Anti-diabetic, anti-inflammatory and muscle relaxant activities of extracts from Spirogyra varians (Hassall) Kuetzing.

Spirogyra varians (Hassall) Kuetzing is one of the edible freshwater filamentous green algae. This alga is commonly used as local food in northern and northeastern Thailand. A study on pharmacological activities of S. varians has not yet been extensively performed. Therefore, this study was established to investigate the anti-diabetic, anti-inflammatory and muscle relaxant activities of the extracts from S. varians. The In vitro α-glucosidase inhibition assay revealed that the propylene glycol extract exhibited the highest α-glucosidase inhibition activity compared to the methanol and ethanol extracts. However, all the extracts possess α-glucosidase inhibition activity less potent than Acarbose, an α-glucosidase inhibitor. The propylene glycol extract showed the highest inhibition of nitric oxide production in LPS-stimulated RAW 264.7 macrophage cells compared to the methanol and ethanol extracts. Nevertheless, the inhibition activity of the extracts was less potent than diclofenac, an anti-inflammatory drug. Whereas, the methanol extract exhibited the highest muscle relaxant activity on frog gastrocnemius compared to the ethanol and propylene glycol extracts. The methanol extract displayed muscle relaxant activity with a similar potent to Indomethacin, a pain relief drug. This study indicates that S. varians can be used as an effective novel natural resource for developing anti-diabetic, anti-inflammatory and muscle relief agents.