## 3 Results
### Analysis of Phenolic Compounds in SF and SSF Extracts in Different Solvents
Lastly, naringin, as in the case of naringenin, was detected only in the ethanol extracts, with 298.08 \(\mathrm{\SIUnitSymbolMicro g}\)/g in SF and 517.98 \(\mathrm{\SIUnitSymbolMicro g}\)/g in SSF extract. According to [PERSON] et al. [84], naringenin and naringin are nonpolar polyphenol compounds that are mainly extracted using organic solvents such as methanol and ethanol. Consistently, naringenin and naringin were not detected in the SF and SSF water extracts in the present study, and ethanol was deemed more suitable for the extraction of naringenin and naringin from SF. In addition, the total flavonoid content was approximately 1.4-fold higher in the SSF ethanol extract than that of the SF ethanol extract, presumably due to the higher contents of naringenin and naringin in the SSF ethanol extract. As such, changes of phenolic compounds in SF were observed according to the method of extraction and the cooking (steaming) process, and steaming along with ethanol or methanol extraction seems more suitable for the extraction of phenolic compounds from SF. [PERSON] et al. [85] evaluated the phenolic compound in _Sargassum fusiforme_ ethanol extract under different drying conditions. They reported a higher retention of 4-hydroxybenzoic acid content in freeze-dried samples. They also reported that the content of 4-hydroxybenzoic acid was affected by the drying temperature. Thus, it is required to examine the phenolic compound content of SF and SSF extracts under various drying conditions. Principal component analysis (PCA) was used to analyze the total polyphenol and flavonoid contents as well as the antioxidant activities (DPPH and ABTS radical scavenging activities, FRAP activity, and SOD, CAT, and APX activities) and compare the patterns across SF and SSF extracts in different solvents. The PCA results showed a variation of 76.7% and 16.5% for PC1 and PC2, respectively, which accounted for approximately 93.2% of the variation in bioactivity between SF and SSF (Figure 3a). The PC1 appears to be mainly correlated with the antioxidant activity and thus determines the distribution of SF and SSF extracts along the x-axis. The PC2 is correlated with the total polyphenol and flavonoid contents as well as the antioxidant enzyme (SOD, CAT, and APX) activities, and differentiate between the SSF2, SF3, and SSF3 groups and the SF1, SF2, and SSF1 groups. The SF and SSF water extracts were found within the same ellipse, and based on the antagonistic direction of arrows for the total polyphenol and flavonoid contents and the antioxidant activities seen in Figure 3b, the antioxidant activities in the SF and SSF water extracts were determined to be low, whereas the total polyphenol content, DPPH, and ABTS radical scavenging activities, and antioxidant enzyme activities were high in the SSF methanol extract. In the multivariate analysis, a VIP score greater than 1 indicates a factor with an influence on the group differentiation [86]. The VIP scores of SF and SSF exceeded 1 for the DPPH radical scavenging activity (2.14) and SOD activity (1.48), indicating that these factors are useful for differentiating SF and SSF in different extraction solvents (Figure 4a). A positive correlation (r = 0.586-0.898) was found between the total polyphenol content and the DPPH and ABTS radical scavenging activities and antioxidant enzyme (SOD, CAT, and APX) activities for SF and SSF, with a significantly high positive correlation (r = 0.898, \(p\) = 0.015) between the total polyphenol content and the APX activity (Figure 4b). [PERSON] et al. [87] reported a high positive correlation between the phenolic content and the DPPH and ABTS radical scavenging activities based on the increase in these activities with an increase in the phenolic compound contents in the extracts of 19 _Sargassum_ species.