A series of novel 1-(substituted-phenyl)-3-(4,5-dihydro-1,3-oxazol-2-yl)-9H-β-carboline (8a-8i) and 1-(substituted-phenyl)-3-(5,6-dihydro-4H-1,3-oxazin-2-yl)-9H-β-carboline (9a-9h) derivatives, as well as their respective N-(chloroalkyl)-1-(substituted-phenyl)-9H-β-carboline-3-carboxamide precursors (6a-6i and 7a-7h), were synthesized and evaluated for their in vitro antileishmanial activity against promastigote and intracellular amastigote forms of Leishmania amazonensis. Compounds 8d, 8i, 9e and 9h exhibited significant activity for both promastigote and amastigote forms, with IC50 (50% inhibitory concentration) values ranging from 2.9 to 23.0 µM. In addition, spin label electron paramagnetic resonance (EPR) spectroscopy studies were carried out for the most active compounds against L. amazonensis promastigotes. The studies indicated that the tested compounds cause strong stiffness in the parasite plasma membrane and are capable of inducing internal metalloproteins oxidation of the parasite, resulting in their cross-linking to skeletal proteins. Compounds 8d and 8i produced the largest effect, showing that the presence of oxazoline group at C-3 of β-carboline nucleus is important for antileishmanial activity.

Marine strains of Bacillus are known to produce secondary metabolites different from that accumulated by their terrestrial counterparts, for example, lipopeptides such as surfactins, iturins and fengycins, which exhibit a variety of biological activities. Another important class of lipopeptides are pumilacidins, identified specially from Bacillus pumilus strains, usually by using liquid chromatography-mass spectrometry (LC-MS) techniques. In this work, five knowns pumilacidins were isolated from the solid culture of the marine-derived bacterium Bacillus sp. 4040. The structures of compounds, pumilacidins A-E, were determined using a combination of mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy and comparison with reported data. The 1H and 13C NMR data of pumilacidin B is being described here for the first time. All compounds were evaluated against five microorganisms, but no antimicrobial activity was detected.

Sesquiterpene lactones are an important class of secondary metabolites frequently isolated from Vernonanthura genus that present a variety of biological properties, including antiproliferative activity. Due to the limitation of pharmacological studies on Vernonanthura nudiflora, the aim of this work was to investigate their antioxidant potential and antiproliferative activity against human tumor cells, as well as to isolate and identify the chemical constituents present in their aerial parts. The phytochemical investigation resulted in the isolation of the sesquiterpene lactones piptocarphins A, B, D, and a new hirsutinolide derivative, 8α-tigloyloxy-10α-hydroxy-hirsutinolide, besides triterpenes, glycosylated steroids, flavonoids, and one chlorogenic acid derivative. Also, other sesquiterpene lactones were identified by ultra-high performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS) from dichloromethane fraction. This fraction showed activity against the tumor cells tested, mainly against leukemia, glioma, ovarian and kidney, with growth inhibitory activity (GI50) less than 0.80 µg mL-1. Piptocarphins A and B, in mixture, showed strong activity against all human cancer cell lines tested, with GI50 values ≤ 0.15 µg mL-1. Piptocarphin D was selective for glioma and resistant ovarian cell lines. The new hirsutinolide derivative showed potent activity against breast (GI50= 0.96 µg mL-1) and resistant ovarian (GI50 = 3.60 µg mL-1) cell lines.

Bioguided fractionation of a hydroethanolic extract from the stem bark of Croton echioides Baill. led to isolation of the new indole alkaloid N-trans-feruloyl-3,5-dihydroxyindolin-2-one as a stereoisomeric mixture and the known alkaloids N-trans-p-coumaroyl-tryptamine, N-trans-p-coumaroyl-5-hydroxytryptamine, N-trans-4-methoxy-cinnamoyl-5-hydroxytryptamine, N-trans-feruloyl-5-hydroxytryptamine (moschamine), from the ethyl acetate fraction. The flavonoids 3-o-methyl kaempferol, 3-o-methyl quercetin, 3,7-di-o-methyl quercetin and 3,3'-di-o-methyl quercetin, together with the benzoic acid derivatives 4-hydroxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid and 4-hydroxy-3,5-dimethoxybenzoic acid were also isolated. Alkaloids and the flavonoids showed strong antioxidant properties in vitro radical scavenging assay (2,2-diphenyl-1-picrylhydrazyl, DPPH), with IC50 values ranging from 9.2 to 17.5 µmol L-1, lower than those of the positive control Trolox (IC50 = 17.9 µmol L-1). Alkaloids showed cytotoxic activity against the HCT-116 human cancer cell line, with IC50 values ranging from 86.8 to 210.7 µmol L-1. Compound N-trans-4-methoxy-cinnamoyl-5-hydroxytryptamine was the most active, with an IC50 value of 86.8 µmol L-1.

A series of β-carboline derivatives with amino or guanidinium were synthesized and evaluated in vitro against anti-Mycobacterium tuberculosis and for antiproliferative activities against nine human cancer cell lines. The compounds 1-(4-hydroxyphenyl)-3-carboxamide(ethylamine) β-carboline (24.9 µg mL-1) and 1-(4-methoxyphenyl)-3-carboxamide(ethylamine) β-carboline (26.9 µg mL-1) were the most active against M. Tuberculosis (MTB). Compounds 1-(4-hydroxyphenyl)-3-carboxamide(ethylamine) β-carboline and 1-(4-methoxyphenyl)-3-carboxamide(propylamine) β-carboline, which had the same substituted groups, inhibited the growth of all human tumor cell lines with growth inhibitory activity (GI50) values from 1.37 to 9.20 mmol L-1. Also in this series, compounds 1-(4-hydroxyphenyl)-3-carboxamide(propylamine) β-carboline and 1-(3-nitrophenyl)-3-carboxamide(propylamine) β-carboline demonstrated significant activity against NCI/ADR cells. Among compounds with a terminal guanidine group, compounds 1-(4-hydroxyphenyl)-3-carboxamide(ethyl)guanidine β-carboline (27.8 µg mL-1) and 1-(3-nitrophenyl)-3-carboxamide(ethyl)guanidine β-carboline (37.4 µg mL-1) demonstrated the greatest activity against MTB. Additionally, compounds 1-(4-methoxyphenyl)-3-carboxamide(ethyl)guanidine β-carboline (GI50 = 0.45 mmol L-1) effectively inhibited growth and was highly selective against NCI/ADR. The in silico study revealed that 1-(4-hydroxyphenyl)-3-carboxamide(ethylamine) β-carboline, 1-(4-methoxyphenyl)-3-carboxamide(ethylamine) β-carboline, 1-(4-hydroxyphenyl)-3-carboxamide(propylamine) β-carboline, 1-(4-methoxyphenyl)-3-carboxamide(propylamine) β-carboline and 1-(3-nitrophenyl)-3-carboxamide(propylamine) β-carboline compounds follow the rules established by Lipinski, suggesting that this compound has no problems with oral bioavailability.

Croton echioides Baill., Euphorbiaceae, is a small tree found in Bahia, Northeastern Brazil. Its stem bark has been widely sold as an aphrodisiac and tonic, as a substitute for the roots of Ptychopetalum olacoides Benth. Olacaceae, the Amazon Muira Puama or Marapuama, and C. echioides is characterized as the "Northeastern Marapuama". This contribution describes a morphoanatomical analysis and pharmacognostic study of stem bark of this species. The stem has a thick cortex with compound starch grains and laticifers; a sclerenchymatic sheath which consists of brachysclereids with large crystals externally to the phloem, and abundant fiber in the secondary xylem, as the main features of the species. The data obtained for water content (9.26±0.07%), water-soluble extractives (3.92±0.19%), total ash (1.24±0.06%) and acid-insoluble ash (0.16±0.01%), together with the chromatographic profile obtained by TLC, contribute to the quality control and standardization for the plant drug. The pharmacological screening indicated LD50 values above 500 mg/kg orally and equal to 500 mg/kg by the i.p. route, as well as some stimulant potential, depending on the dose.

O estudo fitoquímico das folhas de Calycorectes psidiiflorus (O. Berg) Sobral, Myrtaceae, resultou no isolamento e identificação de: sesquiterpeno [8-hidroxicalameneno (1)], triterpenos [α-amirina (2a) e β-amirina (2b)], flavonóide [3-O-α-ramnopiranosil-7-O-bglucopiranosil canferol (3)], e alcalóide [1,2,3,4-tetraidro-1-metil-β-carbolina (4)]. As estruturas das substâncias isoladas foram elucidadas com base nos seus dados de RMN em comparação com os da literatura. A substância 8-hydroxicalameneno apresentou atividade antibacteriana (MIC = 7,8 µg/mL) e antifúngica (MIC = 15,6 µg/mL).

The phytochemical study of Calycorectes psidiiflorus (O. Berg) Sobral leaves resulted in isolation and identification of the sesquiterpene 8-hydroxycalamenene (1), triterpenes α-amyrin (2a) and β-amyrin (2b), flavonoid 3-O-α-rhamnopyranosyl-7-O-β-glucopyranosyl kaempferol (3), and of the alkaloid 1,2,3,4-tetrahydro-1-methyl-β-carboline (4). The structures of the isolated compounds were elucidated based on their spectroscopic NMR data and comparison with those reported in literature. Substance 1 presented antibacterial (MIC = 7.8 µg/mL) and antifungal (MIC = 15.6 µg/ mL) activities.

Extratos de Croton fluribundus (Euphorbiaceae), ácido caurenóico e dois derivados do ácido caurenóico foram avaliados como moluscicida, cercaricida e também foi verificada a letalidade destas amostras frente a larvas de Artemia salina Leach. Nestes ensaios foram observadas significantes atividades moluscicida e cercaricida associadas a uma reduzida toxicidade frente ao camarão de água salgada.

Lethality of the extracts of Croton floribundus (Euphorbiaceae), a medicinal plant from south Brazil, and of the kaurenoic acid, an isolated compound, and two of its derivatives against adult Biomphalaria glabrata snails, Schistosoma mansoni cercariae and Artemia salina Leach. brine shrimp larvae are reported. Both extracts and the isolated compound showed significant molluscicidal and cercaricidal activities and reduced toxicity in brine shrimp assays.

No presente trabalho descrevemos a síntese e a avaliação da atividade antiproliferativa, frente a linhagens de células tumorais humanas, de derivados do R-(+)-limoneno (3-18) contendo uma unidade tiouréia substituída. Os derivados com substituintes arílicos (3-6) exibiram atividade citostática frente a todas linhagens testadas, com inibição de 50% do crescimento celular (GI50) em concentrações na faixa de 2,5 a 24 µmol L-1. Os compostos 3, 10, 12 e 16 foram os mais ativos, com GI50 na faixa de 0,41 a 3,0 mmol L-1, frente a diferentes linhagens celulares.

A series of R-(+)-limonene derivatives bearing a substituted thiourea moiety (3-13) and five S-methyl analogs (14-18) were synthesized and evaluated for their in vitro antiproliferative activity against human cancer cell lines. Compounds bearing aromatic substituents (3-6) exhibit cytotastic activity in the full panel of cell lines tested, with GI50 values in the range of 2.5 to 24 µmol L-1. Compounds 3, 10, 12 and 16 were the most active with GI50 values in the range of 0.41 to 3.0 µmol L-1, against different cell lines.

Este trabalho descreve um procedimento rápido e eficiente para a separação e identificação de alcalóides indólicos do extrato etanólico de Tabernaemontana fuchsiaefolia (Apocynaceae). As frações alcaloídicas obtidas dos extratos etanólicos (das folhas, das cascas do caule e das cascas das raízes) foram fracionadas e analisadas por cromatografia em camada delgada (CCD) e por cromatografia gasosa acoplada a espectrometria de massa (CG-EM). Foram identificados os alcalóides indólicos ibogamina, coronaridina, pseudoindoxil ibogaina, hidroxiindolenina voacangina, pseudoindoxil voacangina, tabernantina, catarantina, voacangina, 19-oxovoacangina, 10-hidroxicoronaridina, afinisina, 16-epi-afinina, voachalotina, ibogalina e conofaringina.

This paper describes a fast and efficient procedure to separate and identify indole alkaloids from the ethanolic extract of Tabernaemontana fuchsiaefolia (Apocynaceae). The alkaloidal fractions obtained from ethanolic extracts of leaves and stem barks and root barks were fractioned and analyzed by Thin-Layer Chromatography (TLC) and by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The following indole alkaloids were identified: ibogamine, coronaridine, ibogaine pseudoindoxyl, voacangine hydroxyindolenine, voacangine pseudoindoxyl, tabernanthine, catharanthine, voacangine, 19-oxovoacangine, 10-hydroxycoronaridine, affinisine, 16-epi-affinine, voachalotine, ibogaline, and conopharyngine.