## 4 Empirical Strategies for Improving TIA Production
### Empirical Optimization of the Culture Medium and Culture Conditions
\begin{table}
\begin{tabular}{l l l l l} \hline
**Material** & **Strategy** & **Total TIAs** & **Observations** & **Refs** \\ \hline \multirow{3}{*}{Compact callus cluster} & Medium & 4.13-fold increase & 5.05-fold increase in catharanthine & \multirow{3}{*}{[65]} \\  & supplemented with & increase & (19.7 mg/L) & \\  & mannitol (250 mM) & (75 mg/L) & 2.77-fold increase in serpentine (13.6 mg/L) & \\  & & 4.54-fold increase in ajmalicine (42.3 mg/L) & \\ \hline \multirow{3}{*}{Compact callus cluster} & Medium & 3.15-fold increase in catharanthine & \multirow{3}{*}{[68]} \\  & supplemented with & increase & (12.3 mg/L) & \\  & KCl (4g/L) & (57.8 mg/L) & 2.42-fold increase in serpentine (11.9 mg/L) & \\  & & (57.8 mg/L) & 3.62-fold increase in ajmalicine (33.5 mg/L) & \\ \hline \multirow{3}{*}{Compact callus cluster} & Medium & 1.16-fold increase & \multirow{3}{*}{[65]} \\  & supplemented with & increase & (10 mg/L) & \\  & sucrose & (46.7 mg/L) & 1.20-fold increase in ajmalicine (14.5 mg/L) & \\  & (50 g/L) & & \\ \hline \multirow{3}{*}{Suspension cultured cells} & High cell density & \multirow{3}{*}{ND} & \multirow{3}{*}{120-fold increase in ajmalicine (60 mg/L)} & \multirow{3}{*}{[73]} \\  & (200 g FW/L) & & \\ \hline \multirow{3}{*}{Immobilized cells} & High cell density & \multirow{3}{*}{ND} & \multirow{3}{*}{2-fold increase in ajmalicine (120 mg/L)} & \multirow{3}{*}{[71]} \\  & (100 g FW/L) & & \\ \hline \multirow{3}{*}{Immobilized cells} & Elicitation with & \multirow{3}{*}{ND} & \multirow{3}{*}{45-fold increase in ajmalicine (90 mg/L)} & \multirow{3}{*}{[72]} \\  & _Phytophthora_ & & & \\  & _cactorum_ & & & \\ \hline \multirow{3}{*}{Shoot culture} & MS medium & \multirow{3}{*}{ND} & The concentrations of 8.90 \(\upmu\)M BA and 2.85 & \multirow{3}{*}{[74]} \\  & supplemented with & & \(\upmu\)M IAA increased the production of & \\  & plant growth & & & ajmalicine (0.85 g/L) & \\  & regulators & & & \\ \hline \multirow{3}{*}{Callusus} & MS medium & \multirow{3}{*}{ND} & The concentrations of 2.21 \(\upmu\)M BA and & \multirow{3}{*}{[68]} \\  & supplemented with & & 5.7 \(\upmu\)M IAA increased the production of & \\  & plant growth & & & \\  & regulators & & & \\  & regulators & & & \\ \hline \multirow{3}{*}{Immobilized cells} & Variation of O\({}_{2}\) and & \multirow{3}{*}{ND} & \multirow{3}{*}{1.1-fold increase in ajmalicine (275 g/L )} & \multirow{3}{*}{[75]} \\  & CO\({}_{2}\) concentration & & & \\ \hline \multirow{3}{*}{Suspension cultured cells} & Feeding with & \multirow{3}{*}{ND} & 17.73-fold increase in strictosidine & \multirow{3}{*}{[76]} \\  & loganin and & & (53.19 \(\upmu\)m/g DW) & \\  & tryptamine & & 6.4-fold increase in ajmalicine & \\  & (3.2 \(\upmu\)m/g DW) & & \\ \hline \multirow{3}{*}{Compact callus cluster} & Feeding with & 4.86-fold & 3.5-fold increase in catharanthine (7 mg/L) & \\  & succinic acid & increase & 7.5-fold increase in serpentine (15 mg/L) & \\  & (10 mM) & (73 mg/L) & 16-fold increase in ajmalicine (32 mg/L) & \\ \hline \multirow{3}{*}{Hairy root culture} & Feeding with & 3.86-fold & 2.5-fold increase in catharanthine (5 mg/L) & \\  & tryptamine & increase & 7-fold increase in serpentine (14 mg/L) & \\  & (3.12 mM) & (58 mg/L) & 15.5-fold increase in ajmalicine (31 mg/L) & \\ \hline \multirow{3}{*}{Hairy root culture} & Feeding with & \multirow{3}{*}{5.53-fold increase in carbaranthine (2.44 mM)} & \multirow{3}{*}{[77]} \\  & geraiol (0.5 mM) & & & \\ \hline \multirow{3}{*}{Hairy root culture} & Elicitation with & \multirow{3}{*}{1.42-fold increase} & \multirow{3}{*}{2-fold increase in lochnericine (1 mg/g DW)} & \multirow{3}{*}{[78]} \\  & sodium & increase & 2.3-fold increase in lötseronine & \\  & nitroptrusside & (3.7 mg/g DW) & & \\ \cline{1-1}  & (0.1 mM) & & \\ \hline \end{tabular}
\end{table} 
Table 1: Strategies to increase the production of TIAs in _C. roseus_.