Larvicidal activity of piperovatine and dichloromethane extract from Piper corcovadensis roots against mosquitoes Aedes aegypti L / Actividad larvicida de piperovatina y extracto de diclorometano de las raíces de Piper corcovadensis contra mosquitos vectores del dengue Aedes aegypti L

The research of new substances capable of controlling the Aedes aegypti mosquito is urgent due to the increase in the transmission of the diseases such as dengue, chikungunya and Zika virus by the vector. Thus, the aim of this study was to evaluate the larvicidal activity of crude extract of Piper corcovadensis roots, a native plant from Brazil, and of the isolated compound piperovatine against larvae of A. aegypti by the larval immersion test. The lethal concentration that killed 50% (LC50) and 99% (LC99) of larvae was determined by Probit analysis. The results indicated high larvicidal activity on A. aegypti larvae for crude extract of Piper corcovadensis roots with LC50 of 4.86 µg/mL and LC99 of 15.50 µg/mL and piperovatine with LC50 of 17.78 µg/mL and LC99 of 48.55 µg/mL. This work opens new perspectives to the development of future products with crude extract of Piper corcovadensis roots and piperovatine that can be applied to mosquito control.

La investigación de nuevas sustancias capaces de controlar el mosquito Aedes aegypti es urgente debido al aumento en la transmisión de enfermedades como el dengue, el chikungunya y el virus Zika por el vector. Por lo tanto, el objetivo de este estudio fue evaluar la actividad larvicida del extracto crudo de las raíces de Piper corcovadensis, una planta nativa de Brasil, y del compuesto aislado piperovatine contra larvas de A. aegypti mediante la prueba de inmersión larvaria. La concentración letal que mató al 50% (LC50) y al 99% (LC99) de larvas se determinó mediante análisis Probit. Los resultados indicaron una alta actividad larvicida en larvas de A. aegypti para extracto crudo de las raíces de Piper corcovadensis con LC50 de 4.86 µg/mL y LC99 de 15.50 µg/mL y piperovatine con LC50 de 17.78 µg/mL y LC99 de 48.55 µg/mL. Este trabajo abre nuevas perspectivas para el desarrollo de futuros productos con extracto crudo de las raíces de Piper corcovadensis y piperovatine que pueden aplicarse al control de mosquitos.

Occupational exposure to benzene and changes in hematological parameters and urinary trans, trans-muconic acid

For its toxicity, benzene exposure is one of the main health concerns for high risk occupations like gasoline station workers. However, there is little knowledge about the effect of benzene metabolites on hematological parameters. To evaluate the correlation between the urinary level of trans, trans-muconic acid [t, t-MA], a benzene metabolite, and some hematological parameters in gasoline workers. We studied 102 gasoline station workers from 11 gasoline stations in Pathumwan district, central area of Bangkok, Thailand. Their blood and urine samples were analyzed for some hematological parameters and urinary t, t-MA analysis by high performance liquid chromatography [HPLC]. We found an inverse correlation between urinary t, t-MA concentration and hemoglobin level [r = 0.281, p<0.05], hematocrit [r = 0.264, p<0.05]. Those with higher urinary t, t-MA had a significantly [p<0.05] lower eosinophil counts than those with lower exposure. No significant correlation was found between urinary t, t-MA level and other white blood cell parameters and platelets count. Exposure to benzene would cause bone marrow depression presenting as drop in hemoglobin, hematocrit and eosinophil counts

Classification of risk occupation for benzene exposure by urine trans, trans-munconic acid level.

Leukemogenesis due to benzene exposure is of particular concern because of ongoing exposure to thousands of workers in industrial plants. Monitoring of at-risk workers is recommended and of several biomarkers, urine trans,trans-muconic acid (ttMA) determination is a helpful test. The aim of this work was to classify risk occupation for benzene exposure by urine ttMA level. Here, the author compared exposure risk ratios from 6 previous reports concerning urine ttMA determination. Of interest, the high risk occupations were found to be those which have direct contact with benzene in environmental ambient air, with petroleum fuel as the common source.

Evaluation of benzene exposure in adults and urinary s-phenylmercapturic acid in children living in Adelaide, South Australia

Benzene Exposure was evaluated in adults and children living in Adelaide, South Australia by measuring benzene and urinary s-phenylmercapturic acid [SPMA]. To determine of benzene exposure in each subject the personal passive samplers was used and samples were analyzed by gas chromatography system equipped to flame ionization detector. The level of SPMA was determined by competitive enzymelinked immunosorbent assay [ELISA] in children. The mean concentration of benzene in Summer and Winter were 1.62 +/- 1.43 and 1.36 +/- 0.87 ppb respectively. There was a significant difference between exposure to benzene for subjects with less and more than 6 hours activity over days of week [p<0.05]. The mean urinary concentrations levels of SPMA adjusted to creatinene for children that living less and more than 200 meters mol/mol creatinene, respectively and distance from main road were 1.56 and 4.67 the significant difference was seen in two groups [p<0.005]. Data shows, that SPMA can be utilized as a biomarker for exposure to benzene in children. Exposure to benzene is more for children that living near to main road compare to other children. Adults have more activity in out side of home has more exposure to benzene than other people

Effects of Air Pollutants on Childhood Asthma

Epidemiologic studies have suggested the association between environmental exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and the increased risk of incurring asthma. Yet there is little data regarding the relationship between personal exposure to air pollution and the incidence of asthma in children. This study was designed to evaluate the effect of exposure to air pollution on children with asthma by using exposure biomarkers. We assessed the exposure level to VOCs by measuring urinary concentrations of hippuric acid and muconic acid, and PAHs by 1-OH pyrene and 2-naphthol in 30 children with asthma and 30 children without asthma (control). The mean level of hippuric acid was 0.158+/-0.169micromol/mol creatinine in the asthma group and 0.148+/-0.249micromol/mol creatinine in the control group, with no statistical significance noted (p=0.30). The mean concentration of muconic acid was higher in the asthma group than in the control group (7.630+/-8.915micromol/mol creatinine vs. 3.390+/-4.526micromol/mol creatinine p=0.01). The mean level of urinary 1-OHP was higher in the asthma group (0.430+/-0.343micromol/mol creatinine) than the control group (0.239+/-0.175micromol/mol creatinine), which was statistically significant (p=0.03). There was no difference in the mean concentration of 2-NAP between the two groups (9.864+/-10.037micromol/mol in the asthma group vs. 9.157+/-9.640micromol/mol in the control group, p=0.96). In conclusion, this study suggests that VOCs and PAHs have some role in asthma.

Simultaneous determination of trans, transmuconic acid and s-phenylmercapturic acid by high pressure liquid chromatography and its application.

The simultaneous determination of urinary trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA) was performed by liquid extraction with ethyl acetate and reversed-phase high performance liquid chromatography (RP-HPLC) on a Hypersil-ODS column using the gradient mobile phase of methanol and 0.0012 N perchloric acid and diode array detection at 205 and 264 nm for S-PMA and t,t-MA, respectively. The retention times for t,t-MA and S-PMA were 3.8 and 12.3 minutes, respectively. The recoveries of t,t-MA and S-PMA were > 97%; between-day precisions were all within 8% RSD (100x SD/mean). The method was applied to analyze the urinary t,t-MA and S-PMA of 59 service station attendants exposed to average benzene concentrations in the air of 0.20+/-0.18 ppm. Significant differences in pre-shift and post-shift urinary t,t-MA between smokers and non-smokers were found.

High urine ttMA levels among fishermen from a Thai rural village.

The ongoing industrialization of Thailand, a developing country in Southeast Asia, has put many occupations at high risk of benzene exposure. However, there are few reports about monitoring the biomarkers of benzene exposure among Thais. In this study, we report on high urine trans, trans-muconic acid (ttMA) levels among the fishermen of a rural community. Using high-performance liquid chromatography (HPLC) for urine ttMA determination, 49 subjects (30 fishermen and 19 control subjects) were studied. The mean urine ttMA level in fisherman (0.180 +/- 0.130 mg/g creatinine) was significantly higher than that of the control group (0.015 +/- 0.053 mg/g creatinine) (p < 0.05). We recommend the monitoring of urine ttMA in these workers. The monitoring of the possible benzene contamination of the water and fish is recommended for further study.

Feasibility of urinary trans, trans-muconic acid determination using high performance liquid chromatography for biological monitoring of benzene exposure.

Benzene is an important carcinogenic substance used in many industrial processes. Inhalation of this substance can cause both acute and chronic toxicity. In this study, monitoring of benzene exposure by high-performance liquid chromatography (HPLC) for urine trans, trans-muconic acid (ttMA) determination was adapted. We described a new adapted sensitive and specific HPLC method. We mixed 0.5 mL of urine sample with 2 mL of Tris Buffer containing vanillic acid as internal standard (IS) and percolate this through a preconditioned ion-exchange column. After rinsing the column with phosphoric acid solution, acetate buffer, and deionized water, we eluated the analytes with 2 mL of an equivolume solution of 1.5 mol/L sodium chloride and methanol. Of this, 10 microliter was injected into the HPLC column. The mobile phase consisted of, per liter, 10 ml of acetic acid, 100 ml of methanol, and 5 mmol/L sodium acetate. The flow rate was started at 1.2 ml/min. The ttMA and IS were detected at 4.2 to 4.4 and 12.6-13.3 minutes, respectively. The lowest detection limit was 0.05 mg/L.

Urine trans,trans-muconic acid determination for monitoring of benzene exposure in mechanics.

Benzene is an important carcinogenic substance used in many industrial processes. Inhalation of this substance can cause both acute and chronic toxicity. In this study, monitoring of benzene exposure by high-performance liquid chromatography for urine trans,trans-muconic acid (ttMA) determination in 94 subjects, (49 control subjects and 45 mechanics) was performed. The mean urine ttMA level in the control group was 0.116 +/- 0.027 mg/g creatinine. The mean urine ttMA level in the mechanics group was 0.280 +/- 0.131 mg/g creatinine. There was a significant difference between the groups (p < 0.05). Based on this study, we recommend the use of urine ttMA determination for monitoring of benzene exposure in high risk workers.