Search Results (2)

The brown alga Sargassum fusiforme (SF) is historically consumed as a food material in Japan. A steaming process is often required for SF products on the market due to their moderate hardness and astringent taste. This investigation aimed to elucidate the effect of steaming on the anti-diabetic activity of SF and its related chemical components. Acetone extracts of SF were prepared after it were steamed for 0, 1, 2, or 4 h (SF-0h, SF-1h, SF-3h, and SF-4h, respectively). Alpha-glucosidase inhibitory profiles of each SF extract were made based on activity-guided separation. The active fractions were collected and NMR was applied for a further chemical composition analysis. Our results suggested that total polyphenol levels decreased drastically after steaming, which resulted in a drop in α-glucosidase inhibitory activity. The fatty acid, pheophytin a, and pyropheophytin a contents were elevated significantly after steaming, which contributed to the majority of the activity of steamed SF (SF-1h). However, prolonging the steaming time did not significantly affect the activity of SF further since the content of free fatty acids in steamed SF (SF-2h and SF-4h) almost did not change with a longer time of steaming. Moreover, palmitic acid, 8-octadecenoic acid, and tetradecanoic acid were identified as the top three important fatty acids for the inhibition of α-glucosidase by steamed SF. Further molecular docking results revealed that these fatty acids could interact with residues of α-glucosidase via hydrogen bonds, salt bridges, and hydrophobic interactions. In conclusion, steaming altered the α-glucosidase inhibitory properties of SF by changing the contents of polyphenols, fatty acids, and chlorophyll derivatives. Full article

Sargassum fusiforme (SF), a perennial brown, is often steamed for consumption. SF contains many bioactive compounds; however, the effect of steaming these compounds is unknown. This study investigates phenolic component contents and antioxidant and antiaging activities of fresh (SF) and steamed (SSF) extracts in different solvents (95% ethanol, 95% methanol, hot water). Total polyphenol and flavonoid content was highest in SSF methanol (9.76 mg TAN/g) and SF methanol extracts (13.42 mg QUE/g). The DPPH radical scavenging activity was highest in SF methanol extracts (IC₅₀ = 5.83 μg/μL), whereas the FRAP activity was higher in SSF extracts. Methanol SSF extract exhibited higher SOD, CAT, and APX activities. Collagenase inhibition activity was higher in all SSF extracts, whilst tyrosinase inhibition activity was highest in SSF methanol extract (30.5%). Analysis of phenolic compound contents revealed that 4-hydroxybenzoic acid content was highest in SF methanol extract, whilst steaming increased naringenin and naringin contents in ethanol extracts. Finally, antioxidant activity of both extracts showed a positive correlation with polyphenol content. Overall, these results suggested that SSF ethanol and methanol extract had higher phenolic component content and antioxidant and antiaging activities. Thus, SSF can be potentially used in health functional foods and cosmetic products. Full article