Larvicidal activity of neem oil (Azadirachta indica) formulation against mosquitoes
TL;DR: The neem oil formulation was found effective in controlling mosquito larvae in different breeding sites under natural field conditions and may prove to be an effective and eco-friendly larvicide, which could be used as an alternative for malaria control.
Abstract: Background
Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of botanical origin have been reported as useful for control of mosquitoes. Azadirachta indica (Meliaceae) and its derived products have shown a variety of insecticidal properties. The present paper discusses the larvicidal activity of neem-based biopesticide for the control of mosquitoes.
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TL;DR: It is concluded that this novel potentially non-toxic neem oil emollient cream can either be used per se or as a base matrix for loading active ingredients and hence function as an efficient delivery system for the same.
Abstract: Azadirachta indica A. Juss (Neem) is attested to be an important medicinal tree whose parts and extracts are known to cure several ailments since the Vedic era. But knowledge regarding their concoctions and dosages has remained largely esoteric. Dilute neem oil emulsions are used to deliver active ingredients to body parts by the topical route of administration. This possibly attenuates its dose dumping and concentration related noxious effects to a large extent. However, almost all such products incorporate synthetic organic and bio hazardous chemicals for purposes of formulation and stability, posing ultimate risks to the user. Hence in the present study, an emollient cream using 10% neem oil and an arachidyl glucoside emulsifier of completely biological origin has been formulated. Octa and hexadecanoic acid derivatives were the major fatty acid components identified in the oil. The creamy white product showed a mean particle size of 137 nm and a Z average of 19 nm, with a polydispersity index of 0.245. Zeta potential and electrophoretic mobility were measured as -47.2 and -0.000328 cm2/Vs, respectively thus conferring good stability. FTIR analysis revealed the incidence of extensive hydrogen bonding in its structure and SEM image captured its undulating surface topography. The emollient cream was not susceptible to cracking, creaming or phase separation even after a period of 180 days, when stored at 37° or under low speed centrifugation. Similar results were observed when it was stored at 40°, 4° and -18° for three days and brought to 37° for three cycles. It is concluded that this novel potentially non-toxic neem oil emollient cream can either be used per se or as a base matrix for loading active ingredients and hence function as an efficient delivery system for the same.
5 citations
Cites background from "Larvicidal activity of neem oil (Az..."
...Most parts of this plant, including its seed oil, have been traditionally valuable for their potent antimicrobial, antiinflammatory, antipyretic, analgesic, immunostimulatory, antiulcerous and antioxidant effects[1,2]....
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30 Apr 2010
TL;DR: In this paper, the authors present outcomes and insights from these processes, relating to our inventory of local neem trees, and discuss the results of our initial effort to identify and process neem locally: an understanding of the baseline neem tree resource in Moléntah, but also of the community processes that shaped its use during this project.
Abstract: .................................................................................................................................... 2 Introduction ............................................................................................................................ 4 Theoretical Perspective: Broad‐Based, Sustainable Community Development ..... 5 Geographic & Cultural Context: the Bissa of South‐Central Burkina Faso .............. 11 Neem: Tree of a Thousand Uses .................................................................................... 15 Methods .................................................................................................................................. 17 Key Concepts in Qualitative Research .......................................................................... 17 Tradition of Inquiry: Action Research in Case Study Context ................................... 19 Qualitative Data Collection ............................................................................................ 21 Quantitative Forestry Methods ..................................................................................... 24 Data Analysis .................................................................................................................... 26 Results & Discussion ............................................................................................................. 27 Note on Timing of Research .......................................................................................... 27 Introducing Neem to Community Groups ................................................................... 27 Resource Assessment: Neem Tree Inventory ............................................................. 29 Seed Collection ............................................................................................................... 44 Oil Extraction ................................................................................................................... 47 Market Identification ..................................................................................................... 50 Implications for Future Neem Activity in Moléntah .................................................. 52 Conclusion .............................................................................................................................. 55 Appendix A: Semi‐Structured Interview Sample Questions ............................................ 60 Appendix B: Regression Results for Neem Tree Heights .................................................. 62 Acknowledgements .............................................................................................................. 64 Literature Cited ..................................................................................................................... 65 Additional References ......................................................................................................... 74 Neem Tree Assessment for Socioeconomic Empowerment in Rural Burkina Faso Page 4 of 78 INTRODUCTION The people of Burkina Faso are known to be warm and welcoming, full of smiles and thanks. But their generosity often belies profound struggle – to eat, to obtain healthcare, to send children to school, to earn income, to make life more stable, a little bit easier. Vast potential is muted by the strain of day‐to‐day life. The neem tree of India is hardy and full of biological potential, full of health and agricultural applications. But it mostly sits idle in South‐Central Burkina Faso, aside from offering shade, wood, and the occasional toothbrush. This research aimed to unlock the potential of neem within the communities of Moléntah, Burkina Faso, by introducing the value of neem and how to process it in order to increase opportunities to enhance quality of life. The project is based on work completed during the summer of 2009 in rural Burkina Faso, West Africa, where I worked in conjunction with local community members in Moléntah to assess the neem resource base as well as the feasibility of utilizing the naturalized neem tree to generate income. The study was designed as participatory learning and action research, meant to bridge informational gaps around neem and facilitate the community’s desire, if any, to process neem for agricultural inputs or salable product. The work was introductory and educational in nature, with the goal of diversifying economic activity by helping interested parties better understand their natural resource base and the market potential available via its processing. The myriad uses of the neem tree are largely unknown in South‐Central Burkina Faso, and thus the tree is generally underutilized there; the disparity between actual and potential neem use in Moléntah motivated my work. I facilitated the conceptualization and utilization of neem as an economically useful natural resource in four neighboring communities, completing with them an assessment of neem as a potential driver of socioeconomic empowerment. The following pages first establish the context for community development in Moléntah and then discuss the results of our initial effort to identify and process neem locally: an understanding not only of the baseline neem tree resource in Moléntah, but also of the community processes that shaped its use during this project. After framing the research in theory, geography, and method, the paper presents outcomes and insights from these community processes, relating to our inventory of local neem trees, the constraints we encountered in working with neem, community capacity built around neem, and the potential local value of neem processing. Moléntah is a pseudonym. Neem Tree Assessment for Socioeconomic Empowerment in Rural Burkina Faso Page 5 of 78 Theoretical Perspective: Broad‐Based, Sustainable Community Development My theoretical perspective in approaching this work is broad‐based, integrated, sustainable community development. I will dissect that terminology to elucidate assumptions implicit in my approach. Broad‐Based, Integrated Development The term development carries implicit assumptions and judgments regarding desirable progress (Kumar 2003), and has often been used synonymously with economic growth, largely modeled on industrialization. Over the years, its interpretation has broadened to account not only for increasing gross domestic product and productive capacity, but for equity and rights within the political economy. Broad‐based development emerged, taking account not only of a growing and widely distributed economy, but also of effective governance and environmental preservation (Weaver et al 1997). Development came to focus increasingly on standard of living and quality of life in addition to economic productivity. Amartya Sen (1997) highlights these differences in distinguishing between the development of human capital – valuing people’s ability to contribute to economic growth – and development of the more broadly defined human capability – those opportunities which enable people to choose a meaningful life. For example, education may provide value to someone’s life, which is an end in and of itself, in addition to serving as a means for enhanced economic productivity. As such, Sen (1999) places humans, not economic growth, at the center of development, characterizing development as freedom – the opportunity to choose the life desired, with income and wealth as a means to that end. I support this broader context for development, focusing on helping people attain the goals they seek for a ‘better’ life, which often include aspects related to basic needs such as food, water and shelter; education; health care; income generation; and social and political participation. Indeed I ascribe to the idea that each such segment of life is interlinked, and that a development solution remains incomplete until all are addressed, or at a minimum, are balanced. Thus development hinges not only on economic progress, but is based on a broad set of factors that influence human capability and opportunity. Integrated development refers to development efforts that address multiple needs within the same project; most common are integrated conservation and development programs that are designed to address environmental conservation alongside human or economic development goals. Integrated development has been both criticized as no more effective than single‐sector development projects as well as lauded for being more relevant and sustainable than single‐ sector approaches (Alpert 1996). I prefer to bypass that debate in favor of focusing on serving community needs in a way fitting the local context – often somewhat integrated, being based in Neem Tree Assessment for Socioeconomic Empowerment in Rural Burkina Faso Page 6 of 78 life’s complexities, but usually with a particular need at the core. A simple example: a farmer struggles to make ends meet. Cutting down trees to gain income may leave the farmer with cash, but with limited fruit and shade, and without revegetation, also with a degraded soil and a bleaker future. A more integrated scenario might incorporate natural resource management into small business development, to sustainably generate income through rotational timber or non‐timber forest product harvests. A still more integrated scenario might both share financial management techniques to build wealth and incorporate preventive health strategies to reduce incidence of disease, plan pregnancy, and thus increase productivity of the entire family. Sometimes, crisis may necessitate intermediate, sectoral problem‐solving, but community needs may be best met when development efforts recognize and address the multiple factors at play. Community and Participation The second term to consider then is community. Development takes place at many levels – from ind
5 citations
TL;DR: This study provides first report on the mosquito larvicidal activity the combined effect of T. purpurea leaf extract and B. sphaericus against as target species of A. aegypti and established that there is a substantial amount of synergist act.
5 citations
TL;DR: This study combined the GC-MS spectral similarity network approach with larvicidal assays as a new strategy for the discovery of potential bioactive substances in complex biological samples, enabling the systematic and simultaneous annotation of substances in 20 essential oils through LC50 larv suicidal assays.
Abstract: Dengue is a neglected disease, present mainly in tropical countries, with more than 5.2 million cases reported in 2019. Vector control remains the most effective protective measure against dengue and other arboviruses. Synthetic insecticides based on organophosphates, pyrethroids, carbamates, neonicotinoids and oxadiazines are unattractive due to their high degree of toxicity to humans, animals and the environment. Conversely, natural-product-based larvicides/insecticides, such as essential oils, present high efficiency, low environmental toxicity and can be easily scaled up for industrial processes. However, essential oils are highly complex and require modern analytical and computational approaches to streamline the identification of bioactive substances. This study combined the GC-MS spectral similarity network approach with larvicidal assays as a new strategy for the discovery of potential bioactive substances in complex biological samples, enabling the systematic and simultaneous annotation of substances in 20 essential oils through LC50 larvicidal assays. This strategy allowed rapid intuitive discovery of distribution patterns between families and metabolic classes in clusters, and the prediction of larvicidal properties of acyclic monoterpene derivatives, including citral, neral, citronellal and citronellol, and their acetate forms (LC50 < 50 µg/mL).
4 citations
TL;DR: This study revealed promising activity of NA on A. coluzzii and G. palpalis gambiensis but additional research is needed to assess field efficacy of neem products to be possibly integrated in vector control programmes.
Abstract: Research efforts to identify possible alternative control tools for malaria and African trypanosomiasis are needed. One promising approach relies on the use of traditional plant remedies with insecticidal activities. In this study, we assessed the effect of blood treated with different doses of NeemAzal ® (NA, neem seed extract) on mosquitoes (Anopheles coluzzii) and tsetse flies (Glossina palpalis gambiensis) (i) avidity to feed on the treated blood, (ii) longevity, and (iii) behavioural responses to human and calf odours in dual-choice tests. We also gauged NeemAzal ® toxicity in mice. In An. coluzzii, the ingestion of NA in bloodmeals offered by membrane feeding resulted in (i) primary antifeedancy; (ii) decreased longevity; and (iii) reduced response to host odours. In G. palpalis gambiensis, NA caused (i) a knock-down effect; (ii) decreased or increased longevity depending on the dose; and (iii) reduced response to host stimuli. In both cases, NA did not affect the anthropophilic rate of activated insects. Overall, the most significant effects were observed with NA treated bloodmeals at a dose of 2000 μg/ml for mosquitoes and 50 μg/ml for tsetse flies. Although no mortality in mice was observed after 14 days of follow-up at oral doses of 3.8, 5.6, 8.4 and 12.7 g/kg, behavioural alterations were noticed at doses above 8 g/kg. This study revealed promising activity of NA on A. coluzzii and G. palpalis gambiensis but additional research is needed to assess field efficacy of neem products to be possibly integrated in vector control programmes.
4 citations
Cites background from "Larvicidal activity of neem oil (Az..."
...In fact, a substantial number of studies conducted with neem extracts, limonoid enriched preparations or purified azadirachtin report ovicidal, larvicidal, adulticidal, anti-feedant, and repellent properties against different mosquito vectors [17–23]....
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References
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TL;DR: In order to make experimental studies comparable and statistically meaningful, the article recommends the following formula: per cent control = 100(X - Y)/X, which eliminates errors due to deaths in the control sample which were not due to the insecticide.
Abstract: There are several statistical methods used in biology (entomology) for computing the effectiveness of an insecticide, based on relating the number of dead insects in the treated plat to the number of live ones in the untreated plat. In order to make experimental studies comparable and statistically meaningful, the article recommends the following formula: per cent control = 100(X - Y)/X, where X = % living in the untreated check sample and Y = % living in the treated sample. Calculation using this method eliminates errors due to deaths in the control sample which were not due to the insecticide. An example based on treatments of San Jose scale includes computation of probable errors for X and Y, and the significance of the difference between the two counts. Common biometric convention holds that when the difference between the results of two experiments is greater than three times its probable error, the results are significant and due to the treatment applied.
11,700 citations
"Larvicidal activity of neem oil (Az..." refers methods in this paper
...The percent corrected mortality was calculated using Abbott's formula [13] and Log probit analysis was used to determine the median lethal concentration (LC50)/90% lethal concentration (LC90) of the formulation....
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TL;DR: In the context of agricultural pest management, botanical insecticides are best suited for use in organic food production in industrialized countries but can play a much greater role in the production and postharvest protection of food in developing countries.
Abstract: Botanical insecticides have long been touted as attractive alternatives to synthetic chemical insecticides for pest management because botanicals reputedly pose little threat to the environment or to human health. The body of scientific literature documenting bioactivity of plant derivatives to arthropod pests continues to expand, yet only a handful of botanicals are currently used in agriculture in the industrialized world, and there are few prospects for commercial development of new botanical products. Pyrethrum and neem are well established commercially, pesticides based on plant essential oils have recently entered the marketplace, and the use of rotenone appears to be waning. A number of plant substances have been considered for use as insect antifeedants or repellents, but apart from some natural mosquito repellents, little commercial success has ensued for plant substances that modify arthropod behavior. Several factors appear to limit the success of botanicals, most notably regulatory barriers and the availability of competing products (newer synthetics, fermentation products, microbials) that are cost-effective and relatively safe compared with their predecessors. In the context of agricultural pest management, botanical insecticides are best suited for use in organic food production in industrialized countries but can play a much greater role in the production and postharvest protection of food in developing countries.
2,996 citations
"Larvicidal activity of neem oil (Az..." refers background in this paper
...Many of these derived products have antifeedancy, ovicidal activity, fecundity suppression besides insect growth regulation and repellency against insects [ 5-10 ]....
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TL;DR: Les substances derivees du «neem», efficaces contre les insectes sont examines (influence sur le comportement de fixation, the ponte, the prise de nourriture, the metamorphose, the fecondite, the fitners) ainsi que les capacites potentielles des insecticides extraits du neem pour le controle des insectes nuisibles and leurs effets sur les animaux.
Abstract: Les substances derivees du «neem», efficaces contre les insectes sont examines (influence sur le comportement de fixation, la ponte, la prise de nourriture, la metamorphose, la fecondite, la fitners) ainsi que les capacites potentielles des insecticides extraits du neem pour le controle des insectes nuisibles et leurs effets sur les animaux a sang chaud et sur l'homme
1,595 citations
Journal Article•
TL;DR: Examples of phytochemicals evaluated against mosquitoes as general toxicants, growth and reproduction inhibitors, repellents and ovipositional deterrents are given.
Abstract: A review on the reported uses of chemicals derived from botanical sources is presented, along with the part of the plant used for extraction, the mosquito species studied and the bioactivity observed for 344 plant species. Examples of phytochemicals evaluated against mosquitoes as general toxicants, growth and reproduction inhibitors, repellents and ovipositional deterrents are given. The effects of mosquito species and life stage specificity, solvents used for extraction, phototoxic activity and the geographical source from where the plant compounds are derived are discussed.
735 citations
Book•
01 Jan 1995
TL;DR: The tree and its characteristics biologically active ingredients effects on viruses and organisms neem products for pest management and practical results of neem applications against arthropod pests, and probability of development of resistance toxicity of neems to vertebrates and side effects on beneficial and other non-target organisms as discussed by the authors.
Abstract: The tree and its characteristics biologically active ingredients effects on viruses and organisms neem products for pest management and practical results of neem applications against arthropod pests, and probability of development of resistance toxicity of neem to vertebrates and side effects on beneficial and other non-target organisms various uses of neem products economic, socioeconomic and policy considerations, and neem in sociocultural life in South Asia other meliaceous plants containing ingredients for pest management and other purposes register of scientific and common names. (Part contents).
414 citations