Browsing by Subject "Antibacterial activity"
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Item Antibacterial Activity of Selected Medicinal plants of Nepal(Department of Botany, 2013) Joshi, Govinda BallabNot availableItem Antibacterial activity of selected orchid species of Nepal(Department of Botany, 2023) Dulal, SajanOrchidaceae, a highly advanced and widely spread family of monocotyledonous plants. Orchids have been found to contain a rich source of natural compounds with significant therapeutic activities against various disease. So this study mainly focused on antibacterial activity to generate natural medicines to substitute synthetic drugs. The orchid plants were collected from various regions of Nepal and subsequent extract preparation and laboratory work conducted at the Annapurna Research Center. A total of fifteen orchid species were selected for the purpose of this study. The different parts of orchids were used for extraction using methanol through a combination of the Percolation and intermittent sonication methods. After that in vitro antibacterial evaluation was conducted using the agar well diffusion technique with different concentration. Out of 15 species, the highest yield was obtained from Habenaria marginata 15%, and the lowest was from Coelogyne stricta 1%. In the qualitative analysis, various reagents were used to quantify tannins, flavonoids, glycosides, phenols and alkaloids. A qualitative phytochemical screening indicate that alkaloids and flavonoids were present in the extracts of all the orchid species that were tested. Both Phenol and Carbohydrate were absence in Coelogyne stricta and Eria graminifolia. The antibacterial activity of the methanol extracts from these plants was evaluated against medically significant bacteria. Enterococcus faecalis, Acinetobacter baumannii, Escherichia coli and Shigella sonnei were Gram negative whereas Staphylococcus aureus was Gram positive bacteria. All 15 plants showed activity against at least one bacterium. The two orchid plants, Coelogyne stricta and Otochilus albus, exhibited broad-spectrum activity by showing a high zone of inhibition against all tested bacteria with zone of inhibition (20mm) and (21mm) against Acinobacter baumannii respectively. Similarly, The MIC values for the tested orchid extracts range from 1.25 mg/ml to 2.5 mg/ml, while the MBC values range from 0.3125 mg/ml to 0.625 mg/ml. So Otochilus albus exhibits strong antibacterial properties against Acinobacter baumannii species, and its corresponding MIC and MBC values provide further evidence of its antibacterial effectiveness. Therefore, it is worthy to conduct additional investigations into this specific species to reveal its potential benefits. Furthermore, there is scope for conducting additional laboratory experiments and research work to develop new pharmaceutical products. Keywords: Orchids, Phytochemical compounds, Antibacterial activity, MBC, MICItem “Chemical Analysis and Biological Activities of Crude Extracts and Green Synthesized Silver Nanoparticles of Medicinal Plants from Mustang and Kaski Districts of Nepal(Institute of Science & Technology, 2023-06) Khanal, Lekha NathMedicinal plants contain numerous secondary metabolites with significant biological activities. Due to diverse geographical and climatic conditions, several indigenous plants that comprise unique phytochemicals having a wide spectrum of biological assets are found in Nepal. This study aims to synthesize, characterize, and evaluate the biological activities of silver nanoparticles (AgNPs) by using some of the active medicinal plants of the study area. Methanol extracts of the selected plants were evaluated for antioxidant, antibacterial and α-amylase inhibition activities by using the DPPH radical scavenging, agar well diffusion, and CNPG3 methods respectively. The chemical profiling of essential oil isolated from the aerial parts of Ephedra pachyclada and Ayenia grandifolia was performed by the GC-MS analysis. This study exposed the phytochemical and biological activities of methanol extract, chemical profiling of essential oil, and green synthesis of AgNPs by using an aqueous extract of A. grandifolia for the first time. Among the 22 plants evaluated, Rubus ellipticus, E. pachyclada, Pyrus pashia, Drynaria coronans, Mimosa rubicaulis, and Ziziphus mauritiana extracts exhibited significant antioxidant properties with the highest activity of A. grandifolia (IC50 = 12.87 ± 0.14 µg/mL). The GC-MS analysis of the essential oil (EO) of stem barks of A. grandifolia contained di-n- octyl phthalate (28.39%), 2,6,11 trimethyl dodecane (15.77%), 4,6 dimethyl dodecane (12.79%), and o-guaiacol (7.07%). The methanol extracts of R. ellipticus and P. pashia exhibited the highest antibacterial activity. The resazurin microtiter assay method revealed the MIC and MBC of the methanol root extract of R. ellipticus as 3.12 and 12.5 mg/mL respectively against Staphylococcus aureus ATCC 25923. The methanol stem bark extract of P. pashia exhibited the highest α-amylase inhibition activity with an IC50 value of 24.22 ± 0.10 µg/mL. From the preliminary investigation, A. grandifolia, R. ellipticus, P. pashia, and Z. mauritiana which exhibited the highest biological activities were used for the fabrication of AgNPs. Each of the plant extracts and AgNO3 (1 mM) in the ratio of 1:9 by volume were mixed with constant stirring at lab temperature (25 ± 2ºC), and neutral pH with constant stirring over a magnetic stirrer. The change of color into light brown within an hour was considered a visual indication of the growth of AgNPs which was further confirmed by the appearance of sharp SPR peaks in the UV-visible spectra. The UV-visible spectra at different reaction conditions of temperature, pH, and concentration were used to optimize the fabrication of AgNPs. FTIR spectra of the extract and the AgNPs were examined to detect the functional groups responsible for the reduction, capping, and stabilizing of AgNPs. The face-centered crystalline nature of the silver nanoparticles was established by the X-ray diffraction patterns by matching the diffractogram with the Joint Committee on Powder Diffraction Standards (JCPDS file no: 03-0921). It was further confirmed by the selected area electron diffraction (SAED) pattern having four discrete rings corresponding to the crystal planes at 110, 200, 220, and 311. The energy dispersive X-ray (EDX) analysis showed the presence of silver in the highest proportions and trace quantities of oxygen, chlorine, calcium, and carbon in the AgNPs. The surface morphology and nearly spherical shapes were determined by field emission scanning electron microscopy (FESEM) images. Transmission electron microscopy (TEM) was used to confirm the topographical, compositional, and morphological status of the AgNPs. Further, TEM images were used to find the sizes of the synthesized AgNPs which ranged from 28.05 ± 11.8 nm of A. grandifolia extract-mediated AgNPs to 16.73 ± 4.94 nm of Z. mauritiana extract-mediated AgNPs. The antioxidant activities of AgNPs synthesized by using Z. mauritiana (with an IC50 value of 37.02 ± 1.0 µg/mL) and A. grandifolia (with an IC50 value of 142.77 ± 10.75 µg/mL) were found to be nearly twice as potent as their respective crude extracts. The AgNPs synthesized using A. grandifolia demonstrated notable antibacterial activity, whereas its crude extract showed no such activity. The process of transforming plant material into AgNPs not only enhanced their antioxidant and antibacterial properties but also indicated the potential biomedical applications of these plant-based nanoparticles. Further investigation involving the synthesis of controlled-sized AgNPs from other plants, toxicity testing, and exploring potential applications would greatly benefit humanity.Item Chemical analysis and biological activities of crude extracts and green synthesized silver nanoparticles of medicinal plants from Mustang and Kaski districts of Nepal(Institute of Science and Technology, Chemistry, 2023) Khanal, Lekha NathAvailable with full textItem Evaluation of Antibacterial Activities of medicinal Plants(Department of Microbiology, 2008) Maharjan, NareshIn this study, antibacterial activities of 9 different medicinal plants were tested against 10common pathogenic bacterial species. Medicinal plants were selected on the basis of their common use among the differentethnic groups for common disorder. The selected medicinal plants wereAcorus calamus,Aegle marmelos, Asparagus racemosus, Holarrhena antidysenterica, Mimosa pudica,Terminalia bellirica, Terminalia chebula, Tinospora cordifolia and Woodfordiafruticosa. These medicinal plants were subjected to solvent extraction using hot solventof increasing polarity into 3 fractions viz: hexane, ethylacetate and methanol usingsoxhlet apparatus. After removing the solvent under reduced pressure, residues weresuspended separately in DMSO. The highest yield was obtained in methanol fraction ofTerminalia chebula(46.1%) while lowest in hexane fraction of Asparagus racemosus(0.7%). The bacteria selected for the study were Staphylococcus aureus, Escherichia coli,Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris,Pseudomonas aeruginosa, Salmonella Typhi, Salmonella Paratyphi A and Shigelladysenteriae. Out of nine tested plants, four plant extracts (44%) showed activity against at least five ormore test bacteria and 5 plant extracts (56%) were active against three or less than threebacteria. None of the tested plants extracts were active against all the tested bacteria.Asparagus racemosuswas the least effectiveagainst the tested bacterial species. Plants extracts showed significant antibacterial activity towards Gram positive bacteriathan Gram negative bacteria.Staphylococcus aureuswas the most susceptible bacteriabeing sensitive to 18 fractions from 8 medicinal plants.Proteus vulgariswas the mostresistance bacteria being resistance to all selected plants. Largest ZOI (31 mm) wasproduced by ethylacetate fraction of Terminalia belliricawhile lowest MBC of 3.12mg/ml was shown by ethylacetate fraction ofT. belliricaagainstE. coli. Key words: Medicinal plants, Antibacterial activity, Plant extractsItem Evaluation of Antibacterial Activity of some Medicinal plants Frequently used in Respiratory and Gastrointestinal Diseases in Nepal(Department of Microbiology, 2006) Thapa, OliviaIn this study, antibacterial activity of 16 different medicinal plants were tested against 14bacteria. Both, zone of inhibition (ZOI), and minimum bactericidal concentration (MBC)values were determined. Medicinal plants were selected on the basis of their common use among the differentethnic groups for common disorder. The selected plants wereAchyranthes bidentata,Acorus calamus, Azadirachta indica, Cumminum cyminum, Glycyrrhiza glabra,Jasminum humile, Justicia adhatoda, Juniper indica, Mentha piperita, Myrica esculenta,Ocimum sanctum, Piper nigrum, Spilanthes calava, Syzygium aromaticum,Trachysperum ammiandZanthoxylum armatum. For the chemical extraction plants weresubjected to soxhlet extraction with ethanol whileJ. indicaandM.piperita to steamdistillation. After removing the solvent under reduced pressure residues were suspendedseparately in water, DMSO, ethanol and methanol.Myrica esculentagave the highestyield of 46.64%, yield obtained with essential oil was lowest. The bacteria selected for the inhibition test wereBacillus subtilis, Staphylococcus aureus,Streptococcus pneumoniae, Streptococcus pyogens, E.coli, Enterobacter aerogenesKlebsiella pneumoniae. Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa,Salmonella paratyphi, Salmonella typhi, Salmonella typhimurium and Shigelladysentriae. Among 16 tested plants, 12 plants(75%) showed activity against at least six or moretest bacteria and 4 plants(25%) were active against 3 or less than 3 bacteria .Syzygiumaromaticum was the most active plant as it was effective for all the test bacteria.Acorus calamuswas the least effective against the test organisms. Gram positive organisms were more sensitive to medicinal plants extracts than Gramnegative bacteria. Staphylococcus aureus was most susceptible among the 14 testbacteria. It was inhibited by 13 out of 16 medicinal plants extracts tested.Salmonellatyphimuriumwas found to be the most resistant species, being susceptible to only 5 plantextracts. The largest zone of inhibition (30mm) was observed withM. piperita(essentialoil) against B.subtilis while lowest minimum bactericidal concentration (0.097mg/ml)was given by DMSO suspension ofSyzygium aromaticumagainstK. pneumoniae. Antibiotic sensitivity test showed that Ps. aeruginosa was resistant to Amikacin,Cortimoxazole, Ciprofloxacin, Tetracycline and Gentamicin, but inhibited by 10 plantextracts. Glycyrrhiza glabra(Jethi madhu) was subjected to solvent extraction using solvent ofincreasing polarity into 4 fractions viz., hexane, chloroform, n-butanol and D/W.Among these n-butanol fraction was active against seven test bacteria that showedenhanced spectrum activity againstE.coli, however, ethanolic extract didnot showedzone of inhibition. The result obtained in this study reveal the confirmation of theantibacterial potential of theplants investigated, and their usefulness in treatment ofrespiratory and gastrointestinaldisease.Item Evaluation of Antimicrobial Activities of Medicinal Plants Against Some Fungi and Antibiotic Resistant Bacteria(Central Department of Microbiology, 2008) Marasini, Bishnu PrasadABSTRACT Bioactive chemicals from the medicinal plants are source of both traditional and modern medicines can be searched by ethno botanical approach or on the traditional knowledge of plants used. The secondary metabolites have the ability to kill microorganisms and have been used to cure diseases. The aim of the study is to evaluate the antimicrobial activities of some medicinal plants used in Ayurvedic medicine to treat gastrointestinal and dermatological diseases. Altogether, 16 plants belonging to 15 families were tested for their antimicrobial activities against 8 fungal and 15 bacterial strains. The plants were extracted in ethanol by percolation or soxhlet method. The percentage yield was the most in Centella asiatica (30.9%) and the least in Curculigo orchioides (6.8%). The antimicrobial susceptibility of selected clinical bacterial isolates was determined by modified Kirby-Bauer disk diffusion technique. The inhibitory effect was observed by agar cup-well method and minimum bactericidal concentration (MBC) by two fold serial broth dilution method. Fifteen plant extracts exhibited antifungal activity against at least one fungus. Acorus calamus exhibited the highest (6 out of 8) antifungal activity. Similarly 13 plant extracts exhibited the antibacterial activity against at least 5 bacteria. Cynodon dactylon exhibited the highest antibacterial activity (13 out of 15) in ethanolic extract. Then C. dactylon was extracted in solvents of increasing polarity into 4 fractions and the highest yield was in water (8.7%) and the lowest in chloroform (1.4%) fraction. Chloroform and n-butanol fraction exhibited better inhibitory effect than hexane and water. The highest zone of inhibition (ZOI) exhibited by Curcuma longa against Enterococcus faecalis (diameter 19 mm) and by A. calamus against Aspergillus niger (15 mm). Cinnamomum camphora gave the lowest value of minimum bactericidal concentration (MBC) (0.2 mg/ml) against S. pyogenes. Gram-negative bacteria were rather resistant; some plants (Adhatoda vesica and C. asiatica) did not exhibit any inhibitory effect against any Gram-negative bacteria. Only one plant extract exhibited inhibitory effect against Escehrichia coli (MDR), Salmonella enteritidis and Citrobacter freundii, however, these bacteria were resistant to the most of the common antibiotics. Some of the plant extracts exhibited substantial inhibitory effect against fungi and antibiotic resistant bacteria that could be used to treat for fungal and bacterial infection especially in dermatological and diarrheal diseases. Key words: Medicinal plants, Antibacterial activity, Antifungal activity, Multidrug resistance.Item Phytochemical investigation of Eupatorium Odoratum L. for Cytotoxicity Antimicrobial and Antioxidant Activities(Faculty of Chemistry, 2006) Amatya, SajanAvailable with Full Text