## 2 Results and Discussion
### Antileishminal Activity  
Initially, a screening of the activity of _C. longa_ extracts and **1** was performed against _L. amazonensis_ and _L. infantrum_ promastigotesome forms, showing a dose-response effect (Supplementary Material, Figure S5). The IC\({}_{50}\) for _L. amazonensis_ ranged from 5.5 to 102.3 \(\mathrm{\SIUnitSymbolMicro}\)g/mL, while for _L. infantrum_ it ranged from 15.5 to 74.7 \(\mathrm{\SIUnitSymbolMicro}\)g/mL (Table 4). Interestingly, a previous study described that a mix of curcuminoids exhibits better biological activity than curcumin alone [51]. Here, **1** exhibited better activity than the extracts against both _Leishmania_ species, achieving the highest selectivity index (SI) values: 12.7 for _L. amazonensis_, which was higher than that of the reference drug control, PAT, and 4.5 for _L. infantrum_. In contrast, the extracts displayed SI values that indicate their important cytotoxicity in the host macrophage lineage tested here (Table 4). The turmerone-rich extract, HEXCURC, had the lowest selectivity index (SI) for both _Leishmania_ species, being more toxic to host cells than to the parasite. [PERSON] et al. (2019) reported the presence of 55.43% turmerone and 12.02% \(\mathrm{\SIUnitSymbolMicro}\)g/turmerone in the essential oil of _C. longa_. This essential oil showed no cytotoxicity to BALB/c peritoneal macrophages at the highest tested concentration (1000 \(\mathrm{\SIUnitSymbolMicro}\)g/mL) and exhibited an IC\({}_{50}\) of 63.3 \(\pm\) 1.369 \(\mathrm{\SIUnitSymbolMicro}\)g/mL against intracellular _L. amazonensis_astigotesome [33]. Additionally, ar-turmerone alone demonstrated low cytotoxicity against J774.A.1 macrophages, with a CC\({}_{50}\) of 720.06 \(\mathrm{\SIUnitSymbolMicro}\)g/mL \begin{table}
\begin{tabular}{l c c c} \hline  & **RAW 264.7** & **VERO** & **RBC** \\ \hline HEXCURC & 47.87 \(\pm\) 6.9 \({}^{\mathrm{a,b}}\) & 60 \(\pm\) 3 \({}^{\mathrm{a}}\) & 119.65 \(\pm\) 3.4 \({}^{\mathrm{a}}\) \\ DCCURC & 55.08 \(\pm\) 5.4 \({}^{\mathrm{a,b}}\) & 58 \(\pm\) 3.7 \({}^{\mathrm{a}}\) & 101.85 \(\pm\) 9.6 \({}^{\mathrm{a}}\) \\ ETOHCURC & 70.16 \(\pm\) 3.3 \({}^{\mathrm{a}}\) & 89.3 \(\pm\) 7.9 \({}^{\mathrm{a}}\) & 144.15 \(\pm\) 13.35 \({}^{\mathrm{a}}\) \\ Curcumin (**1**) & 69.75 \(\pm\) 2.8 \({}^{\mathrm{a}}\) & n.d. & \textgreater{}200 \\ PAT & 30.8 \(\pm\) 0.73 \({}^{\mathrm{b}}\) & 23.9 \(\pm\) 1.5 \({}^{\mathrm{b}}\) & \textgreater{}100 \\ \hline \end{tabular} Results are expressed as the mean values \(\pm\) standard error from three independent experiments. Means with different superscript letters within a column indicate significant differences (One-way ANOVA, [PERSON] post hoc test, \(p\) + 0.05). HEXCURC: _C. longa_ hexane extract; DCCURC: _C. longa_ dichloromethane extract; ETOHCURC: _C. longa_ ethanol extract; PAT: potassium antimony(II) tartrate hydrate, as a source of trivalent antimony (Sb(III)), reference drug control; n.d.: not determined.  
\end{table} 
Table 3: Cytotoxicity (CC\({}_{50}\)) against RAW 264.7 macrophages and VERO renal epithelial cells and hemolytic activity (CH\({}_{50}\)) against red blood cells (RBCs) of _C. longa_ extracts and curcumin (**1**), expressed in \(\mathrm{\SIUnitSymbolMicro}\)g/mL. and a SI of 21.1 for _L. major_ amastigotes [32]. Therefore, further studies are needed to assess the cytotoxicity of turmerones against RAW 264.7 and VERO cells, as the toxicity observed in this study may be attributed to other components of the HEXCURC extract. Despite the potential hepatotoxicity for **5** and **6**, the in silico toxicological parameters of turmerones were satisfactory. In addition, all compounds were approved in the Ames test, as well as carcinogenicity, acute toxicity, and cardiotoxicity assessments. There are limited data on the effect of **2**, the predominant curcuminoid in the DCCURC extract, against _Leishman_ spp. In the study by [PERSON] et al. (2000), demethylox curcumin exhibited an IC\({}_{50}\) of 14.1 \(\pm\) 4.8 \(\upmu\)g/mL against _L.