Journal of Nepal Chemical Society

Structural Equilibrium Configuration of Benzene and Aniline: A First-Principles Study

Wed, 21 Feb 2024 00:00:00 +0000

The present work describes the equilibrium configuration of aromatic compounds like benzene and aniline molecules using the first principle (ab initio) calculation method implemented by the Gaussian 98 programs. The ground state energy for benzene and aniline molecules obtained using the DFT (B3LYP) calculation is lower than that obtained with the HF+MP2 method which, in turn, is lower than that obtained with the HF calculation. The calculated values of bond length, bond angle, and dihedral angle for these molecules with HF, HF+MP2, and DFT (B3LYP) levels of calculation agree with each other within 2%. The calculated C-C and C-H bond lengths of the benzene molecule are 1.394 Å and 1.084 Å at DFT (B3LYP) calculation and these values agree well with the experimental value of 1.395 Å and 1.084 Å for C-C and C-H bond. Also, the calculated value of bond angles and dihedral angles for benzene molecule are 120° and 180° respectively. For aniline molecule, the C-N and N-H bond lengths are found 1.378 Å and 1.003 Å respectively at DFT (B3LYP) calculation, which agrees with the experimental value of C-N and N-H bond lengths with values of 1.475 Å and 1.008 Å within 7% respectively. For the benzene molecule, there is a symmetrical charge distribution. The total dipole moment of the benzene molecule is zero, indicating that the centers of positive and negative charge coincide with each other such that the benzene molecule is non-polar whereas aniline is a polar molecule with a dipole moment of 1.9828 Debye

Effect of pH, Amount of Metal Precursor, and Reduction Time on The Optical Properties and Size of Zinc Oxide Nanoparticles Synthesized Using Aqueous Extract of Rhizomes of Acorus calamus

Melina Tamang, Kamal Prasad Sapkota, Sabita Shrestha — Wed, 21 Feb 2024 00:00:00 +0000

Nanoparticles possess various unique characteristics compared to the corresponding bulk materials. Large band gap, non-toxic nature, and multi-applicability are the worthwhile characteristics of zinc oxide to be synthesized and studied. The size of nanoparticles can be controlled by varying the different experimental conditions. This paper reports the synthesis of zinc oxide nanoparticles by using an aqueous extract of rhizomes of Acorus calamus, where the bio-components present in aqueous extract acted as reducing agents. The size and band gap energy of zinc oxide nanoparticles were studied by varying different parameters such as pH, concentration of the metal precursor, and reduction time. The variations in the size of nanoparticles were studied by UV-visible spectroscopy. FTIR showed phenolic compounds, primary amines, and amides (proteins/enzymes) as the functional groups responsible for the reduction of metal precursors to form nanoparticles. The surface morphology of nanoparticles was studied by FE-SEM image. The FE-SEM image displayed the formation of various shapes and agglomeration of the nanoparticles. XRD pattern revealed that the average size of zinc nanoparticles is 10 nm. In vitro antibacterial activity of ZnO nanoparticles has been assayed against gram-positive and gram-negative bacteria. The growth inhibitory activity of nanoparticles against different bacterial pathogens has also been determined

Study of Antimicrobial Activity of ZnO Nanoparticles Dopped Natural Hydroxyapatites

Wed, 21 Feb 2024 00:00:00 +0000

Bone replacements and repairs often encounter infections from diverse microbes, necessitating costly and painful secondary surgeries and treatments. Developing antimicrobial bone implants is crucial to mitigate these complications and enhance regeneration. Moreover, the biological synthesis of hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, a primary component of human bone, presents advantages over chemically synthesized alternatives due to lower impurity and cost. This study focuses on synthesizing hydroxyapatite powders from buffalo and goat femoral bones, with the incorporation of ZnO nanoparticles. Analyzed via XRD and FTIR, the prepared powder exhibited potent antimicrobial properties against various bacterial strains. Specifically, the hydroxyapatite powder doped with ZnO nanoparticles displayed superior antimicrobial activity. Consequently, this synthesized material holds significant promise for applications in bone tissue engineering and related fields.

Bio-pesticidal, Antimicrobial, and Anti-inflammatory Potentials of n-Hexane Fraction of Zanthoxylum armatum DC and its Chemical Profiling

Janaki Baral, Achyut Adhikari — Wed, 21 Feb 2024 00:00:00 +0000

Zanthoxylum armatum DC, commonly known as toothache tree, is utilized for treating inflamed gums. The plant’s volatile constituent possesses a robust fragrance and contributes to its tangy taste. This study investigates the bioactivities, including bio-pesticidal, antimicrobial, and anti-inflammatory properties as well as the chemical profiling of the n-hexane fraction based on GC-MS analysis. The evaluated activities involve contact toxicity, microplate alamar blue assay, against three different insects, five bacteria, and seven fungi, and oxidative burst assay. The NIST library serves as a standard reference database for constituent identification. Remarkable insecticidal activities comparable to the standard drug permethrin were observed, particularly against Rhyzopertha dominica (100%), Tribolium castaneum (60%), and Sitophilus oryzae (50%). The fraction exhibited significant antifungal activity against Fusarium lini (85%) and notable inhibition against B. subtillis (67.27%) and S. aureus (65.25%). Potent anti-inflammatory effects were noted with an IC50 value of 11.2±1.9 μg/ml, equivalent to standard ibuprofen at various concentrations. GC-MS analysis identified twenty compounds, with major ones including trans-13-octadecenoic acid (36.08%), cis-9 hexadecenoic acid (18.66%), and 2-propenoic acid 3 phenyl methyl ester (11.08%). The diverse bioactivities observed may be attributed to the varied nature of compounds such as polyunsaturated fatty acids and their oxides. This research revealed the potential of Z. armatum as a potential bio-pesticide, anti-inflammatory, and antimicrobial agent.

Evaluation of heavy metals in different brands of chocolates marketed in Kathmandu, Nepal, and their associated health risks

Jasana Maharjan, Pawan Raj Shakya — Wed, 21 Feb 2024 00:00:00 +0000

Chocolates are among the sweet food items consumed by all age groups particularly children in Nepal. However, this foodstuff may be contaminated with heavy metals from the raw ingredients, production, and packaging methods, which could bring serious health issues. Therefore, this study aimed to determine cadmium (Cd), nickel (Ni), and lead (Pb) by Flame Atomic Absorption Spectrophotometer (FAAS) in a total of thirty-seven different brands of milk-based, cocoa-based, and sugar-based chocolates available in local grocery shops of Kathmandu city, Nepal and to evaluate associated health risks in children and adults using USEPA deterministic approaches. The results revealed concentrations of Cd, Ni, and Pb in the range of 0.021 – 0.585, 1.90 – 7.24, and 0.57 – 4.29 mg/kg respectively in studied chocolates and an overall mean concentration of 0.199, 4.22, and 1.94 mg/kg respectively. The observed concentrations exceeded the maximum permissible limits set by FAO/WHO (2001). A higher concentration of all studied metals was found in cocoa-based chocolate compared to milk-based and sugar-based chocolates. The positive and significant correlations (p < 0.05) among Cd, Ni, and Pb in studied chocolates indicate the possibility of contamination from common sources. Similarly, the estimated ADDing values were higher for all metals in cocoa-based chocolate for both children and adults. However, children were more prone to metals exposure than adults since their dietary intake was higher than adults. Cocoa-based chocolate in this study posed a non-carcinogenic risk to both children and adults since their hazard index (HI) values exceeded the acceptable limit (>1.0). In addition, Cd and Ni posed carcinogenic risks to both receptor groups through the consumption of all three categories of chocolate. Therefore, this study suggested the use of less contaminated raw materials in chocolates as well as regular monitoring of the production chain as an attempt to ensure the quality and safety of the food products.

Phytochemical Screening and In Vitro Antioxidant Activity of Three Nepalese Plants

Wed, 21 Feb 2024 00:00:00 +0000

Nepal is rich in plant resources and holds the 49^th spot in the world’s biodiversity. The variation in altitude, climatic conditions, and geographical features across Nepal make it a rich source of Medicinal and Aromatic Plants (MAPs). The study was carried out to perform the preliminary phytochemical screening and assess antioxidant properties in Ficus neriifolia, Rubus treutleri, and Periploca calophylla. Plants were selected based on their ethnomedical use and scant scientific research. Ethanol (70%) and aqueous extracts were prepared by using the cold maceration method and preliminary phytochemical screening was conducted using the previously established method to test the presence of biologically active phytoconstituent. In vitro, antioxidant activity was examined by DPPH free radical scavenging assay. The results revealed the variation in phytoconstituents among the 70% ethanol and aqueous extracts of all three plant samples. Among the samples, the 70% ethanol extract of P. calophylla exhibited the highest antioxidant activity with an IC₅₀ value of 94.36 μg/mL, while the aqueous extract of F. neriifolia showed the minimum antioxidant activity with an IC₅₀ value of 902.23 μg/mL. This study indicates that these plant samples possess potent natural antioxidants capable of scavenging free radicals that cause cellular damage and contribute to various diseases in our bodies.

Acute Oral Toxicity Analysis of Nano-Hydroxyapatite-Gelatin Suspension in Albino Wistar Rats

Wed, 21 Feb 2024 00:00:00 +0000

Hydroxyapatite (HAp), a calcium phosphate-based bio-ceramic, was prepared from waste ostrich bone using the thermal decomposition method, and the nano-HAp was segregated by the water-in-oil microemulsion technique. A single acute dose of oral toxicity of nano-HAp in gelatin suspension was tested in eleven female Albino Wistar rats following the OECD 420 guidelines. The rats were divided into three groups: three for control, three for group I, and five for group II. The first group was given 300 mg of nano-HAp in gelatin suspension per kg of body weight, while group II was given 2000 mg per kg of body weight. Results show that no signs or symptoms of toxic effects were seen in the group during the 14-day study period. Furthermore, no significant change in their average body weight or other physical behaviors such as autonomic, respiratory, or somatomotor effects were observed in the rats. The macroscopic examination of internal organs and bodyweight observation have shown no symptoms of toxicity in either group. It could be concluded that the nano-HAp suspension in gelatin does not show any acute toxic effect. The lethal 50% dose (LD₅₀) of the nano-HAp-Gel suspension has been estimated to be more than 2000 mg/kg of the body weight, suggesting that nano-HAp extracted from ostrich bone is safe to use for calcium supplements and other biomedical applications.

Design of Hydrogel for the Drug Delivery of Less Permeable Ursolic Acid Isolated from Rhododendron arboreum Flower in Animal Skin Membrane

Wed, 21 Feb 2024 00:00:00 +0000

Ursolic acid (UA) is a pentacyclic triterpene that has antioxidant, anticancer, and anti-inflammatory properties. As it belongs to the biopharmaceutical classification system IV due to its poor water solubility and permeability restricts its use in clinical application. So, the research is focused on the development of hydrogel containing encapsulated liposomes of ursolic acid to increase its permeability. The ursolic acid liposomal gel was prepared with a 0.5%, 1%, and 1.5% mixture of carbopol 934P and HPMC K4M as gelling agents. The pH and spreadability of liposomal gel were found to be in the range of (6.93±0.035 to 7.12±0.03) and (15.41±0.36 to 24.47±0.90) g.cm/sec respectively. The drug content was found to be in (19.77±0.02 to 20.11±0.02)%. The study of drug release kinetics showed Higuchi release followed by a non-Fickian diffusion mechanism. The result of the permeation study by Franz diffusion cell showed 1.55 times higher compared to the plain gel at the 5^th hour of the study with a flux value of 0.455(mg/cm²/hr). It resolved the fast and enhanced delivery of liposomal ursolic acid through the skin membrane.

Assessment of Microplastics in Hanumante River of Kathmandu Valley

Wed, 21 Feb 2024 00:00:00 +0000

Plastic debris is one of the most significant organic pollutants in the aquatic environment. Researchers are currently focusing on the impact of micro and nano-scale plastic waste on aquatic systems. In this study, we investigated the distribution of plastic pellets and fragments present in the freshwater ecosystem. The goal was to assess microplastic (MP) abundance in the Hanumante River, a tributary of the Bagmati River, and analyze their properties. Sample collection involved the bottle sampling method. Filtration, wet peroxide oxidation, density separation, gravimetric analysis, and microscopic examination were performed to study the characteristics of microplastics. The study was conducted by following the guidelines of the National Oceanic and Atmospheric Administration (NOAA) protocol. Gravimetric analysis was applied to calculate the reduced mass of the sample after total organic carbon reduction. Results showed that the maximum amount of reduced sample was obtained from the sample taken from sample taken from Madhyapur Thimi area (~3.593g) and the minimum amount of reduced sample was obtained from the sample taken from the Shiva temple Jagati area (~2.130g). Microscopic inspection showed that samples taken from different locations were composed of an average of 14–23 microplastics per liter of sample. FT-IR analysis was performed to analyze the characteristics of microplastics and the type of polymers present in the sample which showed the abundance of polymer materials like polyethylene, polypropylene, and polycarbonates. The findings imply that appropriate plastic waste management measures be implemented in the communities to safeguard the ecosystem benefits derived from the river.

Index Based Irrigation Suitability of Ramsar Sites (Rara and Ghodaghodi) in Western Nepal

Wed, 21 Feb 2024 00:00:00 +0000

The present study highlights the water quality of two important Ramsar sites of western Nepal (Ghodaghodi and Rara lakes) in terms of irrigation use. Based on land use patterns and location accessibility, 13 sites in Ghodaghodi and 18 in Rara were considered and the samplings were performed in the pre-monsoon and post-monsoon seasons. Different physicochemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), major cations, and anion (Na⁺, K⁺, Ca²⁺, Mg²⁺, and HCO₃^-) were measured. The calculated indices were permeability index percentage (PI), sodium percentage (%Na), sodium adsorption ratio (SAR), magnesium hazard ratio (MAR), residual sodium carbonate (RSC), and Kelly’s index (KI). Major ions were analyzed using ion chromatography including field and procedural blanks to maintain quality standards, whereas on-site parameters were measured by using standard multi-meter probes. The studied irrigation water quality parameters (pH, EC, TDS, TH) and indices (PI, MAR, RSC, KI, SAR, and %Na) fall within the permissible limit in both lakes, indicating the suitability of such water for irrigation purposes. In addition, based on the SAR vs. EC plot, all the results from both lakes fall in the S1 category, signifying low sodium hazard. Concerning EC, most of the samples demonstrate the C1 category and few are in the C2 category (in Ghodaghodi) whereas the C1 category predominates for Rara. According to IWQI, all water samples in both lakes fall in the class I category, which supports the results of other indices indicating the suitability of water for irrigation purposes.

Formulation and Evaluation of Herbal Antioxidant Tablets of Urtica Dioica Extract

Wed, 21 Feb 2024 00:00:00 +0000

This study explores the formulation and assessment of herbal antioxidant tablets derived from Urtica dioica (stinging nettle) extracts for arthritis and osteoarthritis treatment. Various extraction methods were compared, revealing that 100% dehydrated ethanol at 45 degrees Celsius for four hours in a Soxhlet apparatus resulted in an 89% phenolic extraction. Although ethyl acetate yielded the highest phenolic extract (187%), its toxicity led to the selection of ethanol for further extraction. The Folin-Ciocalteu method determined the total phenolic content. The DPPH assay demonstrated positive antioxidant activity of the Urtica dioica ethanolic extract, with an IC₅₀ value of 37.5761201 μg/mL, compared to the standard ascorbic acid with an IC₅₀ value of 21.23506 μg/ml. Herbal tablets were formulated using the direct compression method. The findings highlight the potential of Urtica dioica extracts as effective herbal antioxidants for arthritis and osteoarthritis treatment. This research enhances our understanding of natural remedies and their therapeutic applications. Future investigations should delve into the clinical efficacy and safety of these herbal antioxidant tablets, paving the way for their potential integration into clinical settings. This study contributes valuable insights into the development of alternative therapies for managing arthritic conditions, emphasizing the importance of exploring nature's remedies in healthcare.

The interfacial tension at the liquid junction of petrol and Sodium dodecyl sulphate solution

Ajaya Bhattarai, Man Singh — Wed, 21 Feb 2024 00:00:00 +0000

The precise measurements of petrol interfacial tension (IFT) in the presence of Sodium dodecyl sulphate (SDS) at room temperature by Mansingh Survismeter are reported. The concentration of sodium dodecyl sulphate was varied from above and below the critical micelle concentration (CMC) to cover the minimum and maximum concentrations of the investigated surfactant. Petrol was taken from the dealer in Nepal and used without purification. Therefore, when surfactant is added to the system, the surfactant decreases its free energy, thus decreasing its surface tension

Microwave-Accelerated Synthesis of Flavanones through Oxidative Cyclization of 2'-Hydroxychalcones Using Acetic Acid as a Sole Catalyst

Gan B. Bajracharya, Rabina Dhakal, Sulochana Timalsina — Wed, 21 Feb 2024 00:00:00 +0000

Under microwave irradiation conditions, 2'-hydroxy chalcones 1a-c underwent AcOH-mediated cyclization in an oxa-Michael addition manner to afford flavanones 2a-c in acceptable yields (up to 82%). These reactions proceeded in a shorter reaction time (~ 30 min) through microwave activation; otherwise, the reaction would take several days and even weeks, if a conventional heating process was employed. For example, cyclization of (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one (1a) has required 4 days of stirring with AcOH (0.25 M), under conventional heating at 100 °C, to produce 2-phenylchroman-4-one (2a), in 75% yield; while under microwave conditions, the reaction has yielded 82% of compound 2a, after 30 min. Thus obtained products 2a-c were fully characterized by recording of melting point together with UV, ¹H NMR, and ¹³C NMR spectra.

Antidiabetic and Antibacterial Activities of Syzygium cumini Seeds

Bidhya Bhattarai, Lekha Nath Khanal, Surya Kant Kalauni — Wed, 21 Feb 2024 00:00:00 +0000

Bioactive compounds of plants have been used in treating various diseases from ancient times. In this study, Syzygium cumini seed extract was studied for its antioxidant, antibacterial, and anti-diabetic potentials. The antioxidant potential was evaluated by DPPH assay. Whereas, the antibacterial feature was tested against Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Klebsiella pneumonia by agar well diffusion method. The in vitro anti-diabetic potential was performed by the α-amylase enzyme inhibition method using CNPG3 (2-chloro-4-nitrophenyl-α-D-maltotriose) as a substrate. The methanolic extract showed a total phenolic content of 128.8 ± 1.44 mg GAE/g and a total flavonoid content of 115.6 ± 8.01 mg QE/g. The extract scavenged free radicals where strong antioxidant activity was observed with IC₅₀ values of 91.63 ± 6.54 μg/mL in the concentration range of 50-6.25 μg/mL. The DCM and EA fractions exhibited moderate antidiabetic potentials with IC₅₀ values of 92.1 ± 0.5 μg/mL, 150.8 ± 0.8 μg/mL, and 42.2 ± 4.6 μg/mL in the concentration range of 400-25 μg/mL against acarbose standard having IC₅₀ values of 6.02 ± 0.1 μg/mL in the concentration range 50-1.6 μg/mL. The methanolic extract having ZOI (19mm) showed antibacterial activity however standard neomycin demonstrated ZOI (22.5 mm) against S. aureus at the dosage of 50 μg/mL. Methanolic extract having ZOI (20 mm) demonstrated effective antibacterial activity when compared to standard neomycin with ZOI (15mm) against K. pneumonia at the dosage of 50 μg/mL.

Study of Anti-Corrosion Properties of Sodium Dodecyl Sulphate and Cetyl Pyridinium Chloride

Wed, 21 Feb 2024 00:00:00 +0000

Surfactant is a surface-active agent. Surfactants have both hydrophilic (water-attracting) and hydrophobic (water-repelling) portions in their molecular structure, effective inhibitors for the protection of mild steel in an acidic medium, the weight loss methods were used at lab temperature to evaluate the effect of surfactant cetyl pyridinium chloride (CPC) and sodium dodecyl sulfate (SDS) on the corrosion protection behavior of Mild steel in 0.5 M H₂SO₄ solution. Inhibition efficiency, weight loss, corrosion rate, and surface coverage area of Mild steel in different concentrations of surfactant were studied. The results showed that the Inhibition efficiency of cetyl pyridinium chloride is 99.86%, which is greater than that of sodium dodecyl sulfate (99.85%) in the presence of 0.5 M H₂SO₄.

Chemical Composition, Antibacterial, Antioxidant, and Cytotoxicity Activities of Essential Oil of Leaf of Ageratina adenophora (Spreng.) R.M. King and H. Rob.

Wed, 21 Feb 2024 00:00:00 +0000

Modern medicine recognizes the therapeutic applications of medicinal plants, which are utilized in indigenous therapies. Ageratina adenophora (Banmara) is an invasive plant growing in tropical and subtropical regions, traditionally used for treating wounds, sleeping disorders, jaundice, ulcers, etc. Using Clevenger apparatus for hydro-distillation, the essential oil was extracted, and gas chromatography-mass spectrometry (GC-MS) was used to determine its chemical constituents. GC-MS analysis of essential oil showed 14 possible compounds in which α-Muurolol (24.56%) was found to be most abundant. The essential oil exhibited a total phenolic content of 53.42 mg of gallic acid equivalent per gram of dry extract, while the total flavonoid content was determined to be 3.37 mg of quercetin equivalent per gram of dry extract. Essential oil of A. adhenophora showed a high antibacterial action against Staphylococcus aureus of ZOI of 12 mm. The antioxidant assay revealed weak activity of essential oil of IC₅₀ 17.21 mg/mL, while the brine shrimp lethality assay revealed its LC₅₀ value to be 64.56 μg/mL.