This work aimed to determine the chemical composition of essential oils from rhizomes and leaves of Renealmia chrysotricha Petersen, R. breviscapa Poepp. & Endl. and R. nicolaioides Loes., and to evaluate the biological activities of these oils on three Candida species and the parasite Trypanosoma cruzi. The rhizomes and leaves were collected in the Atlantic and Amazon rainforests. Essential oils were isolated and characterized by gas chromatography. Βeta-Caryophyllene was found to be the most predominant compound in the essential oils of rhizomes and leaves of R. breviscapa, and the rhizomes of R. nicolaioides, whereas (E)-nerolidol was the most abundant compound in the oils of leaves of R. nicolaioides. In R. chrysotricha, α-terpineol, coronarin-E and 1,8-cineole were found to be the most predominant compounds in the essential oils of rhizomes, whereas cis-3hexenol was predominant in the leaves. The tested oils did not inhibit C. albicans growth at 1000 µg/mL, whereas leaf oils from R. chrysotricha and R. nicolaioides inhibited the growth of C. buinensis and C. tropicalis by about 50%. Essential oils from the rhizomes and leaves of R. chrysotricha exhibited efficient antiparasitic activity against Trypanosoma cruzi. Damage to T. cruzi epimastigotes was confirmed by LM and TEM.

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Based on field observations of several natural populations of Renealmia chrysotricha (Zingiberaceae) in the Brazilian Atlantic Forest and comparison with other specimens in different herbarium collections, the morphological circumscription of this species was broadened with the inclusions of Alpinia humilis, R. angustifolia, R. brasiliensis, R. longipes, R. petasites, and R. reticulata as synonyms. The expanded analysis of the morphological characteristics, such as the presence of sessile leaves, reticulation patterns of its leaf-sheaths, flowers with short pedicels, and membranous bracts, suggest that these species share the same characteristics used to circumscribe them.

How to cite: GeVÚ KV, CARVAlhO mG, SIlVA IG, lImA hRP, CASTRO RN AND DA CUNhA m. 2019. Phenolic compounds from the rhizome of Renealmia nicolaioides loes.: a new diarylheptanoid. An Acad Bras Cienc 91: e20180312.Abstract: This study aims to identify phenolic compounds in dichloromethane and methanolic extracts of the rhizome of Renealmia nicolaioides collected in the North Region of Brazil. Two known diarylheptanoids, 1,7-bis(4-hydroxyphenyl)-(1e)-1-hepten-3-one (1), and 5R-1,7-bis(4-hydroxyphenyl)-1e-hepten-5-ol (2), and a new one (1R,2S,5S)-2-hydroxy-1,7(p-hydroxyphenyl)-centrolobine (3), as well as one flavonoid, 3-metoxi-quercetin (4) were isolated by chromatographic procedure and identified by spectroscopic techniques (1h and13C NmR, hRmS and CD). The acetyl derivative of 2 was used to confirm its structure. All four compounds are reported for the first time for this genus, and this is the first occurrence of compound 1 as a natural metabolite. The results reported here are unprecedented for the genus Renealmia.

Avaliação das Substâncias Fenólicas em Rizomas de Três Espécies de Renealmia L. f.: Quantificação, Atividade Antioxidante e Histolocalização Resumo: A histolocalização das substâncias fenólicas foi feita por técnicas usuais em Anatomia Vegetal. A determinação do teor de fenóis totais e do teor de flavonoides foram realizadas por métodos espectrofotométricos. A atividade antioxidante foi avaliada pelos métodos DPPH, ABTS e FRAP. Todos os extratos avaliados apresentaram capacidade antioxidante; entretanto, os melhores resultados foram para os extratos de R. nicolaioides. Correlação positiva foi encontrada entre o conteúdo total de fenólicos e os ensaios de capacidade antioxidante. Os resultados são inéditos para o gênero em questão e contribuem para novas pesquisas sobre substâncias fenólicas e suas atividades antioxidantes.

This aim of this study was to evaluate the lignification in young stems of the Lophanthera lactescens Ducke plant grown in vitro L. lactescens (Malpighiaceae), a species endemic in the Brazilian Amazon that possesses both medicinal properties and could be used in the forest product industry. Plants grown in vitro condition in MS medium were analyzed using Infrared (IR) microspectroscopy in a diffuse reflectance mode, fluorescence microscopy. Moreover, histochemical tests such as the Wiesner and Maüle test were run to monitor the process of lignification in cell walls. The spectra of IR microscopy recorded using cross section tissue are representative of guaiacyl/syringyl lignin, based on the 1336 and 1246 cm -1 signal. Individuals presenting stem sprains, resulting from the marked development, produced gelatinous fibers with a clear cellulose layer. Initially, fluorescence microscopy demonstrated lignin deposition in the cell corner region having progressive deposition in the secondary wall of tracheary elements of the stem.Keywords: lignification, fluorescence, infrared microspectroscopy. Anatomia e status da lignificação de plantas de Lophanthera lactescens Ducke crescidas in vitro ResumoEsta pesquisa teve como objetivo avaliar a lignificação em caules jovens de plantas de Lophanthera lactescens Ducke crescidas in vitro. L. lactescens (Malpighiaceae) é uma espécie endêmica da Amazônia Brasileira que, além de propriedades medicinais, apresenta potencial para a indústria de produtos florestais. As plantas foram crescidas in vitro, usando-se meio nutritivo MS. As análises foram realizadas por microespectrometria no infravermelho, no modo reflectância difusa. Microscopia com fluorescência e testes histoquímicos de Wiesner e Maüle foram realizados para o acompanhamento do processo de lignificação. Os espectros registrados a partir da microscopia no infravermelho mostraram sinais em 1336 e 1246 cm -1 , característicos de ligninas siringílica e guaiacílica. Indivíduos que apresentaram entorses no caule, em decorrência do acentuado desenvolvimento, produziram fibras gelatinosas, com a camada de celulose evidente. A microscopia com fluorescência evidenciou deposição de lignina inicialmente nos ângulos das células, com depósito progressivo ocorrendo na parede secundária dos elementos traqueais do caule.Palavras-chave: lignificação, fluorescência, microscopia infravermelho.