A COMPARATIVE STUDY OF HIBISCUS (Rosa sinensis), LEMONGRASS (Cymbopogon citrates) and DAISY (Chrysanthemum cinerariifolium) AS NATURAL REPELLANTS AGAINST MOSQUITOES

A COMPARATIVE STUDY OF HIBISCUS (Rosa sinensis), LEMONGRASS (Cymbopogon citrates) and DAISY (Chrysanthemum cinerariifolium) AS NATURAL REPELLANTS AGAINST MOSQUITOES

Introduction

Background of the study

            I live in Davao City, where because of the abundance of water and the warm climate, mosquitoes are active year-round. All over the world, people are at risk from mosquito-borne diseases such as malaria, dengue, yellow fever, encephalitis and filariasis.  Mosquitoes are estimated to transmit disease to more than 700 million people annually in Africa, South America, Central America, Mexico, and much of Asia with millions of resulting deaths. At least 2 million people annually die of these diseases.  Today, not just our whole country, Philippines, but also the entire world is facing huge problems in relation to the abundance of mosquitoes in the community. In fact, many alternatives and methods such as different kinds of drugs, vaccines, insecticides, nets and repellants are now discovered and created in order to eradicate mosquitoes, prevent diseases, and protect individuals. Personal protection from mosquito bites is currently the most important way to prevent transmission of these diseases.

            Throughout the world, there are about 3,500 species of mosquitoes. . Although a few species are harmless or even useful to humanity, most are considered a nuisance because they consume blood from living vertebrates, including humans. The female mosquito bites people and animals because they need the protein found in blood to help develop their eggs. Mosquitoes rely on various cues to find potential hosts on which to feed. Heat, movement, exhaled carbon dioxide, and body scent allow hungry mosquitoes to home in on their prey from long and short distances. Some mosquito species feed on humans; many feed on wild and domestic birds and mammals. A few even feed on reptiles and amphibians. The use of repellents makes a person unattractive for feeding and therefore repels the mosquito.

            The most common mosquito-repellent formulations available on the market contain a synthetic chemical called N, N-diethyl-3-methylbenzamide (DEET). N, N-Diethyl-meta-toluamide, abbreviated DEET, is a slightly yellow oil. It is the most common active ingredient in insect repellents. It is intended to be applied to the skin or to clothing, and provides protection against mosquito bites, tick bites, flea bites, chiggers, and many other biting insects. DEET was developed by the United States Army, following its experience of jungle warfare during World War II. It was originally tested as a pesticide on farm fields, and entered military use in 1946. It was used in Vietnam and Southeast Asia. DEET was recognized as one of the few products effective against mosquitoes and biting flies. It was registered for use by the general public in the U.S. in 1957 (EPA 1980). The efficacy of DEET in providing long-lasting protection against a wide variety of mosquito species has been documented in several studies that have shown excellent repellency against mosquitoes. (Schreck and McGovern 1989, Fradin and Day, 2002, Roberts and Reigart 2004).

            As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications. DEET can act as an irritant; in rare cases, it may cause severe epidermal reactions.

            In the DEET Reregistration Eligibility Decision (RED), the United States Environmental Protection Agency (EPA) reported 14 to 46 cases of potential DEET-associated seizures, including 4 deaths. The EPA states: "... it does appear that some cases are likely related to DEET toxicity," but observed that with 30% of the US population using DEET, the likely seizure rate is only about one per 100 million users.

            Although DEET is an effective repellent against mosquitoes, there are concerns associated with its use. It is irritating to mucous membranes, and concentrated formulations dissolve plastic. DEET is an effective solvent, and may dissolve some plastics, rayon, spandex, other synthetic fabrics, and painted or varnished surfaces including nail polish. DEET also will cause a great amount of damage to musical instruments that have one of the traditional finishes that are used on wooden instruments. It will cause the finish to become sticky to the touch and cloudy in appearance.   Some human toxicity effects have been reported after applications of DEET, varying from mild to severe (Briassoulis et al. 2001; Bell and Veltri 2002). Because of these undesirable side effects, research on repellents derived from plant extracts is needed to find alternatives that would be safer but still effective.

            Biopesticide insect repellants (sometimes called “natural”, “botanical” or “plant-based”) has been proven to be as effective as those containing synthetic chemical compounds like DEET. Remember, however, that “natural” doesn’t always mean safe, so you should use plant-based insect repellants as carefully as any other.

            The repellent properties of plants to mosquitoes and other pest insects were well known before the use of synthetic chemicals. Traditionally, people used natural compounds to protect themselves against insect bites. Some plant species contain insecticidal and/or insect-repellent substances. A review by Sukumar (1991) highlighted the potential of plants for use in mosquito control, either as repellents, larvicides, or insecticides. Extracts of several plants—hibiscus (Rosa sinensis), lemongrass (Cymbopogon citrates) and daisy (Chrysanthemum cinerariifolium)—have been studied as possible mosquito repellents and have demonstrated good efficacy against some mosquito species. The research is promising, but the number of plants that has been extensively studied is relatively small. Plants contain a wide range of chemical compounds. When extracted from the plant material, these compounds show useful biological activities such as repelling insects or altering insect feeding behavior, killing larvae, or disrupting growth (Duke 2000).

            Hibiscus (Rosa sinensis) or gumamela, known colloquially as rose mallow, Chinese hibiscus, China rose and shoe flower, is a species of flowering plant in the family Malvaceae, native to East Asia. In the Philippines, gumamela is cultivated as an ornamental plant. It is quite large, containing several hundred species that are native to warm-temperate, subtropical and tropical regions throughout the world. The genus includes both annual and perennial herbaceous plants, as well as woody shrubs and small trees. The generic name is derived from the Greek word ἱβίσκος (hibískos), which was the name Pedanius Dioscorides (ca. 40–90) gave to Althaea officinalis. Other studies concluded that the use of Hibiscus (Hibiscus rosasinensis) Ash Oil is very acceptable in repelling mosquitoes (Ratay 2013).

            Lemon grass, (Cymbopogon citratus), a native herb from temperate and warm regions such as India, is widely used in Asian cooking and is an ingredient in many Thai and Vietnamese foods. Lemon grass use in cooking has become popular in the Caribbean and in the United States for its aromatic citrus flavor with a trace of ginger. Lemon grass, or Cybnopogon citrates in the family Poaceae, is a member of a species of grass that grows to as high as 1 meter with leaves of 1 to 1.5 centimeters in width that grows from a stalk of about 30 to 80 cm long with bulbous lower end. Lemon grass oil is extracted by steam distillation. Lemongrass oil has a lemony, sweet smell and is dark yellow to amber and reddish in color, with a watery viscosity. It is also known as 'choomana poolu' and is also referred to as 'Indian Verbena' or 'Indian Melissa oil'. Lemon grass oil is a valuable ingredient in cosmetics, perfumes and as fragrances for soaps and insect repellants. Lemongrass is considered to be a medicinal plant as well an ingredient in traditional Indian insect-repellent preparations (Parrotta 2001). Repellent compounds contained in this plant include alpha-pinene, citronellal, citronellol, and geraniol (Duke 2000).

            Pyrethrum was a genus of several Old World plants now classified as Chrysanthemum or Tanacetum (e.g., C. coccineum) which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants formerly included in the genus Pyrethrum. Pyrethrum is also the name of a natural insecticide made from the dried flower heads of Chrysanthemum cinerariifolium. Another plant-derived substance, pyrethrum, is an insecticide. Pyrethrum comes from the flowers of the daisy Chrysanthemum cinerariifolium. Common names for Chrysanthemum cinerariifolium include: Pyrethrum, Pyrethrum daisy, Dalmatian pyrethrum, Dalmatian chrysanthemum, Dalmatian insect flower, Dalmatian pellitory and big daisy. It looks more like the common daisy than other pyrethrums. Its flowers, typically white with a yellow center, grow from numerous fairly rigid stems. Plants have blue-green leaves and grow to between 45 to 60 cm in height. The plant is economically important as a natural source of insecticide. The flowers are pulverized and the active components, called pyrethrins, contained in the seed cases, are extracted and sold in the form of an oleoresin. This is applied as a suspension in water or oil, or as a powder. Pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. When not present in amounts fatal to insects, they still appear to have an insect repellent effect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides and are not persistent, being biodegradable and also breaking down easily on exposure to light. They are considered to be amongst the safest insecticides for use around food. Kenya produced 90% (over 6,000 tonnes) of the world's pyrethrum in 1998, called py for short. Production in Tanzania and Ecuador is also significant. Insecticides Sprays Pyrethrum was used for centuries as an insecticide, and as a lice remedy in the Middle East (Persian powder, also known as "Persian pellitory"). It was sold worldwide under the brand Zacherlin by Austrian industrialist J. Zacherl.

            I opted to make this study to pursue an alternative organic agent of mosquito eradication. The result of this study is to propose an alternative but organic and safe solution in treating the abundance of mosquito in our locality. Moreover, this aimed to significantly help the residents who are greatly affected by these mosquitoes in a way that his study will provide them a new avenue in treating the great number of mosquitoes.

Statement of the problem:

            This study is conducted to answer the following question:

            Which of the following plant extracts namely: hibiscus, lemongrass and daisy is/are an effective natural mosquito repellant?

Objectives of the study:

            This study is designed to determine the possible potential of various plants: hibiscus (Rosa sinensis), lemongrass (Cymbopogon citrates) and daisy (Chrysanthemum cinerariifolium) as natural repellents against mosquitoes.

Specifically, it seeks to answer the following questions:

            a. Are the plants: hibiscus, lemongrass and daisy extracts effective in repelling                            mosquitoes?
            b. What are the effects of these plants namely: hibiscus, lemongrass and                                      daisy extracts to the environment and to human beings?
            c. Which of these plant extracts is more effective as a natural mosquito repellent?

Steps and Procedures:

Mosquitoes

            The mosquito type used in this study was female Anopheles gambiae, as they are easy to raise and are avid biters .All Anopheles gambiae females are temporary ectoparasites, living in the environment and coming to the host to feed. The females require blood meals to mature their eggs. Females do not display a tremendous amount of host specificity, but research indicates Anopheles gambiae preferentially feeds on humans. Females locate their hosts using a variety of sensory receptors, but respond to movement, carbon dioxide gradients, and sweat. Also, two odorant-binding proteins (OBP) have been isolated in Anopheles gambiae, which are hypothesized to aid female's search for human hosts. ("World Health Organization", 2004; Konate, et al., September, 1999; Meijerink, et al., June, 2000; Roberts and Janovy, Jr., 2000).

            This study did not make use of male mosquitoes since they are non-parasitic and feed only on nectar and plant juices. Adult male mosquitoes do not bite and they live 1 to 2 weeks. (Potter, Townsend, and Knapp, 2012)

 

Plant extracts

            Test sample extracts were made from the three plants; hibiscus, lemongrass and daisy. Leaves of each plant were used to produce the same amount of extracts.

Note: This study preferably used the replaceable parts of the plant, which is the leaves, rather than parts that, when removed, kill or damage the plant like roots or shoots.

1. The leaves were cut and weighed into ten grams.

2. The leaves were then washed, diced up thoroughly, and 100 milliliters of bottled         water was added to each sample.

3. The samples were filtered/ drained into separate transparent glass containers,             covered, labeled, and allowed to sit for 24 hours then filtered again to remove any remaining plant material.

            Label no. 1 for hibiscus extract

            Label no. 2 for lemongrass extract

            Label no. 3 for daisy extract

4. Afterwards, each sample was placed into each corresponding labeled spray bottles.

5. For the testing procedures, the effectiveness of each plant extract sample is tested     using arm-in-cage method, wherein a treated arm is inserted into a cage with ten            numbers of unfed Anopheles gambiae mosquitoes, for 5 minutes time.

6. Prior to each test, a control arm was washed from elbow to fingertips and air-dried,      before inserting it into the cage.

7. The plant sample extract being tested was sprayed evenly from the elbow to the          fingertips. Then, the treated arm was inserted into a cage for 5 minutes. In order         to provide a standard for comparing the effectiveness of each plant sample               extract as a natural repellant for mosquitoes, a number of times the arm is bitten         by the mosquitoes is recorded.

8. Plant extract sample No. 1 was being tested first and sprayed to the control arm           following the item number 7 procedure. After counting the number of mosquito    bites, the treated arm was washed and air-dried again.

9. For the other two plant sample extracts, it follows the procedure No. 8.

(Note:  A.) The number of mosquito bites is the basis in comparing the effectiveness of the three plant sample extracts as natural repellant. The more mosquito bites, the less effective the plant sample extract is. The less mosquito bites, the more effective the plant extract will be.

            B.) For each trial, test mosquitoes to be used that had not been exposed to any of the three plant sample extract.)

Bibliography

http://prezi.com/_fg0zpuzic3t/hibiscus-hibiscus-rosasinensis-ash-lemongrass-     andropogon/

http://en.wikipedia.org/wiki/Hibiscus_rosa-sinensis

http://stuartxchange.com/Gumamela.html

http://rullanamador.blogspot.com/2010/01/gumamela-hibiscus-rosa-sinensis-linn.html

http://shodhganga.inflibnet.ac.in/bitstream/10603/5942/14/14_chapter%205.pdf

http://homeguides.sfgate.com/insecticidal-properties-lemon-grass-55229.html

http://www.newtechbio.com/articles/Lemongrass-as-an-insect-repellent.htm

http://www.slideshare.net/gumbanjohndaniel/the-effectiveness-of-lemon-grass-as-         natural-insect-repellent
http://www.motherearthliving.com/gardening/fresh-clips-herbs-to-repel-      insects.aspx#ixzz2xpnz48QT

http://sipsamplespotlightowned.blogspot.com/2012/07/combined-solution-of-garlic-         allium.html

http://chemistry.about.com/cs/howthingswork/a/aa050503a.html

http://www.amazon.com/gp/product/B00DSFSPQU

http://davesgarden.com/guides/articles/view/3855/#ixzz2xq16yIAy

http://mindypopeboutique.com/30-pyrethrum-daisy-seeds-kill-bugs-insects-natural-        mosquito-repellent-39t/