## 3 Results and Discussions
### Structural Identification of Alkaloids  
Analysis of Nuclear Magnetic Resonance (NMR) Spectra Obtained from the Selective Extract of Alkaloids from the Peel of the Soursop Fruit  
The peel from soursop was selected to obtain alkaloid extract due to the highest content of them. The separation of the above extract by column chromatography gave a total of 180 fractions from which fractions 105 to 150 showed an alkaloid positive test when visualized with [PERSON]'s reagent. It was possible to perform the structural identification of these compounds without further purification, using mainly proton and carbon-13 nuclear magnetic resonance (\({}^{1}\)H and \({}^{13}\)C NMR). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameters** & **Peel** & **Seeds** & **Columella** & **Pulp** \\ \hline Extraction time (min) & 5 & 5 & 5 & 5 \\ Pulses-cycles (s) & 1 & 0.4 & 1 & 0.55 \\ Sonication amplitude (\%) & 70 & 70 & 70 & 100 \\ Optimal response (mg/g DW) & 7.48 & 2.31 & 0.74 & 1.20 \\ \(-95\%\) Confidence limit & 7.24 & 2.11 & 0.63 & 1.14 \\ +95\% Confidence limit & 7.71 & 2.52 & 0.85 & 1.26 \\ \hline \hline \end{tabular} Confidence interval, the difference between upper and lower limits. \(-95\%\) confidence limit, lower limit. \(+95\%\) confidence limit, upper limit. DW = dry weight.  
\end{table} 
Table 4: Optimal conditions of ultrasound-assisted extraction in total alkaloids from _A. muricata_ peel, seed, columnella, and pulp. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter/Method**} & **UAE** & **CE** & **UAE** & **CE** & **UAE** & **CE** & **UAE** & **CE** \\ \cline{2-10}  & \multicolumn{2}{c}{**1 Peel**} & \multicolumn{2}{c}{**2 Seeds**} & \multicolumn{2}{c}{**3 Columbia**} & \multicolumn{2}{c}{**4 Pulp**} \\ \hline Total alkaloid content (mg/g DW) & 7.32 \(\pm\) 0.02 a & 0.13 \(\pm\) 0.01 c & 2.02 \(\pm\) 0.01 d & 0.66 \(\pm\) 0.00 d & 0.83 \(\pm\) 0.01 b & 0.28 \(\pm\) 0.01 c & 1.09 \(\pm\) 0.01 d & 0.20 \(\pm\) 0.00 d \\ \hline Effectiveness UAE (n-times) & 56.31 & 3.06 & 2.96 & & & & & \\ \hline \hline \end{tabular}  
All values are the means \(s\) standard deviation of three determinations. Different letters in each row indicate significant statistical difference between treatments (\(p<0.05\)). CE \(s\) Conventional extraction. Ultrasound-assisted extraction (UAE) experimental conditions. (1) X\({}_{\rm{gr}}\) = 5 min, X\({}_{\rm{cc}}\) = 1 s, X\({}_{\rm{ca}}\) = 70%, (2) X\({}_{\rm{gr}}\) = 5 min, X\({}_{\rm{cc}}\) = 0.4 s, X\({}_{\rm{ca}}\) = 70%, (3) X\({}_{\rm{gr}}\) = 15 min, X\({}_{\rm{cc}}\) = 1 s, X\({}_{\rm{ca}}\) = 100%.  
\end{table} 
Table 5: Total alkaloid content and yield in peel, seed, columnla, and pulp of _Amona muratica_ using the optimal conditions of ultrasonic-assisted extraction and conventional extraction. Figure 2 shows the \({}^{1}\)HNMR spectrum (bottom) of this set of fractions (F105-F150), which highlights the residual signal of the CH\({}_{2}\)O group of ethanol used in the washing process of glass material during the analysis as well as the CHCl\({}_{3}\) signal normally present as a reference signal in deuterated chloroform (CDCl\({}_{3}\)) used as solvent for NMR analysis. The rest of the signals belong to aromatic protons, methoxy groups (OMe), and protons attached to \(sp^{3}\) carbons (signals appearing between 2.50 and 4.30 ppm) (Figure 2). In the same figure is shown an expansion between 5.90 and 8.45 ppm, where the chemical shifts, integral sections (area under the curve), and multiplicity for the signals of aromatic and dioxolane protons can be appreciated in greater detail. The assignment of the \({}^{1}\)H NMR spectrum was supported by establishing correlations of vicinal (\({}^{3}\)_J_) and geminal (\({}^{2}\)_J_) protons in the homonuclear correlation spectrum (COSY) (Figure 2, top) from which adjacent scalar-coupled protons could be identified. For instance, correlations between protons H-8 and H-9 of aporphines 3 and 4 was established through their respective cross-peaks correlations, as shown in Figure 2 (top).