<i>Mentha arvensis</i> essential oil suppressed airway changes induced by histamine and ovalbumin in experimental animals

<p>The present investigation aimed to evaluate the activity of the essential oil of <i>Mentha arvensis</i> L. on exogenously induced bronchoconstriction in experimental animals. The anti-asthmatic effect of <i>M. arvensis</i> essential oil (MAEO) was studied using histamine aerosol-induced bronchoconstriction in guinea pigs and ovalbumin (OVA) sensitised albino mice. Treatment with <i>M. arvensis</i> oil significantly (<i>p</i> < 0.001) increased the time of preconvulsive dyspnoea in histamine-induced guinea pigs. Oral treatment of MAEO significantly (<i>p</i> < 0.001) decreased absolute eosinophil count, serum level of IgE and the number of eosinophils, neutrophils in BALF. Histopathological examination of lungs showed that essential oil rescinded bronchial asthma. The present investigation provides evidence that MAEO relaxes bronchial smooth muscles and suppressed immunological response to OVA.</p

Iodine-Stabilized Cu Nanoparticle Chitosan Composite for Antibacterial Applications

We report herein the synthesis of a new composite consisting of Cu nanoparticles (NPs) and chitosan (CS), which has been found to be stable in the presence of molecular iodine and has also high antimicrobial activities. The composite could be obtained when aqueous CuSO₄ was treated with hydrazine in the presence of CS. The spherical Cu NPs present in the composite were of average diameters 8±4 nm. The NPs were unstable in atmospheric conditions leading to the formation of oxides of Cu. On the other hand, when molecular iodine was added to the medium following synthesis the NPs were rather stable. Studies of antibacterial property were carried out on Gram-negative green fluorescent expressing <i>Escherichia coli</i> bacteria & Gram-positive <i>Bacillus cereus</i> bacteria. The minimum inhibitory concentration (MIC) of the iodinated composite on <i>Escherichia coli</i> was found to be 130.8 μg/mL, which contained 21.5 μg/mL Cu NPs. This determined value of MIC for Cu NPs was much lower than those reported in the literature. Zeta potential (ζ) measurements supported an attractive interaction between iodinated CS-Cu NP composite and bacteria which was further supported by electron microscopic images. Electron microscopic and flow cytometric studies revealed that the iodinated CS-Cu NP composite was attached to the bacterial cell wall, which caused irreversible damage to the membrane, eventually leading to cell death. Mechanism of bactericidal action of the iodinated composite is discussed in light of our findings