Larvicidal activity of hydroalcoholic extracts of Persea americana Mill. Seeds against Aedes aegypti

This study aimed to evaluate the phytochemical composition of hydroalcoholic extracts from the seeds of Persea americana (avocado) and evaluate the larvicidal activity against Aedes aegypti. The extracts were obtained by maceration in a 70% PA ethanol extractant solvent in 1:4/1:6/1:8 hydromodules (7 days), with subsequent concentration in a rotaevaporator. The larvicidal activity was performed by the method recommended by the WHO Lethal Concentration 50% against Aedes aegypti larvae with statistics by the Probit method. Toxicity to non-target organisms was verified by the Artemia salina test. Activity was observed against Aedes aegypti larvae with LC50 ranging from 181.72-401.96 mg L-1 with a 95% confidence interval. Finally, it states that the extract of P. americana has potential for larvicidal activity and does not present toxicity to target organisms, showing itself to be a sustainable alternative for the control and combat of Aedes aegypti larvae.

Uji Efektivitas Ekstrak Etanol Daun Angsana (Pterocarpus Indicus Willd) sebagai Biolarvasida terhadap Larva Nyamuk Culex Sp.

Mosquitoes are often associated with health problems because mosquito bites not only cause itching but some species can also transmit various types of parasites that are harmful to human health. One of them is Culex sp mosquito which is a class of infectious insects (vectors). This study aimed to test the activity of compounds in angsana leaf extract (Pterocarpus indicus Willd) as biolarvasides on Culex sp. mosquitoes and determine the concentration of LC50 value needed. Extraction was carried out by maceration method using 70% ethanol solvent. The extract collected was then tested biolarvaside activity on Culex sp. The study subjects were divided into 8 treatment groups, namely aquades (negative control), 0.05%, 0.1%, 0.2%, 0.5%, 1%, 2% and ABATE 0.1% (positive control). Each group contained 20 mosquito larvae with three replications (triplo). Observations were made for 24 hours at intervals of 1 hour, 4 hours, 8 hours, 12 hours and 24 hours. The biolarvaside activity of angsana leaf extract was analyzed using the probit method. Based on the results of the Probit analysis, the LC50 value was 0.83%. These results indicate that the angsana leaf extract (Pterocarpus indicus Willd) was effective as a biolarvaside. Abstrak. Nyamuk sering dikaitkan dengan masalah kesehatan karena gigitan nyamuk tidak hanya menimbulkan gatal saja tetapi beberapa spesies nyamuk juga dapat menularkan berbagai jenis parasit yang berbahaya bagi kesehatan manusia. Salah satunya yaitu nyamuk Culex sp yang merupakan golongan serangga penular (vektor). Penelitian ini bertujuan untuk pengujian aktivitas senyawa dalam ekstrak daun angsana (Pterocarpus indicus Willd) sebagai biolarvasida pada nyamuk Culex sp dan penentuan nilai LC50. Ekstraksi dilakukan dengan metode maserasi menggunakan pelarut etanol 70%, Ekstrak yang diperoleh kemudian diuji aktivitas biolarvasida pada nyamuk Culex sp. Subjek penelitian dibagi menjadi 8 kelompok perlakuan, yaitu akuades (kontrol negatif), 0,05%, 0,1%, 0,2%, 0,5%, 1%, 2% dan ABATE 0,1% (kontrol positif).Setiap kelompok berisi 20 ekor larva nyamuk dengan tiga kali pengulangan (triplo) . Pengamatan dilakukan selama 24 jam dengan interval 1jam, 4jam, 8jam, 12jam dan 24jam. Aktivitas biolarvasida ekstrak daun angsana dianalisis dengan menggunakan metode probit. Berdasarkan hasil analisis Probit didapatkan nilai LC50 berada pada konsentrasi 0,83%.Hasil tersebut menunjukkan bahwa Ekstrak daun angsana (Pterocarpus indicus Willd) efektif sebagai biolarvasida.

Toxicological Characterization of Ten Medicinal Plants of the Beninese Flora Used in the Traditional Treatment of Diarrheal Diseases

The use of medicinal plants in traditional medicine is a common practice in developing countries. However, this unregulated or poorly rational use may present a dose-dependent risk of toxicity to humans. This study aimed to explore the phytochemical and toxicological characteristics of ten (10) plant species used in the traditional treatment of infectious diarrhea in Benin. The acute toxicity of aqueous and hydroethanolic extracts of Khaya senegalensis, Daniellia oliveri, Rauvolfia vomitoria, Vernonia amygdalina, Manihot esculenta, Ocimum gratissimum, Senna italica, Diospyros mespiliformis, Pterocarpus erinaceus, and Anacardium occidentale was evaluated following the OECD 423 protocol at a single dose of 2000 mg/kg. This safety test was complemented by a larval cytotoxicity test. Hematological and biochemical examinations, as well as a histological study of the liver and kidneys, were performed. Larval cytotoxicity was assessed by the sensitivity of Artemia salina larvae to different concentrations of the plant extracts studied. Testing for chemical compounds was performed on the basis of differential staining and precipitation reactions. The mean lethal concentration (LC50) was determined by the probit method. The qualitative phytochemical screening of the plants studied revealed the presence of catechic tannins, gallic tannins, flavonoids, anthocyanins and sterol-terpenes, alkaloids, saponosides, and reducing compounds. This composition varied according to the plants studied. Acute toxicity data indicated that there was no mortality and no structural and functional alterations of the liver and kidneys of treated animals. Larval cytotoxicity data suggest that the plants studied are not cytotoxic (LC50 ≥ 0.1 mg/mL). These observations reflect the safety of these plants and justify their use in traditional medicine in the treatment of many diseases including diarrheal diseases.

Chemical profile and larvicidal activity of essential oil obtained from the leaves of Plectranthus amboinicus (Lour.) Spreng

This study aimed to determine the chemical constituents and larvicidal activity of the essential oil of Plectranthus amboinicus (Lour.) Spreng against larvae of the Aedes aegypti mosquito. The essential oil (EO) was extracted by hydrodistillation at 100 ° C for 3 hours. The chemical composition was obtained by Gas Chromatography coupled to Mass Spectrometry (GC / MS). To assess larvicidal activity, Aedes aegypti larvae were subjected to EO solutions in concentrations of 10-100 mg L-1, where larval mortality was assessed and the LC50 was determined using the Probit method. The main chemical constituent found in the EO was carvacrol, which is considered to be very promising for pharmaceutical synthesis. The EO showed larvicidal activity with an LC50 of 28.52 mg L-1. According to the results found, it was possible to evaluate that the analyzed EO is composed of substances that have an efficient larvicidal effect against Aedes aegypti, thus encouraging its potential for application.

Chemical and Toxicological Hazard Assessment when Handling Rocket Fuel 2-dimethylaminoethylazide and its Derivatives

The hazard was studied related to toxic effects on the production personnel of the aerospace industry for the experimental rocket fuels of 2-dimethylaminoethylazide and its derivatives — 2-azido-N-methylethanamine and 2-azido-N-cyclopropylethanamine used for liquid propellant rocket engines. The calculation and analysis of physical and chemical constants that characterize the bioavailability of substances based on the rules of N.V. Lazarev, С.A. Lipinsky, and S.M. Jorgensen are made. Pharmacophore analysis and search for active sites of a number of receptors related to carcinogenesis, psychotropic and nerve processes, and the cardiovascular system were performed in the Schrödinger software package. Molecular docking of the receptors and the studied compounds was performed, and the results were analyzed in AutoDock Vina. The values are determined concerning approximately safe exposure levels, hazard classes of substances, and the maximum possible concentrations (volatility) of the rocket fuels that occur in the event of an emergency leak. Through the use of probit method the assessment was related to the immediate non-carcinogenic health risks that service personnel are exposed to in the event of accidental fuel leaks (irritating effect, diseases of the respiratory, nervous, and cardiovascular systems). The results have practical application in the search and synthesis of the rocket fuels - safe analogues of the more toxic heptyl (1,1-dimethylhydrazine), the use of which leads to the development of occupational diseases in the operating personnel and environmental pollution by the aerospace industry facilities.

Collection of Non-Timber Forest Products in Chinese Giant Panda Reserves: The Effect of Religious Beliefs

Religious belief play an irreplaceable role in the protection of natural resources. This paper explores the influence of religious beliefs on the Non-Timber Forest Products (NTFPs) collection behaviors of farmers, in order to provide new ideas on how to rationally use natural resources for nature reserves. Based on survey data of giant panda reserves in Sichuan and Shaanxi provinces in China, we analyze the differences of NTFPs collection between farmers with or without religious beliefs and those with different religious beliefs. Our results show that: (i) The SUR-Probit method can be used to overcome the endogeneity problem of the model and test the causal effect between religious belief and NTFPs collection; (ii) farmers with religious beliefs collect NTFPs to a lesser extent; and (iii) the collection of NTFPs by farmers with different religious beliefs can be distinguished. The important role of religious belief in the use of natural resources has often been neglected in previous studies. In our research, we find that religious belief can indeed guide the individual choice of resource utilization behavior, to a certain extent, ultimately achieving the mutual co-ordination of ecological protection and economic development, which can also be used as a reference for policy-making.

Larval Cytotoxic and Subacute Toxicity of Gardenia ternifolia, Rourea coccinea, and Cassytha filiformis Used in Traditional Medicine of Benin (West Africa)

The use of medicinal plants in traditional medicine is a common practice in developing countries. However, this unregulated or irrational use may pose a risk of toxicity to humans in the short and/or long term. Recent studies reported interesting ethnopharmacological, antioxidant, and phytochemical data on some medicinal plants used in the traditional treatment of male infertility in Benin. Unfortunately, very little data exist on the long-repeated dose toxicity of these medicinal plants. This study was aimed at evaluating the larval cytotoxicity and subacute toxicity of the hydroethanolic extract of Cassytha filiformis whole plant, Gardenia ternifolia roots, and Rourea coccinea leaves. The subacute toxicity of these plants was evaluated in male Wistar albino rats at three different doses (200, 400, and 800 mg/kg) according to the OECD 407 guidelines. Hematological and biochemical examinations and the histological study of the liver and kidneys were carried out. Larval cytotoxicity was assessed by the sensitivity of Artemia salina larvae to different concentrations of the studied plants extracts. The mean lethal concentration (LC50) was determined by the probit method. Subacute toxicity data indicated that there was no mortality or structural alterations of the liver and kidneys in the lot of treated animals. However, significant alterations in certain hematological and biochemical parameters (hematocrit, ASAT, and uremia) were noted. These abnormalities were observed in the lot of rats treated with Rourea coccinea and Cassytha filiformis extracts. Larval cytotoxicity data indicate that the studied plants extracts are not cytotoxic (LC50 > 0.1 mg/mL). These data suggest that the use in traditional medicine of studied plants at high doses and repeated over a long period of time requires special attention.

Health Outcomes Before, During and After the Great Recession in Canada: A Longitudinal Analysis

Using panel data from Canadian National Population Health Survey (2006-2011), this study examined what happened to individuals’ self-reported health during and in the aftermath of great recession of 2008-2009. The study used different methods such as ordered probit method, ordinary least square method and panel fixed effects method. Once individual specific fixed effects are controlled for, the results show that great recession had no statistically significant detrimental impact on self-reported health status. The results further show that health status in the aftermath of great recession did not significantly differ from the health status before the great recession.

Snake venoms and purified toxins as biotechnological tools to control Ralstonia solanacearum

The objective of this work was to evaluate the in vitro antibacterial activity of snake venoms and purified toxins on the phytopathogenic bacterium Ralstonia solanacearum. The evaluations were performed with 17 crude venoms (13 from Bothrops, 3 from Crotalus, and 1 from Lachesis) and seven toxins (1 from Bothrops and 6 from Crotalus). Antibacterial activity was assessed in MB1 medium containing solubilized treatments (1 μL mL-1). A total of 100 μL bacterial suspension (8.4 x 109 CFU mL-1) was used. After incubation at 28°C, the number of bacterial colonies at 24, 48, and 72 hours after inoculation was evaluated. SDS-PAGE gel at 15% was used to analyze the protein patterns of the samples, using 5 μg protein of each sample in the assay. Furthermore, the minimum inhibitory concentration (MIC) and lethal concentration (LC50) values were determined by the Probit method. Venoms and toxins were able to reduce more than 90% of R. solanacearum growth. These results were either equivalent to those of the positive control chloramphenicol or even better. While MIC values ranged from 4.0 to 271.5 μg mL-1, LC50 ranged from 28.5 μg mL-1 to 4.38 mg mL-1. Ten crude venoms (7 from Bothrops and 3 from Crotalus) and two purified toxins (gyroxin and crotamine) are promising approaches to control the phytopathogenic bacterium R. solanacearum.

Toxicity and Organ Distribution of Mercury in Freshwater Fish (Oreochromis niloticus) after Exposure to Water Contaminated Mercury (HgII)

The purpose of this study was to investigate the toxicity and the distribution of mercury (Hg) in the main tissues of freshwater fish (Oreochromis niloticus) after being exposed to water containing Hg(II). A sample group of 10 fish, of mean weight 80–100 g wet weight, were exposed to different concentrations of Hg (0.0012; 0.0049; 0.0141; 0.0524; 0.1126; and 0.5110 mg-HgII/L) for 72 hours under controlled conditions using the static method in ponds. A control medium was also prepared in two replications. Mortality of fish was closely monitored, and the test was repeated three times. For the toxicity test, observations were based on behavior, mortality, and anatomical pathology. The methodology was based on the OECD guidelines for testing of chemicals and lethal concentration (LC50) and particularly using the probit method. Thus, the mean value was obtained from two replications and then further calculated by a software (MiniTab® 16 version). Prior to analysis, samples were first lyophilized. The total concentration of Hg accumulation in the fish organs was analyzed using heat-vaporization atomic absorption spectrometry (HV-AAS) and a MA2000 automatic mercury analyzer. Results showed that toxicity (LC50) of freshwater fish was 0.1435 mg-Hg(II)/L. The internal organs showed some pathological changes including pale gills, anemic eyes, and a whitish body color after the exposure. Furthermore, histopathologically, exposure to mercury might also affect other organs, such as gills, liver, and hepatopancreas. Mercury was found in trace amounts, and its accumulation was found to be at least in the gills. Meanwhile, the highest accumulation was found in the muscle tissue with approximately 5.7183 µg/g dry weight. If they are put in order, the mercury accumulation in the tissue organs was varied from the highest to lowest one: Muscle > eye > bone > head > gill. Finally, it can be concluded that the Hg exposure could affect the histopathological condition of the tested fish.