Limits...
Usnic acid potassium salt: an alternative for the control of Biomphalaria glabrata (Say, 1818).

Martins MC, Silva MC, Silva LR, Lima VL, Pereira EC, Falcão EP, Melo AM, da Silva NH - PLoS ONE (2014)

Bottom Line: However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota.No toxicity to A. salina was found.The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Bioquímica, Universidade Federal de Pernambuco, Pernambuco, Brazil.

ABSTRACT
In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.

Show MeSH

Related in: MedlinePlus

Toxicity of potassium usnate to B. glabrata embryos.Mortality of blastula stage embryos subjected to 24 h of treatment with potassium usnate at 2.5; 5 and 10 µg/ml and control group (Crtl 1 – dechlorinated water). Letter A to indicate bars are the same (ANOVA ***p<0.0001); and letter B to indicate that the bars are significantly different from each other (Tukey's test **p<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4222767&req=5

pone-0111102-g004: Toxicity of potassium usnate to B. glabrata embryos.Mortality of blastula stage embryos subjected to 24 h of treatment with potassium usnate at 2.5; 5 and 10 µg/ml and control group (Crtl 1 – dechlorinated water). Letter A to indicate bars are the same (ANOVA ***p<0.0001); and letter B to indicate that the bars are significantly different from each other (Tukey's test **p<0.05).

Mentions: The embryos in the blastula stage of development were treated with potassium usnate at 2.5, 5 and 10 µg/ml and the solutions were lethal at all concentrations tested when compared to control groups (p<0.0001, F = 42.46). The mortality rate was 100% at 10 µg/ml (Figure 3). The treatments were significant between the groups: Ctrl vs 5 µg/ml (95% Cl of diff −77,61 to −18.39 **p<0.005), Ctrl vs 10 µg/ml (95% Cl of diff −129.3 to −70.05 ***p<0.0001), 2.5 vs 10 µg/ml (95% Cl of diff −105.3 to −46.05 ***p<0.0001) and 5 vs 10 µg/ml (95% Cl of diff −81.28 to −22.05 **p<0.05) (Figure 4).


Usnic acid potassium salt: an alternative for the control of Biomphalaria glabrata (Say, 1818).

Martins MC, Silva MC, Silva LR, Lima VL, Pereira EC, Falcão EP, Melo AM, da Silva NH - PLoS ONE (2014)

Toxicity of potassium usnate to B. glabrata embryos.Mortality of blastula stage embryos subjected to 24 h of treatment with potassium usnate at 2.5; 5 and 10 µg/ml and control group (Crtl 1 – dechlorinated water). Letter A to indicate bars are the same (ANOVA ***p<0.0001); and letter B to indicate that the bars are significantly different from each other (Tukey's test **p<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222767&req=5

pone-0111102-g004: Toxicity of potassium usnate to B. glabrata embryos.Mortality of blastula stage embryos subjected to 24 h of treatment with potassium usnate at 2.5; 5 and 10 µg/ml and control group (Crtl 1 – dechlorinated water). Letter A to indicate bars are the same (ANOVA ***p<0.0001); and letter B to indicate that the bars are significantly different from each other (Tukey's test **p<0.05).
Mentions: The embryos in the blastula stage of development were treated with potassium usnate at 2.5, 5 and 10 µg/ml and the solutions were lethal at all concentrations tested when compared to control groups (p<0.0001, F = 42.46). The mortality rate was 100% at 10 µg/ml (Figure 3). The treatments were significant between the groups: Ctrl vs 5 µg/ml (95% Cl of diff −77,61 to −18.39 **p<0.005), Ctrl vs 10 µg/ml (95% Cl of diff −129.3 to −70.05 ***p<0.0001), 2.5 vs 10 µg/ml (95% Cl of diff −105.3 to −46.05 ***p<0.0001) and 5 vs 10 µg/ml (95% Cl of diff −81.28 to −22.05 **p<0.05) (Figure 4).

Bottom Line: However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota.No toxicity to A. salina was found.The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Bioquímica, Universidade Federal de Pernambuco, Pernambuco, Brazil.

ABSTRACT
In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.

Show MeSH
Related in: MedlinePlus