Poincianella pluviosa is a tree whose stem bark is reputed to have antidiarrheal, wound healing, antitumoral and antimalarial properties. Considering that the leaves of the tree are a more abundant and renewable source than the stem bark, we chose to study the antimalarial potential of this organ part. The aqueous leaf extract exhibited a rich phenolic profile. It was active (IC50= 6.88 ± 1.64 µg mL-1) against chloroquine resistant Plasmodium falciparum (W2) without toxicity to HepG2 A16 cells. The organic fraction was more active (IC50= 1.83 µg mL-1) than the aqueous leaf extract itself. Ten phenolic compounds were obtained from the latter. This is the first report on the phenolic composition of P. pluviosa leaves. Ellagic acid (IC50= 0.215 ± 0.007 µg mL-1) proved to be 32 fold more active than the aqueous leaf extract itself. Considering their renewable aspect, leaves of P. pluviosa appear to be a more interesting source of antimalarial compounds than stem bark.

A partir das folhas de Kalanchoe pinnata (Crassulaceae), uma planta medicinal amplamente utilizada contra processos inflamatórios e que apresenta importante atividade imunossupressora e anti-leishmania, foi isolado um álcool vinílico diglicosilado minoritário, caracterizado como 1-octeno-3-O-alfa-L-arabinopiranosil-(1 -> 6)-beta-glicopiranosídeo baseado em RMN mono e bi-dimensional e em CG-EM, após sucessivos processos cromatográficos em coluna. Esta molécula é um derivado hidrossolúvel da aglicona 1-octen-3-ol, molécula que atua como atrativo para polinizadores e sinalizador de defesa contra herbivoria.

From the leaves of Kalanchoe pinnata (Crassulaceae), a medicinal plant widely used against inflammatory processes which exhibit a important immunosuppressive and anti-leishmanial activities, was isolated a minor vinylic aliphatic alcohol diglycoside which structure was proposed as the known 1-octen-3-O-alpha-L-arabinopyranosyl-(1 -> 6)-beta-glucopyranoside based on ¹H and 13C mono and bi-dimensional NMR experiments and GC-MS analysis, after successive chromatographic column procedures. This molecule is a water-soluble derivative of the volatile aglicone 1-octen-3-ol that appears to be attractant of pollinators and signalling of defence against herbivores.

O extrato da espécie medicinal Alternanthera brasiliana Kuntze forneceu seis derivados di- e triglicosilados de kaempferol e quercetina. As estruturas foram elucidadas com base em RMN de ¹H e 13C. Os seis flavonóides são inéditos no gênero. Kaempferol 3-O-robinobiosídeo e kaempferol 3-O-rutinosídeo inibiram mais eficientemente a proliferação de linfócitos humanos in vitro.

The extract of the medicinal species Alternanthera brasiliana Kuntze afforded six di- and triglycosyl kaempferol and quercetin derivatives. Their structures were elucidated based on the ¹H- and 13C-NMR data and are reported here for the first time in this genus. Kaempferol 3-O-robinobioside and kaempferol 3-O-rutinoside significantly inhibited the human lymphocyte proliferation in vitro.