http://ir.bdu.edu.et/handle/123456789/1834 2026-10-13T04:03:24Z http://ir.bdu.edu.et/handle/123456789/17088 Green Synthesis And Characterizaton Of Zinc Oxide Nanoparticles Using Justicia Schimperiana (Simiza) Leaf Extract And Investigation Of Its Antibacterial Activities Yihunie, Biadglegn Desta In this study, green synthesis, characterization and antibacterial activity of zinc oxide nanoparticles were investigated. The zinc oxide nanoparticles were successfully synthesized a fast, convenient, cost effective, and environmentally friendly method by biologically reducing zinc nitrate hexahydrate (Zn (NO3)26H2O) solution with Justicia Schimperiana leaf extract under optimum conditions. The presence of active flavonoids, carbohydrates, phenolic groups, alkaloids, terpenoids and tannins in the Justicia Schimperiana extract was, identified using qualitative screening methods (observing the colour changes) and FT-IR Spectroscopy. The formation of ZnO NPs was visually indicated by the color changes from colorless to yellow color. Biosynthesized nanoparticles were further characterized by UV-Visible, FT-IR, and XRD spectroscopies. The reduction process was simple and easy to manage, monitored by UV-Visible spectroscopy which showed surface plasmon resonance (SPR) of the ZnO NPs at 367 nm, confirming their formation. X-ray diffraction was employed to investigate the crystal structure revealing an average particle size of approximately 12.67 nm calculated using the line width of the plane and refraction peak in Scherer‟s equation. Green synthesized zinc oxide nanoparticles were evaluated for antibacterial activities against both gram positive and gram negative bacteria. Nanoparticles exhibited maximum zone of inhibition against S.pyogene (18.5 mm) while least activity was observed against K.pneumonia. 2025-11-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/17074 Synthesis, Characterization and Assessment of Antibacterial Activity of Novel Homobinuclear Mixed Ligand Copper (Ii) Complexes Containing Resorcinol ate, Acetone and Ethylene Demine. Misganaw, Tegegne Transition metal complexes are endowed with properties suitable for inhibition of bacterial infectious diseases. Based on this, identification and synthesis of new transition metal complexes is a passion for scientists. In this report copper (II) homobinuclear mixed ligand complexes containing resorcinolate (R), acetone (Ac) and ethylenediamine (en) with formula H4[Cu2(R2- )2(R-)4], H4[Cu2(R2-)2(R-)4Ac2], H8[Cu2(R2-)6en], H8[Cu2(R2-)6en2], H4[Cu2(R2-)2(R-)4enAc], and Na8[Cu2(R2-)6] were synthesized. The structures of the synthesized complexes were characterized using various analytical, electrochemical and spectroscopic techniques, particularly using UVVis, FT-IR, ICP-OES, CV, Molar conductivity, pH, Melting point, Qualitative chloride test and Solubility tests. Furthermore, the synthesized complexes were evaluated for their in vitro antibacterial activities against some Gram-positive (Staphyloccus aureus and Streptococcus pyogens) and Gram-negative (Escherichia coli, Klebsiella Pneumonia) bacterial species by disc diffusion method and the result obtained were compared with the commercially available drug gentamicin by calculating percent activity index. The complexes were found to be active against all the tested bacteria. According to the percent activity index data, most complexes have higher antibacterial activity than gentamicin even in gram-negative bacterial strains. So, after the in vivo cyto toxicity investigation, per-clinical and clinical tests the newly synthesized complexes could be considered as potential antimicrobial agent. 2020-08-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/17073 Determination of Total Phenolic Compounds, Total Flavonoids and Antioxidant Activity of Barley Grain (Hordeum Vulgare L.) Commercially Available In Derahamusit, Burie and Jabitehena Districts of Amhara Region, Ethiopia Banchayehu, Baylie Barley is among the most ancient cereal crops, evolving over eons. The purposes of this study was to determine the total phenolic content, total flavonoids and total antioxidant capacity of barley grain collected from selected areas of Amhara region; and to compare it with other country barley and other cereal grains. A70% acetone in water was used to extract the phytochemicals. Total phenolic content was determined by Folin-Ciocalteu’s method, total flavonoids was determined by aluminium chloride methods while DPPH radical scavenging activity method was used to determine the total antioxidant activity and results were expressed as gallic acid equivalent), catechin equivalent and ascorbic acid equivalent respectively. Results of the determination revealed that total phenolic content, total flavonoids and total antioxidant capacity was ranging from 4.85±0.4 to 5.65±0.7 mg GAE/g, 3.45±0.4 to 4.01±0.7mg CE/g, and 2.98±0.8 to 3.69±0.4 mg AAE/g of sample respectively. Among the studied samples, sample from Derahamusite district exhibited a highest scavenging effect and the reducing capability on DPPH solution compared to samples from other district. Pearson correlation showed there were positive correlations between total phenolic content and total flavonoids content with antioxidant capacity. At 95% confidence level one way ANOVA displayed that the levels of total polyphenol, total flavonoid and antioxidant activity were not significantly varied between sampling sites. Furthermore, the magnitude of these bioactive chemicals are comparable amount with the other barley grain and other cereals reported in other literature. 2020-08-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/17071 Phytochemical Investigation and Evaluation of Biological Activity on the Stem Bark Extract of Clematis Simensis (Azo Hareg Yekedem, Getnet Medicinal plants have been used for treatments of various diseases and still play an important role to cover the basic health needs in the developing countries. In this study, phytochemical screening, determination of total phenolic and flavonoid content, antioxidant and antibacterial activity of the stem bark of Clematis simensis [known by its vernacular name as “azohareg” (in Amharic)], is reported. Thus the successive extraction by using petroleum ether, chloroform and ethanol result in 0.4 %, 0.7%, and 0.9% crude extract yield respectively. The phytochemical screening of crude extracts showed the presence of flavonoid and steroid in all solvent extract, terpenoid and cardiac glycoside in chloroform extract, phenolics in ethanol extract, and tannin in ethanol and chloroform extract. The total flavonoid and phenolic content of ethanol extract is higher than chloroform and petroleum ether extracts. This could lead to potential biological activity of the plant extract. The antioxidant and antibacterial activity against two Gram positive bacteria (Staphylococcus aureus and Streptococcus pyogenes and two Gram negative bacteria, Escherichia coli and Klebsiella pneumonia) of ethanol extract is higher than chloroform and petroleum extracts as well as isolated fractions, F1 and F2. 2020-08-01T00:00:00Z