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Simple herbs are a remedy for various problems and holds good even for mosquito menace. Mosquitoes are well known vectors of several disease-causing pathogens. They are a cause of concern for various diseases like malaria, filariasis, dengue haemorrhagic fever and chikungunya.DEET (N, N-diethyl-3-methylbenzamide) is so far the golden standard for mosquito repellant effect. Many synthetic mosquito repellants are available but question of safety is an issue. Thus the need for a safer alternative with herbs has aroused. In Ayurveda treatise the combination of Chandana (Santalum album) and Sarshapa (Brassica campestris) as dhupana (fumigation) has been said as krimighna (insecticidal). The extracts of these two drugs have proved to have mosquito repellant action against Aedes aegypti. The study was conducted by Cone bioassay and Cage Bioassay methods. The repellency activity of these plant extracts were tested at five different concentration (1.0, 2.0, 3.0, 4.0 and 5.0 mg/cm2) and at the density of 100 mosquitoes against 3-4 days old, blood starved female Ae.aegypti. The skin repellency activity of Santalum album and Brassica campestris plant extract gave maximum protection at 5.0 mg/cm2 concentration (6.30 hours).

This work reports the synthesis of silver nanoparticles (AgNPs) using aqueous extract of Plumbago auriculata, and evaluates their antibacterial and larvicidal activities. The synthesized silver nanoparticles were characterized by various spectroscopy techniques, such as FTIR, XRD, TEM, EDX, Zeta potential, and DLS. The synthesized AgNPs exhibited significant antibacterial activity against Gram-positive and Gram-negative bacteria, such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae. Furthermore, synthesized nanoparticles inhibited the fourth instars larvae of Aedes aegypti and Culex quinquefasciatus at the concentration of 45.1 and 41.1 µg/mL respectively. Results of dose-dependent studies showed that synthesized nanoparticles were also effective at low concentrations. Molecular docking studies performed with the salivary protein and odorant-binding protein of Aedes aegypti and Culex quinquefasciatus demonstrated that the naphthoquinone compound plumbagin exhibited reliable binding affinity towards the two enzymes. The findings thus reveal that the plant extract and its nanoparticles can be a better alternative to available chemicals to control mosquitos.

Background In tropical and subtropical regions, mosquitoes represent a significant public health concern, serving as primary carriers of numerous diseases. Due to Bangladesh’s in the subtropical monsoon climate, this country has heavy rainfall. In addition, the hot, humid climate makes Bangladesh a perfect procreation place for mosquito-borne diseases. Mosquito-transmitted diseases continue to contribute significantly to global mortality, with over 700 million people experiencing such diseases annually. Fortunately, Bangladesh has a great resource of essential oils containing aromatic plants, these are belonging to various families such as Meliaceae, Asteraceae, Lauraceae, Rutaceae, Apiaceae, Poaceae, Zingiberaceae, Leguminosae Myrtaceae, Lamiaceae, Myristicaceae, Ranunculaceae, Piperaceae, Cupressaceae. The major goal of this review is to examine the essential oils of aromatic plants grown in Bangladesh that have been shown to have repellent, larvicidal, and adulticidal activity against various species of mosquitoes. Methods Several keywords were searched to collect data about medicinal plants with mosquito-repellent and larvicidal properties and their phytochemical constituents from August 2019 to June 2024. Results This review revealed that identifying compounds in essential oils responsible for repellent, larvicidal, and adulticidal activity mostly relied on gas chromatography (GC) combined with mass spectrometry (MS). The most common groups of compounds are monoterpenes, diterpenes, isoprenoids, and sesquiterpenoids. According to WHO guidelines, the human bait technique and Technique and technique have been extensively used for testing repellency, while the rabbit bait technique and excite repellency chamber test are less commonly used. In addition, Laboratory larvicidal test is most widely used for Larvicidal bioassay. Recorded potency was counted mainly as LC 50 (Lethal Concentration), LD 50 (Lethal Dose), Kd (Knockdown Time), KC 50 (Knockdown Concentration), LT 50 (Lethal Time), KT 50 (Knockdown Time), percentage of protection, repellency time, percentage of mortality, etc. Conclusions It can be concluded that the chemical compounds contained in essential oils from aromatic plants in Bangladesh have the potential to be environmentally friendly repellents, larvicidal, and adulticidal activity in controlling and preventing various disease vectors such as Anopheles , Aedes , and Culex . The efficacy of their essential oils is possibly based on their chemical compositions in which major and/or minor compounds have the aforementioned activities.

Mosquito bites are endured by most populations worldwide. Reactions to mosquito bites range from localized wheals and papules with associated pruritus to rare systemic reactions and anaphylaxis in certain populations. The mechanism of itch is due to introduction of mosquito saliva components into the cutaneous tissue, although the exact pathophysiology is unclear. Histamine is thought to be a key player through mosquito saliva itself or through activation of mast cells by IgE or through an IgE-independent pathway. However, other salivary proteins such as tryptase and leukotrienes may induce non-histaminergic itch. Some individuals have a genetic predisposition for mosquito bites, and people with hematologic cancers, HIV, and other conditions are susceptible to robust reactions. Prevention of mosquito bites is key with physical barriers or chemical repellents. Treatment consists of second-generation antihistamines and topical corticosteroids. Further research on topical treatments that target neural-mediated itch is needed.

Aedes aegypti , Culex quinquefasciatus , and Anopheles stephensi are the domestic vectors of tropical diseases include dengue, malaria, zika, filariasis. To control these vectors, ethnobotanical knowledge provides pragmatic solutions that are compatible with nature. Hence an attempt has been made to coalesce the ethnobotanical knowledge of tribes from Kadambur hills with the nano emulsification technology to formulate an herbal-based larvicidal and repellent nanocrystal emulsion. The ethanol extract from Ficus glomerata was used as the larvicidal and repellant agent against A. aegypti , C. quinquefasciatus and A. stephensi. For the improved stability, shelf life and sustained release of bioactive compounds, a novel methodology has been followed to synthesize nanocrystal emulsion. F. glomerata extract based nanocrystal emulsion (FON) was prepared by ultrasonication and characterized by Zeta potential (− 73.6 mV) and dynamic light scattering (104 nm), ATR-FTIR for the functional groups, high-resolution transmission electron microscope and selective area energy diffraction. The maximum shelf life was evaluated to be more than 3 years. The prepared nanocrystal emulsion was challenged for larvicidal and repellent activities against all the three species. The FON larvicidal results were comparable to the conventional neem oil based nanoemulsion and the repellant activity results were effective than the commercial formulation.

Mosquitoes utilize their sense of smell to locate prey and feed on their blood. Repellents interfere with the biochemical cascades that detect odors. Consequently, repellants are highly effective and resource‐efficient alternatives for controlling the spread of mosquito‐borne illnesses. Unfortunately, the discovery of repellents is slow, laborious, and error‐prone. To this end, we have taken a giant stride toward improving the speed and accuracy of repellant discovery by constructing a prototypical whole‐cell biosensor for accurate detection of mosquito behavior‐modifying compounds such as repellants. As a proof‐of‐concept, we genetically engineered Pichia pastoris to express the olfactory receptor co‐receptor (Orco) of Anopheles gambiae mosquitoes. This transmembrane protein behaves like a cationic channel upon activation by stimulatory odorants. When the engineered Pichia cells are cultured in calcium‐containing Hank's buffer, induction of the medium with a stimulatory odorant results in an influx of calcium ions into the cells, and the stimulatory effect is quantifiable using the calcium‐sequestering fluorescent dye, fluo‐4‐acetoxymethyl ester. Moreover, the stimulatory effect can be titrated by adjusting either the concentration of calcium ions in the medium or the level of induction of the stimulatory odorant. Subsequent exposure of the activated Pichia cells to a repellant molecule inhibits the stimulatory effect and quenches the fluorescent signal, also in a titratable manner. Significantly, the modular architecture of the biosensor allows easy and efficient expansion of its detection range by co‐expressing Orco with other olfactory receptors. The high‐throughput assay is also compatible with robotic screening infrastructure, and our development represents a paradigm change for the discovery of mosquito repellants. We have constructed a prototypical whole‐cell biosensor in Pichia pastoris that can be used to study the molecular interactions of the mosquito olfactory receptor co‐receptor (Orco). The sensor can also be expanded through co‐expression of olfactory receptors to study olfactory cascades and identify molecules that can modulate these receptors.