Antioxidant and Hypoglycemic Activities of Ethanol Extracts from Different Products of Blechnum orientale L. in Vitro

Objective: The antioxidant and hypoglycemic effects in vitro of the extract from Blechnum orientale L. were compared. Methods: By using Folin-Ciocalteu method, the total polyphenol content of extracts were determined. The content of flavonoids was determined by NaNO₂-Al(NO₃)₃ method. In addition, radicals scavenging (DPPH·, ABTS⁺·), reducing ability, α-glucosidase and α-amylase inhibitory were carry out to evaluate their antioxidant and hypoglycemic activities. Pearson correlation analysis method was used to measure the correlation of component content and activities. Results: The results showed that there were significant differences in the content of total phenolic and flavonoids, antioxidant activity and α-glucosidase inhibitory activity among different processing products of ethanol extracts from Blechnum orientale L. The alcohol extract from fresh product had the highest content of total phenols ((593±3.45) mg GA/g) and total flavonoids ((156.75±1.28) mg RT/g), and the fresh product showed the strongest iron ion reduction ability, ABTS free radical scavenging ability and DPPH free radical scavenging ability. The alcohol extract from wet product had the strongest inhibitory effect on α-glucosidase and α-amylase. The contents of total phenols and flavonoids in Blechnum orientale L. with different processing methods were significantly positively correlated with their antioxidant (P<0.01) and were significant positive correlated with their hypoglycemic activity (P<0.05). Conclusion: The alcohol extract from fresh product had the highest antioxidant activity and wet product had the strongest hypoglycemic activity in vitro. The active ingredient may be total phenolic and flavonoids.