## 4 Discussion  
Sodium alginate was extracted from _S. lilicifolium_ to give a pale-yellow solid with a 14.36% yield. The obtained yield is very similar to the one reported by [PERSON] et al. (2015), who reported yields ranging from 12% to 16.5% ([PERSON] et al. (2004)). [PERSON] et al. (2004) extracted _S. lititains_ and _S. oligocytum_ using high temperature and base conditions to obtain 21.1-22.8% and 18.9-20.5% yields, respectively ([PERSON] (2011)). [PERSON] (2011) reported that alginate from several species of _Sargassum_ sp. had 16.93 to 30.50% yields ([PERSON] (2011)). Based on this study, the yield of the  
Figure 10: Collagen density was evaluated at the three variation times. Notation on the graph shows the result of the statistical test (\(\alpha<0.05\)). * and ** notation shows insignificant differences with NC but significant differences with DC. * = 0.01 \(\leq\alpha<0.05\); ** = \(\alpha\leq 0.01\). NC: normal group; DA: alginate treatment group; DAM: alginate-magnosteen rind extract treatment group; and DC: diabetic group. Figure 9: Number of fibroblasts at the three variation times. Notation on the graph shows the result of the statistical test (\(\alpha<0.05\)). * notation shows insignificant differences with NC but significant differences with DC. * = 0.01 \(\leq\alpha<0.05\). NC: normal group; DA: alginate treatment group; DAM: alginate-magnosteen rind extract treatment group; and DC: diabetic group. extracted alginate not only depends on the extraction method and the _Sargassum_ species used but also on the seasonal variation. It is in fact well known that there are marked seasonal variations of polysaccharide contents in seaweeds, as polysaccharides are stored in winter as a food source and therefore a harvest at the end of summer will give higher polysaccharide levels than in the spring. The \({}^{1}\)H NMR analysis of _S. ilicifolium_ alginate showed that the signals in the range 4-4.8 ppm belong to protons from the \(\beta\)-glycosidic bond, whereas the signals between 5.1 and 5.8 ppm are resonances of protons from the \(\alpha\)-glycosidic bond. The identification was performed by comparison with the \({}^{1}\)H NMR spectrum of alginate from [PERSON] et al. (1997) [31]. The structure of alginate from _S. ilicifolium_ consists of \(\beta\)-D-mannuronic acid (4.3-4.8 ppm) and \(\alpha\)-L-galuronic acid (5.1-5.8 ppm). The M/G ratio of alginate was determined by the integration of each proton with their monomers. The M/G ratio of alginate was 0.77, indicating that _S. ilicifolium_ alginate has a higher galvanonic acid monomer than mannuronic acid. The protons G\({}_{1}\) and M\({}_{1}\) are the most de-shielded protons (8 5.1-5.8 and 5.1-5.5, respectively). M\({}_{1}\) is more shielded than G\({}_{1}\), because G\({}_{1}\) is located at an equatorial position in comparison to an axial one in M\({}_{1}\). In fact, [PERSON] et al. performed a pretreatment to partly hydrolyze the alginate before \({}^{1}\)H NMR analysis, while in our case we decided to work with non-hydrolyzed alginate as it was fully soluble in the NMR solvent. This can be an explanation for the slightly more structured peaks and possibly also for the small shifts downfield we observed. The number of M\({}_{\rm n}\) and M\({}_{\rm w}\) of alginate were 1.49 \(\times\) 10\({}^{4}\) and 2.77 \(\times\) 10\({}^{4}\) Dalton, respectively. Furthermore, the M\({}_{\rm n}\) and M\({}_{\rm w}\) obtained were used in the calculation of the dispersity index (D) using the following equation:  
\[\mathrm{D}=Mw/Mn \tag{1}\]  
The dispersity index (D) was 1.73. The D value of alginate from _S. ilicifolium_ was below 2, indicating that the extracted alginate showed good homogeneity and was classified as chain-growth polymerization. Chain-growth polymerization is a process in which the high molecular weight polymer is generated at the beginning of the polymerization process and the polymer yield (the percentage conversion of the monomer into the polymer) gradually increases with time [32]. Based on TGA, alginate from _S.