# Biosynthesis of Silver Nanoparticles Using _Tabernaemontana ventricosa_ Extracts
## 3 Results and Discussion
### Fourier Transform Infrared (FTIR) Spectroscopy
These peaks correspond to the strong broad O-H stretch of alcohols, C-H stretch of alkynes, C=O, C-O, O-H stretching of carboxylic acids, and H-bonded to phenols [2; 29; 41; 59], whereas the bands observed between 2922 cm\({}^{-1}\) and 2936 cm\({}^{-1}\) correspond to the medium C-H stretch of alkanes and the strong broad N-H stretch of amine salts [41; 59]. Strong peaks displayed by bands from regions between 2339 cm\({}^{-1}\) and 2395 cm\({}^{-1}\) resemble O=C=O carbon dioxide stretching; however, bands in the 2100 cm\({}^{-1}\) to 2140 cm\({}^{-1}\) region represent weak C\(\equiv\)C alkyne stretching [2; 59; 29]. Interestingly, the compound group isothiamate N=C=S showed strong stretching at 2095.91 cm\({}^{-1}\) (FL) and 2091.37 cm\({}^{-1}\) (FS) in fresh extracts only [2; 57]. The sharp peaks from 1588.93 cm\({}^{-1}\) to 1623.91 cm\({}^{-1}\) indicate C=C, C-O, and N-H stretching to alkenes and amines. The C-H plane bends to alkanes and aldehydes, C-O and O-H medium/strong stretches, bending of alcohols and phenols, CO-O-CO strong broad stretching of anhydrides, and strong S=O stretches of sulfoxide and sulfonate/sulfonamide all correspond to the 1043 cm\({}^{-1}\)-1384 cm\({}^{-1}\) region [2; 41; 59; 29]. The medium peaks at 690 cm\({}^{-1}\)-895 cm\({}^{-1}\) correspond to medium C=C bending of alkenes and strong C-I halo compounds [57]. The observed FTIR spectra indicated the presence of a variety of functional groups at varying positions. The results suggest that the capping of the NPs may contain phenolic and terpenoid compounds, with functional groups of carboxylic acids, alcohols, alkanes, and esters, which may have been influenced by the different treatments (various solvents and ratios of the leaf and stem material) and have reduced AgNO\({}_{3}\) to AgNPs using a variety of bioactive compounds [60]. The results of the present study are consistent with [PERSON] et al. [41]; however, additional research regarding which compound is responsible for capping is require. Furthermore, the occurrence of medium-intensity peaks in the amide region, more specifically the amide I (one) area, also suggests that proteins/enzymes are likely responsible for the reduction of Ag ions for the synthesis of AgNPs [2; 35]. According to the results of this study, the occurrence of proteins may be accountable for the formation of a thin film (cap) surrounding the AgNPs [60]. Studies have confirmed that amino acid residues and peptides of proteins usually coat AgNPs to prevent the agglom  
Figure 7: The FTIR spectra of AgNPs synthesized using leaf and stem (methanolic, fresh, and powdered) extracts of _T. ventricosa._ (**A**) Leaf methanol extract; (**B**) Stem methanol extract; (**C**) Fresh leaf extract; (**D**) Fresh stem extract; (**E**) Leaf powder extract; and (**F**) Stem powder extract. eration of particles, allowing the stability of NPs in solution [51; 61; 62]. In addition, the occurrence of impurities may be attributed to other organic substances in the various plant extracts [47].