Larvicidal activity of the methanol extract and fractions of the green fruits of Solanum lycocarpum(Solanaceae) against the vector Culex quinquefasciatus (Diptera: Culicidae)

Abstract

The species Culex quinquefasciatus (Diptera: Culicidae) is a mosquito inhabiting urban regions, with a wide geographical distribution. This species is involved in the transmission of lymphatic fi lariasis in the Americas, particularly in Brazil. C. quinquefasciatus is of great importance in public health as it creates administrative and public challenges for the control of mosquito vectors 1 . Synthetic insecticides have been widely used to control mosquito vectors of disease in various parts of the world; however, resistance to these insecticides has recently become problematic in vector control programs. Moreover, the continuous monitoring of mosquito populations may play an important role in attempting to develop management strategies that will prevent or minimize the development of resistance to pesticides, as well as to develop new products to combat insects 2 . Thus, the use of biological products is an alternative approach for preventing the development of resistance in mosquitoes.Plants are a source of bioactive compounds that have insecticidal properties and therefore may be suitable for mosquito control 3 . Phytoextracts have previously been shown to be successful in various biocontrol programs, and essential The species Solanum lycocarpum A. St. Hil., belonging to the Solanaceae family, is popularly known as lobeira and is widely distributed in the Brazilian cerrado 6 . It is widely used in traditional medicine as a sedative, in the treatment of epilepsy, asthma, diabetes, obesity, for the reduction of cholesterol levels, and for abdominal and renal pain 7 .To our knowledge, for the fi rst time, we show the larvicidal activities of the extracts and fractions obtained from the green fruits of S. lycocarpum against C. quinquefasciatus.The green fruits of S. lycocarpum A. St. Hil. were collected in the City of São Sebastião do Oeste, State of Minas Gerais, Brazil, in August 2011. The plant material was identifi ed by Dr. Alexandre Salino, and a voucher specimen (BHCB 159397) was deposited at the Instituto de Ciências Biológicas Herbarium, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. Methanol was used as solvent to obtain the extract from 170.01g of dried and powdered green fruits, using a Soxhlet extractor. The extract was then concentrated in a rotary evaporator at 50°C under reduced pressure to yield the methanol extract (MET, 14.53g). Some of this extract (6.82g) was dissolved in MeOH/H 2 O (1:1) and then partitioned successively with hexane, dichloromethane, and ethyl acetate (Vetec®, São Paulo, Brazil; 100 mL, twice with each solvent), yielding 0.09, 0.23, 0.34, and 5.50g of hexane (HEX), dichloromethane (DCM), ethyl acetate (AC), and hydromethanolic (HM) fractions, respectively. The extract and fractions were screened for the presence of different phytoconstituents such as saponins, tannins, alkaloids, steroids, triterpenes, coumarins, and fl avonoids Culex quinquefasciatus larvae were obtained from a laboratory culture, as previously described by Gerberg 9 . Both the third and...

Phytochemical screening and evaluation of phytotoxic activity of Solanum lycocarpum (Solanaceae) ripe fruit

“…A previous study with ripe fruits of this species (Morais et al, 2013) detected the presence of similar compounds in the ethanol extract as in our research; the exception was the absence of tannins. Phytochemical tests also showed the presence of coumarins, flavonoids, and tannins in the methanol extract from unripe fruits (Pereira et al, 2014). Many biological activities are correlated to the bioactive secondary metabolites present in plants (Oliveira, Gualtieri, Domíngues, Molinillo, & Montoya, 2012).…”

“…This species is widely used in folk medicine as a sedative, in the treatment of epilepsy, diabetes, obesity, reduction of cholesterol levels, and in the preparation of influenza syrups (Dall'Agno & Von Poser, 2000). Previous studies have shown that fruits of S. lycocarpum exhibit allelopathic, anti-inflammatory, antimicrobial, antioxidant, antitumoral, cytotoxic, genotoxic and larvicidal activities (Morais, Silva, Oliveira, Ferreira, & Lima, 2013;Pereira, Silva, Ribeiro Neto, Alves, & Lima, 2014;Morais et al, 2015;Silva, Ribeiro Neto, Alves, & Lima, 2015;Chiavegatto, Chaves, Silva, Lima, & Techio, 2017;Morais et al, 2017;Bahia et al, 2018;Morais et al, 2018;Silva et al, 2018;Silva, Fonseca, Coimbra, Duarte-Almeida, & Lima, 2019).…”

Larvicidal activity of oils, fatty acids, and methyl esters from ripe and unripe fruit of Solanum lycocarpum (Solanaceae) against the vector Culex quinquefasciatus (Diptera: Culicidae)

“…Sakthivadivel and Daniel (4) demonstrated the larvicidal effect of the ethanolic extract of leaves of Solanum trilobatum on fourth instar larvae of C. quinquefasciatus, with an LC 50 value >200mg/L. In a recent study (5) , methanolic extract and extract fractions from unripe S. lycocarpum fruit showed larvicidal effects against C. quinquefasciatus, with LC 50 values of 75.13-207.05mg/L.…”

“…Sakthivadivel and Daniel (4) demonstrated the larvicidal effect of the ethanolic extract of leaves of Solanum trilobatum on fourth instar larvae of C. quinquefasciatus, with an LC 50 value >200mg/L. In a recent study (5) , methanolic extract and extract fractions from unripe S. lycocarpum fruit showed larvicidal effects against C. quinquefasciatus, with LC 50 values of 75.13-207.05mg/L.In this study, OUF, FAUF, FARF, and MERF showed the lowest LC 90 values (139.47, 93.03, 147.02, and 125.13mg/L, respectively) and were thus the most toxic of the fractions against C. quinquefasciatus. Ethanolic extracts of the leaves of S. xanthocarpum also showed activity against third and fourth instar larvae of C. quinquefasciatus (4) , with LC 90 values of 1,011.89 and 1,058.85mg/L, respectively.…”

“…Several species of the genus Solanum have demonstrated larvicidal and pupicidal activities against the mosquito Culex quinquefasciatus (3) (4) (5) . Solanum lycocarpum A. St. Hil.…”