Estudo químico e avaliação das atividades antiprotozoárias in vitro do óleo essencial de piper marginatum jacq (piperaceae)

Abstract

Neglected diseases are responsible for millions of deaths per year. They are debilitating diseases and affect, mainly, the population of poor regions. Due to the limitations of the existing treatment, the search for new drugs become urgent. In this sense, the study of plant species leads as an alternative to obtaining a phyto-pharmaceutical for their treatment and control. Many Piper species are used for curative purposes by various cultures and they are composed by unsaturated amides, flavonoids, lignans, aristolactams, long/short-chain esters, terpenes, steroids, propenyl phenols and alkaloids. Piper marginatum is also known as capeba, malvarisco, wild pepper, capeba-fragrant and nhandi. It is popularly used against liver and vesicular disease, snakes and insects bites. Volatile compounds and Piper marginatum were investigated by determining the chemical constitution, seasonal variation and anti-protozoan in vitro activity. Essential oils were extracted by hydro-distillation, for 6 hours, and yields ranged from 0.10-0.23% v/m. Essential oil components have been identified through gas chromatography analysis coupled to a mass spectrometry (GC/MS), the main constituents were: δ-3-careno, (Z) β-ocimene, β-ocimene, α-terpinolene, Ecaryophyllene, biciclogermacrene D, α-copaene, linalool, myristicin, 3.4-(methylenodioxy) propiophenone. This is the first work that describes in vitro activity of the essential oil of P. marginatum against adult forms of S. mansoni, trypomastigote forms of T. cruzi and promastigotes forms of L. amazonensis. P. marginatum oil presented a promising schistosomiasis activity, reducing the motility and causing death of the parasites directly proportional to the concentration and incubation time. When tested at concentrations of 12.5 μg/mL, this oil was capable to causes 100% of the motor activity of worms decreased after 24 hours of incubation and 100% death of the worms in a concentration of 50 μg/mL after 120 h of incubation. For T. cruzi, the essential oil shown to be active in the concentration of 20 g/mL, resulting in 71% mortality of parasites, however the selectivity index was below 2.3, far below the selectivity index (less than 50) considered for in vivo tests. For the infectious forms of L. amazonensis, the oil proved to be inactive. The results obtained in this study against the S. mansoni adult worms, demonstrate the importance of phytochemical study of species found in the Amazon region, as an alternative to the existing restricted therapy to treat schistosomiasis.