# _Sponias mombin_ Seed Oil Compounds Identification by Raman Spectroscopy and NMR
## 3 Results and Discussion  
_Spondias mombin_ L. has a variety of applications; indeed, previous reports demonstrated that the leaf and stem bark extracts have been used in traditional medicine [3; 4]. In this study, we described the molecular vibrations and functional groups contained in the oil extracted from the seed of _Spondias mombin_ L. identified by Raman spectroscopy, \({}^{1}\)H-NMR and \({}^{13}\)C-NMR. Figure 1a shows the Raman spectrum for _Spondias mombin_ L. oil seed obtained from different weights (40, 80, 120 and 160 g of seeds, processed separately). Figure 1b indicates a linear correlation between mass and yield. The corresponding yield is 2.58%. Different amounts of extracted oil exhibit slight changes in peak intensities in the Raman spectrum; however, no significant changes are shown in the Raman frequencies' positions. _Spondias mombin_ L. oil measurements were carried out, which allowed a qualitative analysis through the identification of the characteristic Raman frequencies associated with carotenoids [29] (Figure 2). Indeed, no literature on the characterization of _Spondias mombin_ L. seed oil using the RS technique was found. The characteristic frequencies identified in the Raman spectra of _Spondias mombin_ L. oil are shown in Table 1. The frequencies are related to previous reports from other vegetable oils [30; 31; 32; 33; 34]. Raman spectra recorded from _Spondias mombin_ L. vegetable oil samples showed signals associated with the vibrational modes C-C (v), C-H (\(\delta\)), C = O (v), C = C (v), as well as bands assigned to functional groups such as CH\({}_{2}\) and CH\({}_{3}\)[32; 35]. Registered Raman spectra showed very strong characteristic bands in the range of 2850 and 2900 cm\({}^{-1}\), which are associated with lipids, lignins and the functional groups C-CH\({}_{3}\), CH\({}_{2}\) and OH [34]. Raman frequency region between 1006 and 1300 cm\({}^{-1}\) showed characteristic  
Figure 1: Raw Raman spectra recorded. (**a**) Average Raman spectra recorded for each batch of oil extracted with different amount of seed. (**b**) The weight ratio between the processed seed versus extracted oil shows a linear tendency. Figure 2: Region of the Raman spectrum of an oil sample from _Sondias mombin_ L. where Raman frequencies are located at 1006, 1158 and 1523 cm\({}^{-1}\), which are associated with carotenoids compounds. shifts corresponding to alkyl aryl ether; in particular, at the frequency of 1006 cm\({}^{-1}\), it showed a stretching vibration corresponding to a C-O group. On the other hand, these shifts can also be attributed to vibrations of groups CH\({}_{3}\), HC-CH\({}_{3}\), aromatic rings and \(\upsilon\) C-C aliphatic chains [35]. In addition, the level of unsaturation of the fatty acids can be determined by the vibrational band at 1300 cm\({}^{-1}\) by the group =CH-[30]. The relatively weak band at 1080 cm\({}^{-1}\) is characteristic of vegetable oils, attributed to the presence of the terpene 1,8-cineole, aromatic rings or \(\upsilon\) C-C aliphatic chains [35, 36]. Bands at 1006 (bending), 1158 (stretching) and 1523 cm\({}^{-1}\) (stretching) correspond to CH\({}_{3}\), C-C and C=C, respectively, and can also be attributed to carotenoids [34, 37]. CH\({}_{3}\) and CH\({}_{2}\) are associated with the vibrational band at 1440 cm\({}^{-1}\) and are related to modes of inflection between both groups and phenolic compounds. The shift at 1657 cm\({}^{-1}\) was associated with the stretching of the functional group C = C assigned to monocyclic monoterenes and showed relative intensity in relation to the level of unsaturation of fatty acids. The band located at 1746 cm\({}^{-1}\) was assigned to the stretching of group C = O in triglycerides structures and the presence of polyesters, pectins and lignins [30, 38]. The vibrational frequency located at 3010 cm\({}^{-1}\) was associated with unsaturated fatty acids and stretching groups CH = CH, C-H aromatic, =CH\({}_{2}\) and =C-H [39].