VCD to determine absolute configuration of natural product molecules: secolignans from Peperomia blanda

The absolute configuration and solution-state conformers of three peperomin-type secolignans isolated from Peperomia blanda (Piperaceae) are unambiguously determined by using vibrational circular dichroism (VCD) spectroscopy associated with density functional theory (DFT) calculations. Advantages of VCD over the electronic form of CD for the analysis of diastereomers are also discussed. This work extends our growing knowledge about secondary metabolites within the Piperaceae family species while providing a definitive and straightforward method to assess the absolute stereochemistry of secolignans.

Further monoterpene chromane esters from Peperomia obtusifolia: VCD determination of the absolute configuration of a new diastereomeric mixture

A reinvestigation of the monoterpene chromane ester enriched fraction from Peperomia obtusifolia using chiral chromatography led to the identification of a minor peak, which was elucidated by NMR and HRMS as fenchyl-3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3 ''-methyl-2 ''-butenyl)-2-(4'-methyl-1',3'-pentadienyl)-2H-1-benzopyran-6-carboxylate, the same structure assigned to two other fenchyl esters described previously, pointing out a stereoisomeric relationship among them. Further NMR analysis revealed that it was actually a mixture of two compounds, whose absolute configurations were determined by VCD measurements. Although, almost no vibrational transitions could be assigned to the chiral chromane, the experimental VCD spectrum was largely opposite to that obtained for the average experimental VCD [(2S,1'''R,2'''R,4'''S + 2R,1'''R,2'''R,4'''S)/2] for fenchol derivatives. These results allowed us to assign the putative compounds as a racemic mixture of the chiral chromane esterified with the monoterpene (1S,2S,4R)fenchol, which had not been identified in our early work. (C) 2012 Elsevier Ltd. All rights reserved.

Leishmanicidal activity of an alkenylphenol from Piper malacophyllum is related to plasma membrane disruption

Leishmaniasis and Chagas disease are parasitic protozoan infections that affect the poorest population in the world, causing high mortality and morbidity. As a result of highly toxic and long-duration treatments, novel, safe and more efficacious drugs are essential. In this work, the methanol (MeOH) extract from the leaves of Piper malacophyllum (Piperaceae) was fractioned to afford one alkenylphenol, which was characterized as 4-[(3'E)-decenyl]phenol (gibbilimbol B) by spectroscopic methods. Anti-protozoan in vitro assays demonstrated for the first time that Leishmania (L.) infantum chagasi was susceptible to gibbilimbol B. with an in vitro EC50 of 23 mu g/mL against axenic promastigotes and an EC50 of 22 mu g/mL against intracellular amastigotes. Gibbilimbol B was also tested for anti-trypanosomal activity (Trypanosoma cruzi) and showed an EC50 value of 17 mu g/mL against trypomastigotes. To evaluate the cytotoxic parameters, this alkenylphenol was tested in vitro against NCTC cells, showing a CC50 of 59 mu g/mL and absent hemolytic activity at the highest concentration of 75 mu g/mL. Using the fluorescent probe SYTOX Green suggested that the alkenylphenol disrupted the Leishmania plasma membrane upon initial incubation. Further drug design studies aiming at derivatives could be a promising tool for the development of new therapeutic agents for leishmaniasis and Chagas disease. (C) 2012 Elsevier Inc. All rights reserved.

Schistosoma mansoni: In vitro schistosomicidal activity and tegumental alterations induced by piplartine on schistosomula

Schistosomiasis is one of the most important parasitic infections in humans that occur in many tropical and subtropical countries. Currently, the control of schistosomiasis rests with a single drug, praziquantel, which is effective against adult worms but not the larval stages. Recent studies have shown that piplartine, an amide isolated from plants of the genus Piper (Piperaceae), reveals interesting antischistosomal properties against Schistosoma mansoni adult worms. Here, we report the in vitro antischistosomal activity of piplartine on S. mansoni schistosomula of different ages (3 h old and 1, 3, 5, and 7 days old), and examine alterations on the tegumental surface of worms by means of confocal laser scanning microscopy. Piplartine at a concentration of 7.5 mu M caused the death of all schistosomula within 120 h. The lethal effect occurred in a dose-dependent manner and was also dependent on the age of the parasite. Microscopy observation revealed extensive tegumental destruction, including blebbing, granularity, and a shorter body length. This report provides the first evidence that piplartine is able to kill schistosomula of different ages and reinforce that piplartine is a promising compound that could be used for the development of new schistosomicidal agent. (c) 2012 Elsevier Inc. All rights reserved.

Composição, diversidade e distribuição geográfica de plantas vasculares de uma Floresta Ombrófila Densa Atlântica do Sudeste do Brasil

In the Montane and Submontane Rain Forest of the Carlos Botelho State Park - PECB (ca. 37,000 ha) the composition, richness and geographical distribution of native, vascular forest species was evaluated. The analysis of 1143 species of 140 families supported the pattern found for other forests of Eastern Brazil, showing high species richness of Myrtaceae (85 species), Orchidaceae (81), Fabaceae (57), Asteraceae, Melastomataceae (54), Lauraceae (53), Rubiaceae (51), Bromeliaceae (43), Piperaceae (30) and Solanaceae (25), besides ferns (123). The most species-rich genera were Eugenia (34), Ocotea (26), Leandra, Myrcia, Vriesea (18), Piper, Solanum (16), Miconia (14), Mollinedia (13), and Peperomia (12). The richness and composition varied greatly among life forms, as well as the number of families represented in each one of them (only Rubiaceae had species in all life forms, except parasites). Trees had the largest contribution of total richness (39.1%), a value that represented more than 20% of the species listed for the whole Atlantic Forest of Southeastern Brazil. Trees were followed by epiphytes (22.4%), herbs (18.4%), shrubs (10.1%), lianas (9.1%), and parasites (0.9%). The overall richness and composition of life forms was quite close to other neotropical forests (e.g. high contribution of ferns among epiphytes), although some life forms remain undersampled in the PECB (mainly herbs, lianas and epiphytes). The occurrence of species endemic to the Atlantic Forest was pronounced (65%), with a predominance of species restricted to the Southern Atlantic Forest (43%). Pantropical species were rare (2%), being more common among ferns. Myrtaceae and Melastomataceae were the families with greater number and proportion of endemic species.

Grandisin caused morphological changes larval and toxicity on Aedes aegypti

Dengue is a tropical disease caused by an arbovirus transmitted by Aedes aegypti. Since no effective vaccine is available for treating dengue, the present study focused on population vector control through investigating the use of the lignan grandisin, isolated from Piper solmsianum C. DC., Piperaceae, against the larvae of A. aegypti. Grandisin caused larval (L3) mortality at LC50 150 µg/mL. Histological analysis on A. aegypti larvae treated with grandisin (LC50 50 µg/mL) showed changes in the anterior-middle midgut, with intense tissue destruction and cell disorganization.

Chemical constituents from three medicinal plants: Piper renitens, Siparuna guianensis and Alternanthera brasiliana

Chemical study of three medicinal plants: from leaves of Piper renitens (Miq.) Yunck, Piperaceae, and Siparuna guianensis Aubl., Siparunaceae, and from flowers of Alternanthera brasiliana (L.) Kuntze, Amaranthaceae, resulted in isolation of nine compounds: three steroids, β-sitosterol, stigmasterol from P. renitens and sitosterol-3-O-β-D-glucopyranoside from A. brasiliana, the diterpene kaurane ent-kauran-16α,17-diol from P. renitens, two derivatives kaempferol-methylether, kumatakenine (kaempferol-3,7-dimethylether) and kaempferol-3,7,3'-trimethylether from S. guianensis and three flavones, crysoeriol (5,7,4'-trihydroxy-3'-methoxyflavone), tricin (5,7,4'-trihydroxy-3',5'-dimethoxyflavone) and 7-O-β-D-glucopyranoside-5,4'-dihydroxy-3'-methoxyflavone from A. brasiliana. Compounds structures were determinate using 1D and 2D ¹H NMR and 13C spectral data, mass and IR spectra, comparing with literature data.

Sedimentological and palynological study of sediment cores from the northern Mekong River Delta

A sedimentological and palynological study of three sediment cores from the northern Mekong River Delta shows the regional sedimentary and environmental development since the mid-Holocene sea level highstand. A sub- to intertidal flat deposit of mid-Holocene age is recorded in the northernmost core. Shoreline deposits in all three cores show descending ages from N to S documenting 1) the early stages of the late Holocene regression and 2) the subsequent delta progradation. The delta plain successions vary from floodplain deposits with swamp-like elements to natural levee sediments. The uppermost sediments in all cores show human disturbance to varying degrees. The most intense alteration is recorded in the northernmost core where the palynological signal together with a charcoal peak indicates the profound change of the environment during the modern land reclamation. The sediments from at least one of the three presented cores do not show a "true" delta facies succession, but rather estuary-like features, as also observed in records from southern Cambodia. This absence is probably due to lack of accommodation space during the initial phase of rapid delta progradation which impeded the development of "true" delta successions as shown in cores from the southern Mekong River Delta.

Table 2. Percentage of palynomorphs found in each sample through Longling section

The Longling Coal Mine (W. Yunnan) is situated in an area of substantial geotectonic activity. Its Late Pliocene palynoflora is of considerable interest, since the area represents a centre of biodiversity. Eighty-two palynomorphs belonging to 61 families were recovered from the lignite. The palynoflora is dominated by angiosperms (68.3%), with ferns (24.4%), gymnosperms (4.9%) and algae (2.4%). Comparisons indicate that most of the palynoflora was derived from the Montane Humid Evergreen Broad-leaved Forest, with lesser contributions from the Tsuga dumosa Forest and Evergreen Coniferous Broad-leaved Mixed Forest, as well as the Montane Mossy Evergreen Broad-leaved Forest. This indicates that the Late Pliocene climate was cooler than that of the present. In the course of the accumulation of the lignite, the climate underwent five major phases of warming and cooling.

Metabolismo secundário e ligninas de espécies de Piper

O estudo químico das folhas e dos frutos de P. richardiaefolium resultou no isolamento de oito lignanas, sendo duas lignanas furofurânicas (sesamina e kobusina), quatro lignanas dibenzilbutirolactônicas (hinokinina, kusunokinina, arctigenina e haplomirfolina), duas lignanas dibenzilbutirolactólicas (cubebina e 3,4- dimetoxi-3,4-desmetilenodioxicubebina), dois cinamatos de bornila (ferulato de bornila e cumarato de bornila) e na identificação de duas amidas (piplartina e diidropiplartina). Das folhas de P. richardiaefolium foi extraído e analisado o óleo volátil. As estruturas das substâncias isoladas foram identificadas através de métodos espectroscópicos (RMN de 1H e de 13C e espectrometria de massas). O estudo de análise de componentes principais (PCA) das espécies Piper (P. truncatum - k 616, P. richardiaefolium - k 290, P. richardiaefolium - k 350, P. richardiaefolium - k 593, P. truncatum - k 597, P. pseudopotifolium - k 598, P. richardiaefolium - k 854, P. richardiaefolium - k 610, P. truncatum - k 112, P. pseudopotifolium - k 211 e P. cernuum - k 137) permitiu agrupar as espécies em dois grandes grupos e quatro subgrupos em relação à similaridade entre elas. Ligninas do caule de seis espécies de Piper foram extraídas utilizando o método de degradação de Klason e método de Bjorkman, e analisadas por métodos espectroscópicos (IV, RMN de 1H e de 13C). O método de degradação por oxidação por nitrobenzeno foi o escolhido para determinar a relação entre os monolignóis siringila e guaiacila. Os principais metabólitos das espécies estudadas foram comparados com os tipos de ligninas das mesmas espécies e os resultados sugeriram uma independência entre as vias biossintéticas de ligninas e lignanas.

Historia natural de la malagueta ó Pimienta de Tavasco y noticia de los usos, virtudes y exêncion de derechos de esta saludable y gustosa especia, con la lámina de su arbol /

Mode of access: Internet.

Studien über Süd-und Central-Americkanische. Peperomien mit besonderer Berücksichtigung der Brasilianischen Sippen.

Bibliography: 207-209.

Atividade biológica do óleo essencial de Piper hispidum e Piper hispidinervum.

Piper hispidum e Piper hispidinervum são duas espécies arbustivas pertencentes à família Piperaceae. Essas são plantas aromáticas, e há, na literatura, relatos da atividade antimicrobiana dos seus óleos essenciais (OEs). Sendo assim, o objetivo deste trabalho foi determinar a composição química dos OEs de ambas as espécies, bem como avaliar suas atividades biológicas.

Qualidade fisiológica de sementes de Piper marginatum Jacq. em função da época de colheita.

O objetivo deste trabalho foi avaliar a qualidade fisiológica e germinação de sementes de Piper marginatum Jacq. em função da época de colheita.