A biodegradable device for the controlled release of Piper nigrum (Piperaceae) standardized extract to control Aedes aegypti (Diptera, Culicidae) larvae

Abstract: INTRODUCTION: The significant increase in dengue, Zika, and chikungunya and the resistance of the Aedes aegypti mosquito to major insecticides emphasize the importance of studying alternatives to control this vector. The aim of this study was to develop a controlled-release device containing Piper nigrum extract and to study its larvicidal activity against Aedes aegypti. METHODS: Piper nigrum extract was produced by maceration, standardized in piperine, and incorporated into cotton threads, which were inserted into hydrogel cylinders manufactured by the extrusion of carrageenan and carob. The piperine content of the extract and thread reservoirs was quantified by chromatography. The release profile from the device was assessed in aqueous medium and the larvicidal and residual activities of the standardized extract as well as of the controlled-release device were examined in Aedes aegypti larvae. RESULTS The standardized extract contained 580mg/g of piperine and an LC50 value of 5.35ppm (24h) and the 3 cm thread reservoirs contained 13.83 ± 1.81mg of piperine. The device showed zero-order release of piperine for 16 days. The P. nigrum extract (25ppm) showed maximum residual larvicidal activity for 10 days, decreasing progressively thereafter. The device had a residual larvicidal activity for up to 37 days. CONCLUSIONS: The device provided controlled release of Piper nigrum extract with residual activity for 37 days. The device is easy to manufacture and may represent an effective alternative for the control of Aedes aegypti larvae in small water containers.

Toxicidade de extratos de Piper nigrum, piperina e piperamidas para o diplópodo Orthoporus fuscipes em condições de laboratório / Toxicity of extracts from Piper nigrum, piperine and piperamides to the millipede Orthoporus fuscipes under laboratory conditions

The toxicity of an ethanolic extract of black pepper (Piper nigrum), of piperine and of the synthetic amides adamantylpiperamide, sopentylpiperamide and diisopropylpiperamide was evaluated using the millipede Orthoporus fuscipes. For the experiments, the test organism was exposed to a diet of wheat bran and sugar (9:1) supplemented with the test substance in solution and mortality was monitored over a period of 17 days. Mortality was 100 percent for 0.3 g of the ethanolic extract of black pepper fruits and for diisopropylpiperamide after 4 and 14 days of exposure, respectively. Piperine at a concentration of 0.3 g resulted in 70 percent mortality after 4 days and remained at this rate until the end of the exposure period. Thus, among the compounds tested the ethanolic extract of black pepper fruit was the most effective and most promising for the control of Orthoporus fuscipes populations since it promoted a higher rate of mortality of the test organism within a shorter period of exposure.

A toxicidade do extrato etanólico da pimenta-do-reino (Piper nigrum), da piperina e amidas sintéticas: adamantilpiperamida, isopentilpiperamida e diisopropilpiperamida foi avaliada para o diplópodo Orthoporus fuscipes. Os experimentos consistiram na exposição dos organismos-teste a uma dieta de farelo de trigo e açúcar (9:1) a qual foi adicionada a substância teste em solução observando-se a mortalidade por um período de 17 dias. Verificou-se na dose contendo 0,3 g do extrato etanólico de frutos da pimenta-do-reino e da diisopropilpiperamida, 100 por cento de mortalidade após 04 e 14 dias de exposição, respectivamente. A piperina na concentração de 0,3 g causou 70 por cento de mortalidade após 4 dias, mantendo-se até o final do período de exposição. Dessa forma, dentre os compostos testados, o extrato etanólico do fruto da pimenta-do-reino foi considerado o mais eficiente e promissor no controle de populações de Orthoporus fuscipes, pois foi o que promoveu maior porcentagem de exposição.

Antimutagenic effects of piperine on cyclophosphamide-induced chromosome aberrations in rat bone marrow cells.

Piperine is a major pungent substance and active component of black pepper (Piper nigrum Linn.) and long pepper (Piper longum Linn.). Both plants are used worldwide as household spices and condiments. They are also used as important ingredients in folklore medicine in many Asian countries. Therefore, it is of interest to study antimutagenic effects of piperine. In this study, its influence on chromosomes was investigated in rat bone marrow cells. Male Wistar rats were orally administered piperine at the doses of 100, 400 and 800 mg/kg body weight for 24 hours then challenged with cyclophosphamide at a dose of 50 mg/kg body weight by intraperitoneal injection. Twenty-four hours thereafter, all animals were sacrificed and bone marrow samples were collected for chromosomal analysis. The results demonstrated that piperine at a dose of 100 mg/kg body weight gave a statistically significant reduction in cyclophosphamide-induced chromosomal aberrations. In conclusion, piperine may have antimutagenic potential. The underlying molecular mechanisms now require attention.

Potential use of Piper nigrum ethanol extract against pyrethroid-resistant Aedes aegypti larvae

Fractionation of Piper nigrum ethanol extract, biomonitored by assays on pyrethroid-resistant Aedes aegypti larvae yielded isolation of the larvicidal amides piperolein-A and piperine. Comparing LC50 values, the ethanol extract (0. 98 ppm) was the most toxic, followed by piperolein-A (1. 46ppm) and piperine (1. 53ppm).

O fracionamento do extrato etanólico de Piper nigrum biomonitorado por ensaios em larvas de Aedes aegypti resistentes a piretróides resultou no isolamento das amidas larvicidas piperoleína-A e piperina. Comparando-se os valores de CL50, o extrato etanólico (0. 98ppm) foi o mais tóxico, seguido pela piperoleína-A (1. 46ppm) e piperina (1. 53ppm).

Repellent activity of essential oils against cockroaches (Dictyoptera: Blattidae, Blattellidae, and Blaberidae) in Thailand.

Seven commercial essential oils extracted from the plant species Boesenbergia rotunda (L.) Mansf., Citrus hystrix DC., Curcuma longa L., Litsea cubeba (Lour.) Pers., Piper nigrum L., Psidium guajava L. and Zingiber officinale Roscoe, and naphthalene as a control, were evaluated for repellent activity against the three cockroach species Periplaneta americana (L.), Blattella germanica (L.) and Neostylopyga rhombifolia (Stoll) under laboratory conditions. The essential oil derived from Citrus hystrix showed the best repellency over other candidate essential oils and naphthalene. The essential oil of Citrus hystrix exhibited complete repellency (100%) against P. americana and B. germanica, and also showed the highest repellency (among the essential oils tested) of about 87.5% against N. rhombifolia under laboratory conditions. In the field, Citrus hystrix essential oil formulated as a 20% active ingredient in ethanol and some additives provided satisfactory repellency of up to 86% reduction in cockroaches, mostly P. americana and N. rhombifolia with a residual effect lasting a week after treatment. Citrus hystrix essential oil has good potential for being used as a cockroach repellent. Further improvements in efficacy and residual activity may be realized with appropriate formulations.