| Abstract: | This study is the first phytochemical investigation of Selaginella sellowiiand demonstrates the antileishmanial activity of the hydroethanolic extractfrom this plant (SSHE), as well as of the biflavonoids amentoflavone androbustaflavone, isolated from this species. The effects of these substances wereevaluated on intracellular amastigotes of Leishmania (Leishmania)amazonensis, an aetiological agent of American cutaneous leishmaniasis.SSHE was highly active against intracellular amastigotes [the half maximum inhibitoryconcentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolationof the two bioflavonoids with the highest activity: amentoflavone, which was about200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and3 μg/mL, respectively on NIH/3T3 and J774.A1 cells), with a high selectivity index(SI) (22 and 30), robustaflavone, which was also active against L.amazonensis (IC50 = 2.8 µg/mL), but more cytotoxic, with IC50 = 25.5µg/mL (SI = 9.1) on NIH/3T3 cells and IC50 = 3.1 µg/mL (SI = 1.1) on J774.A1 cells.The production of nitric oxide (NO) was lower in cells treated with amentoflavone(suggesting that NO does not contribute to the leishmanicidal mechanism in thiscase), while NO release was higher after treatment with robustaflavone. S.sellowii may be a potential source of biflavonoids that could providepromising compounds for the treatment of cutaneous leishmaniasis. |
