Antimicrobial Properties of Derris scandens Aqueous Extract
ABSTRACT The objective of this study is to evaluate the antimicrobial activity of D. scandens aqueous extract against various bacteria. The stems of D. scandens were extracted using aqueous extraction with yield 1.5-2% of dried weight of plant stems. The antimicrobial activity was screened by using agar diffusion method. Minimum Inhibitory Concentrations (MICs) and MBCs values were determined using agar dilution method and broth macro-dilution method. The agar diffusion tested revealed that the plant aqueous extract showed inhibition zone against S. aureus ATCC 25923, S. epidermidis ATCC 12228 and E. coli ATCC 25922. Among three bacteria, S. aureus and S. epidermidis is gram positive bacteria, while E. coli is gram negative bacteria. Minimum Bactericial Concentration (MICs) of the plant aqueous extract were in range of 2-4 g L-1, while MBCs were in the range of 4-16 g L-1. In conclusion, the plant extract showed good inhibitory effect on growth of S. aureus and E. coli which are nosocomial infection bacteria and those S. epidermidis which is normal flora.
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ABSTRACT: The use of natural compounds from plants can provide an alternative approach against food-borne pathogens. The mechanisms of action of most plant extracts with antimicrobial activity have been poorly studied. In this work, changes in membrane integrity, membrane potential, internal pH (pH(in)), and ATP synthesis were measured in Vibrio cholerae cells after exposure to extracts of edible and medicinal plants. A preliminary screen of methanolic, ethanolic, and aqueous extracts of medicinal and edible plants was performed. Minimal bactericidal concentrations (MBCs) were measured for extracts showing high antimicrobial activity. Our results indicate that methanolic extracts of basil (Ocimum basilicum L.), nopal cactus (Opuntia ficus-indica var. Villanueva L.), sweet acacia (Acacia farnesiana L.), and white sagebrush (Artemisia ludoviciana Nutt.) are the most active against V. cholera, with MBCs ranging from 0.5 to 3.0 mg/ml. Using four fluorogenic techniques, we studied the membrane integrity of V. cholerae cells after exposure to these four extracts. Extracts from these plants were able to disrupt the cell membranes of V. cholerae cells, causing increased membrane permeability, a clear decrease in cytoplasmic pH, cell membrane hyperpolarization, and a decrease in cellular ATP concentration in all strains tested. These four plant extracts could be studied as future alternatives to control V. cholerae contamination in foods and the diseases associated with this microorganism.Applied and Environmental Microbiology 10/2010; 76(20):6888-94. · 3.95 Impact Factor
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ABSTRACT: The chemical composition of the volatile extract (yield ≈ 0.13%, v/w) from the bark of Quercus leucotrichophora (Fagaceae) was analysed for the first time by GC-MS. Twenty-three constituents, amounting to 93.0% of the total detected contents of the volatile extract, were identified. The volatile extract contained approximately 86.36% monoterpenoids, 6.53% sesquiterpenoids and 0.11% aliphatic aldehydes. 1,8-Cineol (40.359%) followed by γ-terpinene (16.369%) were the major monoterpene constituents of the volatile extract. The residue of volatile extract (0.00025-250 µg mL(-1)) exhibited a potent antimicrobial activity against Streptococcus pyogenes ATCC 19615. This study concludes that residues of the volatile extract of Q. leucotrichophora could serve as an important bioresource for the extraction and isolation of monoterpenoids exhibiting antimicrobial activity, and thus has good potential for use in the pharmaceutical industry.Natural product research 09/2011; 26(9):869-72. · 1.01 Impact Factor