Estudos Quimiofenético e Farmacognóstico de Piper gaudichaudianum Kunth e Piper multinodum C. DC. (Piperaceae)

Abstract

Piper gaudichaudianum Kunth and Piper multinodum C. DC. are species that show distinct spatial distribution patterns, being the former medicinal and the latter new from the chemical and pharmacological points of view. These species were studied with the purpose of evaluating how the chemical phenotypic plasticity is presented and how it is influenced by spatial (distribution areas and different vegetative organs) and temporal (circadian rhythm and seasonality) factors, as well as how these alterations may influence the biological activities. To understand this complex biological issues, collections, cultivations, application of chromatographic techniques and spectrometric methods, as well as antimicrobial and antifungal activities were performed. Evaluations of chemophenetic patterns from the chemical composition of essential oils (EOs) of P. gaudichaudianum and P. multinodum were carried out. A predictive methodology was developed and conceptually tested for quantitative evaluation of the oxidation-reduction of complex mixtures of compounds by the unpublished Weighted Average Redox standard (SRO) and Ecological Oxirreduction Index (EIRO) (General Mixture Redox Index - GMRO, or Ramos & Moreira index), developed in this Thesis. The EOs of P. gaudichaudianum presented in the leaves the majority compounds bicyclogermacrene, E-caryophyllene, eudesmadiene, E-nerolidol, α-cadinol and spatulenol. The performed chemometric analyses and the correlations allowed evidencing that there were changes in the chemical composition in different phenological stages and, more evidently, between days and nights than between the dry and rainy periods. The existence of nine possible chemotypes for P. gaudichaudianum was determined. The analyses of SRO and EIRO showed that there is a direction for a possible redox balance from day to night. It was possible to demonstrate that the diversification in number of compounds by carbon skeleton in the EOs is followed by the increase of the level of oxidation weighted of the compounds. Furthermore, it was recorded by chemometric analyses that the volatile compositions did not vary under controlled cultivation condition. Considering P. multinodum, it was possible for the first time to characterize the chemical composition of the EO, and to demonstrate significant chemical and biosynthetic differences among the different organs. Aerial parts (leaves, branches, inflo- and infructescences) recorded mostly α-pinene and a predominance of metabolites from the mevalonate or methylerythrose phosphate pathways; and the non-aerial parts (stems and roots) showed higher percentage of E-methyl-isoeugenol and euasarone, with a predominance of compounds from the shikimate pathway. These chemical composition variations were important for determination of the biological activity, because samples containing arylpropanoids showed higher inhibition of bacterial growth. Analysis of the results of EIRO made possible to infer about an oxidative gradient in P. multinodum, being the most oxidized mixtures present in the leaves and the most reduced ones in the roots. In seasonal and circadian variations, α-pinene (15-60%) was determined as the major component. It was possible to evidence for P. multinodum that the chemical variations in the EOs are associated to abiotic factors and phenology, as well as to associate these chemical variations to the activity against fluconazole resistant Candida glabrata. Based on all the results obtained, we describe for the first time the high chemical phenotypic plasticity presented in different temporal and spatial scales and its implications for chemophenetics, chemosystematics and ecology in two Piperaceae species that may be used for future studies with other species of this family.