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Journal of the American Mosquito Control Association, 2O(2):146_149,2004 Copyright @ 2OO4by the American Mosquito Control Association, Inc.
REPELLENCY OF AROMATIC MEDICINAL PLANT EXTRACTS AND A STEAM DISTILLATE TO AEDES AEGYPTI
YOUNG-CHEOL YANG,T EUN-HAE LEE,' HOI-SEON LEE,3 DONG-KYU LEE4 AND YOUNG-JOON AHNr5
ABSTRACT The repellent activity of methanol extracts from 23 aromatic medicinal plant species and a steam distillate against female blood-starved Aedes aegypti was examined in the laboratoiy Uy skin test and compared with that of N,N-diethyl-z-toluamide (deet). Responses varied according to plant-speties. At a dose of 0.1 mg/cm' , the repellency of extracts of Cinnamomum cassia bz,rk (9l%o), Naidostichys chinensis rhrzome (\l%o), Paeonia suffruticosa root bark (8OVo), and Cinnamomum camphora steam distillate (94Vo) was compa- rable to deet (82Vo). The duration of the effectiveness for extracts from C. cassia bark and N. chinensis rhizome was comparable to deet and lasted for -l h. Relatively short duration of repellency was observed in P. suffru- ticosa root bark extract and C. camphora steam distillate. The plants described merit further study as potential mosquito repellent agents.
KEY WORDS Natural repellent, mosquito, Aecles aegypti, aromatic plant, deet, skin test
INTRODUCTION perspiration and abrasion, sensitivity of the insects to repellents, and biting density (Rozendaal 1997). Mosquito repellents could be one of the most ef- This paper describes a laboratory study that was fective tools for protecting humans from mosquito made to assess the potential of plant extracts for attack and from mosquito-borne diseases, such as use as commercial mosquito repellents. Repellent dengue hemorrhagic fever, malaria, encephalitis, activity of methanol extracts from 23 aromatic me- and filariasis (Curtis et al. 1990). Repeated use of dicinal plant species and a steam distillate were as- synthetic insecticides for mosquito control has dis- sessed against female blood-starved Aedes aegypti rupted natural biological control systems and led to (L.) and compared with that of deet. resurgences in mosquito populations (Croft and Brown 1975). k has also resulted in the develop- ment of resistance (Brown 1986), had undesirable MATERIALS AND METHODS effects on nontarget organisms, and fostered envi- ronmental and human health concerns (Hayes and Insects: The Ae. aegypti used in this study were Laws l99l). The most commonly used mosquito from cultures maintained in the laboratory for 7 repellent is N,N-diethyl-z-toluamide (deet), which years without exposure to insecticide. Adult mos- is still most effective. However, this compound has quitoes were reared on a lOVo sucrose solution and an unpleasant odot can damage plastics and syn- blood-fed on live mice. Larvae were reared in plas- thetic rubber, and has high skin penetration char- tic trays (24 x 35 X 5 cm) containing 2,0O0 ml of acteristics (Qiu et al. 1998). These problems indi- water supplied with 0.5 g of sterilized diet (40- cate a need for new and improved repellents and mesh chick chow powder and yeast, 4: I by weight). -r + strategies for protection from mosquito attack. They were held at 28 2"C and 75 57o relative Plants could be an alternative source for mos- humidity (RH) and a 16:8 h photoperiod. quito repellents because they constitute a potential Plants and sample preparation: A total of 24 source of bioactive chemicals (Wink 1993) and typ- aromatic medicinal plant species were selected ically are free from harmful effects (Isman 1995). (Namba 1993). The parts of each plant that have Because of this, much interest has focused on plant been used in Chinese medicine (Namba 1993) were extracts, or plant essential oils, as potential mos- purchased from Boeun medicinal herb shop, quito repellent agents. The effectiveness and dura- Kyungdong market, Seoul, and used in extractions tion of repellency depend on the type of repellent (Table l). With the exception of Chaenomeles si- (active ingredient and formulation), mode of appli- nensi.s (Thouin) Koehn. and Cinnamomum campho- cation, local conditions, attractivenessof individual ra Presl, the plants were dried in an oven at 40'C people to insects, loss of repellent with removal by for 2 days and finely powdered with a blender. Each sample (50 g) was extracted twice with 300 ml of methanol at room temperature for 2 days and fil- I Department of Advanced Organic Materials Engineer- tered. Slices (200 g) of the fresh Chaenomeles fruits ing, Chonbuk National University, Chonju 561-756, Re- were ground in a blender, extracted twice each with public of Korea. 900 ml of methanol at room temperature for I day, 2 School of Agricultural Biotechnology, Seoul National and filtered. The combined filtrate was concentrated University, Seoul I5l-742, Republic of Korea. to dryness by rotary evaporation at 4O'C. The yield r Faculty of Biotechnology, Chonbuk National Univer- given l. sity, Chonju 561-756, Republic of Korea. of each methanolic extraction is in Table 4 Department of Biological Sciences, Kosin University, Cinnamomum camphora was purchased as a steam Busan 606-701, Republic of Korea. distillate. 5 Author to whom correspondence should be addressed. Bioassay: The method of Frances et al. (1996)
146 147 JuNe,20O4 Moseutro RBpeI-l-BNcv nNo Plnlm ExrRAcrs
Table 1. Aromatic medicinal plants tested. (Vo)2 Familv Species Tissue usedr Yield t7.7 Apiaceae Angelica dahurica Ro 10.1 Araceae Acorus calamus vaL angustdtus Rh Acorus gramineus Rh 9.5 6.6 Compositae A rtemis ia princ eps v ar. o rientali s Wp Inula helenium Ro 16.3 2.4 Dioscoreaceae Dioscorea batatas Rh t7.3 Fabaceae Gleditsia horrida Fr Glycyrrhiza glabra Ro 21.9 9.5 Labiatae Agastache rugosa Wp Sc h izon ep et a te nuifo I i a Wp 8.1 Lauraceae Cinnamomum camphora3 Cinnamomum cassia Ba 5.1 5.8 Magnoliaceae Magnolia obovata Ba Myrtaceae Eugenia caryophyllata Fb 37.8 Paeoniaceae Paeonia suffruticosa Rb 18.6 Piperaceae Piper nigrum Fr 10.1 Polygonaceae Rheum coreanum Rh 4t.6 Prumulaceae Lysimachia davurica Wp 9.O Rosaceae Chaenomeles sinensis Fr 60.8 Rutaceae Evodia mtaecarpa Fr 9.5 Solanaceae Solanum melongena Fr Stemonaceae Stemona japonica Ro 15.2 Thymelaeaceae Aquilaria agallocha Hw 6.6 Valerianaceae N ardostachys c hinensis Rh t2.9
'Ba, bmk; Fb, flower bud; Fr, fruit; Hw, heart wood; Rb, root brk; Rh, rhizome; Ro, root; md wp, whole plant. , (Weight of crude methmol extract/weight of dried test material) x 100; except Chaenomeles sinensis, (weight of crude methanol extract/weight of fresh fruits) X 100. 3 Steam distillate.
with a slight modification was used to determrne termined and transformed to arcsine square root the repellent activity of test samples against female values for ANOVA. Treatment means were com- : blood-starved Ae. aegypti. Every bioassay was con- pared and separated by the Scheffe test at P 0.05 -r ducted from 1200 to 1700 h. In a preliminary test, (SAS Institute 1990). Means SE of untrans- 0.1 mg of each plant extract was solubilized in 20 formed data are reported. pl of ethanol by sonication for l0 sec and provided for repellent bioassays. Eth- an appropriate amount RESULTS AND DISCUSSION anol (20 pl) was applied directly to exposed skin through a 5-cm-diameter hole on the back of a rub- The repellent activity of methanol extracts from ber glove and dried for 3 min. Because biting den- 23 aromatic medicinal plant species and a steam sity plays an important role in studies of repellency distilfate against starved Ae. aegypti females varied (Rozendaal 1997), skin was exposed for 5 min in according to plant species (Table 2). At a dose of a screen wire cage (30 x 30 X 3O cm) containing 0.1 mg/cm2, potent repellency against mosquito 300 blood-starved females (6-8 days old). Imme- adults was obtained with the extracts of Cinnamo- diately after the control exposure, the hand was re- mum cassia Blume bark (9l%o), Nardostachys chi- moved from the cage and a dose of 0.1 mg/cm2 of nensis Batalin rhizome (8IVo), Paeonia suffruticosa each test plant material and deet (Sigma, St. Louis, Andrews root bark (8OVo), and C. camphora steam MO) in 20 pl of ethanol were applied evenly over distillate (94Vo). Repellency in each case was com- the skin surface. After air drying for 3 min, the parable to that of deet (82Vo). Eugenia caryophyl- treated hand was exposed to mosquitoes in the lata Thunb. extract provided 15Vo repellency. The same test cage for 5 min at 30-min intervals. The other 19 plant extracts exhibited
Table 2. Repellent activities of aromatic medicinal against female Aedes aegypti _plants skin test. + P. suffruticosa + /V. Plant speciesl 7o repellency2 - chrrensls .o + C. cassla Acorus calamus yar. angustatus 56 + 9.6 CDEF o + C.camphora Acorus gramineus 44 + 1.8ourc o + Deet o Agatache rugosa 54 + 1.6cnep L Angeliccr dahurica 50 + 1.5 coprc I Aquilariet agallocha 62 + 2.2 ecoep Artemis ia princeps + q) var. orie ntalis 60 3.6 ecorF o Chaenomeles sinensis 49 + 2.5 cDEFc o Cinnamomun camphora 94 + 1.8n o_ Cinnamomum cassia 9l + 3.9 ns + Dioscorea batatas 39 1.6rpc 0r Eugenia caryophyllata 75 + 3.3 ABCDE 0 30 60 90 120 150 180 Evodia rutaecarpa 32 + 3.2pc Gleditsia horrida 57 + 3.6cozp Hours Post Application Glycyrrhiza glabra 28 + 4.5 po Fig. l. Duration Inula helenium 50 + 3.7 coerc of protection of methanol extracts fiom 3 plant species, Lysimachia davurica 50 + 2.7 CDEFG a steam distillate of C. camphora, and deet against female Magnolia obovata 59 + 2.3 corp Ae. aegypti when dosed at a rate of 0.1 mg/cm,. Bar Nardostachys chinensis 8l + 5.8 e.sct representsstandard error. Paeonia suffruticosa 80 + 4.3 ABCD Piper nigrum 52 + 3.9 coBpc Rheum coreanum 5l + 1.9 cnepc ample, reported that a l7o neem oil-kerosene Schizonepeta tenuifolia 53 + 4.O CDEF mixture could provide economical personal protec- + Solanum melongena 15 3.2c tion from mosquito bites. Lantana camara L. flow- Stemona japonica + 6l 1.3 BCDEF er extract in coconut oil provided 94.5Vo protection Deet 82 + 3.7 ABC from Aedes albopictus (Skuse) and Ae. aegypti I Exposed to 0-1 mg/cm, for 15 min. without adverse effects on the human volunteers , for Means within a column followed by the sme letter ile not a 3-month period after the application (Dua et al, significantly different (P = 0.05, Scheffe test; SAS lnstiture 1990). 1996). Repellency was trmsformed to trcsine square root values before ANOVA. Means a SE of untransformed data are reDorted. Results of this study indicate that some plant ex- tracts could be useful for protecting human and do- mestic animals from mosquito attack, provided a slow-release effect for the ing botanical mosquito control agents are in the repellents can be devel- oped. For practical families Asteraceae, Cladophoraceae, Labiatae, use of these plants as novel mosquito repellents to proceed, Meliaceae, Oocystaceae, and Rutaceae. In this however, further re- search on their study, repellency against female Ae. aegypti com- safety in human health, as well as formulations that parable to deet was observed for extracts from improve repellent potency and stability, is necessary. plants in the Lauraceae, Myrtaceae, Paeoniaceae, and Valerianaceae families. Repellent activity of the extracts of C. cassia bark, E caryophyllata ACKNOWLEDGMENTS flower bud, N. chinensis rhizome, and P. suffruti- cosa root bark, as well as the steam distillate of C. This work was supported by grants from the Ko- camphora, against female Ae. aegypti was compa- rea Science and Engineering Foundation (R0l- rable to that of deet. 2000-000088-0) and the Ministry of Education (Brain The repellent activity of extracts from C. cassia Korea 2l Project) to YJA. bark, N. chinensis rhizome, P. suffruticos.z root bark, and C. camphora steam distillate against fe- REFERENCES CITED male Ae. aegypti at 0.1 mg/cm2 was comparable to Brown AWA. 1986. Insecticide resistancein mosquitoes: (Fig. that of deet l). Their efficacy lasted for I h. pragmatic review. "/ Am Mosq Control Assoc 2:123- Relatively short duration of repellency (30 min) 140. was observed in P. suffruticosa extract and C. cam- Croft BA, Brown AWA. 1975. Responsesof arthropod p ho ra steam distillate. natural enemies to insecticides.Ann Rev Entomol 20: Many plant extracts and essential oils with high 285-335. volatility, such as alkanes, terpenoids, alcohols, and Curtis CI] Lives JD, Baolib LU, Renz A. 1990. Natural aldehydes are repellent to mosquitoes for periods and synthetic repellents.In: Curtis C\ ed. Appropriate technology in vector control Boca Raton, FL: CRC ranging from 15 min to 10 h (Rozendaal 1997). Press.p 75-92. Furthermore, various formulations for controlled Dua VK, Gupta NC, PandeyAC, SharmaVP 1996.Re- release have been developed to increase the protec- pellency of Lantana camard (Verbenaceae)flowers tion period provided by repellents (Gupta and Rut- againstAedes mosquitoes.J Am Mosq Control Assoc ledge 1989). Sharma and Ansari (1994), for ex- 12:4O6-408. Exrnecrs 149 JUNE 2004 MoseulTo REPELLENCYAND PLANT
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