The antileishmanial activity assessment of unusual flavonoids from Kalanchoe pinnata.
The importance of flavonoids for the antileishmanial activity of Kalanchoe pinnata was previously demonstrated by the isolation of quercitrin, a potent antileishmanial flavonoid. In the present study, the aqueous leaf extract from the medicinal plant K. pinnata (Crassulaceae) afforded a kaempferol di-glycoside, named kapinnatoside, identified as kaempferol 3-O-alpha-L-arabinopyranosyl (1-->2) alpha-L-rhamnopyranoside (1). In addition, two unusual flavonol and flavone glycosides already reported, quercetin 3-O-alpha-L-arabinopyranosyl (1-->2) alpha-L-rhamnopyranoside (2) and 4',5-dihydroxy-3',8-dimethoxyflavone 7-O-beta-D-glucopyranoside (3), have been isolated. Their structures were determined via analyses of mono and bi-dimensional (1)H and (13)C NMR spectroscopic experiments and HR-MALDI mass spectra. Because of its restricted occurrence and its abundance in K. pinnata, flavonoid (2) may be a chemical marker for this plant species of high therapeutic potential. The three flavonoids were tested separately against Leishmania amazonenis amastigotes in comparison with quercitrin, quercetin and afzelin. The quercetin aglycone - type structure, as well as a rhamnosyl unit linked at C-3, seem to be important for antileishmanial activity.
Muzitano
Michelle F
MF
Núcleo de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil.
Tinoco
Luzineide W
LW
Guette
Catherine
C
Kaiser
Carlos R
CR
Rossi-Bergmann
Bartira
B
Costa
Sônia S
SS
D000818:Animals; D000981:Antiprotozoal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D005419:Flavonoids / Q000737:chemistry* / Q000494:pharmacology*; D031962:Kalanchoe / Q000737:chemistry*; D007891:Leishmania / Q000187:drug effects*; D008362:Mannosides / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D021261:Parasitic Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D044945:Proanthocyanidins / Q000737:chemistry / Q000494:pharmacology; D011794:Quercetin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology
D000981:Antiprotozoal Agents; D005419:Flavonoids; D008362:Mannosides; D010936:Plant Extracts; D044945:Proanthocyanidins; C012526:quercitrin; C477954:afzelin; D011794:Quercetin