Antibacterial Activity Of Various Extracts Research Articles

Antibacterial activities of extracts of leaf, fruit, seed and bark of Phoenix dactylifera

The antibacterial activities of different parts of local Phoenix dactylifera were investigated in vitro. Dried leaf, fruit, seed and tree bark were extracted with water, methanol and acetone. Antibacterial property of the extracts was evaluated against Staphylococcus aureus , Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa using the disc diffusion method. Overall analysis of the antibacterial activity of various extracts revealed that the highest inhibitory activity was produced by the fruit extract (18.2 ± 0.55 mm) as compared to the leaf, bark and seed extracts. All the extracts from the different parts of the plant showed antibacterial activity against most tested microorganisms. On the whole, aqueous extracts have the least antibacterial activity as compared to methanol and acetone extracts. The antibacterial activity against the Gram-positive strains was the highest in the acetone fruit extract against S. aureus (18.2 ± 0.55 mm). The most active extract against Gram-negative bacteria was methanol extract from the leaves with a 13.5 ± 0.33 mm inhibition zone for E. coli followed by 12.5 ± 0.88 mm for P. aeruginosa. Phytochemical analysis revealed the presence of carbohydrates and alkaloids in all parts, and flavonoids, steroids, saponins and tannins were present in some parts. Key words : Antibacterial activity, Phoenix dactylifera, disc diffusion assay, extracts, inhibition zone.

Therapeutical Effect of Extracts of Terminalia chebula In Inhibiting Human Pathogens and Free Radicals

In recent years, multiple drug resistance has been developed due to indiscriminate use of existing antimicrobial drugs in the treatment of infectious diseases. Conventional antibiotics are strong medicines, which if not used in precise way may cause harmful effects. The major thrust is to establish alternative antimicrobial agent in order to treat microbial infections with less or no toxic effect to body and less negligible side effects. The herbal medicines have shown potential to overcome the limitation associated with conventional drugs. However, the appropriate choice of source for herbal medicine is also very important. Terminalia chebula possesses potential pharmaceutical activities and used in several Ayurvedic formulations. The study of solvent-free organic (ethylacetate, acetone, methanol of increasing polarity) and aqueous extracts of the fruits of T. chebula, showed the potential to reduce growth of microorganisms, minimizing the risk of infection, while optimizing the conditions to encourage healing. In our study we found, methanol extract as a potential bactericidal and potent antioxidant while aqueous extract showed the least potential as an antimicrobial agent, though a moderate antioxidant. The finding may provide scientific rationale for the use of crude extract of the plant as a new drug compound as potential antioxidant and antimicrobial agent. Terminalia chebula is used as a mild laxative and as an astringent against wounds and abscesses. Practictioners of folk medicine in India and Southeast Asia use the fruit for homeostatic, laxative and as cardiotonic. It is used as a remedy against a sore throat and cough, against diarrhoea connected with a prolapsed rectum in China and against ulcers and dysentery in Tibet. The antibacterial activity of various extracts of Chebula myrobalan powder was tested against Streptococcus species, Staphylococcus aureus and Pseudomonas aeruginosa. II. MATERIALS T. chebula powder was purchased from local market of Mumbai, India. Pathogens of MTCC grade were obtained from IMTECH (Chandigarh, India). Gallic acid and Glutaraldehyde was purchased from s.d. fine-chemicals limited (Mumbai, India). Gentamicin and 2,4,6-tripyidyl-s-triazine (TPTZ) were procured from Hi-Media(Mumbai,India), 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT, 98%) reagent, 4'-6-diamidino-2-phenylindole (DAPI), propidium iodide (PI) and nystatin was purchased from Sigma (St. Louis, USA). Fetal bovine serum (FBS) and streptomycin-penicillin antibiotic solutions were bought from HyClone (Utah, USA). All other chemicals used were of analytical grade. SIRC (rabbit corneal epithelial cells) cell line was obtained from NCL, Pune, India

Antibacterial Effects of Extracts of Thuja Orientalis cv Aurea Nana Cones against Food-spoilage and Food-borne Pathogens

BACKGROUND: Nowadays, Chemical antiseptics have become great problems for health and environmental, so that developing of new substitutes for chemical antiseptics is more and more important. Natural product is a kind of environment-friendly additive that could be used as antiseptic in food industry. Thuja orientalis cv Aurea Nana is a gymnospermous plant of the family Cupressaceae, native to northwestern China and widely naturalised elsewhere in Korea and Japan. This study was aimed to investigate the antibacterial potential of various organic extracts from T. orientalis cones against some food-borne and food-spoilage bacteria. METHODS AND RESULTS: Hexane extract (HE), chloroform extract (CE), ethyl acetate extract (EAE) and methanol extract (ME) were obtained from female cones of T. orientalis. The antibacterial activities of various extracts were tested by standard agar diffusion and minimum inhibitory concentrations (MICs) against five gram-positive and six gram-negative bacteria. Cell viability and morphology change of L. monocytogenes ATCC 10943 treated with hexane extract were also observed. The various extracts displayed remarkable antibacterial effects against all the gram-positive bacteria but did not show any effect against the gram-negative bacteria. Hexane extract has the highest inhibitory effect on cell viability of L. monocytogenes ATCC 10943. SEM observation also demonstrated the damaging effect of the hexane extract on the morphology of L. monocytogenes ATCC 10943 at the minimum inhibitory concentration. CONCLUSION(s): The tested gram-positive bacteria were significantly inhibited by organic extracts of T. orientalis cone. Hexane extract was the most potent against Listeria monocytogenes ATCC 10943, as evidenced by the lowest MIC level and the complete inhibition of cell viability within shortest exposure time, along with SEM observation.

Antioxidant and Antibacterial Activities of Various Extracts and Fractions of Fresh Tea Leaves and Green Tea

Polyphenol content, polyphenol yield, antioxidant and antibacterial activities of methanol, ethanol and water extracts and their crude, ethyl acetate and water fractions derived from fresh tea leaves (FTL) and green tea (GT) were evaluated. Ethyl acetate fractions of ethanolic extracts contained the highest polyphenol content in FTL and GT samples (680.2 and 560.8 mg gallic acid equivalent g -1 dry extract, respectively). For each of 3 extraction solvents, ethyl acetate fractions always had highest polyphenol content, for both teas. Ethyl acetate fractions of water extracts of FTL and GT had highest antioxidant activity (80.8 and 78.6 g ascorbic acid 100g -1 dry extract). A rather high correlation coefficient (R 2 = 0.9376 for FTL and 0.9783 for GT) was obtained between antioxidant activity to total polyphenol content for both tea. Ethyl acetate fractions of extracts showed antibacterial activity on S. aureus and B. cereus . Crude extract of FTL were also effective on S. aureus .