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In vitro activity of the hydroethanolic extract and biflavonoids isolated from Selaginella sellowii on Leishmania (Leishmania) amazonensis.

Rizk YS, Fischer A, Cunha Mde C, Rodrigues PO, Marques MC, Matos Mde F, Kadri MC, Carollo CA, Arruda CC - Mem. Inst. Oswaldo Cruz (2014)

Bottom Line: SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL].The production of nitric oxide (NO) was lower in cells treated with amentoflavone (suggesting that NO does not contribute to the leishmanicidal mechanism in this case), while NO release was higher after treatment with robustaflavone.S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Parasitologia Humana, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil.

ABSTRACT
This study is the first phytochemical investigation of Selaginella sellowii and demonstrates the antileishmanial activity of the hydroethanolic extract from this plant (SSHE), as well as of the biflavonoids amentoflavone and robustaflavone, isolated from this species. The effects of these substances were evaluated on intracellular amastigotes of Leishmania (Leishmania) amazonensis, an aetiological agent of American cutaneous leishmaniasis. SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolation of the two bioflavonoids with the highest activity: amentoflavone, which was about 200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and 3 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 = 25.5 µg/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 this case), while NO release was higher after treatment with robustaflavone. S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

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: antileishmanial activity of amentoflavone (A) and robustaflavone (B) onintracellular amastigotes. Peritoneal macrophages were infected withLeishmania amazonensis and treated with differentconcentrations of the compounds. Infection index was calculated 72 h aftertreatment. Bars represent the mean ± standard deviation of six replicates. p< 0.01 (**) and p < 0.0001 (*) for the different concentrations comparedto untreated cells (control) (Student’s t test).
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f04: : antileishmanial activity of amentoflavone (A) and robustaflavone (B) onintracellular amastigotes. Peritoneal macrophages were infected withLeishmania amazonensis and treated with differentconcentrations of the compounds. Infection index was calculated 72 h aftertreatment. Bars represent the mean ± standard deviation of six replicates. p< 0.01 (**) and p < 0.0001 (*) for the different concentrations comparedto untreated cells (control) (Student’s t test).

Mentions: Once the highest activity was found 72 h after the treatment with SSHE, the isolateswere evaluated at that point. Purification resulted in compounds with even higheractivity. Treatment of intracellular amastigotes at all concentrations tested ofamentoflavone caused a significant decrease (p < 0.0001) in the infection index whencompared to the control, with a reduction greater than 90.6%, reaching almost 100% atthe highest concentration (3 µg/mL) (Fig. 4A).Amentoflavone was about 200 times more potent than SSHE (IC50 = 0.1 µg/mL).The excellent antileishmanial activity of amentoflavone obtained in our study is inagreement with those obtained by Oubada et al.(2014), who observed the effects on L. amazonensisintracellular amastigotes 48 h after the aforementioned treatment. Amentoflavone was notactive on axenic amastigotes of Leishmania donovani (Weniger et al. 2006, Kunert et al. 2008) and showed poor activity on promastigotes of the samespecies (Camacho et al. 2000). Therefore, theantileishmanial action of this compound may be mediated by the host cell. This fact,coupled with the delayed action of SSHE (72 h), leads us to consider the compound as apro-drug, which needs to be metabolised by the cell to exert its effect.


In vitro activity of the hydroethanolic extract and biflavonoids isolated from Selaginella sellowii on Leishmania (Leishmania) amazonensis.

Rizk YS, Fischer A, Cunha Mde C, Rodrigues PO, Marques MC, Matos Mde F, Kadri MC, Carollo CA, Arruda CC - Mem. Inst. Oswaldo Cruz (2014)

: antileishmanial activity of amentoflavone (A) and robustaflavone (B) onintracellular amastigotes. Peritoneal macrophages were infected withLeishmania amazonensis and treated with differentconcentrations of the compounds. Infection index was calculated 72 h aftertreatment. Bars represent the mean ± standard deviation of six replicates. p< 0.01 (**) and p < 0.0001 (*) for the different concentrations comparedto untreated cells (control) (Student’s t test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325620&req=5

f04: : antileishmanial activity of amentoflavone (A) and robustaflavone (B) onintracellular amastigotes. Peritoneal macrophages were infected withLeishmania amazonensis and treated with differentconcentrations of the compounds. Infection index was calculated 72 h aftertreatment. Bars represent the mean ± standard deviation of six replicates. p< 0.01 (**) and p < 0.0001 (*) for the different concentrations comparedto untreated cells (control) (Student’s t test).
Mentions: Once the highest activity was found 72 h after the treatment with SSHE, the isolateswere evaluated at that point. Purification resulted in compounds with even higheractivity. Treatment of intracellular amastigotes at all concentrations tested ofamentoflavone caused a significant decrease (p < 0.0001) in the infection index whencompared to the control, with a reduction greater than 90.6%, reaching almost 100% atthe highest concentration (3 µg/mL) (Fig. 4A).Amentoflavone was about 200 times more potent than SSHE (IC50 = 0.1 µg/mL).The excellent antileishmanial activity of amentoflavone obtained in our study is inagreement with those obtained by Oubada et al.(2014), who observed the effects on L. amazonensisintracellular amastigotes 48 h after the aforementioned treatment. Amentoflavone was notactive on axenic amastigotes of Leishmania donovani (Weniger et al. 2006, Kunert et al. 2008) and showed poor activity on promastigotes of the samespecies (Camacho et al. 2000). Therefore, theantileishmanial action of this compound may be mediated by the host cell. This fact,coupled with the delayed action of SSHE (72 h), leads us to consider the compound as apro-drug, which needs to be metabolised by the cell to exert its effect.

Bottom Line: SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL].The production of nitric oxide (NO) was lower in cells treated with amentoflavone (suggesting that NO does not contribute to the leishmanicidal mechanism in this case), while NO release was higher after treatment with robustaflavone.S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Parasitologia Humana, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil.

ABSTRACT
This study is the first phytochemical investigation of Selaginella sellowii and demonstrates the antileishmanial activity of the hydroethanolic extract from this plant (SSHE), as well as of the biflavonoids amentoflavone and robustaflavone, isolated from this species. The effects of these substances were evaluated on intracellular amastigotes of Leishmania (Leishmania) amazonensis, an aetiological agent of American cutaneous leishmaniasis. SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolation of the two bioflavonoids with the highest activity: amentoflavone, which was about 200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and 3 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 = 25.5 µg/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 this case), while NO release was higher after treatment with robustaflavone. S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

Show MeSH
Related in: MedlinePlus