VI). Also, the chemically modified adsorbents exhibited a higher adsorption capacity than unmodified adsorbents.

Phytochemical Screening, GC-MS Analysis and Biological Activities of Extracts of Artemisia vulgaris Linn.

The aerial parts of Artemisia vulgaris were subjected for successive extraction in solvents methanol, hexane and chloroform, respectively, and compounds present in extract were analysed by GC-MS analysis 12 different compounds were found in chloroform extract in which Germacrene was found most abundantly (33.84%). Chloroform extract showed strong antibacterial activity, which was examined against 6 bacteria using the disc diffusion method. The IC50 value of chloroform extract accounted for 1.50 mg/mL. The TPC content of the extract was found to be 87.75 mg gallic acid equivalent/g of dry extract, whereas TFC content was found to be 47.25 mg quercetin equivalent/g of dry extract and exhibited LC50 value of 0.18 mg/mL.

Identification of Suitable Plant Species for Vegetation Restoration at Manthali, Nepal

The present study aims to find out the suitable native plant species for restoring degraded land in the mountain from 450 m asl to 819 m asl in Khurkot of Manthali. Altogether thirty quadrats were laid to observe frequency, density and coverage of plant species present there, and ultimately, IVI was calculated. Eight plant species – 3 trees like Acacia catechu, Aegle marmelos and Annona squamosa; 3 shrubs like Rhus parviflora, Cipadessa baccifera and Abrus precatorius (woody climber), and 2 herbs like Uraria lagopodiodes and Polypogon monospeliensis were considered for the detailed study based on their high IVI values. Altogether fourteen traits (growth form, life-span, phenology, Raunkiaer’s life-form, canopy height, stem density, mean ramet distance, leaf size, specific leaf area, leaf thickness, seed mass, propagules mass, seed shape and nitrogen fixation) were studied in those eight species. Based on these traits, through this protocol, the plants were again categorized into five syndromes, i.e., establishment syndrome, dispersal syndrome, biomass producing syndrome, persistence syndrome and effect on environment syndrome. From this study, Annona squamosa and Abrus precatorius can be suggested as candidate species for early succession. Similarly, Aegle marmelos, Acacia catechu, Annona squamosa, Rhus parviflora and Abrus precatorius can be recommended to plant for restoration of degraded bushy lands, which are in the phase of secondary succession.

Green Approach for Synthesis of Manganese Nanoparticle using Banana Peel (Musa paradiasca) and its Characterization

This research mainly aims at implementing green approach for synthesizing multifunctional manganese nanoparticles (MnNPs) using aqueous extract of banana peel (Musa paradiasca) and potassium permanganate (KMnO4) as the precursor. As synthesized MnNPs were confirmed initially by a color change and later on characterized by UV-visible (UV-vis) Spectrophotometer, Energy Dispersive Spectroscopy (EDX), X-ray Diffraction Spectroscopy (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Green approach was carried at various parameters like concentration of precursor solution, reaction time, temperature, etc for optimization. The formation of MnNPs was confirmed by the presence of surface plasmon absorbance band (450 nm) and band at 6 and 6.5 keV of EDX spectrum. Likewise, so formed MnNPs were crystalline nature depicted from the sharp peak observed at 28.5º and 41° in X-ray diffraction pattern. Various types of biomolecules associated with the banana peel extract acting as natural reducer and stabilizer were analyzed from characteristic absorption bands present in the FT-IR spectrum.

Adsorption Isotherm and Activation Energy of Inhibition of Alkaloids on Mild Steel Surface in Acidic Medium

Alkaloids as green inhibitors were extracted from three different plants Rhynchostylis retusa, Artimesia vulgaris,and Solanum tuberosum. Weight loss measurement in mild steel has been carried out in the presence and absence of green inhibitors individually in an acidic medium. Weight loss measurements at different temperatures are used to calculate thermodynamic parameters. The weight loss measurements at different concentrations are used to find adsorption isotherm and found that it obeys Langmuir adsorption isotherm with R2 values 1, 1, 0.996 for three inhibitors. Activation energy, enthalpy, and entropy of the three inhibitors have been calculated. It is found that the value of all these parameters increased in the addition of inhibitors. The free energy of the system is calculated and found (-17.46 kJ mol-1) indicating that the adsorption process is spontaneous and there is physical adsorption at the MS-Inhibitor interface.

An Investigation on Biological Efficacies of Fruits and Leaves of Ficus auriculata (Timilo) from Kanchanpur District, Nepal

Ficus auriculata is a native Asian plant found in the temperate, tropical and subtropical regions and has been commonly used in traditional medicine and as fodder in animal husbandry. The comparative antibacterial and antioxidant efficacies of leaves and fruits have been studied using their hexane, chloroform, ethyl acetate and methanol extracts. Phytochemical screening exhibited the presence of important secondary metabolites like alkaloids, carbohydrates, glycosides, flavonoids and tannins. Antibacterial activities of fruit and leaf extracts in different concentrations were studied against E. coli, S. aureus and S. typhi by agar well diffusion method. The highest inhibition was found to be in 1% methanol extracts of leaves and fruits with a zone of inhibition (ZOI) ± 16 mm against S. aureus followed by E. coli and S. typhi with ZOI ±14 mm. The crude and 50% extracts of various solvents of both fruits and leaves were found to be ineffective against bacteria. These results reveal that there is a significant antibacterial activity in methanol extract of both fruit and leaves, against gram-positive and gram-negative bacteria. The antioxidant activities of methanol extracts of fruits and leaves were studied by DPPH radical scavenging assay. The IC50 values of methanol extract of leaves and fruit for DPPH radical scavenging assay were found to be 114.84 μg/mL and 78.28 μg/mL, respectively. These results reveal that methanol fruit extract exhibits better antioxidant activity as compared to the leaves. The result of this investigation has revealed the applicability of this plant as a potential source of several bioactive compounds for the discovery of new and efficacious drugs in days to come.

Different Crude Extracts of Cinnamomum tamala with Antioxidant and Antibacterial Capabilities

In this present study, crude extracts of young and mature leaves of Cinnamomum tamala were evaluated for their antioxidant and antibacterial capabilities. The cold percolation method was carried out with polar solvents methanol and ethanol. The antioxidant activities of all the extracts were assessed by DPPH assay and antibacterial properties were performed against Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Klebsiella pneumoniae by agar well diffusion method. All extracts were able to scavenge free radicals in which strong antioxidant activity was found in methanolic extract of young leaves, and its IC50 value was estimated as (67.19±14.96 μg/mL) at a concentration range of 31.25-500 μg/mL while IC50 value of standard ascorbic acid was found to be 33.53±0.97 μg/mL at the concentration range of 10-50 μg/mL. The ethanolic extract of leaves (ZOI = 19 mm) showed strong antibacterial activity while standard neomycin showed (ZOI = 23 mm) against Escherichia coli at a concentration of 50 μg/mL. These results may provide scientific evidence of the traditional uses of C. tamala. Isolation and characterization of pure active compounds should be done in the future.

First-Principles Study of Vacancy and Impurities Defects in Graphene

In this work, we have studied the electronic and magnetic properties of 1C atom vacancy defects in graphene (1Cv-d-G), 1N atom impurity defects in graphene (1NI-d-G) and 1O atom impurity defects in graphene (1OI-d-G) materials through first principles calculations based on spin-polarized density functional theory (DFT) method, using computational tool Quantum ESPRESSO (QE) code. From band structure and density of states (DOS) calculations, we found that supercell structure of monolayer graphene is a zero bandgap material. But, electronic bands of 1Cv-d-G, 1NI-d-G and 1OI-d-G materials split around the Fermi energy level and DOS of up & down spins states appear in the Fermi energy level. Thus, 1Cv-d-G, 1NI-d-G and 1OI-d-G materials have metallic properties. We have studied the magnetic properties of pure and defected materials by analyzing density of states (DOS) and partial density of states (PDOS) calculations. We found that graphene and 1OI-d-G materials have non-magnetic properties. On the other hand, 1C vacancy atom and 1N impurity atom induced magnetization in 1Cv-d-G & 1NI-d-G materials by the rebonding of dangling bonds and acquiring significant magnetic moments of values -0.75μB/cell & 0.05μB/cell respectively through remaining unsaturated dangling bond. Therefore, non-magnetic graphene changes to magnetic 1Cv-d-G and 1NI-d-G materials due to 1C atom vacancy defects and 1N atom impurity defects. The 2p orbital of carbon atoms has main contribution of magnetic moment in these defected structures.

In Vitro Studies on Alpha-amylase Inhibitory Activities of Zanthoxylum armatum of Mid-Western Regions of Nepal

The alpha-amylase inhibitors are used as a drug to control hyperglycemia in type II diabetes mellitus. The plant extract is a natural source to minimize toxicity and other side effects. The alpha-amylase inhibition assay shows that the methanol extracts of fruits, seeds, leaves, and barks of Z. armatum exhibit 50% alpha-amylase inhibition activity at concentration 47.73 μg/mL, 50.25 μg/mL, 67.25 μg/mL, 152.6 μg/mL respectively, and hexane extracts of fruits, seeds, leaves and barks of Z. armatum exhibits 50% alpha-amylase inhibition activity at concentration 86.24 μg/mL, 84.02 μg/mL, 98.8 μg/mL, 138.81 μg/mL respectively, whereas the 50% alpha-amylase inhibition activity of Acarbose (standard) was found to be 33.66 μg/mL. Therefore, methanol and hexane extracts of fruits, seeds, and leaves show potential alpha-amylase inhibition activity and can be used as anti-diabetes.