# Microalgae as Potential Sources of Bioactive Compounds for Functional Foods and Pharmaceuticals
## 3 Results and Discussion
### Evaluation of Bioactivities of Microalgal Extracts
#### 3.1.3 Anti-Tumoral Activity
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Microbial** & **Fractioning** & & & & & \\
**Extract** & **Solvent** & **HepG2** & **S17** & **THP-1** & **HepG2 vs. S17** & **THP1 vs. S17** \\ \hline \multirow{4}{*}{_Phaeodactylum_ (PHA ET)} & Crude ET & & & & & \\  & extract & 39.8 \(\pm\) 4.3 \({}^{\text{b}}\) & \textgreater{}125 \({}^{\text{b}}\) & \textgreater{}125 \({}^{\text{d}}\) & \textgreater{}3.14 \({}^{\text{b}}\) & n.s \\ \cline{2-6}  & H & \textgreater{}125 \({}^{\text{a}}\) & \textgreater{}125 \({}^{\text{b}}\) & \textgreater{}125 \({}^{\text{d}}\) & n.s & n.s \\  & DCM & 27.5 \(\pm\) 1.6 \({}^{\text{c}}\) & \textgreater{}125 \({}^{\text{b}}\) & 22.3 \(\pm\) 1.8 \({}^{\text{c}}\) & \textgreater{}4.54 \({}^{\text{a}}\) & \textgreater{}5.60 \({}^{\text{b}}\) \\  & EA & 84.2 \(\pm\) 3.7 \({}^{\text{a}}\) & \textgreater{}125 \({}^{\text{b}}\) & 81.9 \(\pm\) 2.0 \({}^{\text{b}}\) & 1.48 \(\pm\) 0.13 \({}^{\text{c}}\) & 1.53 \(\pm\) 0.15 \({}^{\text{a}}\) \\  & W + ET & \textgreater{}125 \({}^{\text{a}}\) & \textgreater{}125 \({}^{\text{b}}\) & \textgreater{}125 \({}^{\text{d}}\) & n.s & n.s \\ \hline \multirow{4}{*}{Etoposide} & & 29.0 \(\pm\) 3.2 \({}^{\text{c}}\) & 45.4 \(\pm\) 0.5 \({}^{\text{a}}\) & 0.924 \(\pm\) 0.241 \({}^{\text{a}}\) & 1.56 \(\pm\) 0.11 \({}^{\text{c}}\) & 49.4 \(\pm\) 1.2 \({}^{\text{c}}\) \\ \hline \hline \end{tabular}  
* Results are expressed as mean \(\pm\) SD (\(\mu\) = 3). Different superscript letters within each column represent significant differences (\(\rho<0.05\)) between the fractions and the positive control (etoposide). EA = ethyl acetate; ET = ethanol; H = hexane; DCM = Dichloromethane; EA = ethyl acetate; W + ET = water + ethanol; n.d. = not determined; n.s = non-selective (Selectivity Index equal or less than one).  
\end{table} 
Table 7: In vitro cytotoxicity activity (IC\({}_{50}\): \(\mu\)g/mL) and Selectivity Index of fractions from ethanol extract from _Phaeodactylum tricornutum_, on HepG2 and S17 cell lines. the composition of biomass in between batches, including in the amount of the compounds responsible for the bioactivity (e.g., cytotoxic capacity). The fresh ethanol crude PHA extract displayed better selectivity for tumorous cells (THP-1 and HepG2) than for non-tumoral S17 cells when compared to its hexane and aqueous fractions. The ethyl acetate fraction displayed better results than crude extract for the cytotoxicity of THP-1 but not for HepG2. The dichloromethane (DCM) fraction prepared from PHA ET showed promising results in terms of cytotoxicity and selectivity index for all cell lines, with better values than etoposide in the HepG2 cell line (of Table 7). Microscopic examination confirmed that both PHA ET and its DCM fraction decreased the number and size of cancerous cells, while the untreated cells maintained their original morphology. These findings may suggest that the tested extracts/fractions could have some sort of apoptogenic effect, which is consistent with outcomes of other studies [63] where it is believed to be linked to the high content of PUFAs (specifically EPA) [64] and carotenoids (mainly fucoxanthin) [28], as these compounds have reported anti-inflammatory, antioxidant and anti-proliferative effects on different cell lines (including HepG2) [65; 66]. These compounds may even have synergistic effects, further increasing the microalgae's extract anti-tumorous effect [67]. Dichloromethane is a solvent of intermediate polarity and high volatility, which is helpful in the extraction of both polar and non-polar compounds like pigments, hydrophilic polar lipids and fatty acids such as PUFAs [68; 69].