One of the most upsetting bloodsucking insects that humans have to deal with is the mosquito. Everywhere that the environment is not maintained, clean, and orderly, mosquitoes proliferate. In the current situation, mosquito control or prevention is crucial. Mosquito repellents can be a useful tool for protecting individuals from mosquito bites that pose a danger of spreading diseases including chikungunya virus, dengue virus, and plasmodia. In addition to being widely utilized, mosquito repellent coils are quite effective. Numerous viruses and parasites that cause disease are spread by mosquitoes.  halting the spread of numerous infectious diseases via mosquitoes. Nowadays, more people are using plant-based mosquito repellents because synthetic repellents include a lot of harmful chemicals that can be toxic and cause swelling, redness, itching, and other symptoms. Orange peel powder, turmeric, limonene oil, lemongrass oil, and charcoal were used to make the herbal insect repellent coils. There are insecticidal properties in lemongrass. Lemon grass oil, which comes from Cymbopogon flexuosus, and limonene oil, which is found in orange peel, both have deadly or fatal effects on mosquitoes and other insects. Lemon grass exhibits the highest level of activity and efficacy in lowering mosquito populations. Within smoking restrictions, it can be used as an active element to make mosquito coils that, when ignited, will repel insects or mosquitoes.  Given the long history of usage of plant-based insect repellents due to their low toxicity, natural products serve as a good substitute. Essential oils have become more popular as insect repellents because of their many useful bioactive components. The objective of the present study is to develop effective plant-based mosquito repellent products.^[1,2,3] In poor nations, mosquitoes are the cause of numerous ailments in specific areas. All around the world, mosquito bites are a widespread problem, and in some places, insects can spread dangerous diseases. One of the most upsetting bloodsucking insects that humans have to deal with is the mosquito. Numerous mosquito species are responsible for a number of illnesses, including Japanese encephalitis, dengue fever, malaria, and yellow fever. Over 700 million people are infected by mosquitoes alone, and over a million deaths are reported worldwide each year. Humans contract the Japanese encephalitis virus from infected Culex mosquitoes.  In endemic areas, malaria, which is brought on by Plasmodium parasites and spread by female Anopheles mosquito bites, continues to pose a serious threat to newborns and young children. The Aedes aegypti mosquito is the cause of dengue disease, which infects about 100 million people annually globally. Around the world, mosquito control is a major public health concern.  One strategy for controlling these diseases spread by mosquitoes is to stop the spread of the disease by either eliminating the mosquitoes or stopping them from biting people. By taking a virus or parasite with them when they bite an infected person or animal, these mosquitoes typically spread diseases from one people to another or from one animal to another.

Applying a material to skin, clothing, or other surfaces that prevents mosquitoes from leading or climbing on them is known as a mosquito repellent. Repellants for mosquitoes are used to shield the body from bites that may have systemic or localized consequences. mosquito-repelling coil with lemongrass oil as the primary ingredient. Polyherbal formulations were methodical attempts to demonstrate the effectiveness of herbal extracts using experimental methods. Many people are aware of the plant's ethnobotanical and therapeutic benefits. Its oil and extracts have been claimed to have antibacterial, insecticidal, and medicinal qualities^{. [4,5,6]}

       
           
       
Fig.1 Ingredient

Classification of Mosquito Repellents:

The mosquito repellents currently available can be widely divided into the following categories:

1. Physical methods of Mosquito Repellents
2. Chemical methods of Mosquito Repellents

a) Natural mosquito repellents

b) Synthetic mosquito repellents

3. Mechanical methods of Mosquito Repellents

1. Physical Method

It means to keep mosquitoes from biting. This technique serves as a barrier to prevent mosquito bites.Using this technique, the stagnant water is emptied into buckets, old tires, rain gutters, plastic coverings, etc. Additionally, it is advised that you dress in long sleeves, particularly at dawn and dusk. To further keep mosquitoes out of the house, windows and door screens need to be repaired. Changing the water in bird baths, fountains, pools, rain barrels, etc. is quite desirable. Regularly, at least once a week, to prevent mosquitoes from locating the ideal spot to lay their eggs.

2. Chemical Method

This approach uses repellents with a chemical foundation. The best way to protect yourself from insects is to use chemical repellents, which also help prevent and manage diseases that are spread by insects. This can be further divided into two groups according to the source:

a) Natural repellents:

Repellants are made from natural materials in this manner. Since ancient times, these herbal insect repellents have been created and marketed, which has resulted in the development of personal defense techniques. Herbal insect repellents have less negative effects and are safe. Natural resources that have the ability to repel have been crucial in reducing the spread of vector-borne diseases in both humans and animals. Essential oils are among the natural repellents: Citronella, eucalyptus, lavender, lemongrass, peppermint, and other essential oils can be used topically or diffused. Garlic and Neem: It has been observed that the scent of garlic and neem oil deters mosquitoes. Herbs and Plants: Place mosquito-repelling plants throughout your house, such as catnip, marigold, and basil. Burning camphor in a space produces smoke that is

b) Synthetic repellents:

Due to the limitations and disadvantages of natural herbal repellents, certain synthetic repellents were employed. In contrast, the effectiveness of these natural repellents seems to last less time and diminish more quickly. Due to the drawbacks of using natural plant resources as mosquito repellents, including their short repellent time and expensive cost, extensive research was conducted to create a synthetic alternative. Although chemicals produced from plants have long been used to repel mosquitoes, the same drawbacks have been noted.Plant-based mosquito repellents are different from synthetic ones.

3. Mechanical Method

This technique uses a few mechanical devices to keep mosquitoes away.A mechanical mosquito repellent system can be made using the well-known fact that yellow light attracts fewer insects than white light. In order to kill mosquitoes when they come into touch with their deadly electric charge dose, an electric mosquito zapper uses ultraviolet light to trap them. Other strategies that are classified as mechanical mosquito repellents include mosquito magnets and the Electric Mosquito Zapper. ^[6,7,8,9,10]

1. Behavioral Methods

Appropriate Clothes: When in mosquito-prone locations, wear light-colored, long-sleeved clothing and trousers.

Time management: Refrain from going outside between dawn and nightfall, when mosquito activity is at its highest.

Chemistry of mosquito repellents

There are several categories into which mosquito repellents fall. They are classified as either chemical or herbal repellents, depending on where they come from. They can also be divided into groups based on their behavior.

1.On the basis of source

a) Natural / Herbal repellents

? Citronella oil

? Castor oil

? Clove oil

? Rosemary oil

? Lemongrass oil

? Neem

? Eucalyptus oil

? Limonene

? Peppermint oil

b) Chemical repellents

? DEET ( Di-ethyl Meta Toluamide)

? Allethrin & Permethrin

? Picaridin

? Bog Myrtle

2. On the basis of haw they act

a) Repellent Insecticides

b) Contact Insecticides

Mode of action of mosquito repellent

Five potential ways that insect and mosquito repellents work were examined:

1. Preventing host attractant sensory neurons from responding.

2. Turning on the receptor system that controls an improper or competitive behavior.

3. Behaving as a repellent at high concentrations yet as an attractant at low concentrations.

4. Increasing the noise signal ratio by activating receptors connected to many behavioral programs in order to "jam" the appropriate sensory circuit

5. Turning on the distinct aversive/avoidance receptors. [11,12,13,14]

Plants Description:

Pharmacognosy:

1. Lemongrass:

       
           
       
Fig.3

Synonyms: East India Lemongrass, Malabar or cochin lemongrass.

Biological Source: Lemongrass oil is obtained from Cymbopogon Flexuosus Stapf.

Belonging to family Poaceae

Chemical constituents:

Lemongrass oil is the principal source of Citral(68-85%)

from which ionone is derived. The oil also contains methyl heptanone, decyl aldehyde, and geraniol.

Uses:

The Lemongrass oil is used in perfume, soaps, cosmetics, and mosquito repellent.

2). Orange peel:

       
           
       
Fig.4

Synonyms:

Orange cortex, Bigarade orange, Seville orange, China orange, Bitter orange peel

Biological Source:

Orange peel is consisting of fresh and dried outer part of the pericarp of citrus aurantium linn

Belonging to the family Rutaceae

Chemical constituent:

Limonene (90%)

Citral(4%)

Vitamin C

Pectin

Hesperidin

Aurantimarin and Aurantimaric acid (both are glycosides and responsible for bitterness)

Uses:

Stomachic

Aromatic

Carminative

Flavoring agent in oral liquid preparation

Use for Bitter tonic^[2]    

3). Turmeric:

       
           
       
Synonyms: Saffron Indian, haldi (Hindi), Curcuma Rhizoma.

Biological Source: Turmeric is the dried rhizome of Curcuma longa Linn. belonging to the family Zingiberaceae.

Chemical constituents: Curcuminoids, curcumin, desmethoxy curcumin, bides methoxy curcumin volatile oil (5%) sugars, bitter substances, fixed oils, and acids.

Uses:

1)Turmeric use as aromatic

2)anti-inflammatory

3)stomachic

4)blood purifier

5)alternative

6)spice, coloring agent ^[3]

4). Camphor:

       
           
       
Fig.6

Synonyms: Gum camphor, Japan camphor

Biological Source:

Camphor is a solid ketone, obtained from the volatile oil of Cinnamomum camphora

Belonging to the family Lauraceae.

Chemical Constituents:

Camphor oil contains camphor

cineole, pinene

camphene

phellandrene

limonene, diterpenes, and Camphor is entirely a monoterpenic ketone.

Uses: Camphor is a white, crystalline substance with a strong odor and a pungent taste. It is derived from the camphor tree and has been used for centuries in various cultures for its medicinal and aromatic properties

Pain Relief

It is used externally as a rubefacient, counterirritant

Internally used as a stimulant, carminative and antiseptic.^[3,4]

Gum Acacia:                                                                                                             

       
           
       
Fig.7

Synonyms: Gum Arabic, Acacia

Biological source:

The dried sticky substance known as "Indian gum" is extracted from the stem and branches of the Acacia arabica plant.

A member of the Leguminosae family

Chemical Constituents:

The main component of acacia is Arabin, a complex mixture of potassium, magnesium, and calcium salts of Arabic acid.

Uses:

Gum acacia, also known as gum Arabic, is a natural gum derived from the sap of Acacia trees. It has a wide range of applications across various industries As a thickening, emulsifier, or food stabilizer, gum acacia enhances the texture of food products without compromising other aspects like flavor. It is employed as a demulcent in pharmaceuticals. [16,17,18,19]

Need of Herbal Mosquito Repellents:

Numerous artificial mosquito repellents contain ingredients that are harmful to people's health. Herbal mosquito repellents must be used because those chemicals have a number of negative impacts on people. Because they are created from a variety of herbal ingredients and essential oils, herbal mosquito repellents are safe for human health. Only a small number of cases of dermatitis, allergic reactions, and neurologic and cardiovascular toxicities, including seizures, have been reported and discovered in relation to the extensive use of DEET-containing products, researchers like Tenenbein, and records from poison control center telephone data ^(13,14,15). There have been reports of further detrimental health effects, such as encephalopathy, tremors, slurred speech, aberrant behavior, coma, and even death ^[20,] Herbal mosquito repellents have gained significant popularity due to several advantages over their chemical counterparts:

Health Benefits

• Decreased Chemical Exposure: Chemical repellents may contain ingredients that irritate skin or create breathing issues. In general, natural substances used to make herbal repellents are safer for human health.
• Minimal Side Effects: Herbal repellents are less likely to irritate skin or trigger allergic reactions than chemical repellents.

Environmental Benefits

• Eco-Friendly: Herbal repellents have little effect on the environment and are biodegradable. They do not damage pollinating plants or beneficial insects.
• Sustainable: Herbal repellents frequently contain substances that come from renewable and sustainable sources.

3. Aim And Objective:

Aim:

Formulation and Evaluation of Herbal Mosquito Repellent Coil.

Objective: Creating a safe, efficient, and eco-friendly substitute for chemical-based repellents is the main goal of developing and testing herbal mosquito repellent coils. This entails a number of particular goals:

1. To research the several herbs that have the ability to repel mosquitoes.

2. To research the different pharmacological effects of plants.

3. To investigate the ability of different herbal essential oils to repel mosquitoes.

4. To evaluate the candle's ability to repel insects.

5. To research the formulation's effectiveness and safety.

6. Formulation evaluation.

Materials:

The selection of plants was based on an analysis of several publications, their availability as essential oil-based insect repellents, experimental findings, and their uses..

Herbs used in mosquito repellent formulations:

1)Lemongrass:

Natural compounds with insecticidal and repellent qualities can be found in lemongrass. One of the primary active components in lemongrass that deters mosquitoes is citronela.This volatile oil is frequently found in lotions, sprays, and coils that repel mosquitoes. Other mosquito-repelling volatile oils found in lemongrass include citral, limonene, and geranol.The tall, perennial grass known as lemongrass (Cymbopogon citratus) is indigenous to tropical parts of Australia, Africa, and Asia.

2)Limonene oil:

The rind of citrus fruits, including oranges, lemons, and limes, contains a substance called limonene. About 97% of the essential oils found in orange peels are contained in these peels.Its primary chemical form, d-limonene, is frequently used.Limonene is a member of the terpene family of chemicals, which are recognized for their potent scents that keep predators away from plants. One of the most prevalent terpenes in nature, it may provide a number of health advantages. Vitamin C and citric acid, which are beneficial to our skin, are found in lemon and orange peels, respectively. There are claims that both scents repel gnats and mosquitoes.

4)Activated Charcoal:

It has long been utilized as an antidote and the ideal treatment for insect bites.It has the power to remove the poisons from bites and stings.

5) Camphor:

The main way that camphor works as a mosquito repellent is by interfering with the mosquito's olfactory senses. Here's a breakdown of the mechanism:

1. Strong Odor: Camphor has a strong, pungent odor that masks the human scent that mosquitoes are attracted to, which can interfere with the mosquito's ability to detect and locate its host.
2.  Sensory Disruption: The molecules of camphor can bind to the mosquito's olfactory receptors, which are in charge of detecting odors. This binding can interfere with the normal functioning of the receptors, making it harder for the mosquito to detect and locate its host.
3. Neurotoxic Effects: In rare instances, camphor can also have neurotoxic effects on mosquitoes, which can further impair the mosquito's ability to locate and bite humans.

One typical product that may be used to eradicate mosquitoes in a home is camphor. This chemical, derived from a tree extract, provides the longest-lasting mosquito-repelling effect when compared to other natural treatments. Burning camphor can be a very effective mosquito repellent in a restricted space. ^{[16,17,18,19]}

5. Experimental Work:

A blend of several herbs and essential oils was used to make this coil. The hydrocarbon bases of a blend of stearic acid and beeswax were used to make the candle. The formulation table mentions these ingredients. The following is how to make a mosquito repellant candle:

1) Weigh all powdered components (charcoal, turmeric, camphor, and orange peel powder) precisely.

2)Add in beaker one by one and mix well then adding the Lemongrass oil, Limonene oil and water stir it, then add suitable quantity of Gum acacia.

3) Heat for five minutes.

4) Thoroughly mix the ingredients, form the mixture into dough, roll it out, and form it into a coil. ^[22,23]

       
           
       
Fig no.1 Lemongrass oil and Limonene oil

       
           
       
Fig no.2 Charcoal

       
           
       
Fig no.3 Camphor

       
           
       
Fig no.4 Turmeric

       
           
       
Fig no.5 Orange peel powder

       
           
       
Fig no.6 Potato Starch

6. Evaluation of Mosquito repellent coil: