Unique antioxidant effects of herbal leaf tea and stem tea from Moringa oleifera L. especially on superoxide anion radical generation systems.

This study aimed to investigate the unique antioxidative effects of Japanese moringa products, herbal leaf tea and stem tea, using established free radical assays, focusing on superoxide anion (O2-) radical generation systems. Hot-water extracts from moringa teas resulted in different but lower scavenging activities than Trolox in four synthetic free radical models. Interestingly, these extracts further showed higher O2- radical scavenging effects than Trolox in the phenazine methosulfate-NADH-nitroblue tetrazolium and xanthine oxidase assay systems. Incubating human neutrophils in the presence of these tea extracts rather than Trolox effectively suppressed cellular O2- radical generation. Among the eight known phenolic constituents of moringa leaves, caffeic acid and chlorogenic acid may be responsible for the O2-specific radical scavenging capacity stronger than that of Trolox. These results suggest that moringa herbal teas are a good source of natural antioxidants for preventing O2- radical-mediated disorders. Abbreviations: O2-: superoxide anion; ROS: reactive oxygen species; H2O2: hydrogen peroxide; XOD: xanthine oxidase; DPPH: 1,1-diphenyl-2-picrylhydrazyl; ABTS+: 2,2'-azinobis(2-ethylbenzothiazoline-6-sulfonic acid) cation; CPZ+: chlorpromazine cation; PMS: phenazine methosulfate; NBT: nitroblue tetrazolium; PMA: phorbol 12-myristate 13-acetate.

Inhibitory effects of the ethyl acetate extract from bulbs of Scilla scilloides on lipoxygenase and hyaluronidase activities.

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 µg/mL or homoisoflavones within 1000 µM were determined by colorimetric methods. RAW264.7 cells were incubated with 10 or 50 µM 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 IC50 values 31.5 and 169 µg/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 µM. Calculated IC50 values indicated 5 as the compound responsible for strong lipoxygenase inhibition with 15.8 µM as the IC50 value. In the hyaluronidase assay, all homoisoflavones tested at 1000 µM demonstrated 16.2-58.0% inhibition. Incubating the cells in the presence of all nine homoisoflavones tested at 50 µM 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.

Anti-inflammatory and antioxidative effects of a methanol extract from bulbs of Scilla scilloides.

The extract from bulbs of Scilla scilloides exhibited inhibitory effects in lipoxygenase and hyaluronidase assays and various oxidation models in vitro. Incubating the cells in the presence of this extract ameliorated t-butyl hydroperoxide-induced cytotoxicity from 27% to 57% in a macrophage model. The results may indicate the potential role of S. scilloides for its anti-inflammatory and antioxidative effects.

Homoisoflavones as the antioxidants responsible from bulbs of Scilla scilloides.

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.