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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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: nitric oxide release by L. amazonensis infectedmacrophages 72 h after treatment with hydroethanolic extract fromSelaginella sellowii (A), amentoflavone (B) androbustaflavone (C). Bars represent the mean ± standard deviation of sixreplicates. p < 0.05 (*) for the different concentrations compared tountreated cells (Student’s t test).
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f05: : nitric oxide release by L. amazonensis infectedmacrophages 72 h after treatment with hydroethanolic extract fromSelaginella sellowii (A), amentoflavone (B) androbustaflavone (C). Bars represent the mean ± standard deviation of sixreplicates. p < 0.05 (*) for the different concentrations compared tountreated cells (Student’s t test).

Mentions: Activation of macrophages was investigated by the NO release. NO production wassignificantly increased (p < 0.05) after treatment with the highest concentration ofSSHE (100 µg/mL) (Fig. 5A). NO production byperitoneal macrophages treated with amentoflavone was significantly lower at theconcentrations of 1.5 µg/mL (p < 0.05) and 0.75 µg/mL (p < 0.01), compared tountreated infected cells (Fig. 5B). This may bedue to the antioxidant properties of amentoflavone. Banerjee et al. (2002) observed the inhibition of inducible NO synthase(iNOS) protein expression by amentoflavone. In addition, Woo et al. (2005) demonstrated the inhibitory effect of amentoflavone on NOproduction induced by lipopolysaccharide, which prevents the activation of NF-κB, thegene responsible for transcription of iNOS. They suggest, therefore, that thedestruction mechanism of intracellular amastigotes by this biflavonoid should not bedirectly associated with increased release of NO. Amentoflavone could have a directaction on the parasites and/or influence over other cytotoxic mechanisms forintracellular pathogens. Defense mechanisms independent of NO release can be promisingin cases of ACL associated with strains of L. amazonensis andLeishmania braziliensis resistant to NO, as described by Giudice et al. (2007), who demonstrated that theresistance to NO is directly related to lesion size and severity of the disease.


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)

: nitric oxide release by L. amazonensis infectedmacrophages 72 h after treatment with hydroethanolic extract fromSelaginella sellowii (A), amentoflavone (B) androbustaflavone (C). Bars represent the mean ± standard deviation of sixreplicates. p < 0.05 (*) for the different concentrations compared tountreated cells (Student’s t test).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f05: : nitric oxide release by L. amazonensis infectedmacrophages 72 h after treatment with hydroethanolic extract fromSelaginella sellowii (A), amentoflavone (B) androbustaflavone (C). Bars represent the mean ± standard deviation of sixreplicates. p < 0.05 (*) for the different concentrations compared tountreated cells (Student’s t test).
Mentions: Activation of macrophages was investigated by the NO release. NO production wassignificantly increased (p < 0.05) after treatment with the highest concentration ofSSHE (100 µg/mL) (Fig. 5A). NO production byperitoneal macrophages treated with amentoflavone was significantly lower at theconcentrations of 1.5 µg/mL (p < 0.05) and 0.75 µg/mL (p < 0.01), compared tountreated infected cells (Fig. 5B). This may bedue to the antioxidant properties of amentoflavone. Banerjee et al. (2002) observed the inhibition of inducible NO synthase(iNOS) protein expression by amentoflavone. In addition, Woo et al. (2005) demonstrated the inhibitory effect of amentoflavone on NOproduction induced by lipopolysaccharide, which prevents the activation of NF-κB, thegene responsible for transcription of iNOS. They suggest, therefore, that thedestruction mechanism of intracellular amastigotes by this biflavonoid should not bedirectly associated with increased release of NO. Amentoflavone could have a directaction on the parasites and/or influence over other cytotoxic mechanisms forintracellular pathogens. Defense mechanisms independent of NO release can be promisingin cases of ACL associated with strains of L. amazonensis andLeishmania braziliensis resistant to NO, as described by Giudice et al. (2007), who demonstrated that theresistance to NO is directly related to lesion size and severity of the disease.

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