Antibacterial and antifungal activities of teucrium royleanum (Labiatea)

The crude methanolic extract and subsequent fractions of Teucrium royleanum (Labiatea) were screened for antibacterial and antifungal activities. Against tested pathogens, crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities. Highest antibacterial activity was displayed by the ethyl acetate fraction against S. typhi (100%), against E.coli (76.7%) and against P. aerugenosa (70.8%) followed by the chloroform fraction against S. typhi (85.7%). Similarly, the crude extract and its subsequent fractions showed mild to excellent activities in the antifungal bioassay with maximum antifungal activity against M. canis (87%) by the chloroform fraction followed by the ethyl acetate (71%) and n-butanol (70%) fractions.     

Antifungal and antibacterial activities of Taxus wallichiana Zucc

Current study was undertaken to evaluate the in vitro antifungal and antibacterial potential of methanol extract and subsequent fractions obtained after partitioning in organic solvents with variable polarity of the aerial parts of the tree Taxus wallichiana Zucc. Traditionally, this plant is often used in folk medicines in Pakistan for treating microbial infections. In order to rationalize the traditional use, methanol extracts of leaf, bark, and heartwood of Taxus wallichiana Zucc. were tested against six bacteria and six fungal strains using the Hole diffusion and macro-dilution methods. All extracts and fractions displayed significant antimicrobial effect. Only three fungal strains, Trichophyton longifusus, Microspoum canis, and Fusarium solani were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. In case of bacterial strains, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. Comparison results were carried out using imipinem, miconazole and amphotericin B as standard antibiotics.     

Synthesis and biological evaluation of potential modulators of malarial glutathione-S-transferase(s)

Glutathione-S-transferase(s) (E.C.2.5.1.18, GSTs) have been investigated in parasitic protozoans with respect to their biochemistry and they have been identified as potential vaccine candidates in protozoan parasites and as a target in the synthesis of new antiparasitic agents. In a search towards the identification of novel biochemical targets for antimalarial drug design, the area of Plasmodium glutathione metabolism provides a number of promising chemotherapeutic targets. GST activity was determined in various subcellular fractions of malarial parasites Plasmodium yoelii and was found to be localized mainly in the cytosolic fraction (specific activity, c. 0.058 ± 0.016 μmol/min/mg protein). Hemin, a known inhibitor of mammalian GST(s), maximally inhibited this enzyme from P. yoelii to nearly 86%. In a search towards synthetic modulators of malarial GST(s), 575 compounds belonging to various chemical classes were screened for their effect on crude GST from P. yoelii and 92 compounds belonging to various chemical classes were studied on recombinant GST from P. falciparum. Among all the compounds screened, 83 compounds inhibited/stimulated the enzyme from P. yoelii/P. falciparum to the extent of 40% or more.     

Palmitoylethanolamide and luteolin ameliorate development of arthritis caused by injection of collagen type II in mice

IntroductionN-palmitoylethanolamine (PEA) is an endogenous fatty acid amide belonging to the family of the N-acylethanolamines (NAEs). Recently, several studies demonstrated that PEA is an important analgesic, antiinflammatory, and neuroprotective mediator. The aim of this study was to investigate the effect of co-ultramicronized PEA + luteolin formulation on the modulation of the inflammatory response in mice subjected to collagen-induced arthritis (CIA).MethodsCIA was induced by an intradermally injection of 100 μl of the emulsion (containing 100 μg of bovine type II collagen (CII)) and complete Freund adjuvant (CFA) at the base of the tail. On day 21, a second injection of CII in CFA was administered. Mice subjected to CIA were administered PEA (10 mg/kg 10% ethanol, intraperitoneally (i.p.)) or co-ultramicronized PEA + luteolin (1 mg/kg, i.p.) every 24 hours, starting from day 25 to 35.ResultsMice developed erosive hind-paw arthritis when immunized with CII in CFA. Macroscopic clinical evidence of CIA first appeared as periarticular erythema and edema in the hindpaws. The incidence of CIA was 100% by day 28 in the CII-challenged mice, and the severity of CIA progressed over a 35-day period with a resorption of bone. The histopathology of CIA included erosion of the cartilage at the joint. Treatment with PEA or PEA + luteolin ameliorated the clinical signs at days 26 to 35 and improved histologic status in the joint and paw. The degree of oxidative and nitrosative damage was significantly reduced in PEA + luteolin-treated mice, as indicated by nitrotyrosine and malondialdehyde (MDA) levels. Plasma levels of the proinflammatory cytokines and chemokines were significantly reduced by PEA + luteolin treatment.ConclusionsWe demonstrated that PEA co-ultramicronized with luteolin exerts an antiinflammatory effect during chronic inflammation and ameliorates CIA.     

Photodegradation and Stabilization of Betamethasone-17 Valerate in Aqueous/Organic Solvents and Topical Formulations

The effects of solvent [acetonitrile, methanol, and acetonitrile/water mixture (20:80, v/v)], buffer concentration (phosphate buffer, pH 7.5), ionic strength and commonly employed adjuvants on the photodegradation of betamethasone-17 valerate in cream and gel formulations have been studied on exposure to UV light (300–400 nm). A validated high-performance liquid chromatography method has been used to determine the parent compound and its photodegraded products. The photodegradation data in the studied solvents showed greater decomposition of the drug in solvents with a lower dielectric constant. A comparatively higher rate of photodegradation was observed in the cream formulation compared to that for the gel formulation. The kinetic treatment of the photodegradation data revealed that the degradation of the drug follows first-order kinetics and the apparent first-order rate constants for the photodegradation reactions, in the media studied, range from 1.62 to 11.30 × 10⁻³ min⁻¹. The values of the rate constants decrease with increasing phosphate concentration and ionic strength which could be due to the deactivation of the excited state and radical quenching. The second-order rate constant (k′) for the phosphate ion-inhibited reactions at pH 7.5 has been found to be 5.22 × 10⁻² M⁻¹ s⁻¹. An effective photostabilization of the drug has been achieved in cream and gel formulations with titanium dioxide (33.5–42.5%), vanillin (21.6–28.7%), and butyl hydroxytoluene (18.2–21.6%).Key words: betamethasone-17 valerate, creams and gels, kinetics, photodegradation, photostabilization     

Correction for Irrelevant Absorption in Multicomponent Spectrophotometric Assay of Riboflavin, Formylmethylflavin, and Degradation Products: Kinetic Applications

In the spectrophotometric assay of multicomponent systems involved in drug degradation studies, some minor or unknown degradation products may be present. These products may interfere in the assay and thus invalidate the results due to their absorption in the range of analytical wavelengths. This interference may be eliminated by the application of an appropriate correction procedure to obtain reliable data for kinetic treatment. The present study is based on the application of linear and non-linear irrelevant absorption corrections in the multicomponent spectrophotometric assay of riboflavin and formylmethylflavin during the photolysis and hydrolysis studies. The correction procedures take into account the interference caused by minor or unknown products and have shown considerable improvement in the assay data in terms of the molar balance. The treatment of the corrected data has led to more accurate kinetic results in degradation studies.     

Two new species of trap jaw ant Anochetus (Hymenoptera: Formicidae), with a key to known species from India

A key to the Indian species of the ponerine ant genus Anochetus Mayr, 1861 is presented and two new species are described: Anochetus cryptus sp. nov. and Anochetus validus sp. nov. collected from foothills of Himalaya, the Shivalik. Anochetus cryptus is a cryptobiotic species with minute eyes, light-pigmented integument, relatively reduced size and feeble sculpture; it most resembles Anochetus evansi Crawley, 1922. Anochetus validus is a member of the wide spread graeffei group, with strong sculpture and highly pigmented integument.     

Development of permethrin resistance in Culex quinquefasciatus Say in Kuala Lumpur,Malaysia

The resistance status towards permethrin among the laboratory strain, the permethrin-selected strain and four field strains of Culex quinquefasciatus collected in Kuala Lumpur, Malaysia was determined using three standard laboratory methods: WHO larval bioassay, WHO adult bioassay and biochemical microplate assay. Cx. quinquefasciatus permethrin-selected strain larvae were the least susceptible to permethrin with a resistance ratio of 47.28-folds, whereas all field strain larvae of the same species were tolerant to permethrin with resistance ratios of more than 3-folds. In contrast, in adult stage, the permethrin exposed permethrin-selected strain (resistance ratio = 1.27) was found to be more susceptible to permethrin than all permethrin-exposed field strains (resistance ratios = 2.23–2.48). Complete mortalities for all strains of Cx. quinquefasciatus adults proved the effectiveness of the synergist; piperonyl butoxide (PBO). For the biochemical microplate assay, the reduction of the mean optical density of elevated oxidase activity of three field strains upon exposure to PBO confirmed the association between oxidase activity and permethrin tolerance. On the other hand, irregular patterns of the mean optical density of elevated oxidase activity in the laboratory strain, permethrin-selected strain and Jalan Fletcher strain illustrated the gene variation within these mosquito colonies as well as the involvement of other enzyme activities in the permethrin resistance occurred.     

When to estimate sex ratio in natural populations of insects? A study on sex ratio variations of gall midges within a generation

Precise estimation of arthropods' sex ratio is an important issue in a wide range of ecological studies and biological control programs. Although, in many cases changes in arthropods' sex ratio may be under the control of parents or some symbiotic microorganisms, biased sex ratios in some other species are caused by some extrinsic factors, neglect of which may lead to under/overestimation of true sex ratio. In this paper, we pursued those factors that cause false estimation of sex ratio in insects' species. We studied the predatory gall midge, Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae), an important biological control agent of aphids, that shows protandry (i.e. early male emergence), differential lifespan of sexes, and differential distribution of sexes across habitat. Ten populations of A. aphidimyza were released separately in transparent cages and their sex ratio variations were recorded every 12 hours. The primary sex ratio in this species seems to be slightly male‐biased (52.41% males), however early emergence of males biases the sex ratio up to 72% males in a few hours after emergence. Shortly after the emergence of females, the sex ratio reaches its primary situation, but as a result of male‐biased mortality after mating, the proportion of females increases gradually to 97% by the fourth and fifth days after emergence. These results explicitly suggest that direct estimation of sex ratio in natural populations may be affected by some secondary factors such as differential mortality of sexes, protandry, and differential distribution of males and females over time and/or across habitat.