Atividade inseticida in vitro de Schinus molle L. sobre Ctenocephalides felis felis (Bouche, 1835) (Siphonaptera: Pulicidae).

Abstract

Fleas are insects with great veterinary importance, by causing blood spoliation and anemia to host animals as well as discomfort due to intense itching, to the point of provoking self-mutilation. They also are threats to public health due to their ability to transmit pathogenic agents to humans and cause allergic reactions and irritation. The best way to control fleas is through integrated management employing substances that are safe, selective and biodegradable. An approach that has been investigated in this respect is the application of secondary metabolites of plant origin. The Peruvian pepper tree (Schinus molle L.) contains essential oils and fixed constituents that are widely used in folk medicine. These substances have been found to have antibacterial, anti-inflammatory, antiseptic, insecticidal and repellent activities, among others. The objective of this study was to extract, determine the chemical composition and assess the insecticidal activity in vitro of extracts and essential oils obtained from S. molle, leaves and fruits on adult cat fleas (C. felis felis), as well as on interruption of egg development. Extracts were obtained from the leaves in a Soxhlet extractor using hexane, ethyl acetate and methanol. Essential oils were obtained by hydrodistillation from leaves and fruits. All the extracts and oils were chemically characterized. The fixed extracts were evaluated in vitro against adult fleas and the volatile constituents were tested against immature forms and adults. The filter paper impregnation method was used in both experiments. The main substances identified in the hexane extract were espatulenol, caryophyllene oxide, 14-heptadecenal, n-octadecanal, Z-2 octadecen-1-ol, octadecyl vinyl ether, lupenone and lupeol. In the essential oil from the leaves, the main constituents were espatulenol and cubenol (sesquiterpenes), while that from the fruits contained terpinol and myrtenol (monoterpenes) and espatulenol. The hexane extract had a linear effect with increasing concentration, reaching 100% efficacy at a concentration of 800 μg/cm2 after 48 h. The other extracts were not active against C. felis felis. The oil from the fruits attained 100% efficacy only at the concentration of 800 μg/cm2 while the oil from the leaves was 100% effective at 50 μg/cm2. Essential oils obtained from the leaves and fruits of S. molle presented low efficacy in interrupting the egg-adult development of C. felis felis, with maximum efficacy of 10.53%. S. molle was effective in vitro in controlling adult forms of C. felis felis, so it can be an alternative for control of these fleas