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Analysis of neolignans compounds of Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck by HPLC.

A high performance liquid chromatographic (HPLC) method was developed and validated for quantitative determination of neolignans in extracts of Piper regnellii var. pallescens. The analysis were carried out on a Metasil ODS column (150 mm x 4.6 mm, 5 microm) at 30 degrees C, using as mobile phase acetonitrile-water (60:40, v/v) containing 2% acetic acid. The flow rate was 1.0 ml/min and the detection was at 280 nm. The validation using conocarpan as standard demonstrated that the method presents linearity (linear correlation coefficient=0.9991), precision (relative standard deviation <5%) and accuracy (mean recovery=104.55%) in the concentration range 31.25-500 microg/ml. The limit of detection (LOD) was 1.68 microg/ml and the limit of quantitation was 5.60 microg/ml. This method allowed the identification and quantification of conocarpan, eupomatenoid-5 and eupomatenoid-6 in the hydroethanolic extracts obtained from the leaves, stems and roots by maceration process. All the extracts showed the same chromatographic profile, being that the extract of the roots presented the highest concentration of neolignans.

Chromatography, High Pressure Liquid↗

Metabolite-cytochrome P450 complex formation by methylenedioxyphenyl lignans of Piper cubeba: mechanism-based inhibition.

Five methylenedioxyphenyl lignans, (-)-clusin (1), (-)-dihydroclusin (2), (-)-yatein (3), (-)-hinokinin (4), and (-)-dihydrocubebin (5), were isolated from Piper cubeba as potent and selective inhibitors against cytochrome P450 3A4 (CYP3A4). In this study, we investigated the mechanism of inhibition of CYP3A4 by these lignans and the possibility of their mechanism-based inhibition. Using [N-methyl-14C]erythromycin as a substrate, all lignans appear to be showed mixed-type of inhibition with apparent Ki of 1.96-4.07 microM. Furthermore, all lignans (1-5) inhibited CYP3A4 in a time-, concentration-, and NADPH-dependent manners and thus appear to be the mechanism-based inhibitors of CYP3A4. The apparent inactivation parameter, K(I) for these compounds were in the range of 0.054-0.373 microM, whereas the k(inact) values were 0.225-0.320 min-1. Among them, (-)-clusin (1) and (-)-dihydroclusin (2) were found to be the most potent CYP3A4 inactivator with apparent K(I) and k(inact) values of 0.082, 0.054 microM and 0.253, 0.310 min-1, respectively. Spectral scanning of microsomes with these lignans yielded an absorbance at 455 nm, suggesting that all of them appear to inactivate the cytochrome P450 via the formation of a metabolite intermediate complex. This pattern is consistent with the metabolism of the methylenedioxyphenyl compounds. These results indicate that (-)-clusin (1), (-)-dihydroclusin (2), (-)-yatein (3), (-)-hinokinin (4), and (-)-dihydrocubebin (5) are effective mechanism-based inhibitors of CYP3A4.

Carbon Radioisotopes↗

Antibacterial constituents from the berries of Piper nigrum.

Piper nigrum finds an extensive application in antibacterial preparations belonging to Ayurvedic system of medicine. A bioguided extraction and fractionation of the petroleum ether extract of the berries of P. nigrum afforded 2E, 4E, 8Z-N-isobutyleicosatrienamide (1), pellitorine (2), trachyone (3), pergumidiene (4) and isopiperolein B (5). Pergumidiene and trachyone are isolated for the first time from P. nigrum. All the isolated compounds were active against Bacillus subtilis, Bacillus sphaericus, and Staphylococcus aureus amongst Gram + ve bacteria, and Klebsiella aerogenes and Chromobacterium violaceum among Gram -ve bacterial strains.

Anti-Bacterial Agents↗

ACAT inhibition of alkamides identified in the fruits of Piper nigrum.

In this study, via a bioactivity-guided fractionation of MeOH extracts of the fruits of Piper nigrum, alkamide (5) and five previously-identified alkamides were isolated. Their structures were elucidated via spectroscopic analysis ((1)H, (13)C NMR and ESI-MS), as follows: retrofractamide A (1), pipercide (2), piperchabamide D (3), pellitorin (4), dehydroretrofractamide C (5) and dehydropipernonaline (6). The IC(50) values determined for the compounds were 24.5 (1), 3.7 (2), 13.5 (3), 40.5 (4), 60 (5) and 90 microM (6), according to the results of an ACAT enzyme assay system using rat liver microsomes. These compounds all inhibited cholesterol esterification in HepG2 cells.

Amides↗

Induction of epidermal proliferation and expressions of PKC and NF-kappaB by betel quid extracts in mouse: the role of lime-piper additives in betel quid.

Components of betel quid (BQ) have been investigated for genotoxicity, mutagenicity, and animal toxicity. However, little information exists regarding their carcinogenic characteristics. Considerable attention has already been focused on tumor promoters that occur environmentally for human uptake. In this study, the promoting effects of BQ and lime-piper additives (LPA) in BQ on epidermal hyperplasia in CD-1 mouse skin are investigated. In the present study, we found that BQ and LPA at concentrations of 25,50,75 mg/ml caused significant induction of hyperplasia, but only LPA caused an increase of epidermal ornithine decarboxylase (ODC). Treatment of mouse skin with LPA caused remarkable increases in the production of H(2)O(2) by 2.41-, 3.90-, and 3.76-fold (for the above-indicated concentrations respectively); as well as marked increases of myeloperoxidase (MPO) by 1.43-, 2.70-, and 2.29-fold. Application of LPA or BQ (50,100,150 mg/ml) also caused induction of protein kinase C-alpha (PKC-alpha) and NF-kappaB. LPA exhibited more significant effect than BQ. Thus, LPA might make a major contribution to the BQ-induced expression of PKC and NF-kappaB. These results indicated that BQ has the potential of being promoting agents, and that LPA should play a major role in increasing the effects of BQ-caused skin hyperplasia and inflammation. The promoting effects of BQ and LPA on mouse skin were associated with the induction of the expressions of PKC and NF-kappaB.

Animals↗

Computer-assisted optimization in the development of a high-performance liquid chromatographic method for the analysis of kava pyrones in Piper methysticum preparations.

A computer simulation program was used to optimize the separation for six kava pyrones and two unidentified components obtaining the best resolution and the shortest run time. With DryLab it was possible to find the best separation conditions without running a large number of possible combination of variables in the laboratory. Additionally, due to the systematic progress in method development a new eluent was found with excellent properties, namely 2-propanol. With 2-propanol, the largest number of components could be revealed in the shortest analysis time. Starting with four initial experiments, the software allowed to optimize gradient time tG and temperature T simultaneously. Changing other variables such as type of organic modifier, the eluent pH, the gradient form, and the flow-rate, the optimization resulted in resolution Rs > 1.5 for all kava pyrones and the two additional new bands. The HPLC method is used to analyze kava pyrones in Piper methysticum preparations.

2-Propanol↗

Trypanocidal tetrahydrofuran lignans from inflorescences of Piper solmsianum.

In addition to sitosterol, syringaldehyde, 3,4,5-trimethoxybenzoic acid, isoelemicin and grandisin, two new tetrahydrofuran lignans were isolated from Piper solmsianun and characterized as rel-(7R,8R,7'R,8'R)-3',4'-methylenedioxy-3,4,5,5'-tetramethoxy-7,7'-epoxylignan and rel-(7R,8R,7'R,8'R)-3,4,3',4'-dimethylenedioxy-5,5'-dimethoxy-7,7'-epoxylignan on the basis of spectroscopic data, including 2D NMR spectrometric techniques. Their in vitro activity were determined against the trypomastigote form of Trypanossoma cruzi.

Animals↗

The tumor promoting effect of lime-piper betel quid in JB6 cells.

Betel quid chewing is a general behavior in Taiwan, India, southeastern Asian and South Africa. In this study, microculture tetrazolium test (MTT) showed that the extract of lime-piper betel quid (LPB) (1.0-20 mg/ml) was toxic to JB6 cells. Cells exposed of LPB (0.1, 0.5, 1.0 mg/ml) for 7 days resulted in changes in cytomorphology with characteristics of carcinogenesis. With a long-term treatment (approximately 30 days) of low doses of LPB (1, 5, 10 microg/ml), the production of H2O2 and the activity of myeloperoxidase (MPO) and ornithine decarboxylase (ODC) were increased in JB6 cells. Cell cycle analysis showed a decrease in the G1 phase and an accumulation in the S phase 48 h after LPB treatment. When treating with 0.5 mg/ml LPB for 15 days as a promoter, type III foci were formed in the JB6 culture. These results demonstrated the tumor promotional effect of LPB in JB6 cells.

Animals↗

Constituents from Piper marginatum fruits.

The hexane extract of the dried fruits of Piper marginatum yielded 1-(1Z-propenyl)-2,4,6-trimethoxybenzene, a new natural product, besides 3-farnesyl-4-hydroxybenzoic acid and caryophyllene oxide.

Fruit↗

Amides from Piper tuberculatum fruits.

The fruits of Piper tuberculatum Jacq yielded piperine S (1) and N-(12,13,14-trimethoxydihydrocinnamoyl)-delta(3)-piperidin-2-one (2). Their complete NMR analysis based on one- and two-dimensional experiments is reported.

Amides↗

Antifungal activity of Piper guineense of Cameroon.

The antifungal activity of the ethanol extract of the seeds of Piper guineense and some of its fractions obtained by column chromatography was investigated using filamentous fungi and yeasts. The results indicated a significant antifungal effect. No toxic effect was observed in mice treated per os with the extract.

Animals↗

Phenolic antibacterials from Piper betle in the prevention of halitosis.

Piper betle L. (Piperaceae) leaves which are traditionally used in India and China in the prevention of oral malodor was examined by bioassay-guided fractionation to yield allylpyrocatechol (APC) as the major active principle which showed promising activity against obligate oral anaerobes responsible for halitosis. The biological studies with APC indicated that the potential to reduce methylmercaptan and hydrogen sulfide was mainly due to the anti-microbial activity as established using dynamic in vitro models.

Anti-Bacterial Agents↗

In vitro neuropharmacological evaluation of piperovatine, an isobutylamide from Piper piscatorum (Piperaceae).

Piperovatine, a sialogogic, piscicidal, and buccal local anesthesia producing isobutyl amide from the amazonian piscicidal and toothache-relieving plant, Piper piscatorum Trelease et Yuncker (Piperaceae), was evaluated for its ability to induce changes in neuronal intracellular calcium concentration. Ratiometric calcium imaging of Periplaneta americana neuronal cell cultures upon piperovatine application revealed that this compound induced dramatic increases in intracellular calcium concentration. Calcium flux was not affected by co-application of the muscarinic acetylcholine receptor antagonist, atropine, indicating that the parasympathomimetic system was not involved in piperovatine's sialogogic actions. Calcium flux was, however, totally eliminated by co-application of the voltage-gated sodium channel blocker, tetrodotoxin (TTX). This, in conjunction with the repetitive calcium spikes observed in the assay and previous radioligand binding studies on the chemical class, strongly suggest that activation of voltage-gated sodium channels characterizes piperovatine's mode of action

Animals↗

Investigations of anti-inflammatory and antinociceptive activities of Piper cubeba, Physalis angulata and Rosa hybrida.

The anti-inflammatory activities of Piper cubeba (fruit), Physalis angulata (flower) and Rosa hybrida (flower) were determined by carrageenan-induced paw edema, arachidonic acid-induced ear edema and formaldehyde-induced arthritis in mice. The anti-allergic and analgesic activities of these plants were also studied by using 2,4-dinitrofluorobenzene (DNFB)-induced contact hypersensitivity reaction (type IV) and hot plate test in mice, respectively. These plant extracts clearly exhibited inhibitory effects against acute and subacute inflammation by oral administration (200 mg/kg). Also, administration (200 mg/kg, p.o.) of plant extracts for 1 week significantly inhibited type IV allergic reaction in mice (P<0.05). Rosa hybrida showed an analgesic effect against hot plate-induced thermal stimulation at a dose of 200 mg/kg. These results provide support for the use of Rosa hybrida in relieving inflammatory pain, and insight into the development of new agents for treating inflammatory diseases.

Analgesics↗

Antileishmanial activities of dihydrochalcones from piper elongatum and synthetic related compounds. Structural requirements for activity.

Two dihydrochalcones (1 and 2) were isolated from Piper elongatum Vahl by activity-guided fractionation against extracellular promastigotes of Leishmania braziliensis in vitro. Their structures were elucidated by spectral analysis, including homonuclear and heteronuclear correlation NMR experiments. Derivatives 3-7 and 20 synthetic related compounds (8-27) were also assayed to establish the structural requirements for antileishmanial activity. Compounds 1-11 that proved to be more active that ketoconazol, used as positive control, were further assayed against promastigotes of Leishmania tropica and Leishmania infantum. Compounds 7 and 11, with a C(6)-C(3)-C(6) system, proved to be the most promising compounds, with IC(50) values of 2.98 and 3.65 microg/mL, respectively, and exhibited no toxic effect on macrophages (around 90% viability). Correlation between the molecular structures and antileishmanial activity is discussed in detail.

Animals↗

Antifungal cyclopentenediones from Piper coruscans.

Coruscanones A and B, two new antifungal cyclopentenedione derivatives, have been isolated from Piper coruscans and their structures elucidated by spectroscopic and chemical methods. Coruscanone A exhibits significant antifungal activity against Candida albicans and its azole-resistant strains and may serve as a template for a new class of antifungal agents.

Antifungal Agents↗

Gene expression profiles of Drosophila melanogaster exposed to an insecticidal extract of Piper nigrum.

Black pepper, Piper nigrum L. (Piperaceae), has insecticidal properties and could potentially be utilized as an alternative to synthetic insecticides. Piperine extracted from P. nigrum has a biphasic effect upon cytochrome P450 monooxygenase activity with an initial suppression followed by induction. In this study, an ethyl acetate extract of P. nigrum seeds was tested for insecticidal activity toward adult Musca domestica and Drosophila melanogaster. The effect of this same P. nigrum extract upon differential gene expression in D. melanogaster was investigated using cDNA microarray analysis of 7380 genes. Treatment of D. melanogaster with P. nigrum extract led to a greater than 2-fold upregulation of transcription of the cytochrome P450 phase I metabolism genes Cyp 6a8, Cyp 9b2, and Cyp 12d1 as well as the glutathione-S-transferase phase II metabolism gene Gst-S1. These data suggests a complex effect of P. nigrum upon toxin metabolism.

Alkaloids↗

Antioxidant activity of piper betel leaf extract and its constituents.

The 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay of the ethanol extracts of three varieties (Bangla, sweet, and Mysore) of Piper betel (pan) revealed the Bangla variety to possess the best antioxidant activity that can be correlated with the total phenolic content and reducing powers of the respective extracts. Column chromatography of the extract of the Bangla variety led to the isolation of chevibetol (CHV), allylpyrocatechol (APC), and their respective glucosides. The HPTLC analyses of the extracts revealed similar chemical profiles in all three P. betel varieties, although the concentrations of CHV and APC were significantly less in the sweet and Mysore varieties. Among the isolated compounds, APC showed the best results in all the in vitro experiments. It could prevent Fe(II)-induced lipid peroxidation (LPO) of liposomes and rat brain homogenates as well as gamma-ray-induced damage of pBR322 plasmid DNA more efficiently than CHV. The superior anti-LPO and radioprotective activities of APC vis-à-vis those of CHV could not be explained by their respective Fe(II) chelation and .OH radical scavenging capacities. The better ability of APC to scavenge O2-. radicals and H2O2 might account for the results.

Animals↗