Figure 1.
Chemical structure of usnic acid.
R = OH usnic acid; R = OK potassium usnate.
Figure 2.
High performance liquid chromatograms.
A- Merk usnic acid standard (RT-14.93), B- usnic acid purified from Cladonia substellata (RT-14.59).
Figure 3.
Survival and mortality of B. glabrata embryos.
A- eggs masses treated at 10 µg ml of potassium usnate showing 100% mortality, B – eggs masses not treated with 100% survival in control group 1 (dechlorinated water).
Figure 4.
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).
Figure 5.
Toxicity of potassium usnate to B. glabrata adults.
Mortality B. glabrata subjected to 24 h of treatment with usnate potassium at 0.5; 0.9; 1; 2.5; 5 and 10 µg/ml and control groups (Crtl 1 dechlorinated water; Crtl 2–cupric carbonate). ***p<0.0001 compared to Ctrl 1 (negative control) group.
Figure 6.
Toxicity of potassium usnate to A. salina.
Mortality of A. salina subjected to 24 h of treatment with potassium usnate at 0.5; 1; 5; 10 µg/ml. ***p<0.0001 for concentrations higher than 5 µg/ml when compared to Ctrl (sea water) group. Letter “a” to indicate that the bars are not significantly different from each other (Tukey's test **p<0.05).