Isolation, synthesis and absolute configuration of 4,5-dihydroxypiperines improving behavioral disorder in AlCl3-induced dementia.

A pair of stereoisomers of new 4,5-dihydroxypiperine was isolated from P. retrofractum and showed profound activity on AlCl3-induced dementia. In order to determine their absolute configurations and biological activities, all four possible stereoisomers of 4,5-dihydroxypiperine were synthesized from piperidine by Sharpless asymmetric dihydroxylation and Mitsunobu reaction. Their absolute configurations were established as (4R,5R) (1), (4S,5S) (2), (4S,5R) (3) and (4R,5S) (4) by NMR, optical rotation and CD spectra. It is note that only compound 4 improved behavioral disorder in AlCl3-induced dementia. Accordingly, the pair of stereoisomers isolated from P. retrofractum was determined to be (4S,5S) and (4R,5S)-isomers (2 and 4). The ratio of the epimers was present as 1:0.7 (4:2).

Evaluation of Gibbilimbol B, Isolated from Piper malacophyllum (Piperaceae), as an Antischistosomal Agent.

Infections caused by parasitic worms impose a considerable worldwide health burden. One of the most impactful is schistosomiasis, a disease caused by blood-dwelling of the genus Schistosoma that affects more than 230 million people worldwide. Since praziquantel has also been extensively used to treat schistosomiasis and other parasitic flatworm infections, there is an urgent need to identify novel anthelmintic compounds, mainly from natural sources. In this study, the hexane extract from roots of Piper malacophyllum (Piperaceae) showed to be mainly composed for gibbilimbol B by HPLC/ESI-HRMS. Based on this result, this compound was isolated by chromatographic steps and its structure was confirmed by NMR. In vitro bioassays showed that gibbilimbol B was more active than praziquantel against larval stage of S. mansoni, with effective concentrations of 50 % (EC50 ) and 90 % (EC90 ) values of 2.6 and 3.4 µM, respectively. Importantly, gibbilimbol B showed no cytotoxicity to mammalian cells at a concentration 190 times greater than the antiparasitic effect, giving support for the anthelmintic potential of gibbilimbol B as lead compound for novel antischistosomal agents.

Cardamonin Presents in Vivo Activity against Schistosoma mansoni and Inhibits Potato Apyrase.

Schistosomiasis, a neglected tropical disease caused by Schistosoma species, harms over 250 million people in several countries. The treatment is achieved with only one drug, praziquantel. Cardamonin, a natural chalcone with in vitro schistosomicidal activity, has not been in vivo evaluated against Schistosoma. In this work, we evaluated the in vivo schistosomicidal activities of cardamonin against Schistosoma mansoni worms and conducted enzymatic apyrase inhibition assay, as well as molecular docking analysis of cardamonin against potato apyrase, S. mansoni NTPDase 1 and S. mansoni NTPDase 2. In a mouse model of schistosomiasis, the oral treatment with cardamonin (400 mg/kg) showed efficacy against S. mansoni, decreasing the total worm load in 46.8 % and reducing in 54.5 % the number of eggs in mice. Cardamonin achieved a significant inhibition of the apyrase activity and the three-dimensional structure of the potato apyrase, obtained by homology modeling, showed that cardamonin may interact mainly through hydrogen bonds. Molecular docking studies corroborate with the action of cardamonin in binding and inhibiting both potato apyrase and S. mansoni NTPDases.

Antitrypanosomal activity and effect in plasma membrane permeability of (-)-bornyl p-coumarate isolated from Piper cernuum (Piperaceae).

This work describes the isolation of six metabolites from leaves and branches of Piper cernuum (Piperaceae): (-)-cubebin (1), (-)-hinokinin (2), (-)-kusunokinin (3), trans-dehydroagarofuran (4), 11-hydroxi-4,5-secoeudesmane-4,5-dione (5), and (-)-bornyl p-coumarate (6). Antitrypanosomal activity and toxicity of purified compounds were performed in vitro against trypomastigote forms of Trypanosoma cruzi and NCTC cells, respectively. Compounds 2, 3 and 5 showed moderate activities with IC50 values of 33.1, 31.8 and 45.9 µM, respectively, while compounds 1 and 4 were inactive (IC50 > 100 µM). On the other hand, compound 6 displayed an IC50 value of 2.1 µM, a selectivity index (SI) of 18 and induced a considerable interference in the plasma membrane permeability (87%) in trypomastigotes of T. cruzi. Additionally, the lethal effect of compound 6 in T. cruzi could be associated to the plasma membrane permeability. Finally, experiments using scanning electron microscopy (SEM) confirmed the obtained results in which was possible to observe total alteration parasites topography after treatment with compound 6 in comparison to untreated parasites. These data indicated that the lethal action of compound 6 is directly related to structural disruption of the membrane.

Leishmanicidal Effects of Piperlongumine (Piplartine) and Its Putative Metabolites.

Piperlongumine is an amide alkaloid found in Piperaceae species that shows a broad spectrum of biological properties, including antitumor and antiparasitic activities. Herein, the leishmanicidal effect of piperlongumine and its derivatives produced by a biomimetic model using metalloporphyrins was investigated. The results showed that IC50 values of piperlongumine in promastigote forms of Leishmania infantum and Leishmania amazonensis were 7.9 and 3.3 µM, respectively. The IC50 value of piperlongumine in the intracellular amastigote form of L. amazonensis was 0.4 µM, with a selectivity index of 25. The piperlongumine biomimetic derivatives, Ma and Mb, also showed leishmanicidal effects. We also carried out an in vitro metabolic degradation study showing that Ma is the most stable piperlongumine derivative in rat liver microsome incubations. The results presented here indicate that piperlongumine is a potential leishmanicidal candidate and support the biomimetic approach for development of new antileishmanial derivatives.

Structure-Activity Relationships and Docking Studies of Hydroxychavicol and Its Analogs as Xanthine Oxidase Inhibitors.

Hydroxychavicol (HC), which is obtained from the leaves of Piper betle LINN. (Piperaceae), inhibits xanthine oxidase (XO) with an IC50 value of 16.7 µM, making it more potent than the clinically used allopurinol (IC50=30.7 µM). Herein, a structure-activity relationship analysis of the polar part analogs of HC was conducted and an inhibitor was discovered with a potency 13 times that of HC. Kinetic studies have revealed that HC and its active analog inhibit XO in an uncompetitive manner. The binding structure prediction of these inhibitor molecules to the XO complex with xanthine suggested that both compounds (HC and its analog) could simultaneously form hydrogen bonds with xanthine and XO.

Effect of piplartine and cinnamides on Leishmania amazonensis, Plasmodium falciparum and on peritoneal cells of Swiss mice.

CONTEXT: Plants of the Piperaceae family produce piplartine that was used to synthesize the cinnamides. OBJECTIVE: To assess the effects of piplartine (1) and cinnamides (2-5) against the protozoa responsible for malaria and leishmaniasis, and peritoneal cells of Swiss mice. MATERIALS AND METHODS: Cultures of Leishmania amazonensis, Plasmodium falciparum-infected erythrocytes, and peritoneal cells were incubated, in triplicate, with different concentrations of the compounds (0 to 256 µg/mL). The inhibitory concentration (IC50) in L. amazonensis and cytotoxic concentration (CC50) in peritoneal cell were assessed by the MTT method after 6 h of incubation, while the IC50 for P. falciparum-infected erythrocytes was determined by optical microscopy after 48 or 72 h of incubation; the Selectivity Index (SI) was calculated by CC50/IC50. RESULTS: All compounds inhibited the growth of microorganisms, being more effective against P. falciparum after 72 h of incubation, especially for the compounds 1 (IC50 = 3.2 µg/mL) and 5 (IC50 = 6.6 µg/mL), than to L. amazonensis (compound 1 = 179.0 µg/mL; compound 5 = 106.0 µg/mL). Despite all compounds reducing the viability of peritoneal cells, the SI were <10 to L. amazonensis, whereas in the cultures of P. falciparum the SI >10 for the piplartine (>37.4) and cinnamides 4 (>10.7) and 5 (= 38.4). DISCUSSION AND CONCLUSION: The potential of piplartine and cinnamides 4 and 5 in the treatment of malaria suggest further pre-clinical studies to evaluate their effects in murine malaria and to determine their mechanisms in cells of the immune system.

Intraspecific phytochemical variation shapes community and population structure for specialist caterpillars.

Chemically mediated plant-herbivore interactions contribute to the diversity of terrestrial communities and the diversification of plants and insects. While our understanding of the processes affecting community structure and evolutionary diversification has grown, few studies have investigated how trait variation shapes genetic and species diversity simultaneously in a tropical ecosystem. We investigated secondary metabolite variation among subpopulations of a single plant species, Piper kelleyi (Piperaceae), using high-performance liquid chromatography (HPLC), to understand associations between plant phytochemistry and host-specialized caterpillars in the genus Eois (Geometridae: Larentiinae) and associated parasitoid wasps and flies. In addition, we used a genotyping-by-sequencing approach to examine the genetic structure of one abundant caterpillar species, Eois encina, in relation to host phytochemical variation. We found substantive concentration differences among three major secondary metabolites, and these differences in chemistry predicted caterpillar and parasitoid community structure among host plant populations. Furthermore, E. encina populations located at high elevations were genetically different from other populations. They fed on plants containing high concentrations of prenylated benzoic acid. Thus, phytochemistry potentially shapes caterpillar and wasp community composition and geographic variation in species interactions, both of which can contribute to diversification of plants and insects.

Gibbilimbol analogues as antiparasitic agents--Synthesis and biological activity against Trypanosoma cruzi and Leishmania (L.) infantum.

The essential oils from leaves of Piper malacophyllum (Piperaceae) showed to be mainly composed by two alkenylphenol derivatives: gibbilimbols A and B. After isolation and structural characterization by NMR and MS data analysis, both compounds were evaluated against promastigote/amastigote forms of Leishmania (L.) infantum as well as trypomastigote/amastigote forms of Trypanosoma cruzi. The obtained results indicated that gibbilimbol B displayed potential against the tested parasites and low toxicity to mammalian cells, stimulating the preparation of several quite simple synthetic analogues in order to improve its activity and to explore the preliminary structure-activity relationships (SAR) data. Among the prepared derivatives, compound LINS03003 (n-octyl-4-hydroxybenzylamine) displayed the most potent IC50 values of 5.5 and 1.8 µM against amastigotes of T. cruzi and L. (L.) infantum, respectively, indicating higher activity than the natural prototype. In addition, this compound showed remarkable selectivity index (SI) towards the intracellular forms of Leishmania (SI=13.1) and T. cruzi (SI=4.3). Therefore, this work indicated that preparation of synthetic compounds structurally based in the bioactive natural products could be an interesting source of novel and selective compounds against these protozoan parasites.

Local Anesthetic Activity from Extracts, Fractions and Pure Compounds from the Roots of Ottonia anisum Spreng. (Piperaceae).

Piperaceae species can be found worldwide in tropical and subtropical areas and many of them have been used for centuries in traditional folk medicine and in culinary. In Brazil, species of Piperaceae are commonly used in some communities as local anesthetic and analgesic. Countrified communities have known some species of the genus Ottonia as "anestesia" and it is a common habit of chewing leaves and roots of Ottonia species to relief toothache. The purpose of this study is to report our findings on new molecules entities obtained from the roots of Ottonia anisum Spreng, in which local anesthetic activity (sensory blockage) is demonstrated for the first time in vivo guinea pig model. Phytochemical investigation led to the isolation of three amides (pipercallosidine, piperine and valeramide) and in an enriched mixture of seven amides (valeramide, 4,5-dihydropiperlonguminine, N-isobutil-6-piperonil-2-hexenamide, piperovatine, dihydropipercallosidine, pipercallosidine and pipercallpsine). Our findings demonstrated the anesthetic potential for the methanolic extract from roots, its n-hexane partition and amides from O. anisum and it is in agreement with ethnobotanical survey.

Cytotoxic Amides from Fruits of Kawakawa, Macropiper excelsum.

Cytotoxic amides have been isolated from the fruits of the endemic New Zealand medicinal plant kawakawa, Macropiper excelsum (Piperaceae). The main amide was piperchabamide A and this is the first report of this rare compound outside the genus Piper. Eleven other amides were purified including two new compounds with the unusual 3,4-dihydro-1(2H)-pyridinyl group. The new compounds were fully characterized by 2D NMR spectroscopy, which showed a slow exchange between two rotamers about the amide bond, and they were chemically synthesized. In view of the antitumor activity of the related piperlongumine, all of these amides plus four synthetic analogs were tested for cytotoxicity. The most active was the piperine homolog piperdardine, with an IC50 of 14 µM against HT 29 colon cancer cells.

Investigation of local anesthetic and antimycobacterial activity of Ottonia martiana Miq. (Piperaceae).

Ottonia martiana is a plant popularly known in Brazil by the use for toothache. Ethanolic extract (EE), hexane fraction (HF), dichloromethane fraction (DF) and piperovatine obtained from O. martiana were assayed in vitro and in vivo. The acute toxicity of EE was determined, and LD50 values of 164.5 and 65.0 mg/kg by the oral and intraperitoneal routes, respectively, indicated a high toxicity for EE in vivo, explaining its popular use by topical administration only. A local anesthetic-like effect of EE and its fractions was observed in experimental models using pain induction, and such effect involved an analgesic action. The antimycobacterial activity of EE, HF, DF and piperovatine was evaluated against Mycobacterium tuberculosis H37Rv ATCC 27924. EE, HF, DF, and piperovatine showed a potential antimycobacterial effect with MICs of 16.0, 62.0, 62.0 and 8.0 µg/mL, respectively. Piperovatine was more effective than the EE or the other fractions. The selectivity index (SI=IC50/MIC) values calculated for EE, HF, DF and piperovatine based on the MICs and the cytotoxicity against J774 macrophages (IC50 by MTT assay) revealed values of 6.43, 2.34, 1.5 and 9.66, respectively.

Untangling interactions: do temperature and habitat fragmentation gradients simultaneously impact biotic relationships?

Gaining insight into the impact of anthropogenic change on ecosystems requires investigation into interdependencies between multiple drivers of ecological change and multiple biotic responses. Global environmental change drivers can act simultaneously to impact the abundance and diversity of biota, but few studies have also measured the impact across trophic levels. We firstly investigated whether climate (using temperature differences across a latitudinal gradient as a surrogate) interacts with habitat fragmentation (measured according to fragment area and distance to habitat edges) to impact a New Zealand tri-trophic food chain (plant, herbivore and natural enemy). Secondly, we examined how these interactions might differentially impact both the density and biotic processes of species at each of the three trophic levels. We found evidence to suggest that these drivers act non-additively across trophic levels. The nature of these interactions however varied: location synergistically interacted with fragmentation measures to exacerbate the detrimental effects on consumer density; and antagonistically interacted to ameliorate the impact on plant density and on the interactions between trophic levels (herbivory and parasitoid attack rate). Our findings indicate that the ecological consequences of multiple global change drivers are strongly interactive and vary according to the trophic level studied and whether density or ecological processes are investigated.

Antifungal and cytotoxic 2-acylcyclohexane-1,3-diones from Peperomia alata and P. trineura.

Bioactivity-guided fractionation of the separate CH2Cl2 extracts from the aerial parts of Peperomia alata and P. trineura yielded seven polyketides: alatanone A [3-hydroxy-2-(5'-phenylpent-4'E-enoyl)cyclohex-2-en-1-one, 1a] and alatanone B [3-hydroxy-2-(3'-phenyl-6'-methylenedioxypropanoyl)cyclohex-2-en-1-one, 2a] from P. alata and trineurone A [3-hydroxy-2-(11'-phenylundec-10'E-enoyl)cyclohex-2-en-1-one, 1b], trineurone B [3-hydroxy-2-(15'-phenyl-18'-methylenedioxypentadecanoyl)cyclohex-2-en-1-one, 2b], trineurone C [3-hydroxy-2-(17'-phenyl-20'-methylenedioxyheptadecanoyl)cyclohex-2-en-1-one, 2c], trineurone D [3-hydroxy-2-(hexadec-10'Z-enoyl)cyclohex-2-en-1-one, 3a], and trineurone E [(6R)-(+)-3,6-dihydroxy-2-(hexadec-10'Z-enoyl)cyclohex-2-en-1-one, 3b] from P. trineura. The isolated compounds were evaluated for antifungal activity against Cladosporium cladosporioides and C. sphaeospermum and for cytotoxicity against the K562 and Nalm-6 leukemia cell lines.

Enemy release promotes range expansion in a host plant.

Climate is considered to be the predominant driver shaping species distributions at macroecological scales, yet the importance of incorporating biotic interactions in predicting future range margins under climate change scenarios is increasingly being recognised. We used translocation studies to investigate how survival and growth patterns of an understory shrub planted at latitudes within its range, at its range limit and beyond its polewards boundary (in areas it may colonise as a result of shifting climate envelopes) are affected by the presence of a primary herbivore. Specifically, we tested the null hypotheses that: (1) biotic interactions do not exert a significant role in limiting survival and growth rates across the limits of a host plant's latitudinal range, and (2) at smaller spatial scales biotic interactions do not exert a significant role in determining survival and growth rates at edge versus interior position within a forest fragment. We found that the understory shrub Macropiper excelsum is able to survive polewards of its current latitudinal limit within the first year after transplant; in fact, growth is higher outside the plant's current natural range than within its present-day distribution. This trend is particularly pronounced in forest core environments and corresponds closely to patterns of reduced herbivory outside the plant's range. The absence of the primary herbivore, Cleora scriptaria, and concomitant reduction in the suppressive effects of herbivory outside of the plant's range appear to be supporting enhanced growth and survival. If host plants are able to successfully track their climatic niche and disperse into novel areas prior to the arrival of their natural predators, it is possible that 'enemy release' may facilitate the establishment of plant species. These findings highlight the importance of considering biotic interactions alongside abiotic variables when predicting future species' ranges under climate change.

New Meliolaceae from the Brazilian Atlantic forest 2: species on host families Annonaceae, Cecropiaceae, Meliaceae, Piperaceae, Rubiaceae, Rutaceae and Tiliaceae.

Continuing the study of black mildews in fragments of the Atlantic forest, three new species and five new records are described herein. Irenopsis luheae-grandiflorae, Meliola vicosensis and Meliola xylopia-sericiae are new species. Cecropia hololeuca, Piper gaudichaudianum and Trichilia lepidota are new hosts for Asteridiella leucosykeae, Asteridiella glabroides and Meliola trichiliae respectively. Asteridiella obesa and Meliola psychotriae var. chiococcae are reported for the first time from Brazil. The new species are described and illustrated based on light and scanning electron microscopy and tables with main characteristics of morphologically similar specimens with species collected in Viçosa are provided. Other species belonging to Meliolaceae collected on hosts belonging to the Annonaceae, Meliaceae and Tiliaceae in Brazil also were studied.

Bio efficacy of some piperaceae plant extracts against Plutella xylostella L. (Lepidoptera: Plutellidae).

The extracts of Piper sarmentosum Roxb., Piper retrofractum Vahl, Piper interruptum Opiz and Piper nigrum plants belonging to the family Piperaceae were evaluated for their efficacy against diamondback moth, Plutello xylostella L. third instars under laboratory conditions. Comparative toxicity of various extracts prepared in hexane, dichloromethane, ethyl acetate and ethanol following sequential extraction procedure were applied topically to the larvae. The hexane extract of Piper retrofractum was most active (LD = 237 ppm). The toxicity was dose dependant and correlated to duration of exposure. The hexane extract of P. nigrum was least active with an LD50 of 18,435 ppm. The mode of action of these extracts and effect on other developmental parameters is in progress.

Effect of ethanolic extracts from Piperaceae leaves on the reduction of skin necrosis and wound healing in an animal model of degloving injuries.

PURPOSE: To assess the effect of the ethanolic extract of the leaves of three species of plants from the Piperaceae family on reducing necrosis and enhancing wound healing in an animal model of degloving injuries. METHODS: The animals were divided into six groups, each consisting of six animals: sham, negative control, EEPA (Piper amalago ethanolic extract), EEPG (Piper glabratum ethanolic extract), EEPV (Piper vicosanum ethanolic extract), and positive control receiving hyperbaric oxygenation. The animals underwent surgery to induce excision wounds, and the extent of cutaneous necrosis was evaluated using graphic software, while wound healing was assessed through histopathology. RESULTS: Skin necrosis percentage area was: sham group = 62.84% 6.38; negative control group = 63.03% 4.11; P. vicosanum = 40.80% 4.76 p < 0.05; P. glabratum 32.97% 4.01 p < 0.01; P. amalago = 32.40% 4.61 p < 0.01; hyperbaric oxygenation = 33.21% 4.29 p < 0.01. All treated groups showed higher collagen deposition and less intense, plus predominantly mononuclear inflammatory infiltrate, suggesting improved healing process. CONCLUSIONS: The three tested extracts demonstrated efficacy in reducing the extent of cutaneous necrosis caused by degloving injuries and also showed evidence of improvement in the wound healing process.

Antiparasitic properties of 4-nerolidylcatechol from Pothomorphe umbellata (L.) Miq. (Piperaceae) in vitro and in mice models with either prepatent or patent Schistosoma mansoni infections.

ETHNOPHARMACOLOGICAL RELEVANCE: Roots of Pothomorphe umbellata (L.) Miq. are used in traditional medicine of Africa and South America for the treatment of malaria and helminthiasis. However, neither P. umbellata nor its isolated compounds have been evaluated against Schistosoma species. AIMS OF THIS STUDY: To investigate the antischistosomal effects of P. umbellata root extracts and the isolated compound 4-nerolidylcatechol (4-NC) against Schistosoma mansoni ex vivo and in murine models of schistosomiasis. MATERIALS AND METHODS: The crude hydroalcoholic (PuE) and hexane (PuH) extracts of P. umbellata roots were prepared and initially submitted to an ex vivo phenotypic screening against adult S. mansoni. PuH was analyzed by HPLC-DAD, characterized by UHPLC-HRMS/MS, and submitted to chromatographic fractionation, leading to the isolation of 4-NC. The anthelmintic properties of 4-NC were assayed ex vivo against adult schistosomes and in murine models of schistosomiasis for both patent and prepatent S. mansoni infections. Praziquantel (PZQ) was used as a reference compound. RESULTS: PuE (EC50: 18.7 µg/mL) and PuH (EC50: 9.2 µg/mL) kill adult schistosomes ex vivo. The UHPLC-HRMS/MS analysis of PuH, the most active extract, revealed the presence of 4-NC, peltatol A, and peltatol B or C. After isolation from PuH, 4-NC presented remarkable in vitro schistosomicidal activity with EC50 of 2.9 µM (0.91 µg/mL) and a selectivity index higher than 68 against Vero mammalian cells, without affecting viability of nematode Caenorhabditis elegans. In patent S. mansoni infection, the oral treatment with 4-NC decreased worm burden and egg production in 52.1% and 52.3%, respectively, also reducing splenomegaly and hepatomegaly. 4-NC, unlike PZQ, showed in vivo efficacy against juvenile S. mansoni, decreasing worm burden in 52.4%. CONCLUSIONS: This study demonstrates that P. umbellata roots possess antischistosomal activity, giving support for the medicinal use of this plant against parasites. 4-NC was identified from P. umbellata roots as one of the effective in vitro and in vivo antischistosomal compound and as a potential lead for the development of novel anthelmintics.

Carbonic anhydrase I and II inhibition with natural products: caffeine and piperine.

Novel chemotypes with carbonic anhydrase (CA; EC 4.2.1.1) inhibitory action, in addition to the sulphonamide and sulphamate were discovered, many of which are based on natural products. Caffeine and piperine were extracted and tested for inhibition of the human (h) cytosolic isoforms hCA I and II. The IC(50) values of caffeine against hCA I was of 55 mM, whereas that of piperine of 60 mM. The IC(50) values of caffeine and piperine against hCA II were of 2 mM. Although these are quite weak inhibitors they may constitute leads for developing tighter binding compounds.