Three flavanones, two chalcones and one dihydrochalcone were isolated from the branches of Piper glandulosissimum. All isolated compounds were characterized based on IR, UV, 1H and 13C NMR, including 2D NMR analyses (HMQC, HMBC, COSY and NOESY) and comparison with the literature. The compound 7-hydroxy-5,8-dimethoxyflavanone displayed antimicrobial activity against Staphylococcus aureus, S. epidermidis, Trichophyton mentagrophytes and Microsporum canis.

Três novos compostos: dois flavonóides [(S)-8-formil-3',5-diidroxi-7-metoxi-6-metilflavanona(1) e 3'-formil-3,4',6'-triidroxi-2'-metoxi-5'-metilchalcona (2)] e um fenilpropanóide [3,4-metilenodioxi-5-metoxi-7,8-diidrocinamato de etila (3)] foram isolados dos ramos secos de Piper montealegreanum. As estruturas desses compostos foram estabelecidas através das técnicas espectroscópicas UV, IV, EM e RMN (¹H e 13C, 1D e 2D), além da interpretação dos dados de RMN de ¹H e 13C dos derivados metilados dos compostos 1 e 2.

Three new compounds: two flavonoids [(S)-8-formyl-3',5-dihydroxy-7-methoxy-6methylflavanone (1) and 3'-formyl-3,4',6'-trihydroxy-2'-methoxy-5'-methylchalcone (2)] and one phenylpropanoid [ethyl 3,4-methylenedioxy-5-methoxy-7,8-dihydrocinnamate (3)] were isolated from dried branches of Piper montealegreanum. Their structures were established by UV, IR, MS, 1D and 2D (¹H and 13C) NMR spectroscopic techniques, besides interpretation of spectral data (¹H and 13C NMR) of methylated derivatives of 1 and 2 compounds.

Os flavonóides 5,3’,4’-triidroxi-7-metoxiflavona, 5,3’-diidroxi-7-4’-dimetoxiflavona, 5,4’-diidroxi-7-metoxiflavona e uma mistura de esteróides (β-sitosterol e estigmasterol) foram isoladas das partes aιreas de Piper carniconnectivumC.DC, Piperaceae. As estruturas desses compostos foram estabelecidas por análises espectroscópicas de UV, IV e RMN de ¹H e 13C, incluindo técnicas uni e bidimensionais.

The flavonoids 5,3’,4’-trihydroxy-7-methoxyflavone, 5,3’-dihydroxy-7-4’-dimethoxyflavone, 5,4’-dihydroxy-7-methoxyflavone and steroids mixture (β-sitosterol and stigmasterol) were isolated from the dried aerials parts of Piper carniconnectivumC.DC. Their structures were established by spectroscopic analyses (UV, IV and ¹H, 13C NMR, including 1D and 2D NMR).