Antifungal Amide Alkaloids from the Aerial Parts of Piper flaviflorum and Piper sarmentosum

Abstract

Sixty-three amide alkaloids, including three new, piperflaviflorine A (<b>1</b>), piperflaviflorine B (<b>2</b>), and sarmentamide D (<b>4</b>), and two previously synthesized ones, (1<i>E</i>,3<i>S</i>)-1-cinnamoyl-3- hydroxypyrrolidine (<b>3</b>) and <i>N</i>-[7'-(4'-methoxyphenyl)ethyl]-2-methoxybenzamide (<b>5</b>), were isolated from the aerial parts of <i>Piper flaviflorum</i> and <i>Piper sarmentosum.</i> Their structures were elucidated by detailed spectroscopic analysis and, in case of <b>3</b>, by single-crystal X-ray diffraction. Most of the isolates were tested for their antifungal and antibacterial activities. Ten amides (<b>6</b>-<b>15</b>) showed antifungal activity against <i>Cryptococcus neoformans</i> ATCC 90 113 with IC₅₀ values in the range between 4.7 and 20.0 µg/mL.