Repellent and Lethal Activities of Extracts From Fruits of Chinaberry (Melia azedarach L., Meliaceae) Against Triatoma infestans

Abstract

Triatoma infestans is the principal vector of Trypanosoma cruzi, parasite responsible of Chagas's Disease transmission in Argentina. Pyrethroids have become common pesticides for the control of T. infestans but increasing resistance encourages the search of new alternatives and the use of natural products for biological control arises as a new strategy. Melia azedarach L. is originated from the Himalaya's region and several compounds are part of its rich phytochemistry. Folk medicine of the plant is due to its repellent and insecticidal activities. Aims of this work were to evaluate the repellent activity of methanolic and acetonic extracts from fruits of M. azedarach by means of the area preference method of fifth and first nymph stages as well as to test the acute lethal effect of the more repellent extract by means of direct application on cuticle on both stages. For repellence, qualitative filter papers were divided into two halves, one treated with methanolic (ME) or acetonic (AC) extract and the other without treatment. Controls were impregnated half with methanol or acetone and half without the solvents. One nymph was located in each Petri or well and repellence percentage was determined. For the lethal effect, fasted and fed to repletion 5th stage nymphs were topically administered with different concentrations of AC and deaths were registered after 24, 48, 72, 96, and 120 h. Phytochemical analysis of extracts was performed as well. AC demonstrated high repellent activity (100%, both stages), whereas ME extract activity was slight (10–21%). AC extract was selected for lethal assays due to early repellent activity. Fed to repletion nymphs were more sensitive to the lethal activity of the extract when compared to fasted nymphs (LD50: 11.5 vs. 23.1 μg/insect, respectively). Phytochemistry assays of extracts showed a higher concentration of flavonoids, alkaloids and triterpenes for AC. Considering these results, next assays will include the test of Melia azedarach extract on T. infestans that are resistant to pyrethroids for a possible synergism between AC and the pesticides.

Efecto letal y repelente del monoterpeno geraniol sobre ninfas de Triatoma infestans susceptibles y resistentes a deltametrina

“…Para el ensayo de repelencia se utilizó la técnica de área de preferencia con mínimas adaptaciones (Tapondjou et al, 2005;Dadé et al, 2018). La superficie de trabajo se arma con papeles de filtro de 11 cm de diámetro divididos en dos mitades.…”

Plant-Derived Antimicrobial Peptides as Potential Antiviral Agents in Systemic Viral Infections

“…Some defensins use the same supposed mechanism as the previous peptide: these small (around 50 amino-acids, at maximum) cationic and cysteine-rich peptides protect the host by binding viral glycoproteins before their interaction with host cells [ 42 , 43 ].…”

“…Meliacine is a glycopeptide isolated from leaves of Melia azedarach L ., also called “Chinaberry tree”, from the Meliaceae family—native to Asia, but also found in America, Northern Australia, Africa and Southern Europe [ 43 ]. Meliacine targets the replication cycle of HSV-1 and, more specifically, polypeptides participating in viral DNA synthesis and in the assembly of viral nucleocapsids in the infected cell.…”

Phytochemical and Antioxidant Profile of the Medicinal Plant Melia azedarach Subjected to Water Deficit Conditions

“…Melia azedarach is considered a multipurpose tree native to West Asia. Still, it is nowadays cultivated in several countries (such as India, Pakistan, Nepal, Sri Lanka, East Timor, Indonesia, Lebanon, Palestine, Syria, Tunisia, Algeria, Cyprus, Greece, Argentina, China, Uganda, Kenya, Brazil, Australia, Southern France, Northern Italy, Croatia, and Portugal) with temperate to warm climates [ 18 , 19 , 20 , 21 ]. However, the projected increase in the frequency of extreme weather events in many regions of the globe during this century may reshape M. azedarach future suitable habitats [ 21 ].…”

“…Moreover, extracts of the different parts of this medicinal species are shown to have pharmacological and toxicological characteristics. For instance, leaves are rich in several bioactive molecules, such as flavonoids, terpenoids, limonoids, fatty acids, carbohydrates, steroids, alkaloids, saponins and tannins [ 23 , 24 ], which have been demonstrated to have antibacterial, antifungal, antiparasitic, antiviral and insecticide properties [ 19 , 25 , 26 ].…”