RESUMO Muitos alimentos interagem com medicamentos e podem causar alterações nos efeitos farmacológicos do agente terapêutico coadministrado. A enzima CYP3A4, que pertence ao complexo enzimático do citocromo P450, é responsável pelo metabolismo da maioria dos medicamentos atualmente no mercado e está envolvida em muitas interações medicamentosas. Assim, a interação dessa enzima com sucos de algumas frutas, como a toranja, pode afetar a farmacocinética de vários medicamentos. No entanto, frutas nativas da região amazônica ainda não foram alvo desse tipo de pesquisa. Determinamos polifenóis e flavonoides totais dos frutos amazônicos de açaí (Euterpe precatoria), buriti (Mauritia flexuosa), camu-camu (Myrciaria dubia), cubiu (Solanum sessiliflorum), cupuaçu (Theobroma grandiflorum), jenipapo (Genipa americana) e taperebá (Spondias mombin) e avaliamos os efeitos de cada suco de fruta sobre a atividade de CYP3A4, utilizando o suco de carambola (Averrhoa carambola) como controle positivo. O suco de açaí apresentou o maior teor de polifenóis totais e flavonóides (102,6 ± 7,2 µg equivalente de ácido gálico (GAE) por mL e 7,2 ± 0,6 µg equivalente de quercetina (QE) por mL, respectivamente). Todos os sucos foram capazes de inibir a atividade de CYP3A4. Não houve atividade residual da enzima metabolizadora de fármacos para os sucos de açaí, buriti, cubiu, camu-camu e taperebá, enquanto para cupuaçu, jenipapo e o controle positivo, a atividade residual foi de 44,3, 54,3 e 20,2%, respectivamente. Estudos adicionais devem identificar o(s) fitocomposto(s) responsável(is) por esta atividade de inibição, para esclarecer os mecanismos envolvidos neste fenômeno.

ABSTRACT Many foods interact with drugs and may cause changes in the pharmacological effects of the co-administered therapeutic agent. The enzyme CYP3A4, which belongs to the cytochrome P450 enzyme complex, is responsible for the metabolism of most drugs currently on the market and is involved in many drug interactions. Hence, the interaction of this enzyme with juices of some fruits, such as grapefruit, can affect the pharmacokinetics of various drugs. However, native fruits from the Amazon region have not yet been the target of this type of research. We determined total polyphenols and flavonoids of the Amazonian fruits açaí (Euterpe precatoria), buriti (Mauritia flexuosa), camu-camu (Myrciaria dubia), cubiu (Solanum sessiliflorum), cupuaçu (Theobroma grandiflorum), jenipapo (Genipa americana), and taperebá (Spondias mombin) and evaluated the effects of each fruit juice on CYP3A4 activity, using the star fruit (Averrhoa carambola) juice as positive control. Açaí juice presented the highest content of total polyphenols and flavonoids (102.6 ± 7.2 µg gallic acid equivalent (GAE) per mL and 7.2 ± 0.6 µg quercetin equivalent (QE) per mL, respectively). All juices were able to inhibit the activity of CYP3A4. There was no residual activity of the drug-metabolizing enzyme for açai, buriti, cubiu, camu-camu, and taperebá juice, while for cupuaçu, jenipapo and the positive control, the residual activity was 44.3, 54.3 and 20.2%, respectively. Additional studies should identify the phytocompound(s) responsible for this inhibition activity, to clarify the mechanisms involved in this phenomenon.

ABSTRACTThe genus Erythrina, Fabaceae, is widely distributed in tropical and subtropical regions. Their flowers, fruits, seeds and bark are frequently used in folk medicine for its effects on the central nervous system such as anticonvulsant, antidepressant, analgesic, sedative, and hypnotic effects. Erythraline has been reported as one of the active compounds from Erythrina, but until now there are no pharmacokinetics data about this compound and only few results showing a putative metabolism were reported. To improve the information about erythraline metabolism, this article reports and discusses, for the first time, the in vitrometabolism biotransformation of erythraline by cytochrome P450 enzymes.

The analysis of drugs and metabolites in biological fluids usually requires extraction procedures to achieve sample clean-up and analyte preconcentration. Commonly, extraction procedures are performed using liquid-liquid extraction or solid-phase extraction. Nevertheless, these extraction techniques are considered to be time-consuming and require a large amount of organic solvents. On this basis, microextraction techniques have been developed. Among them, liquid-phase microextraction has been standing out. This review describes the liquid-phase microextraction technique based on hollow fibers as a novel and promising alternative in sample preparation prior to chromatographic or electrophoretic analysis. The basic concepts related to this technique and its applicability in extraction of drugs are discussed.