Context: Scilla scilloides Druce (Liliaceae) is a folk medicine to treat dermal inflammation; however, the medicinal properties of this plant have not been completely established. Objective: The current study investigates the potent anti-inflammatory effects of S. scilloides bulbs for its traditional usage using lipoxygenase and hyaluronidase as the inflammation model. To gain insight into the active constituents, nine homoisoflavones (1-9) were subsequently tested. Materials and methods: Lipoxygenase and hyaluronidase inhibition of ethyl acetate extract from the bulbs of this plant within 2000 mg/mL or homoisoflavones within 1000 mM were determined by colorimetric methods. RAW264.7 cells were incubated with 10 or 50 mM homoisoflavones plus lipopolysaccharide (LPS) for 24 h. The culture media were collected and analyzed for determination of the nitric oxide (NO) level by the colorimetric Griess method to measure the extent of inflammation. Results: The extract exhibited inhibitory effects on lipoxygenase and hyaluronidase activities with IC 50 values 31.5 and 169 mg/mL, respectively. Among the nine homoisoflavones tested, four (1 and 3-5) resulted in 79.3-97.9% higher lipoxygenase inhibition than 6.7-32.7% of the others at 500 mM. Calculated IC 50 values indicated 5 as the compound responsible for strong lipoxygenase inhibition with 15.8 mM as the IC 50 value. In the hyaluronidase assay, all homoisoflavones tested at 1000 mM demonstrated 16.2-58.0% inhibition. Incubating the cells in the presence of all nine homoisoflavones tested at 50 mM significantly suppressed the NO production, downward to 1.5-66.0%, in the LPS-activated macrophage cells as a model. Discussion and conclusion: These results may indicate a potential role of S. scilloides for anti-inflammatory purposes.

Scilla scilloides Druce has been used as a folk medicine to treat dermal inflammation; however, the medicinal property of this plant remains to be entirely clarified. The ethyl acetate extract prepared from bulbs of S. scilloides exhibited antioxidative activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydrogen peroxide (H2O2) and nitric oxide (NO) scavenging assays. Nine homoisoflavones (1-9) yielded from this extract were further examined for their antioxidative activities. Among these chemicals tested, five homoisoflavones (1-3, 5 and 7), six homoisoflavones (1-3 and 5-7) and two homoisoflavones (4 and 5) resulted in showing higher activities than the others in DPPH radical, H2O2 and NO scavenging assays, respectively. Calculated EC50 values indicate 3 as the strongest in the DPPH radical scavenging analysis. These results may indicate a potential role of S. scilloides for its medicinal use and homoisoflavones as the antioxidants responsible.

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