AJCS 14(10):1608-1615 (2020) ISSN:1835-2707 doi: 10.21475/ajcs.20.14.10.p2389 Tetradenia riparia (Lamiaceae) essential oil: an alternative to Rhipicephalus sanguineus Giuliana Zardeto-Sabec1, Renan Almeida de Jesus1, Herika Line Marko de Oliveira1, Caio Franco de Araújo Almeida Campo2, Ezilda jacomassi4, José Eduardo Gonçalves2,3 and Zilda Cristiani Gazim1* 1Programa de Pós-Graduação em Biotecnologia Aplicada à Agricultura. Universidade Paranaense - UNIPAR, Praça Mascarenhas de Moraes, 4282, CEP 87502-210, Umuarama-PR, Brasil 2Mestrado em Tecnologia Limpas e 3Instituto Cesumar de Ciência, Tecnologia e Inovação – ICETI. Centro Universitário Cesumar-UNICesumar, Av. Guedner, 1610. Jardim Aclimação, Maringá, Paraná, 87050-900, Brasil 4Mestrado Profissional em Plantas Medicinais e Fitoterápicos na Atenção Básica, Universidade Paranaense (UNIPAR), Praça Mascarenhas de Moraes, 4282, Umuarama, PR, 87502-210, Brasil *Corresponding author: [email protected] Abstract In Brazil, Rhipicephalus sanguineus resistance to some pyrethroids have been detected, motivating research on new phyto- insecticides such as essential oil from Tetradenia riparia leaves (EOL) and flower buds (EOFB). The essential oils were obtained by hydrodistillation (3h) and identified by GC/MS. In addition, a multivariate exploratory analysis was done to determine the analysis of the major compounds (PCA). The bioassays on R. sanguineus larvae were done by immersion test at different EO concentrations which ranged from 50,000 to 0.47 mg/mL (v/v). The action mechanism of EOs were determined by bioautographic method evaluating the inhibitory potential on the acetylcholinesterase enzyme. The EO yield in leaves was 0.29±0.22 (%) and in flower buds 0.38±0.17 (%). The class projections showed oxygenated sesquiterpenes (43.62%) and diterpenes (15.60%) in EOFB, and hydrocarbon sesquiterpenes (26.44%) and oxygenated monoterpenes (16.44%) in EOL. Four components presented a greater distancing of mass flow: fenchone (11.57 and 6.01 %), α-cadinol (12.21 and 13.69 %), 14-hidroxy-9-epi-caryophyllene (8.56 and 15.38 %), and caryophyllene oxide (1.32 and 4.50 %) in EOL and EOFB, respectively. The lethal concentrations (LCs) to kill R. sanguineus larvae were (LC50: 2.18±0.24 and LC99.9: 9.98±0.10 mg/mL) for EOL, and (LC50: 5.36±2.50 and LC99.9: 20.12±0.54 mg/mL) for EOFB. The action mechanism of EOs by bioautographic methods indicated an inhibition of 0.70 mg/mL (EOL) and 1.40 mg/mL (EOFB) on the acetylcholinesterase enzyme (AChE). Therefore, this species can be considered promising to be part of the chemical larvicides to control this ectoparasite. Keywords: dog ticks, monoterpenes, fenchone, limonene, camphor, acetylcholinesterase, bio insecticides, falsa mirra. Abbreviations: GC/MS_gas chromatographer coupled to mass spectrometer; LC_lethal concentration; LC99.9_lethal concentration to eliminate 99.9% of larvae and ticks, LC50_lethal concentration to eliminate 50% of larvae and ticks. Introduction Rhipicephalus sanguineus, a cosmopolitan tick is probably than it has been imagined (Cunha et al., 2009; Salkeld et al., the most distributed ixodid worldwide (Szabó et al., 2009), 2019). and has been found more and more often in man’s home The control of this mite happens with the utilization of and peridomicilliary environments of the main urban host of chemical acaricides from the classes of Isoxazolines this ectoparasite, the domestic dog Canis familiaris (Paz et (Afoxolaner, Fluralaner, Sarolaner and Lotilaner), al., 2008). In dogs, besides the direct damages, this Phenylpyrazoles (Fipronyl), Spinozins (Spinosad), ectoparasite is responsible for the transmission of Ehrlichia Neonicotinoids (Nitempiram), Carbamates and canis, Babesia canis, Haemobartonella canis and Organophosphates (Pereira et al., 2008; Raimundo et al., Hepatozoon canis. In humans, it is the vector of Rickettsia 2017); however, the indiscriminate use of these substances conorii and Rickettsia rickettsia, and this diagnosis is resulted in the selection of resistant populations especially important once there have been reports on (Jeyathilakan et al., 2019). In Brazil, R. sanguineus resistance human parasitism by tick in Brazil (Borges et al., 2007). The to some pyrethroids were recorded by Fernandes (2001), growing number of cases of human parasitism by R. and since then the literature has been reporting that several sanguineus has indicated that the interaction between synthetic acaricides have lost or reduced their efficiency due human beings and R. sanguineus may be more common to the development of resistant strains (Brito et al., 2011). Another problem regards the number of animal and human 1608 poisonings mostly by organophosphates and carbamates projection showed oxygenated sesquiterpenes (43.62%) and (Raimundo et al., 2017; Bortolucci et al., 2018) due to the oxygenated diterpenes (15.60%) in EOFB; and hydrocarbon easy product acquisition and their indiscriminate utilization sesquiterpenes (26.44%) and oxygenated monoterpenes (Xavier et al., 2007). (16.44%) in EOL) (Fig 1). Therefore, alternative controls have been studied and, Grouping by ACP was done including the major compounds therefore, the exploration of plants as efficient sources of identified in EO from leaves and flower buds. Four botanical acaricides is promising and must be motivated compounds out of them presented greater distancing of (Sugauara et al., 2019). The utilization of secondary mass flow: L-fenchone (11.57 % and 6.01 %), α-cadinol (1.21 phytochemical metabolites have been able to interfere in % and 13.69 %), 14-hidroxy-9-epi-caryophyllene (8.56 % and arthropods’ physiology such as neuroendocrine systems, 15.38 %) and caryophyllene oxide (1.32 % and 4.50 %), feeding, metamorphoses, vulnerable points to population respectively (Fig 2). control based on arthropods’ life cycle (Garcia and Azambuja, 2004). Larvicidal activity by Larval Packet Test Interest in the development of pesticide products with essential oils is based on studies that showed that they have The results found for larvicidal activity of T. riparia EOL and repellent, fumigating, larvicidal and adulticide action EOFB on Rhipicephalus sanguineus ae shown in Table 2. The (Tripathi and Mishra, 2016). The insecticide effect of lethal concentrations (CLs) found to kill Rhipicephalus essential oils occurs due to the variability of phytochemical sanguineus larvae are presented in Table 3. Another standards and the way this phytomolecules penetrate the important aspect within this study was to determine which organism considering that essential oils can be inhaled, action mechanism of the EO acted on R. sanguineus larvae. ingested or absorbed by the skin of insects (Magalhães et al., The Utilized protocol was based on the evaluation of the 2015). Another advantage to the use of essential oils regards inhibitory capacity of EOS on the acetylcholinesterase their fast degradation in the environment and their enzyme by bioautographic method and whose results are increased specificity that favors benefic insects (Tripathi et shown on Table 4. The leaves essential oil presented greater al., 2009). Little is known on the physiological actions of larvicidal activity (CL99.9 9.98 mg/mL) when compared to the essential oils on insects, but Kostyukovsky et al. (2002) essential oil from flower buds (CL99.9 20.12 mg/mL). This suggested a neurotoxic action as it was shown with linalool difference can be related to the greater amount of that acts on the nervous system, affecting the ionic hydrocarbon and oxygenated monoterpenes in EOL (23.21%) transport and the release of acetylcholinesterase in insects when compare to EOFB (10.80%) according to Table 1 and (Junior, 2003). This action mechanism was demonstrated in Figures 1 and 2, because, according to Tripathi and Mishra our study where T. riparia essential oil acted out by (2016), monoterpenes present insecticide potential and, inhibiting acetylcholinesterase enzyme. according to Lee et al. (2004), this potential can be explained Tetradenia riparia (Hochst) Codd, from the Lamiaceae by the fact that the compounds are volatile, lipophilic and family (Souza and Lorenzi, 2005; Martins et al., 2008), is a able to quickly penetrate inside insects interfering in their plant utilized in popular medicine, and the essential oil physiological functions. Analyzing the chemical composition extracted from its leaves has been used to treat malaria, of T. riparia essential oil, four monoterpenes are found in criptococosis, candidiasis and respiratory infections (Van greater amount in EOL when compared to EOFB: L-fenchone Puyvelde et al., 1986; Campbell et al., 1997; Okem et al., (11.57; 6.01%), limonene (1.16; 0.37%), L-camphor (2.38; 2012, York et al., 2012). Studies carried out with this species 1.36%), α-pinene (1.57; 0.23%) and β-caryophyllene (5.70; have shown antimicrobial activity (Boily and Van Puyvelde 3.85%), respectively, which present potential insecticide by 1986; Van Puyvelde et al. 1994; Gazim et al., 2010; Ndamane bibliographic review as described in Table 5. Limonene has et al., 2013; Njau et al., 2014; Melo et al., 2015), repellent pytoinsecticide potential and is an active ingredient in activity against Anopheles gambiae (Omolo et al., 2004), commercially available shampoo against fleas (Athea® acaricidal and larvicidal (Gazim et al., 2011) and Laboratories, Inc., Cornell, USA) (Tripathi et al., 2009). Also, antileishmanial activities (Cardoso et al., 2015, Demarchi et it can be used in combination with detergent to control