Chemical composition and antibacterial, antifungal, allelopathic and acetylcholinesterase inhibitory activities of cassumunar-ginger.

BACKGROUND: Zingiber montanum (J.Koenig) Link ex A.Dietr. (Zingiberaceae), commonly known as cassumunar-ginger, is a folk remedy for the treatment of inflammations, sprains, rheumatism and asthma. The aim of the present study was to assess the chemical composition, and antibacterial, antifungal, allelopathic and acetylcholinesterase inhibitory activities of the essential oil of Z. montanum originating from India. RESULTS: The hydrodistilled essential oil of Z. montanum rhizome was analyzed using gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. A total of 49 constituents, forming 98.7-99.9% of the total oil compositions, was identified. The essential oil was characterized by higher amount of monoterpene hydrocarbons (32.6-43.5%), phenylbutanoids (27.5-41.2%) and oxygenated monoterpenes (11.4-34.1%). Major constituents of the oil were sabinene (13.5-38.0%), (E)-1-(3',4'-dimethoxyphenyl)buta-1,3-diene (DMPBD) (20.6-35.3%), terpinen-4-ol (9.0-31.3%), γ-terpinene (1.1-4.8%) and ß-phellandrene (1.0-4.4%). The oil was evaluated against eight pathogenic bacteria and two fungal strains. It exhibited low to good antibacterial activity (minimum inhibitory concentration: 125-500 µg mL-1 ) and moderate antifungal activity (250 µg mL-1 ) against the tested strains. The oil reduced germination (69.8%) and inhibited the root and shoot growth of lettuce significantly (LD50 : 3.58 µL plate-1 ). However, it did not demonstrate acetylcholinesterase inhibitory activity up to a concentration of 10 mg mL-1 . CONCLUSIONS: The essential oil of Z. montanum can be used as a potential source of DMPBD, terpinen-4-ol and sabinene for pharmaceutical products. The results of the present study add significant information to the pharmacological activity of Z. montanum native to India. © 2017 Society of Chemical Industry.

Chemical Composition and Allelopathic, Antibacterial, Antifungal, and Antiacetylcholinesterase Activity of Fish-mint (Houttuynia cordataThunb.) from India.

Fish-mint (Houttuynia cordataThunb.), belonging to family Saururaceae, has long been used as food and traditional herbal medicine. The present study was framed to assess the changes occurring in the essential-oil composition of H. cordata during annual growth and to evaluate allelopathic, antibacterial, antifungal, and antiacetylcholinesterase activities. The essential-oil content ranged from 0.06 - 0.14% and 0.08 - 0.16% in aerial parts and underground stem, respectively. The essential oils were analysed by GC-FID, GC/MS, and NMR (1 H and 13 C). Major constituents of aerial-parts oil was 2-undecanone (19.4 - 56.3%), myrcene (2.6 - 44.3%), ethyl decanoate (0.0 - 10.6%), ethyl dodecanoate (1.1 - 8.6%), 2-tridecanone (0.5 - 8.3%), and decanal (1.1 - 6.9%). However, major constituents of underground-stem oil were 2-undecanone (29.5 - 42.3%), myrcene (14.4 - 20.8%), sabinene (6.0 - 11.1%), 2-tridecanone (1.8 - 10.5%), ß-pinene (5.3 - 10.0%), and ethyl dodecanoate (0.8 - 7.3%). Cluster analysis revealed that essential-oil composition varied substantially due to the plant parts and season of collection. The oils exhibited significant allelopathic (inhibition: 77.8 - 88.8%; LD50 : 2.45 - 3.05 µl/plate), antibacterial (MIC: 0.52 - 2.08 µl/ml; MBC: bacteriostatic) and antifungal (MIC: 2.08 - 33.33 µl/ml; MFC: 4.16 - 33.33 µl/ml) activities. The results indicate that the essential oil from H. cordata has a significant potential to allow future exploration and exploitation as a natural antimicrobial and allelopathic agent.

Solvent-mediated nonelectrostatic ion-ion interactions predicting anomalies in electrophoresis.

We study the effects of solvent-mediated nonelectrostatic ion-ion interactions on electrophoretic mobility of a charged spherical particle. To this end, we consider the case of low surface electrostatic potential resulting in the linearization of the governing equations, which enables us to deduce a closed-form analytical solution to the electrophoretic mobility. We subsequently compare our results to the standard model using Henry's approach and report the changes brought about by the nonelectrostatic potential. The classical approach to determine the electrophoretic mobility underpredicts the particle velocity when compared with experiments. We show that this issue can be resolved by taking into account nonelectrostatic interactions. Our analysis further reveals the phenomenon of electrophoretic mobility reversal that has been experimentally observed in numerous previous studies.

Compositional and Enantiomeric Analysis of the Essential Oil of Taxodium distichum from India.

The leaf essential oil composition of Taxodium distichum L., collected from the foothills of Uttarakhand, India was analyzed using gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) equipped with DB-5 (5% diphenyl-95% dimethyl polysiloxane) and ß-cyclodextrin (6-tertiarybutyldimethylsiliyl-2,3-diethyl-ß-cyclodextrin) capillary columns. Seventeen constituents, representing 90.3 to 99.4% of composition were identified in the essential oils from different seasons, viz. spring, summer, rainy, autumn and winter. The essential oil composition was mainly dominated by monoterpene hydrocarbons, represented mainly by α-pinene (81.9-94.3%). Other constituents of the oil were myrcene (0.5-4.7%), ß-pinene (2.2-2.9%), limonene (0.5-1.5%), camphene (≤ 0.03-1.5%), and α-terpineol (upto 1.6%). Chiral analysis of T. distichum essential oil on an ethyl substituted ß-cyclodextrin capillary column revealed the presence of a-pinene in racemic form, with an enantiomeric ratio of 49.3% for (1R)-(+)- and 50.7% for (1S)-(-)-α-pinene.

Electrokinetically modulated peristaltic transport of power-law fluids.

The electrokinetically modulated peristaltic transport of power-law fluids through a narrow confinement in the form of a deformable tube is investigated. The fluid is considered to be divided into two regions - a non-Newtonian core region (described by the power-law behavior) which is surrounded by a thin wall-adhering layer of Newtonian fluid. This division mimics the occurrence of a wall-adjacent cell-free skimming layer in blood samples typically handled in microfluidic transport. The pumping characteristics and the trapping of the fluid bolus are studied by considering the effect of fluid viscosities, power-law index and electroosmosis. It is found that the zero-flow pressure rise is strongly dependent on the relative viscosity ratio of the near-wall depleted fluid and the core fluid as well as on the power-law index. The effect of electroosmosis on the pressure rise is strongly manifested at lower occlusion values, thereby indicating its importance in transport modulation for weakly peristaltic flow. It is also established that the phenomenon of trapping may be controlled on-the-fly by tuning the magnitude of the electric field: the trapping vanishes as the magnitude of the electric field is increased. Similarly, the phenomenon of reflux is shown to disappear due to the action of the applied electric field. These findings may be applied for the modulation of pumping in bio-physical environments by means of external electric fields.

Electroosmosis of Powell-Eyring fluids under interfacial slip.

We investigate the EOF of a Powell-Eyring fluid through a slit microchannel, employing Navier slip boundary condition. Using an analytical scheme consistent with the homotopy perturbation method, we bring out the alteration in the underlying flow dynamics as attributable to the nonlinear interactions between fluid rheology and electrostatics over interfacial scales. We validate the approximate analytical solutions by comparing those with results from numerical analysis. We unveil a regime of phenomenal amplification in the net volumetric flow rate, realized as a consequence of an intricate interplay between interfacial electromechanics, slipping hydrodynamics, and the flow rheology. Our results may have far ranging consequences in the design of various biomicrofluidic devises/systems, which are often used for the manipulation of non-Newtonain fluids.

Compositional variability and antifungal potentials of ocimum basilicum, O. tenuiflorum, O. gratissimum and O. kilimandscharicum essential oils against Rhizoctonia solani and Choanephora cucurbitarum.

The composition of hydrodistilled essential oils of Ocimum basilicum L. (four chemovariants), O. tenuiflorum L., O. gratissimum L., and O. kilimandscharicum Guerke were analyzed and compared by using capillary gas chromatography (GC/FID) and GC-mass spectrometry (GC/MS). Phenyl propanoids (upto 87.0%) and monoterpenoids (upto 83.3%) were prevalent constituents distributed in the studied Ocimum taxa. The major constituents of the four distinct chemovariants of O. basilicum were methyl chavicol (86.3%), methyl chavicol (61.5%)/linalool (28.6%), citral (65.9%); and linalool (36.1%)/citral (28.8%). Eugenol (66.5% and 78.0%) was the major constituent of O. tenuiflorum and O. gratissimum. Eugenol (34.0%), ß-bisabolene (15.4%), (E)-α-bisabolene (10.9%), methyl chavicol (10.2%) and 1,8-cineole (8.2%) were the major constituents of O. kilimandscharicum. In order to explore the potential for industrial use, the extracted essential oils were assessed for their antifungal potential through poison food technique against two phytopathogens, Rhizoctonia solani and Choanephora cucurbitarum, which cause root and wet rot diseases in various crops. O. tenuiflorum, O. gratissimum, and O. kilimandscharicum exhibited complete growth inhibition against R. solani and C. cucurbitarum after 24 and 48 h of treatment. O. basilicum chemotypes showed variable levels of growth inhibition (63.0%-100%) against these two phytopathogens.

Chemical analysis of volatile oils from West Himalayan Pindrow Fir Abies pindrow.

The essential oil composition of needle and stem oils of Abies pindrow (Royle ex D.Don) Royle, commonly known as Pindrow or West Himalayan Fir, were analyzed by gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Fifty-six constituents, accounting for 96.0% of needle and 83.5% of stem oil composition, were identified. The oils were characterized by a high content of monoterpenoids (68.9%-79.9%), mainly comprised by limonene (21.0%-34.4%), camphene (0.5%-19.9%), alpha-pinene (13.8%-16.8%), myrcene (6.7%-8.3%) and beta-pinene (6.5%-8.6%). Monoterpene hydrocarbons were predominant in both oils, but the quantitative and qualitative composition of the volatile constituents was specific for each part of the tree; and considerable variations in their terpenoid production pattern were also noticed. Results were compared with earlier reported fir species from different geographic regions.

Regimes of streaming potential in cylindrical nano-pores in presence of finite sized ions and charge induced thickening: an analytical approach.

We obtain approximate analytical expressions for the streaming potential and the effective viscosity in a pure pressure-driven flow through a cylindrical pore with electrokinetic interactions, duly accounting for the finite size effects of the ionic species (steric effects) and charge-induced thickening. Our analytical results show a remarkable agreement with the numerical solution even for high surface potentials and small channel radii. We demonstrate a consistent increment in the predicted value of the streaming potential and effective viscosity when finite size effects of the ionic species are accounted for. In addition to this, we account for the radial variation of in the viscosity of the fluid due to charge-induced thickening. We show that this so-called viscoelectric effect leads to a decrease in the induced streaming potential especially at high steric factors and high surface potentials. However, the viscoelectric effect, which is prominent at high zeta potential and narrow channels, does not cause significant changes in the electrokinetic conversion efficiency. These results shed light on the interesting confluence of the steric factor, the channel radius, the electrical double layer screening length, and the surface charge density in conjunction with the charge induced thickening, and thus provide ion-size dependent analytical framework for accurate system design and better interpretation of electrokinetic data.

Energy transfer through streaming effects in time-periodic pressure-driven nanochannel flows with interfacial slip.

We analytically investigate the prospect of using electrokinetic phenomena to transfer hydrostatic energy to electrical power with high energy transfer efficiencies, by exploiting time periodic pressure-driven flows in narrow fluidic confinements. An expression for the energy transfer efficiency for such pulsating pressure-driven flows is derived by considering wall-slip effects due to hydrophobic interactions, strong electrical double layer interactions in the confined flow passages, possibilities of exploring the regimes of large wall potentials, and the adverse consequences of the finite conductance of the Stern layer. It is revealed from our studies that high-frequency pressure pulsations may be employed in practice to improve the concerned energy transfer efficiency to a considerable extent, instead of using a steady-state pressure field. Such favorable effects are found to be best exploited by utilizing "slipping" electro-hydrodynamics in thick electrical double layers in the presence of high surface potentials.