Two New Insecticidal Amide Dimers from Fruits of Piper nigrum Linn.

The methanolic extract of dried ground seeds of Piper nigrum Linn . afforded fourteen compounds, of which thirteen were amides, including two new isomeric insecticidal amides, pipsaeedine ( 1 ) and pipbinine ( 2 ), along with eleven known amides and piptaline; (this is the first report of isolation of these compounds from this plant). The structures of 1 and 2 have been elucidated as (E,E)‐1‐[(E)‐5‐(7‐{6‐[5‐(piperidin‐1‐yl)‐5‐oxopent‐3‐enyl]‐1,3‐benzodioxol‐4‐yl}‐1,3‐benzodioxol‐5‐yl)‐1‐oxopenta‐2,4‐dienyl]piperidine and (E,E)‐1‐[(E)‐5‐(4‐{6‐[5(piperidin‐1‐yl)‐5‐oxopent‐3‐enyl]‐1,3‐benzodioxol‐4‐yl}‐1,3‐benzodioxol‐5‐yl)‐1‐oxopenta‐2,4‐dienyl]piperidine, respectively, through extensive 1D‐ and 2D‐NMR spectral studies, while the known constituents have been identified through comparison of their spectral data with those reported in the literature. Compounds 1 and 2 exhibited toxicities of 45.0 and 40.0 ppm, respectively, against fourth instar larvae of Aedes aegypti Liston.     

A new natural product and insecticidal amides from seeds of Piper nigrum Linn

Studies on the petroleum ether soluble and insoluble fraction of ethanol extract of dried ground seeds of Piper nigrum resulted in the isolation and structure elucidation of 1 new and 11 known compounds which include 3 hitherto unreported constituents, namely, cinnamylideneacetone, 3,4-methylenedioxyphenylpropiophenone and 2-hydroxy-4,5-methylenedioxypropiophenone from this plant.     

Two New Insecticidal Amides and a New Alcoholic Amide from Piper nigrum Linn.

Three new amides, pipgulzarine ( 1 ), pipzorine ( 2 ), and piptahsine ( 3 ), have been isolated from the dried seeds of Piper nigrum Linn. along with nine known constituents: (2E,4E,8Z)‐N‐(isobutyl)eicosatrienamide, pellitorine, pipercide, piperine, stigmastanol, stigmasterol, decurrenal, stigmasterol 3‐O‐β‐D ‐glucopyranoside, and 5,10(15)‐cadinen‐4‐ol. The structures of the new constituents have been established as (2E,11E)‐12‐(benzo[1,3]dioxol‐5‐yl)‐N‐(2‐methylpropyl)dodeca‐2,11‐dienamide ( 1 ), (2E,12Z)‐N‐(4‐methylpentyl)octadeca‐2,12‐dienamide ( 2 ), and (2E,4S)‐4‐hydroxy‐N‐(2‐methylpropyl)hex‐2‐enamide ( 3 ). The structures of 1 – 3 were derived by spectral studies and chemical reactions, and by comparison of spectral data in the case of known constituents. Compounds 1 and 2 , and most of the already known compounds, exhibited toxicity against fourth instar larvae of Aedes aegypti Liston. The isolated (Z) double bond in 2 was assigned on the basis of its EI‐MS fragmentation pattern and its reaction with OsO₄. The (S) configuration at C(4) of 3 was determined by Horeau's method. This is the first report of the isolation of a 4‐methylpentylamide from P. nigrum, while shorter branched amides have been reported from this genus [1].     

New insecticidal amides from petroleum ether extract of dried Piper nigrum L. whole fruits

The petroleum ether extract of dried ground whole fruits of Piper nigrum L. afforded 20 compounds (1-20) including two new insecticidal amides named as pipnoohine (1), and pipyahyine (2), seven reported for the first time from this plant (12, 13, 15-17, 19, 20), and eleven known compounds (3-11, 14, 18). The structure of 1 has been elucidated as (2E,4E,12Z)-N-(4-methylpentyl)octadeca-2,4,12-trienamide and that of 2 as (2E,4E,11E)-12-(benzo[1,3]dioxol-5-yl)-N-(3-methylbutyl)dodeca-2,4,11-trien-amide through extensive ID-, 2D-NMR spectral studies and chemical reactions. The known compounds have been identified through comparison of their spectral data with those reported in literature. 1 and 2 exhibited toxicity at 35.0 and 30.0 ppm respectively against fourth instar larvae of Aedes aegypti L. by WHO method.     

Anticholinesterases and antioxidant alkamides from Piper nigrum fruits

The anticholinesterase and antioxidant effects of five different extracts of Piper nigrum were evaluated. Twenty-one known alkamides were isolated from active ethyl acetate extract and investigated for their cholinesterase inhibitory and antioxidant effects. Among them, piperine (2), piperettine (5) and piperettyline (20) exhibited dual inhibition against AChE and BChE, and feruperine (18) was the most potent selective inhibitor of BChE. Molecular docking simulation was performed to get insight into the binding interactions of the ligands and enzymes. In addition, N-trans-feruloyltyramine (3) contributed to the strongest DPPH radical-scavenging activity. The self-induced Aβ aggregation inhibition of 2, 5 and 18 was further evaluated. Results indicated that some alkamides could be multifunctional lead candidates for Alzheimer’s disease therapy.     

Piptigrine, a new insecticidal amide from Piper nigrum Linn

A new insecticidal amide piptigrine (1) possessing highly extended conjugation was isolated from the dried ground seeds of Piper nigrum Linn. along with the known amides piperine and wisanine (hitherto unreported from this plant). The structure of 1 has been elucidated as 1-[9-(3',4'-methylenedioxyphenyl)-4E,6E,8E-nonatrienoyl]piperidine through extensive 1D- and 2D-NMR (COSY-45, NOESY, J-resolved, HMQC, HMBC and NOESY studies. The known compounds have been identified through comparison of their spectral data with those reported in literature. 1 exhibited toxicity of 15.0 ppm against fourth instar larvae of Aedes aegypti Liston.     

Phytochemical studies on the seed extract of Piper nigrum Linn

The petroleum ether extract of dried ground seeds of Piper nigrum Linn. and some column fractions of this extract were subjected to GC and GC-MS analysis, resulting in the identification of fourteen compounds (1-14) by using NIST Mass spectral search program 1998 and the Kovat's retention indices. Ten of the compounds (1, 2, 4-12) are reported for the first time from this plant. All the fractions showed insecticidal activity against the fourth instar larvae of Aedes aegypti and against the fourth instar larvae of Anopheles stephensi Liston, determined by the WHO method.     

Insecticidal activity of isobutylamides derived from Piper nigrum against adult of two mosquito species, Culex pipiens pallens and Aedes aegypti

The insecticidal activity of Piper nigrum fruit-derived piperidine alkaloid (piperine) and N-isobutylamide alkaloids (pellitorine, guineensine, pipercide and retrofractamide A) against female adults of Culex pipiens pallens and Aedes aegypti was examined. On the basis of 24-h LD(50) values, the compound most toxic to female C. pipiens pallens was pellitorine (0.4?μg/♀) followed by guineensine (1.9?μg/♀), retrofractamide A (2.4?μg/♀) and pipercide (3.2?μg/♀). LD(50) value of chlorpyrifos was 0.03?μg/♀. Against female A. aegypti, the insecticidal activity was more pronounced in pellitorine (0.17?μg/♀) than in retrofractamide A (1.5?μg/♀), guineensine (1.7?μg/♀), and pipercide (2.0?μg/♀). LD(50) value of chlorpyrifos was 0.0014?μg/♀.     

Nigramides A-S, dimeric amide alkaloids from the roots of Piper nigrum

[structure: see text] Fifteen novel dimeric amide alkaloids possessing a cyclohexene ring, nigramides A-O (1-15), as well as four novel dimeric amide alkaloids possessing a cyclobutane ring, nigramides P-S (17-20), have been isolated from the roots of Piper nigrum. Their structures were elucidated on the basis of their spectroscopic data. The biosynthestic hypothesis of nigramides A-O (1-15) was proposed by an intermolecular Diels-Alder reaction from the corresponding monomeric amides. On the basis of this biosynthetic hypothesis, the first study of the thermal and Lewis acid mediated Diels-Alder reactions of piperine in different organic solvents and under solventless conditions is also described.     

Aedes aegypti larvicide from the ethanolic extract of Piper nigrum black peppercorns

Due to unavailability of a vaccine and a specific cure to dengue, the focus nowadays is to develop an effective vector control method against the female Aedes aegypti mosquito. This study aims to determine the larvicidal fractions from Piper nigrum ethanolic extracts (PnPcmE) and to elucidate the identity of the bioactive compounds that comprise these larvicidal fractions. Larvicidal assay was performed by subjecting 3rd to 4th A. aegypti instar larvae to PnPcmE of P. nigrum. The PnPcmE exhibited potential larvicidal activity having an LC₅₀ of 7.1246 ± 0.1304 ppm (mean ± Std error). Normal phase vacuum liquid chromatography of the PnPcmE was employed which resulted in five fractions, two of which showed larvicidal activity. The most active of the PnPcmE fractions is PnPcmE-1A, with an LC₅₀ and LC₉₀ of 1.7101 ± 0.0491 ppm and 3.7078 ppm, respectively. Subsequent purification of PnPcmE-1A allowed the identification of the larvicidal compound as oleic acid.     

Preparative isolation and purification of amides from the fruits of Piper longum L. by upright counter-current chromatography and reversed-phase liquid chromatography

A versatile counter-current chromatography (CCC) with upright type-J multilayer coil planet centrifuge, named upright CCC, was applied to the isolation and purification of amides from Piper longum L., which is widely used as an anodyne and a treatment for stomach disease in China. After the saponification by KOH of the ethanol extracts solution of 15 kg of crude drug "Piper Longi Fructus", the fruits of P. longum L., the solution was extracted with light petroleum and 500 g of red crude oil was obtained. Using 2.5 g of red crude oil as sample, the preparative upright CCC with a two-phase system composed of light petroleum (bp 60-90 degrees C)-ethyl acetate-tetrachloromethane-methanol-water (1:1:8:6:1, v/v) was successfully performed, which yielded nine fractions. Then these fractions were further purified by use of reversed-phase liquid chromatography (RPLC) with a glass column of 500 x 10 mm i.d. packed with reversed-phase silica gel. As a result, nine target amides with over 95% purity, i.e., 50 mg of (2E,4E)-N-isobutyl-eicosa-2,4-dienamide, 150 mg of (2E,4E,14Z)-N-isobutyl-eicosa-2,4,14-trienamide, 110 mg of (2E,4E,12Z)-N-isobutyl-ocatadeca-2,4,12-trienamide, 50 mg of guineensine, 60 mg of pipernonaline, 75 mg of pellitorine, 63 mg of piperine, 45 mg of piperanine, and 40 mg of piperlonguminine were isolated, respectively. Structures of all compounds were identified by electrospray ionization MS, electron impact ionization MS, one- and two-dimensional NMR spectra.     

New chemical constituents from the Piper betle Linn. (Piperaceae)

The phytochemical investigation of chloroform extract from Piper betle var. haldia, Piperaceae, leaves has resulted in the isolation of two new chemical constituents which were identified as 1-n-dodecanyloxy resorcinol (H1) and desmethylenesqualenyl deoxy-cepharadione-A (H4), on the basis of spectroscopic data 1D NMR (¹H and ¹³C) and 2D NMR (¹H-¹H COSY and HMBC) as well as ESI-MS, FT-IR and HR-ESI-MS analyses. Compounds H1 and H4 showed excellent antioxidant DPPH free radical scavenging activity with IC₅₀ values of 7.14 μg/mL and 8.08 μg/mL compared to ascorbic acid as a standard antioxidant drug with IC₅₀ value of 2.52 μg/mL, respectively. Evaluation of cytotoxic activity against human hepatoma cell line (PLC-PRF-5) showed moderate effect with the GI₅₀ values of 35.12 μg/mL for H1, 31.01 μg/mL for H4, compared to Doxorubicin^® as a standard cytotoxic drug with GI₅₀ value of 18.80 μg/mL.     

Complete 1H and 13C NMR assignments of two phytosterols from roots of Piper nigrum

Using modern NMR techniques, including DQF-COSY, NOESY, HETCOR and HMBC, the full assignments of all 1H and 13C chemical shifts were made for stigmastane-3,6-dione and stigmast-4-ene-3,6-dione, isolated from the roots of Piper nigrum (Piperaceae). Their stereochemistry was resolved by a combination of 2D NOESY data and analysis of coupling constants. The two compounds were isolated from the genus Piper for the first time.     

Antifertility activity of Piper longum Linn. in female rats

The crude extract, its different fractions and the major pure compound from the active fraction of the powdered fruits of Piper longum were studied for the antifertility effect in female rats. The crude extract and its hexane fraction exhibited 100 and 86% efficacy respectively (days 1-7 post-coitum (p.c.) schedule). On the other hand, 1-butanol soluble, 1-butanol insoluble and chloroform fractions were inactive.     

GC-EIMS analysis,antifungal and anti-aflatoxigenic activity of Capsicum chinense and Piper nigrum fruits and their bioactive compounds capsaicin and piperine upon Aspergillus parasiticus

Abstract

GC-EIMS analysis, antifungal- and anti-aflatoxigenic activities of the ethanolic extract of Capsicum chinense and Piper nigrum fruits and their main bioactive compounds were evaluated upon Aspergillus parasiticus. The GC-EIMS analysis showed capsaicin (50.49%) and piperine (95.94%) as the major constituents in C. chinense and P. nigrum, respectively. MIC₅₀ values revealed that capsaicin (39?μg/mL) and piperine (67?μg/mL) were lower than those from fruit extracts of C. chinense (381?μg/mL) and P. nigrum (68?μg/mL). Extracts and bioactive compounds showed anti-aflatoxigenic activity. Maximum aflatoxin inhibition occurred at 150?µg/mL of extracts and compounds. The present study showed satisfactory results concerning the effects of ethanolic extract of C. chinense and P. nigrum fruits upon A. parasiticus, showing the capabilities of inhibiting fungal growth development and altering aflatoxins production.     

Aroma compound analysis of Piper nigrum and Piper guineense essential oils from Cameroon using solid-phase microextraction-gas chromatography,solid-phase microextraction-gas chromatography-mass spectrometry and olfactometry

Three analytical methods were developed for the determination of toxic compounds in recirculating waters of a paper-recycling industry. Three main groups of compounds were considered: (i) wood extractives originated from the raw material; (ii) biocides added during the production process and (iii) surfactants and other adjuvants present in the formulates of these biocides. Wood extractives considered in this study included fatty and resin acids. They were analysed by liquid-liquid extraction using methyl tert.-butyl ether, followed by gas chromatography-mass spectrometry for previous formation of the respective trimethylsilyl esters. Water samples were also extracted with Oasis HLB (copolymer [poly(divinylbenzene-co-N-vinylpyrrolidone]) solid-phase extraction cartridges of 60 mg and analysed by liquid chromatography-electrospray mass spectrometry for the determination of additives and biocides. Using these two approaches levels up to 15 mg/l for total resin and fatty acids, 5 mg/l for alkylbenzene sulfonates and 2-(thiocyanomethylthio)benzotiazol, 100 microg/l for bisphenol A and 2,2-dibromo-3-nitrilepropionamide, and 300 microg/l for nonylphenol ethoxycarboxylate were detected in process waters at different production treatment stages. These levels are of relevance since poor water quality affects the paper-recycling process, the primary water treatment process and eventually, the environmental water quality.     

Purification and antioxidant capacity analysis of anthocyanin glucoside cinnamic ester isomers from Solanum nigrum fruits

In a recent study, anthocyanins, which have a strong free radical‐scavenging activity, were examined for their potential to effectively prevent cancer. However, clinical trials are limited by the purity of the anthocyanin. Multiple methods are used to extract and purify anthocyanins. Based on previous work on Solanum nigrum, which is a widely distributed plant, in this study, DM130 macroporous resin, Sephadex LH20, and a C18 column were used to separate cis–trans anthocyanin isomers. These anthocyanins constitute the majority of total S. nigrum anthocyanins. The results showed that this “DM130‐LH20‐C18 system” can be used to obtain a cinnamic acid‐derived cis–trans anthocyanin, petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside, with a purity of 98.5%, for effective quantitation. In order to determine the antioxidant ability of the petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside cis–trans isomers, three ordinary methods were adopted. The maximum antioxidant ability of the cis–trans anthocyanin was dozens of times higher than that of vitamin C.     

Chemical constituents of Piper betle Linn. (Piperaceae) roots

Column chromatography of the alcoholic extract of Piper betle roots furnished aristololactam A-II and a new phenyl propene, characterized as 4-allyl resorcinol, while the petroleum-ether extract yielded a diketosteroid, viz. stigmast-4-en-3,6-dione. All these compounds were characterized by spectroscopic means. Isolation of these compounds from this source is being reported here for the first time.