Antibacterial and cytotoxic biflavonoids from the root bark of Ochna kirkii.

The new isoflavonoid kirkinone A (1) and biflavonoid kirkinone B (2) along with six known compounds (3-8) were isolated from the methanolic extract of the root bark of Ochna kirkii. The compounds were identified by NMR spectroscopic and mass spectrometric analyses. Out of the eight isolated natural products, calodenin B (4) and lophirone A (6) showed significant antibacterial activity against the Gram-positive bacterium Bacillus subtilis with MIC values of 2.2 and 28 µM, and cytotoxicity against the MCF-7 human breast cancer cell line with EC50 values of 219.3 and 19.2 µM, respectively. The methanolic crude extract of the root bark exhibited cytotoxicity at EC50 8.4 µg/mL. The isolated secondary metabolites and the crude extract were generally inactive against the Gram-negative Escherichia coli (MIC ≥400 µg/mL). Isolation of biflavonoids and related secondary metabolites from O. kirkii demonstrates their chemotaxonomic significance to the genus Ochna and to other members of the family Ochnaceae.

Plasmodium stage-selective antimalarials from Lophira lanceolata stem bark.

Targeting the transmissible stages of the Plasmodium parasite that develop in the human and mosquito host is a crucial strategy for malaria control and elimination. Medicinal plants offer a prolific source for the discovery of new antimalarial compounds. The recent identification of the gametocytocidal activity of lophirone E, obtained from the African plant Lophira lanceolata (Ochnaceae), inspired the evaluation of the plant also against early sporogonic stages of the parasite development. The bioassay-guided phytochemical study led to the isolation of two known lanceolins and of a new glycosylated bichalcone, named glucolophirone C. Its stereostructure, including absolute configuration of the bichalcone moiety, was elucidated by means of NMR, HRMS, ECD and computational calculations. Lanceolin B proved to be a potent inhibitor of the development of Plasmodium early sporogonic stages indicating that the plant produces two different stage-specific antimalarial agents acting on transmissible stages in the human and mosquito host.

Antitubercular evaluation of root extract and isolated phytochemicals from Lophira lanceolata against two resistant strains of Mycobacterium tuberculosis.

CONTEXT: The roots of Lophira lanceolata Van Tiegh. Ex Keay (Ochnaceae) have numerous medicinal values in the Central African region. Even though the MeOH extract of the roots has shown antimycobacterial activities, the constituents responsible for this inhibitory activity remain unknown. OBJECTIVE: Phytochemical investigation of the MeOH root extract of L. lanceolata and determination of the antimycobacterial activities of that extract and constituents against the growth of Mycobacterium tuberculosis. MATERIALS AND METHODS: Column chromatography was used to provide bioactive phytoconstituents. Those compounds were elucidated using MS and NMR spectroscopic data. Antimycobacterial screening of the extract (4.882-5000 µg/mL in DMSO during 24 h at 37 °C) and isolated compounds (0.244-250 µg/mL in DMSO during 24 h at 37 °C) was performed by microplate alamar blue assay (MABA) against two mycobacterial strains. RESULTS: The investigation of L. lanceolata MeOH roots extract provided of mixture of unseparated biflavonoids with a newly described one, dihydrolophirone A (1a) associated to lophirone A (1b). The bioactive compounds that effectively inhibited the growth of M. tuberculosis AC45 were found to be compounds 1 and 2. They exhibited MIC values of 31.25 and 15.75 µg/mL, respectively, and their MIC was found to be 62.5 µg/mL against resistant strain AC83. DISCUSSION AND CONCLUSIONS: It is clearly evident from the results obtained that the mycobacterial activity of L. lanceolata could be related mainly to its steroid and flavonoid contents. Therefore, this study suggests the potential of the above-mentioned classes of compounds as promising candidate agents for developing new anti-tuberculosis drugs.

A Nitrile Glucoside and Biflavones from the Leaves of Campylospermum excavatum (Ochnaceae).

The study of the MeOH extract of the leaves of Campylospermum excavatum led to the isolation of a nitrile glucoside, named campyloside C (1) and an original derivative of ochnaflavone, 7-O-methylochnaflavone (2), along with three known biflavonoids, amentoflavone, sequoiaflavone, and sotetsuflavone (3 - 5). The linkage site of the sub-units of 2 was confirmed by chemical correlation, after semi-synthesis of a trimethoxylated derivative of ochnaflavone (2a). The structures of these compounds as well as their relative and absolute configurations were assigned by 1D- and 2D-NMR experiments, HR-ESI-MS and Electronic Circular Dichroism (ECD) calculations. A low-pass J filter HMBC experiment was performed in order to define the configuration of the double bond of 1. All of the biflavonoids were evaluated against protozoan parasites. Amentoflavone moderately inhibited the promastigote form of Leishmania infantum.

A new procyanidin B from Campylospermum zenkeri (Ochnaceae) and antiplasmodial activity of two derivatives of (±)-serotobenine.

Phytochemical investigation of the stem bark of Campylospermum zenkeri led to the isolation of five known compounds: (Z,Z)-9,12-octadecadienoic acid (1), serotobenine (2), agathisflavone (3), lophirone A (4) and lophirone F (5), together with a new derivative of procyanidin B, a catechin dimer named zenkerinol (6). Serotobenine (2) is structurally related to decursivine which shows moderate activity against D6 and W2 strains of Plasmodium falciparum. For a better understanding of structure-activity relationships, three new semi-synthetic derivatives of serotobenine (2) have been prepared. These are: serotobenine monopropionate (2a), serotobenine monopivalate (2b) and serotobenine cyclohexyl ether (2c) respectively. Two of them (2a) and (2b), were evaluated for their antiplasmodial activity against P. falciparum 3D7 strain in a parasite lactate-dehydrogenase (pLDH) assay. Compound 2b was more active than compound 2a based on their IC50 values (36.6 and 123 µM, respectively).

Water supply and demand remain coordinated during breakdown of the global scaling relationship between leaf size and major vein density.

Vein networks that disobey the global scaling of major vein density with leaf size shed light on functional constraints of vein network formation in dicotyledons. Understanding their evolution, distribution and impact on vein-stomata-climate associations is an important contribution to our global view of vein network organization. Based on vein traits of 55 species of pantropical Ochnaceae, stomata and climatic niche data, and a dated molecular phylogeny, we unveil major structural shifts in vein networks through deep time, relationships between leaf size, vein and stomata traits, and their interplay with climate. Dense 2° veins, reduction of minor veins and the associated breakdown of vein-leaf size scaling evolved multiple times independently in Ochnaceae. In spite of the drastic changes in vein architecture in this venation type, vein and stomatal densities remain correlated. Our study demonstrates that shortening the major vein-stomata distance is economically not less advantageous than by increasing minor vein density, as illustrated by the same degree of coordination between vein and stomatal densities and the similar construction costs across networks with dense 2° veins and those with 'normally' spaced 2° veins.

Isolation of nuclear microsatellites in the African timber tree Lophira alata (Ochnaceae) and cross-amplification in L. lanceolata.

PREMISE OF THE STUDY: Microsatellite markers were isolated in the rainforest tree Lophira alata (Ochnaceae), an important timber tree from Central Africa, and cross-amplified on its savannah counterpart, L. lanceolata. METHODS AND RESULTS: From a microsatellite-enriched library sequenced on a 454 GS FLX platform, 13 primer combinations were identified. Amplification was optimized in two multiplex reactions. The primers amplified di- and trinucelotide repeats, with two to seven alleles per locus. Eleven primers also amplified in L. lanceolata. CONCLUSIONS: Microsatellite primers developed for the genus Lophira displayed sufficient variation to investigate hybridization between congeneric species in the rainforest-savannah transition.

Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana.

Seven flavonoids, hemerocallone (1), 6,7-dimethoxy-3',4'-dimethoxyisoflavone (2), amentoflavone (4), agathisflavone (6), cupressuflavone (8), robustaflavone (9) and epicatechin (10), together with three other compounds, lithospermoside (3), ß-D-fructofuranosyl-α-D-glucopyranoside (5) and 3ß-O-D-glucopyranosyl-ß-stigmasterol (7), were isolated from the ethyl acetate extract of the stem bark of Ochna schweinfurthiana F. Hoffm. All the compounds were characterised by spectroscopic and mass spectrometric methods, and by comparison with literature data. Cytotoxicity of the extracts and compounds against cervical adenocarcinoma (HeLa) cells was evaluated by MTT assay. Compounds 4 and 6 exhibited good cytotoxic activity, with IC50 values of 20.7 and 10.0 µM, respectively.

Biflavones and triterpenoids isolated from Ouratea castaneifolia (DC.) Engl., Ochnaceae / Biflavonas e triterpenóides isolados de Ouratea castaneifolia (DC.) Engl., Ochnaceae

This paper presents the chemical investigation of the leaves and stems of Ouratea castaneifolia (DC.) Engl.. There are no chemical or pharmacological studies with this species. Classic phytochemical investigation of the organic extracts together with high pressure liquid chromatography (HPLC) procedures lead to the identification of seventeen metabolites: seven triterpenes (friedelin, 3β-friedelinol, α-amyrin, β-amyrin, lupeol, germanicol and taraxerol), four steroids (sitosterol, stigmasterol and the glycosides sitosteryl 3-O-β-D-glucopyranoside and stigmasteryl 3-O-β-D-glucopyranoside), one isoflavone (5,7,4'-trimethoxyisoflavone), one flavone (5,4'-dihydroxy-7,3',5'-trimethoxyflavone) and four biflavones (amenthoflavone, 7,7"-O-dimethylamenthoflavone, heveaflavone and tetramethylamenthoflavone). The structures of the compounds were established by the analysis of ¹H, 13C NMR spectra including bidimensional techniques. The classes of the identified metabolites are in agreement with previous studies of the Ouratea genus.

O presente trabalho trata da investigação química das folhas e caule da espécie Ouratea castaneifolia (DC.) Engl., sobre a qual não há registros de estudos químicos ou farmacológicos anteriores. O estudo fitoquímico clássico dos extratos orgânicos do caule e das folhas de O. castaneifolia foi aliado à técnica da cromatografia líquida de alta eficiência (CLAE) e resultou na identificação de dezessete metabólitos: sete triperpenos (friedelina, 3β-friedelinol, α-amirina, β-amirina, lupeol, taraxerol e germanicol), quatro esteróides (sitosterol, estigmasterol e os glucosídeos sitosteril 3-O-β-D-glicopiranosídeo e estigmasteril 3-O-β-D-glicopiranosídeo), uma isoflavona (5,7,4´-trimetoxiisoflavona), uma flavona (5,4´-diidroxi-7,3´,5´-trimetoxiflavona), quatro biflavonas (amentoflavona, 7,7"-O-dimetil-amentoflavona, heveaflavona e tetrametilamentoflavona). A identificação das substâncias foi feita com base na análise de espectros de RMN de ¹H, 13C e técnicas bidimensionais. As classes dos metabólitos identificados estão de acordo com aquelas citadas em estudos químicos do gênero Ouratea.

A new derivative of dihydroochnaflavone isolated from Luxemburgia species (Ochnaceae) and the complete ¹H and 13C NMR chemical shifts assignments / Um novo derivado da dihidroochnaflavona isolada de Luxemburgia species (Ochnaceae) e o completo assinalamento dos dados de RMN de ¹H e 13C

The biflavonoid 2",3"-dihydroochnaflavone, isolated from the Luxemburgia species (Ochanaceae), was treated with diazomethane to obtain the trimethyl-ether that was treated with pyridine/acetic anhydride to yield a new derivative, 5-acetil-7,4'-dimethyl-flavone-(3'→O-4'")-5"-acetil-7"-methyl-flavanone. The complete ¹H and 13C NMR data assignments of the new derivative were made by the one- and two-dimensional spectral analysis.

O biflavonóide 2",3"-diidroochnaflavona, isolada de espécies de Luxemburgia (Ochanaceae), foi tratada com diazometano e forneceu o éter trimetílico que, em seguida, foi tratado com anidrido acético/piridina obtendo-se um novo derivado, 5-acetil-7,4'-dimetil-flavona-(3'→O-4'")-5"-acetil-7"-metil-flavanona. Fez-se o completo assinalamento dos dados de RMN ¹H e 13C através da análise dos espectros uni- e bidimensionais do derivado.

Bioactive flavone dimers from Ouratea multiflora (Ochnaceae)

Chromatographic fractionation of the organic extract from leaves of Ouratea multiflora afforded the flavone dimers heveaflavone, amentoflavone-7'',4''''-dimethyl eter, podocarpusflavone-A and amentoflavone. Their structures were elucidated from spectral data, including 2D-NMR experiments of the natural substances. Biological activities of all isolates were evaluated, using antimicrobial assay against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, cytotoxicity assay against mouse lymphoma (L5178) and KB cell lines, TLC screening for acetylcholinesterase inhibitors and antioxidant activity measured by DPPH test.

O fracionamento cromatográfico do extrato orgânico das folhas de Ouratea multiflora forneceu os flavonóides diméricos, heveaflavona, 7'',4''''-dimetilamentoflavona, podocarpusflavona-A e amentoflavona. Suas estruturas foram elucidadas com base nos dados espectrais, incluindo experimentos bidimensionais de RMN, das substâncias naturais. A atividade antibiótica de todos os isolados foi avaliada, usando-se as bacterias Gram-positivas Staphylococcus aureus and Bacillus subtilis. Teste de citotoxicidade nas linhagens de linfoma de ratos (L5178) e KB também foram conduzidos para avaliar os extratos e os flavonóides isolados. a triagem biológica para a avaliação de atividade antioxidante e inibidora de acetil colinesterase foram conduzidas pela técnica da bioautografia com DPPH e teste pelo teste de Ellman respectivamente.

Ochnaceae endémicas del Perú

Esta es una de las familias que constituye una novedad para la flora endémica peruana. La familia Ochnaceae es reconocida en el Perú por presentar siete géneros y 25 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), la mayoría arbustos y árboles. En este trabajo reconocemos tres especies endémicas en dos géneros. Las especies endémicas se encuentran en las regiones Bosques Muy Húmedos Premontanos y Bosques Húmedos Amazónicos, entre los 260 y 1380 m de altitud. Dos de las especies endémicas se encuentran dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

This family is one of the novelties for the Peruvian endemic flora. The Ochnaceae are represented in Peru by seven genera and 25 species (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), mostly shrubs and trees. Here we recognize three endemic species in two genera. These species grow in Humid Lowland Amazonian Forests and Very Humid Premontane Forests regions, between 260 and 1380 m elevation. Two species have been recorded in the Peruvian System of Protected Natural Areas.

Taxonomic studies on Philacra Dwyer (Ochnaceae) - DOI: 10.4025/actascibiolsci.v28i3.191 / Estudos taxonômicos em Philacra Dwyer (Ochnaceae) - DOI: 10.4025/actascibiolsci.v28i3.191

The species of Philacra are found mainly at the Brazil-Venezuela border. Among other Ochnaceae genera, this is the most closely related to Luxemburgia, which occurs only in Brazil, especially at the Espinhaço Range. The taxonomic analysis of Philacra species was based on the type material and herbarium specimens. This work aimed to redescribe the genus, to prepare a taxonomic key and to redescribe the species. The genus redescription and the geographical distribution, a key to the species and species redescription, are presented. Currently, four Philacra species are recognized: P. auriculata Dwyer, P. duidae (Gleason) Dwyer, P. longifolia (Gleason) Dwyer, and P. steyermarkii Maguire.

As espécies de Philacra são encontradas principalmente na fronteira Brasil- Venezuela, e dentre outros gêneros de Ochnaceae, é o mais próximo a Luxemburgia, cujas espécies ocorrem somente no Brasil, especialmente na Cadeia do Espinhaço. A análise taxonômica das espécies de Philacra foi realizada com base no material tipo e em espécimes depositados em herbários. O trabalho objetivou a redescrição do gênero, a elaboração da chave taxonômica e a redescrição das espécies. É apresentada a redescrição do gênero, sua distribuição geográfica, a chave de identificação e a redescrição das espécies. Atualmente, são reconhecidas quatro espécies de Philacra: P. auriculata Dwyer, P. duidae (Gleason) Dwyer, P. longifolia (Gleason) Dwyer e, P. steyermarkii Maguire.

Constituintes químicos e avaliação preliminar in vivo da atividade antimalárica de Ouratea nitida Aubl (Ochnaceae) / Chemical constituents and in vivo preliminary evaluation of antimalarial activity of Ouratea nitida Aubl. (Ochnaceae)

O presente trabalho descreve o isolamento de triterpenos (ácido 3,4-seco-friedelan-3-óico, friedelina e b-amirina) e outros compostos (éster etílico do ácido p-hidroxibenzóico e tetracosano), bem como a avaliação preliminar in vivo da atividade antimalárica de extratos das folhas de Ouratea nitida Aubl. Análise qualitativa através de CG-EM de uma fração apolar do extrato em hexano também foi efetuada. Ésteres metílicos e etílicos dos ácidos laúrico, mirístico, palmítico, esteárico e oléico, metílicos dos ácidos pentadecanóico, heptadecanóico, araquidônico, behênico e lignocérico e o etílico do ácido linoléico foram os componentes majoritários; enquanto que o estearato de n-butila, o tetracosano e a 6,10,14-trimetil-2-pentadecanona foram os minoritários. Os compostos isolados foram identificados com base na análise dos dados espectrais (IV, EM e RMN, incluindo DEPT) e estão sendo descritos pela primeira vez nesta espécie.

This work describes the isolation of triterpenes (3,4-seco-friedelan-3-oic acid, friedelin, and b-amyrin) and other compounds (p-hydroxybenzoic acid ethyl ester and tetracosane) as well as a preliminary evaluation of in vivo antimalarial activity of the extracts from the leaves of Ouratea nitida Aubl. Qualitative analysis by GC-MS of an apolar fraction from the hexane extract was also carried out. Methyl and ethyl esters of lauric, myristic, palmitic, stearic and oleic acids, methyl ester of pentadecanoic, heptadecanoic, arachidonic, beenic and lignoceric acids, and ethyl ester of linoleic acid were found to be the main constituents while n-butyl stearate, tetracosane and 6,10,14-trimetthyl-2-pentadecanone were the minor. All isolated compounds were identified on basis of the spectral data (IR, MS and NMR, including DEPT) and are being described for the first time in this specie.