Showing papers on "Piperlonguminine published in 2005"

Analysis of Piperaceae germplasm by HPLC and LCMS: a method for isolating and identifying unsaturated amides from Piper spp extracts.

Abstract: A method for extraction and high performance liquid chromatography-mass spectrometer (HPLC-MS) analysis of the medicinally important genus Piper (Piperaceae) was developed. This allows for a rapid and accurate measure of unsaturated amides, or piperamides, in black pepper, Piper nigrum L., and in wild species from Central America. Reflux extraction provided the highest recovery of piperine (>80%) from leaf and peppercorn material. HPLC analysis using a binary gradient of acetonitrile and water separated the major amide peaks between 5 and 12 min. Atmospheric pressure chemical ionization (APCI)-MS improved the detection limit to 0.2 ng, 10-fold below the 2 ng limit of the HPLC-diode array detector (DAD) based on linear standard curves between 0.1 and 250 microg/mL (R2 = 0.999). The HPLC-MS method identified pellitorine, piperylin, 4,5-dihydropiperlonguminine, piperlonguminine, 4,5-dihydropiperine, piperine, and pipercide. The biological activity of six Costa Rican Piper species assessed by mosquito larval bioassays correlated well with piperamide content.

A simple synthesis of piperlonguminine

Abstract: A simple and practical method for the synthesis of an alkaloid piperlongumine, an efficient inhibitor of α-melanocyte stimulating hormone, was established by employing Wadsworth-Horner modified Wittig reaction as a key step. An alkaloid piperolonguminine [W-isobutyl-5-(l,3-benzodioxol-5-yl)-2,4-pentadienamide, la] was first isolated from Piper longttm Linn. (I), then also isolated from other Piper species (2) as well as other genus (3). Piper longum, known as "Pippali", has long been used as an effective drug in the treatment of asthma and chronic bronchitis in the Ayuvedic system of medicine in India (4). Biological properties of the extracts, composed mainly of la, piperine (1c), and /V-isobutyl-(£,£)-2,4-decadienamide, were studied to show anti-allergic (5) and tumor inhibitory activity (6). Recent report on the inhibitory activity of la on α-melanocyte stimulating hormone-induced tyrosinase synthesis, a key step in melanin biosynthesis, opened a new vista of the la as a cosmetic additive (7). Most of the synthetic methods of piperlongumine employed piperic acid ( lb) which could be derived from readily available natural product piperine (8). However, the content of Ic in most pepper plants is low (0.025-6%) and the cost of raw pepper is relatively high. The promising potential of piperolongumine as a whitening agent in cosmetic spurred us to design a simple and practical synthetic method to provide sufficient amount for pursuing further biological properties on experimental animals. Synthetic sequence for la was quite straight forward as shown. Wadsworth-Horner modified Wittig condensation (9) of readily available and cheap piperonal (2) with the anion generated from ethyl (£)-4diethylphosphono-2-butenoate (3) gave ethyl piperate (7) in 6 5 % yield. ' H N M R showed a characteristic doublet of doublet ( J = 15.3 and 10.5 Hz) for H3 at δ 7.39, a doublet (J = 15.3 Hz) at δ 5.92 for H2, a doublet at δ 6.77 ( J = 15.0, 10.0 Hz) for H4, and a doublet ( J = 10.3 Hz) at δ 6.70 for H5 for pentadienoic acid moiety. No isomeric product was observed in 250 M H z 'H N M R and 62.5 M H z C N M R . The starting phosphono ester 3 was prepared in 9 0 % yield by Arbuzov reaction of commercially available ethyl 4-bromo-2-butenoate (4) and triethyl phosphate. Our attempts for an amination of ethyl piperate by isobutylamine in the presence of sodium methoxide (10) suffered from low yield, which led us to employ an alternative synthetic pathway. The ester was, thus, hydrolyzed to corresponding acid (5), which was condensed with isobutylamine in the presence of catalytic amount of boric acid (11) to yield la in 9 1 % two-step yield. Ο l a R = NHCH2CH(CH3)2 b R = Η 407 Unauthenticated Download Date | 6/2/19 11:44 AM Vol. 11, No. 5, 2005 A simple synthesis of piperlongnminine Alternative synthetic route employing aldehyde 7 and triphenylpiperonylphosphonium bromide (8) was also pursued to afford the desired ester 4 in similar yield. It is worthy to noting that reaction with 8 gave better yield compared to the reaction with its diethylphosphono congener.