• Korean journal of applied entomology
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• v.51 no.2
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• pp.149-152
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• 2012

The larvicidal activities of Piper nigrum fruit methanol extracts and its constituents against larvae of the diamondback moth, Plutella xylostella, were investigated using the leaf dipping method. Administering the P. nigrum methanol extract resulted in 100 and 97% mortality against diamondback moth larvae at 5.0 and 2.5 mg/mL concentrations, respectively. Larvicidal activities of the P. nigrum fruit-derived piperidine alkaloids, piperine, and N-isobutylamide, as well as pellitorine, guineensine, pipercide, and retrofractamide A against P. xylostella varied according to test compound. Based on the 48 h $LC_{50}$ values, the most toxic compound to diamondback moth larvae was guineensine (0.013 mg/mL) followed by retrofractamide A (0.020mg/mL), pipercide (0.033mg/mL), and pellitorine (0.046 mg/mL). The $LC_{50}$ value of piperine was >0.5 mg/mL.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.201.1-201.1
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• 2003

Study of Acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors from medicinal plants, we found strong inhibitory activity of ACAT enzyme from rat liver microsome by the CHC1$_3$ extract of Piper longum. Bioactivity-guided fractionation led to the isolation of Guineensine (1), its structure was elucidated by spectroscopic (IR, UV, MS and NMR) means. It inhibited ACAT activity in a dose-dependent manner with IC$\sub$50/ values of 1.2 $\mu\textrm{g}$/ml on in vitro assay using rat liver microsome.

• Journal of Applied Biological Chemistry
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• v.48 no.2
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• pp.65-74
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• 2005

Fungicidal, insecticidal, and mosquito larvicidal activities of piperidine alkaloids, pipernonaline and piperoctadecalidine, and isobutylamide alkaloids, pellitorine, guineensine, pipercide, and retrofractaminde A, derived from Piperaceae fruits were studied. Pipernonaline and piperoctadecalidine showed potent fungicidal activities against Puccinia recondita with 91 and 80% control values at 500 ppm. Against Phytophthora infestans, pipernonaline showed strong fungicidal activity with 91 and 80% control values at 1,000 and 500 ppm. $LD_{50}$ values of pipernonaline and piperoctadecalidine against Plutella xylostella were 125 and 95.5 ppm, respectively, and that of piperoctadecalidine against Tetranychus urticae was 246 ppm. Against larvae of Aedes aegypti and Culex pipiens pallens, $LD_{50}$ values of pipernonaline were 0.35 and 0.21 ppm, respectively. Highest larvicidal activities of pipercide and retrofractamide A were found against A. aegypti, A. togoi, and C. pipiens pallens. $LD_{50}$ values of pipercide and retrofractamide A were 0.10 and 0.039 ppm against A. aegypti, 0.26 and 0.01 ppm against A. togoi, and 0.004 and 0.028 ppm against C. pipiens pallens, respectively. Based upon these results and earlier findings, bioactive components derived from Piperaceae fruits may be valuable for development of useful lead product of possibly safer fungicidal, insecticidal, and mosquito larvicidal agents.

• Bulletin of the Korean Chemical Society
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• v.13 no.4
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• pp.388-391
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• 1992

A chemical investigation of the fruits of Piper retrofractum (Piperaceae) has led to the isolation and characterization of a novel piperidine alkaloid, piperoctadecalidine together with three known alkaloids piperine, pipernonaline and guineensine. The structure of the new compound was detemined to be (2E,4E,14Z)-N-(2,4,14-Octadecatrienoyl) piperidine by spectral and synthetic methods.