Quimiodiversidade de óleos essenciais de folhas de Piper richardiifolium Kunth (Piperaceae) em diferentes elevações no Parque Nacional da Serra dos Órgãos (Teresópolis-RJ)

Abstract

The intra and interspecific variations of species lead to a need to comprehend how secondary metabolites can diversify at individual and collective levels. Piper species are models for ecological and evolutionary studies because of their different plastic responses and their important role in the interaction with insects and fruit bats. Piper richardiifolium is a native and endemic species from Brazil, belonging to the Macrostachys clade and with few literary resources on chemical-volatile constituents present in its essentials. Thus, this work aims to determine how micromolecular trends and influences of different levels of chemodiversity in leaf essences of a population of Piper richardiifolium that occurs in different elevation patterns in Serra dos Órgãos National Park – Teresópolis – RJ. A total of 12 different individuals were collected at different elevation patterns, identified and their essential oils were extracted by hydrodistillation in modified Clevenger apparatus. The identification of chemical constituents was performed by gas chromatography applied to mass spectrometry (GC-MS) and the quantification of substances was elucidated employing gas chromatography coupled to a flame ionization detector (GC-FID). The parameters calculated for the intraspecific and interspecific variations and the micromolecular trends were the chemodiversity indexes (individual and populational) and two new indexes of micromolecular trend for chemophenetics (individuals), one of which was developed in this Dissertation. A total of 111 substances were identified, with abundant non-oxygenated monoterpenes (α-pinene, β-pinene and camphene), non-oxygenated sesquiterpenes (bicyclogermacrene and bicycloelemene) and oxygenated sesquiterpenes (cis-dihydroagarofuran, 10-epi-γ-eudesmol, elemol, E-nerolidol and spathulenol). The elevation did not influence the chemical composition of P. richardiifolium (1000-1600 m), as well as the edaphoclimatic factors. A chemical homogeneity of volatiles substances was observed in analyzed specimens, except in two individuals, that can possibly be chemotype of this species. The indexes of diversity α has shown an homogeneity of the dominance and diversity characteristics in the different elevations, showing an chemical homeostasis. The chemodiversity β indexes has shown low chemical similarity between the specimens. The chemophenetic index, Ramos&Moreira (R&M), has shown that the specimens have a reduced volatile mixture. In lower elevations, was registered a bigger variation of the R&M, but in higher elevations a homogeneity was registered for that index. The new ecological index developed in this manuscript, the CDE, demonstrated big potential to evaluate the metabolic dynamics of the specimens in spacial and temporal scales, showing how biosynthetic routes can benefit the adaptation of species. However, more researches need to be realized for the validatio