Mosquitoes are a serious threat to public health transmitting several dangerous diseases for over 2 billion people in the tropics[1]. Aedes aegypti (Ae. aegypti), the primary carrier for viruses that cause dengue fever, dengue hemorrhagic fever and yellow fever is widespread over large areas of the tropics and subtropics. Mosquito control and personal protection from mosquito bites are currently the most important measures to control these diseases. Many approaches have been developed and tried to tackle mosquito menace. The use of larvicides and repellents is an obvious practicality and economical means of preventing the transmission of these diseases to humans.
The common approach for the control of mosquito vectors and reducing the transmission of human pathogens is based on the chemical insecticide-based intervention measures[2]. However, in the past, the frequent and repeated use of chemical insecticides has resulted in the worldwide development of insecticide resistance, destabilisation of the ecosystem and toxic effects on human beings and nontarget organisms[3]. Thus, there is an urgent need to develop new insecticides for controlling mosquitoes which are more environmentally safe, biodegradable and target-specific against the mosquitoes. In recent years, much effort has, therefore, been focused on plant extracts or phytochemicals as potential sources of mosquito control agents or as lead compounds[4,5]. Many researchers have reported the effectiveness of plant extracts or essential oils as efficient mosquito larvicides and repellents without posing hazards of toxicity to humans[6-10]. Several extracts and compounds from different plant families have been evaluated to show new and promising larvicides[11-13]. Further, repellency is known to play an important role in preventing the vector borne diseases by reducing man-vector contact. Ethno-botanical studies
Objective: To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti). Methods: The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated. Results: The essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm. Conclusions: The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.
Sarita Kumar et al./Asian Pac J Trop Biomed 2011; 1(2): 85-8886 show that in some village communities, the use of plant repellents to reduce human vector contact is a common practice[14]. Essential oils are natural volatile substances found in a variety of plants. Commercially, essential oils are used in four primary ways: as pharmaceuticals, as flavor enhancers in many food products, as odorants in fragrances, and as insecticides. The plant oils have received much attention as potentially useful bioactive compounds against insects showing a broad spectrum of activity, low mammalian toxicity and degrading rapidly in the environment. Peppermint oil extracted by steam distillation from the leaves of Mentha piperita (M. piperita) has a long tradition of medicinal use. It has high menthol content, and is often used in certain food items. It has also been reported that peppermint oil reduces colic abdominal pain and causes a major reduction in irritable bowel syndrome symptoms[15]. The oil is also reported to contain menthone and menthyl esters. Menthone, present in high concentration in peppermint oil, is reported to act as a natural pesticide[16]. Still, the insecticidal properties of peppermint oil have not been explored. Keeping in view the recently increased interest in developing plant origin insecticides as an a
Mosquitoes are a serious threat to public health transmitting several dangerous diseases for over 2 billion people in the tropics[1]. Aedes aegypti (Ae. aegypti), the primary carrier for viruses that cause dengue fever, dengue hemorrhagic fever and yellow fever is widespread over large areas of the tropics and subtropics. Mosquito control and personal protection from mosquito bites are currently the most important measures to control these diseases. Many approaches have been developed and tried to tackle mosquito menace. The use of larvicides and repellents is an obvious practicality and economical means of preventing the transmission of these diseases to humans. The common approach for the control of mosquito vectors and reducing the transmission of human pathogens is based on the chemical insecticide-based intervention measures[2]. However, in the past, the frequent and repeated use of chemical insecticides has resulted in the worldwide development of insecticide resistance, destabilisation of the ecosystem and toxic effects on human beings and nontarget organisms[3]. Thus, there is an urgent need to develop new insecticides for controlling mosquitoes which are more environmentally safe, biodegradable and target-specific against the mosquitoes. In recent years, much effort has, therefore, been focused on plant extracts or phytochemicals as potential sources of mosquito control agents or as lead compounds[4,5]. Many researchers have reported the effectiveness of plant extracts or essential oils as efficient mosquito larvicides and repellents without posing hazards of toxicity to humans[6-10]. Several extracts and compounds from different plant families have been evaluated to show new and promising larvicides[11-13]. Further, repellency is known to play an important role in preventing the vector borne diseases by reducing man-vector contact. Ethno-botanical studies Objective: To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti). Methods: The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated. Results: The essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm. Conclusions: The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.Sarita Kumar et al./Asian Pac J Trop Biomed 2011; 1(2): 85-8886 show that in some village communities, the use of plant repellents to reduce human vector contact is a common practice[14]. Essential oils are natural volatile substances found in a variety of plants. Commercially, essential oils are used in four primary ways: as pharmaceuticals, as flavor enhancers in many food products, as odorants in fragrances, and as insecticides. The plant oils have received much attention as potentially useful bioactive compounds against insects showing a broad spectrum of activity, low mammalian toxicity and degrading rapidly in the environment. Peppermint oil extracted by steam distillation from the leaves of Mentha piperita (M. piperita) has a long tradition of medicinal use. It has high menthol content, and is often used in certain food items. It has also been reported that peppermint oil reduces colic abdominal pain and causes a major reduction in irritable bowel syndrome symptoms[15]. The oil is also reported to contain menthone and menthyl esters. Menthone, present in high concentration in peppermint oil, is reported to act as a natural pesticide[16]. Still, the insecticidal properties of peppermint oil have not been explored. Keeping in view the recently increased interest in developing plant origin insecticides as an a
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