Bacterial resistance to antibiotics is enhanced by unrestricted use of such drugs. In addition, stimulating effects of certain antibiotics on the production of verocytotoxin by enterohemorrhagic Escherichia coli. have been reported. The aim of this communication was to report a medicinal plant species that is effective against a broad range of bacteria of clinical importance including Acinetobacter baumannii., Bacillus cereus., Enterobacter faecalis., Escherichia coli., Helicobacter pylori., Klebsiella pneumoniae., Listeria monocytogenes., Pseudomonas aeruginosa., Salmonella. spp., Shigella flexneri., Staphylococcus aureus., Streptococcus mutans., and Streptococcus pyogenes.. Ethanol extracts of Quercus infectoria. Oliv. (Fagaceae) demonstrate a broad spectrum of activity against all bacterial species tested. Detailed studies were carried out on clinical isolates of pathogens commonly presenting problems with the use of antibiotics, including enterohemorrhagic Escherichia coli. (EHEC), methicillin-resistant Staphylococcus aureus. (MRSA), multidrug-resistant Klebsiella pneumoniae., multidrug-resistant Helicobacter pylori., and Salmonella.spp. The extracts of Quercus infectoria. displayed remarkable activity against MRSA with MICs ranging from 0.02 to 0.4 mg/mL, and MBCs ranging from 0.4 to 1.6 mg/mL. More importantly, this plant species could exhibit strong antibacterial activity against all Gram-Negative organisms. Its significant activity was shown with EHEC, with MICs of 0.05 to 0.1 mg/mL and MBCs of 0.8 to 1.6 mg/mL. The results from this study indicate that Quercus infectoria. is potentially a good source of antibacterial substances with broad spectrum of activities against antibiotic-resistant bacteria.
Seven new compounds constituted by three secoiridoids (1–3), two isocoumarins (4 and 5), an iridoid (6), and an aromatic derivative (7) in addition to 24 known compounds were isolated from the stem bark of Fagraea fragrans. The structures of the new compounds were determined on the basis of spectroscopic data analysis. The isolated compounds showed no antibacterial activity against Staphylococcus aureus and Escherichia coli. However, 5-formylisochromen-1-one (4), (−)-mellein (8), and swermacrolactone C (9) exhibited potent antimycobacterial activities against Mycobacterium smegmatis when used in combination with the antibiotic drug erythromycin.
This investigation was aimed at assessing a possible interaction of a traditional Thai herbal recipe, “Ya-Sa-Marn-Phlae (YSMP),” used for wound treatments with topical antiseptics, povidone-iodine (PI) solution and hydrogen peroxide (H 2 O 2 ), and effects of THR-SK010 alone and the combinations on Staphylococcus aureus . Antibacterial activities of ethanol extracts from the herbal recipe were determined against both methicillin resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). YSMP exhibited remarkable antistaphylococcal activity with MIC values of 3.9–7.8 μ g/mL. This recipe possessed bacteriostatic activity and did not reduce the tolerance of both MRSA and MSSA isolates to the high ionic strength. Interaction between THR-SK010 and the antiseptics was carried out by checkerboard testing and time-kill assay. Both indifferent and slightly antagonistic effects were observed with THR-SK010/PI and THR-SK010/H 2 O 2 combinations against the tested isolates. In addition to commercially available antiseptics, THR-SK010 offered additional therapeutic options for the decolonization of MRSA and MSSA. Topical application of plant extracts with antioxidant activity, such as THR-SK010, should not be used immediately with PI or H 2 O 2 and further investigation on this interaction is needed.
Acinetobacter baumannii is well-recognized as an important nosocomial pathogen, however, due to their intrinsic resistance to several antibiotics, treatment options are limited. Synergistic effects between antibiotics and medicinal plants, particularly their active components, have intensively been studied as alternative approaches.Fifty-one ethanol extracts obtained from 44 different selected medicinal plant species were tested for resistance modifying agents (RMAs) of novobiocin against A. baumannii using growth inhibition assay.At 250 μg/ml, Holarrhena antidysenterica, Punica granatum, Quisqualis indica, Terminalia bellirica, Terminalia chebula, and Terminalia sp. that possessed low intrinsic antibacterial activity significantly enhanced the activity of novobiocin at 1 μg/ml (1/8xminimum inhibitory concentration) against this pathogen. Holarrhena antidysenterica at 7.8 μg/ml demonstrated remarkable resistant modifying ability against A. baumannii in combination with novobiocin. The phytochemical study revealed that constituents of this medicinal plant contain alkaloids, condensed tannins, and triterpenoids.The use of Holarrhena antidysenterica in combination with novobiocin provides an effective alternative treatment for multidrug resistant A. baumannii infections.
Acetone, ethyl acetate, 95% ethanol and aqueous extracts of Quercus infectoria (Q. infectoria) demonstrated significant antibacterial activities against all strains of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA). Inhibition zones were in the range 11.75-16.82 mm. Both MRSA and MSSA strains exhibited minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values at 0.13 and 0.13-1.00 mg/mL, respectively. At 2 MIC, the growth of two representative MRSA strains was continually inhibited for at least 20 h. Surviving MRSA cells were not detected within 12-14 h after treatment with the extract at 4 MIC concentration. Staphylococcus aureus ATCC 25923 demonstrated similar results.
Abstract Properties and antibacterial activity of polymer blend films prepared from polyvinyl alcohol (PVA) and natural rubber (NR) blends, in the presence of maleic acid as a cross-linking agent were studied. The effect of the maleic acid content, curing temperature, and curing time on the properties of the polymer blend was investigated. Cross-linking between PVA and maleic acid was observed by attenuated total reflection mode–Fourier transform infrared spectroscopy at 1152 cm−1. The swelling ratio of the polymer blend decreased as a function of the increase of the maleic acid content. The tensile strength of the polymer blend increased with an increase of both the maleic acid and the curing time. The highest tensile strength of the samples was observed with 40% w/w maleic acid after a 24 h curing time at 120 °C. The elongation at the break of 60/40 NR/PVA was ∼500% at 120 °C for 1 h. In addition, the polymer blend showed good antibacterial activity with Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, and Acinetobacter baumannii JVC 1053 and could find many applications.
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