Mari-mari (Cassia leiandra Benth.) is an Amazonian native fruit that is highly appreciated in the northern region of Brazil, but there are few studies regarding its chemical composition and/or biological properties. A phytochemical study was conducted on the extracts of the pulp, peel and seeds; and their antioxidant, cytotoxic and antimicrobial potential were also determined. Methanol and acetone extracts from different fruit parts were subjected to total phenolic, 2,2-diphenyl-1 picrylhydrazyl (DPPH) radical scavenging and FeIII reducing capacity (FRAP) assays. From the peel extracts, the engeletin and astilbin could also be isolated and characterized based on nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. A quantification using ultra-fast liquid chromatography of acetone dry crude extracts (DCE) of the peel showed that engeletin was the main compound (532.77 mg g-1 DCE). Astilbin content was also determined (131.53 mg g-1 DCE). The antibacterial and antiproliferative activities were evaluated and the methanol extract of the peel showed higher growth inhibition activity against all tested bacteria. Engeletin showed a relevant antimicrobial effect against Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. Acetone and methanol peel extracts exhibited a relevant inhibitory effect on the proliferation of breast carcinoma cells (MCF-7), with no toxicity to the normal cell line (NIH/3T3).

Phytochemical investigation of Endopleura uchi led to the isolation of a gallic acid derivate, known as bergenin (2) and friedelin (1), a pentacyclic triterpene. The present work also reports the bergenin quantification in different Endopleura uchi bark, twig and leaves extracts. Our findings showed the highest bergenin concentration in bark methanol extracts (4.75%) and the lowest concentration in twig aqueous extracts (1.89%). Phenolics quantification by Folin-Ciocalteu, revealed phenolic compounds level values from 16.69 to 43.02 mg GAE g-1 dry extract. The ferric reducing antioxidant activity ranged from 230.43 to 567.89 mmol Fe+2 g-1 dry extract. DPPH IC50 free radicals showed to range from 12.04 to 24.20 μg mL-1. Leaves’ chloroform fraction exhibited the highest nitric oxide inhibiting activity bearing IC50= 3.2 μg mL-1. Results show this species to hold significant bergenin concentrations as well as phenolic and anti-inflammatory compounds in all extracts suggesting it bear therapeutic potential.

In the present study, in vitro techniques were used to investigate a range of biological activities of known natural quassinoids isobrucein B (1) and neosergeolide (2), known semi-synthetic derivative 1,12-diacetylisobrucein B (3), and a new semi-synthetic derivative, 12-acetylneosergeolide (4). These compounds were evaluated for general toxicity toward the brine shrimp species Artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector Aedes aegypti, haemolytic activity in mouse erythrocytes and antimalarial activity against the human malaria parasite Plasmodium falciparum. Compounds 1 and 2 exhibited the greatest cytotoxicity against all the tumor cells tested (IC50 = 5-27 µg/L) and against multidrug-resistant P. falciparum K1 strain (IC50 = 1.0-4.0 g/L) and 3 was only cytotoxic toward the leukaemia HL-60 strain (IC50 = 11.8 µg/L). Quassinoids 1 and 2 (LC50 = 3.2-4.4 mg/L) displayed greater lethality than derivative 4 (LC50 = 75.0 mg/L) toward A. aegypti larvae, while derivative 3 was inactive. These results suggest a novel application for these natural quassinoids as larvicides. The toxicity toward A. franciscana could be correlated with the activity in several biological models, a finding that is in agreement with the literature. Importantly, none of the studied compounds exhibited in vitro haemolytic activity, suggesting specificity of the observed cytotoxic effects. This study reveals the biological potential of quassinoids 1 and 2 and to a lesser extent their semi-synthetic derivatives for their in vitro antimalarial and cytotoxic activities.

Endopleura uchi (Huber) Cuatrec. é uma planta medicinal da Amazônia utilizada no tratamento de inflamações e doenças do aparelho reprodutor feminino. A bergenina pura foi isolada do extrato metanólico das cascas de E. uchi, inicialmente por um processo de partição líquido-líquido, seguido de cromatografia em coluna de permeação em gel Sephadex LH-20 e finalmente de adsorção utilizando sílica gel 60. A elucidação estrutural foi determinada pela análise dos espectros de RMN. A atividade anti-inflamatória in vitro foi determinada pela medida da concentração inibitória (CI) da bergenina frente a três importantes enzimas: COX-1, COX-2 (ciclooxigenases) e fosfolipase A2 (PLA2). Essas enzimas foram selecionadas, porque são importantes alvos terapêuticos no processo de descobrimento de novas drogas anti-inflamatórias associadas com a biossíntese das prostaglandinas. A CI50 da bergenina para a fosfolipase A2 foi de 156,6 µmol L-1. Comparada ao padrão de tioeteramida PC, bergenina foi considerada pouco ativa. A bergenina também não foi capaz de inibir COX-1 (CI50 = 107,2 µmol L-1). Entretanto, bergenina foi capaz de inibir seletivamente COX-2 (CI50 = 1,2 µmol L-1). Considerando o uso de E. uchi na medicina tradicional, a quantidade de bergenina no extrato aquoso preparado da forma popular foi quantificado por CLAE em fase reversa como sendo 3% nas cascas. Esses resultados indicam uma alta concentração de bergenina nos chás e nas cascas. A atividade inibitória seletiva para COX-2 também é importante, uma vez que inibidores seletivos de COX-2 têm sido clinicamente validados como drogas anti-inflamatórias por sua eficácia e por não apresentar efeitos gastrintestinais colaterais.

Endopleura uchi (Huber) Cuatrec. is an Amazon species traditionally used for the treatment of inflammations and female disorders. Pure bergenin was isolated from the methanolic extract of bark of E. uchi, firstly by using liquid-liquid partition chromatography followed by column chromatography over Sephadex LH-20 and then silica gel 60 flash chromatography. The structure of bergenin was identified on the basis of its NMR spectra. The in vitro anti-inflammatory activity was determined by the measurement of the inhibitory concentration (IC) of bergenin against three key enzymes: COX-1, COX-2 (cyclooxygenases) and phospholipase A2 (PLA2). These enzymes were selected because they are important targets for the discovery of new anti-inflammatory drugs associated with the biosynthesis of prostaglandins. The IC50 of bergenin for phopholipase A2 was determined as 156.6 µmol L-1 and bergenin was not considered active as compared to the positive control, tioetheramide PC. Bergenin did not inhibit COX-1 as well (IC50 = 107.2 µmol L-1). However, bergenin selectively inhibited COX-2 (IC50 = 1.2 µmol L-1). Because of the use of E. uchi in traditional medicine, bergenin was quantified in teas prepared as prescribed in traditional medicine by RP-HPLC as being 3% in the bark of E. uchi. The inhibitory activity towards COX-2 is important, since selective inhibitors of COX-2 have been clinically validated as anti-inflammatory therapeutics due to their enhanced gastrointestinal safety.

O trabalho consiste na re-investigação dos frutos de Iryanthera juruensis e Virola pavonis e das folhas de V. michelii, bem como no estudo dos frutos de V. mollissima. A partir de I. juruensis foram isoladas uma neolignana ariltetralínica (1) e uma neolignana tetraidrofurânica (2), enquanto que de Virola pavonis foram isoladas neolignanas benzofurânicas (6-9), tetraidrofurânicas (2, 11-13, 17), bifenílica (10), diastereoisômeros de uma hidróxi-neolignana 8.O.4'(14-15) e outras. V. mollissima acumula a neolignana ariltetralônica 4 ou o seu derivado seco (5). As folhas de V. michelii apresentaram a ocorrência de lignanas furofurânicas (18-19). Os lignóides 1 e 2 obtidos dos arilos de I. juruensis apresentaram atividade leishmanicida contra a forma promastigota de Leishmania amazonensis.

This work revisits the fruits of Iryanthera juruensis and Virola pavonis and the leaves from V. michelii, as well as describing a study of the fruits of V. mollissima. In I. juruensis aryltetraline neolignan (1) and tetrahydrofuran neolignan (2), were found while from V. pavonis neolignans of benzofuran type (6-9), the tetrahydrofuran type (2, 11-13, 17) and the biphenyl type (10), in addition to diastereoisomers of the 8.O.4'-oxyneolignan type (14 and 15) and others were isolated. The V. mollissima accumulates the aryltetralone neolignan 4 and its seco derivative (5). The lignoids 1 and 2 obtained from I. juruensis arils possess antileishmanial activity against the promastigote form of Leishmania amazonensis.

In the present study, a quassinoid, neosergeolide, isolated from the roots and stems of Picrolemma sprucei (Simaroubaceae), the indole alkaloids ellipticine and aspidocarpine, isolated from the bark of Aspidosperma vargasii and A. desmanthum (Apocynaceae), respectively, and 4-nerolidylcatechol, isolated from the roots of Pothomorphe peltata (Piperaceae), all presented significant in vitro inhibition (more active than quinine and chloroquine) of the multi-drug resistant K1 strain of Plasmodium falciparum. Neosergeolide presented activity in the nanomolar range. This is the first report on the antimalarial activity of these known, natural compounds. This is also the first report on the isolation of aspidocarpine from A. desmanthum. These compounds are good candidates for pre-clinical tests as novel lead structures with the aim of finding new antimalarial prototypes and lend support to the traditional use of the plants from which these compounds are derived.

A cromatografia líquida de alta performance vem sendo uma das principais técnicas empregadas no controle de qualidade de produtos fitoterápicos. Nesse trabalho é descrito um método de quantificação dos componentes principais presentes em diferentes extratos hidroalcoólicos de partes aéreas de Piper aduncum.

High performance liquid chromatography is one of the major analytical techniques used in the quality control of phytoterapics. This work describes a HPLC method used to determine the major components present in different hydroalcoholic extracts of aerial parts of Piper aduncum.