Estudo químico e biológico de óleos essenciais de espécies de Piper L. (Piperaceae) com ocorrência no parque estadual do Utinga, Belém - Pará

Abstract

The genus Piper L. is the most representative among Piperaceae, since it constitutes an important source of raw material, natural resources and knowledge, since they have species that produce essential oils (EO), which present several chemical and biological properties. The present study aimed to know the chemical and biological activities of the essential oils from Piper L. species occurring in PEUt, Belém - Pará. Literature searches of Piper L. species found on the trails were conducted using the ISI-Web of Science, Scopus, PubMed and Google Scholar databases for the years 2011 to 2021. Afterwards, the geographic distribution, endemism and conservation status were verified using the Flora and Funga of Brazil and National Center for Flora Conservation (CNCFlora) databases. The EOs were extracted by hydrodistillation and the chemical composition was analyzed by gas chromatography coupled to mass spectrometry (GC/MS). To evaluate the antioxidant potential, the DPPH free radical scavenging method and Trolox Equivalent Antioxidant Capacity (TEAC) were used. The phytotoxic potential was evaluated on two bioindicator species: Mimosa pudica and Senna obtusifolia. Sixteen Piper L. species were found on the trails of the PEUt (P. aduncum L., P. belterraense Yunck., P. brevesanum Yunck., P. carniconnectivum C.DC., P. colubrinum Link, P. consanguineum Kunth, P. cyrtopodon (Miq.) C.DC., P. demeraranum (Miq.) C.DC., P. divaricatum G.Mey., P. hispidum Sw., P. hostmannianum (Miq.) C.DC., P. montealegreanum Yunck., P. pellitum C.DC., P. piresii Yunck., P. schwackei C.DC.and P. wachenheimii Trel.) and of these, 5 are endemic to Brazil and occur only in the North and Northeast regions of the country and have not been evaluated for conservation status by the National Center for Conservation of Flora (CNCFlora). After EOs extraction, yields of 2.67% were quantified for P. aduncum; 0.68% for P. divaricatum; 1.79% for P. hostmannianum and 0.90% for P. wachenheimii. The majority constituents in the EO of P. aduncum were dilapiol (64.03%), (E)-β-ocimene (8.4%) and piperitone (4.65%), P. divaricatum was characterized by eugenol (26.93%), methyleugenol (19.11%), (E)-β-ocimene (10.81%), acetyleugenol (9.25%), (E) - caryophyllene (7.78%), germacrene D (6.97%) and β-elemene (9.93%). P. hostmannianum, showed linalool (21.54%), β-pinene (20.03%), (E)-caryophyllene (15.05%) and (E)-α- bergamotene (6.96%), the EO P. wachenheimii showed linalool (32.34%), myrcene (14.89%), limonene (9.77%), (E)-caryophyllene (6.67%), β-pinene (4.78%) and α-pinene (4.61%). The antioxidant capacity performed with TEAC showed that only P. divaricatum obtained a result higher than the standard (1mM of Trolox) being 1.313 mM, for the DPPH method, P. aduncum (1.03 Mm), P. divaricatum (1.06 Mm), P. hostmannianum (1.09 mM) and P. wachenheimii (1.09 mM) were higher than the standard. The result of phytotoxicity of EOs from P. aduncum, P. divaricatum, P. hostmannianum and P. wachenheimii caused inhibition mainly on germination and elongation of the radicle of M. pudica and S. obtusifolia. For the hypocotyl of M. pudica, it was observed that the EOs of P. divaricatum, P. hostmannianum and P. wachenheimii caused stimulation in the elongation and for S. obtusifolia, all EOs caused inhibition in the elongation of the hypocotyl.