Evaluation of antiplasmodial properties of a cyanobacterium, <i>Spirulina platensis</i> and its mechanism of action

<p>The rapid emergence of antimalarial drug resistance necessitates a continual effort on novel drug discovery. A cyanobacterium, <i>Spirulina platensis,</i> is a potential antimalarial agent that has been widely consumed as food supplement in the form of crude extract. It is known to possess antiviral, antibacterial and antifungi activities. This study examined the antimalarial activities of several <i>Spirulina</i> formulas against <i>Plasmodium falciparum</i> 3D7, <i>in vitro</i>. The tested <i>Spirulina</i> formulas included commercially available capsule, crude extract and alkaloid fraction. Results showed that all tested formula possessed antimalarial activities with the <i>Spirulina</i> capsule exhibited the highest activities (IC₅₀ = 2.16 μg/mL). Light and electron microscopies revealed interference of the <i>Spirulina</i> with the parasite hemozoin formation. In conclusion, all tested <i>Spirulina</i> formulas and fraction exhibited moderate to high antimalarial activities.</p

Intra- and inter-grader agreements for the choroidal thickness measurement at 5 horizontal locations using Spectralis SD-OCT with conventional manual technique.

<p>LOA, Limits of Agreement; ICC, Intraclass Correlation Coefficient; CI, Confidence Interval.</p>a<p>Mean difference was determined from the1^st time measurement minus the 2^nd time measurement.</p>b<p>Mean difference was determined from Grader A measurement minus Grader B measurement.</p

Bland Altman plot of intra-grader reliability of sub-foveal choroidal thickness (CT) measurement.

<p>The difference was calculated by the 1st measurement minus the 2nd measurement. Pink dashed line represents regression line of difference between 1st and 2nd measurements.</p

Intra- and inter-layer contrast (n = 31 subjects).

<p>Intra- and inter-layer contrast (n = 31 subjects).</p

Bland Altman plots of inter-grader reliability of sub-foveal choroidal thickness (CT) measurement.

<p>The difference was calculated by the grader A measurement minus the grader B measurement. Pink dashed line represents regression line of difference between the two graders measurements.</p

Baseline characteristics of study subjects.

<p>Data are expressed as mean (SD) except for gender, which is expressed as number (%).</p><p>*The average of 1st and 2nd measurement of Grader A.</p

Illustration of the raw versus the compensated image.

<p>(A) Raw OCT image of a healthy subject. The choroid-scleral interface is only partially visible. Note the presence of blood vessels shadows as indicated by red asterisks. (B) Adaptive compensation was applied to the raw image in order to remove blood vessels shadows, enhance contrast and improve visibility of the choroid-scleral interface (more uniform).</p

Flow diagram of the measurement protocol.

<p>Flow diagram of the measurement protocol.</p

Summary of choroidal thickness measurements at various locations.

<p>Data are mean (SD).</p

Intra- and inter-grader agreements for the choroidal thickness measurement at 5 horizontal locations using adaptive compensation.

<p>LOA, Limits of Agreement; ICC, Intraclass Correlation Coefficient; CI, Confidence Interval.</p>a<p>Mean difference was determined from the1^st time measurement minus the 2^nd time measurement.</p>b<p>Mean difference was determined from Grader A measurement minus Grader B measurement.</p>c<p>P value of one sample t-tests (comparing between mean difference and zero value) to indicate presence of systemic bias.</p>d<p>Using Pearson’s correlation coefficients of regression line.</p