# Pharmacological and Cosmeceutical Potential of Seaweed Beach-Casts of Macaronesia
## 3 Results and Discussion
### Anticancer Activity
Concerning the DU145 prostate cell line, five samples (1.E; 1.M; 1.E.1; 1.M.1 and 12.E.1) (Figure 2) displayed around 50% or lower cell survival; particularly for the highest tested concentration (50 \(\upmu\)g/mL), although these results were not as effective as those obtained with the anticancer drug adriamycin used as positive control (38% cell survival at 5.43 \(\upmu\)g/mL) (Figure 2). [PERSON] et al. [45] report inhibition of DU-145 cell growth by 90% by algae extracts, but those authors employed extremely high extract concentrations (100-200 \(\upmu\)g/mL) therefore this activity can only be considered as moderate or weak, i.e., much less interesting than the one found in the present study  
The six samples that exhibited the highest values of cell growth inhibition were chosen to determine their IC\({}_{50}\) values (Table 2). The recorded IC\({}_{50}\) values were higher than 20 \(\upmu\)g/mL, which means that this cell line is less sensitive to the samples than the NCI-H1299 cell line. The best results obtained were for two samples with IC\({}_{50}\) around 23-25 \(\upmu\)g/mL, indicating a moderate but close to high anticancer activity. Cell inhibition of the DU145 prostate cell line has also been reported when evaluating purified carotenoids (fucoxanthin) obtained from alga samples, achieving cell viability of ca. 5% when evaluated at a concentration of 20 \(\upmu\)M [46]. Regarding selectivity index (Table 3), only two samples (1.M; 1.M.1) exhibited SI values highest than 2 (2.80 and 2.33), a result less impactful than those obtained against the NCIH1299 cell line but still positive. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample** & **Lung NCIH1299** & **Prostate DU145** & **Breast T47D** & **Colon HT29** \\ \hline
1.E & 2.20 & 2.02 & 3.85 & \\
1.E.1 & 1.53 & 1.12 & 1.55 & 0.57 \\
1.E.2 & 5.14 & - & 4.28 & 1.97 \\
1.M & 3.25 & 2.80 & 4.99 & - \\
1.M.1 & 4.74 & 2.33 & 2.71 & 2.43 \\
1.M.2 & 2.89 & - & 2.38 & \\
2.E & - & - & 3.50 & - \\
2.M.1 & 3.34 & - & 2.02 & \\
4.M & 3.02 & - & - & - \\
5.E & 3.14 & - & - & - \\
5.M.1 & 2.40 & - & 3.46 & \\
6.M & 2.84 & - & - & - \\
7.E & 2.53 & - & - & - \\
10.E & 2.58 & - & 0.99 & - \\
10.M & - & - & 1.03 & \\
11.E & 6.09 & - & 2.07 & - \\
12.E & 7.03 & - & 2.36 & - \\
12.E.1 & 2.55 & 1.35 & 2.65 & 1.11 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Selectivity index (SI) values of samples showing anticancer activity against the cancer cell line studied. For the T47D breast cancer cell line, nineteen samples stood out showing values close or lower than 50% cell survival at the highest concentration tested (Figure 3). The strongest samples, 1.M.1 and 2.M.1, with the lowest cell survival values, corresponded to a cell growth inhibition ranging from 74 to 98% (Figure 3), although this cell line was also more resistant to the anticancer drug adriamycin employed as positive control, when compared with the results obtained with this drug in the other cell lines employed in this study. Regarding the IC\({}_{50}\) values, as seen in Table 2, five samples displayed values lower than of very close to 20 \(\upmu\)g/mL, while three samples exhibited moderate activity (IC\({}_{50}\) values of 21.90 \(\upmu\)g/mL to 23.11 \(\upmu\)g/mL). These results provide evidence of the attractive moderate to high antitumor capacity of the samples against the T47D cell line. The SI recorded for the samples on T47D breast cancer cells showed that for eleven samples the SI was larger than 2, with the best results of 4.99 and 4.28 (1.M and 1.E.2), indicating an attractive selectivity of these samples for the target cancer cells (Table 3). Fucoidans, sulfated polysaccharides, extracted from the seaweeds _Undaria pinmatifida_ and _Sacchararia japonica_ (Ochrophyta, Phaeophyceae) have been evaluated on the T-47D breast cancer cell line, reporting  
Figure 3: Cell survival of a cytotoxic assay against the T47D breast cancer cell line of different samples tested at two concentrations (20 \(\upmu\)g/mL and 50 \(\upmu\)g/mL). Adriamycin at 5.43 \(\upmu\)g/mL was used as reference.