## 2 Results
### Abietic Acid Induces Growth Inhibition in MCF-7 Sensitive Cell Line
The cell cycle phases, and subpopulation were set in gate, as previously documented [39]. The data in Figure 1A, Tables 2 and 3 show that the number of cells arrested in the SubG0-G1 subpopulation increased significantly for cells treated with both abietic acid and pine extract in a way similar to known apoptotic positive controls of Raptinal-treated cells. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{3}{*}{**Studied Plants \&**} & \multicolumn{4}{c}{**IC\({}_{50}\) \(\pm\) SEM and Corresponding SI**} \\ \cline{2-9}  & \multirow{2}{*}{**Wi-38**} & \multicolumn{2}{c}{**HepG-2**} & \multicolumn{2}{c}{**MCF-7**} & \multicolumn{2}{c}{**HCT-116**} \\ \cline{3-9}  & & **IC\({}_{50}\)** & **SI** & **IC\({}_{50}\)** & **SI** & **IC\({}_{50}\)** & **SI** \\ \hline Raptinal & 5.2 \(\pm\) 0.9 & 0.74 \(\pm\) 0.1 & 7 & 4.1 \(\pm\) 0.76 & 1.3 & 96.2 \(\pm\) 1.5 & 0.05 \\ \hline Doxorubicin & 0.1\(\pm\) 0.1 & 0.8 \(\pm\) 1.1 & 0.11 & 1.3 \(\pm\) 1.0 & 0.07 & 0.97 \(\pm\) 0.72 & 0.1 \\ \hline Pine extract & 0.42 \(\pm\) 0.1 & 0.2 \(\pm\) 0.76 & 2.1 & 0.11 \(\pm\) 0.76 & 3.8 & 0.25 \(\pm\) 0.1 & 1.7 \\ \hline Abietic acid & N/A & N/A & — & 0.06 \(\pm\) 0.5 & \textgreater{}1 & N/A & — \\ \hline \hline \end{tabular}  
* IC\({}_{50}\) of the pine extract was represented as (\(\upmu\)g/mL) while IC\({}_{50}\) of pure abietic acid, Raptinal, and Doxorubicin were represented as \(\upmu\)M. ** IC\({}_{50}\) Data represent mean \(\pm\) SEM, \(n\) = 3. N/A (not applicable).  
\end{table} 
Table 1: Antiproliferative activities of pine extract, abietic acid, Raptinal, and Doxorubicin against different cancerous cell lines (HepG-2, MCF-7 and HCT-116) compared to WI-38 normal cell line. SI (selectivity index) calculated as IC\({}_{50}\) compound (WI-38)/ IC\({}_{50}\) compound (cancer cell line). Consequently, the gated G0-G1 region was reduced significantly due to the massive arrest in SubG\({}_{0}\)-G\({}_{1}\) subpopulation after both pine extract and abietic acid treatment compared to control, with 42.07% and 24.98%, respectively, compared to 66.59% of control cells treated with 0.1% DMSO solvent, as shown in Table 2. Moreover, abietic acid showed additional cell cycle arrest for cells at G\({}_{2}\)/M phase, which was not observed in pine extract, with 49.17% and 11.34%, respectively, compared to control at 18.73% and Raptinal at 18.63%. This was reflected in the G\({}_{2}\)M/G\({}_{0}\)-G\({}_{1}\) ratio, which was \(<\)1 (0.71) for negative control, Raptinal, and pine extract. Meanwhile, abietic acid had a significantly higher G\({}_{2}\)M/G\({}_{0}\)-G\({}_{1}\) ratio, 2-fold higher than pine extract, suggesting that abietic acid was reducing the percentage of dividing cell populations in G\({}_{2}\)/M phase. \begin{table} \begin{tabular}{c c c c c} \hline \hline
**Cell Cycle Parameters on MF-7 Cells** & **Control** & **Raptinal** & **Abietic Acid** & **Pine Extract** \\ \hline \% Gated Sub G\({}_{0}\)-G\({}_{1}\) phase & 1.52 \(\pm\) 0.3 & 36.18 *** \(\pm\) 6.2 & 20.96 *** \(\pm\) 1.6 & 37.30 *** \(\pm\) 7.5 \\ \hline \% Gated G\({}_{0}\)-G\({}_{1}\) phase & 66.59 \(\pm\) 4.8 & 33.62 *** \(\pm\) 3.2 & 24.98 * \(\pm\) 5.2 & 42.07 * \(\pm\) 9.1 \\ \hline \% Gated S phase & 13.16 \(\pm\) 3.7 & 11.66 \(\pm\) 1.8 & 4.96 * \(\pm\) 1.04 & 9.29 * \(\pm\) 1.5 \\ \hline \% Gated G\({}_{2}\)M phase & 18.73 \(\pm\) 0.2 & 18.63 \(\pm\) 3.8 & 49.17 * \(\pm\) 2.3 & 11.34 \(\pm\) 2.3 \\ \hline \({}_{\rm G2}\)M/G\({}_{0}\)-G\({}_{1}\) ratio & 0.28 \(\pm\) 0.01 & 0.55 \(\pm\) 0.1 & 2.0 \(\pm\) 0.1 & 0.27 \(\pm\) 0.1 \\ \hline \hline \end{tabular} 
\begin{tabular}{c c c c c} \hline \hline
**Cell Cycle Parameters on MF-7 Cells** & **Control** & **Raptinal** & **Abietic Acid** & **Pine Extract** \\ \hline \% Gated Sub G\({}_{0}\)-G\({}_{1}\) phase & 1.52 \(\pm\) 0.3 & 36.18 *** \(\pm\) 6.2 & 20.96 *** \(\pm\) 1.6 & 37.30 *** \(\pm\) 7.5 \\ \hline \% Gated G\({}_{0}\)-G\({}_{1}\) phase & 66.59 \(\pm\) 4.8 & 33.62 ** \(\pm\) 3.2 & 24.98 * \(\pm\) 5.2 & 42.07 * \(\pm\) 9.1 \\ \hline \% Gated S phase & 13.16 \(\pm\) 3.7 & 11.