The water-soluble exopolysaccharide (WSEPS) from Pantoea agglomerans strain KFS-9 isolated from mangrove forest was prepared by removing bacterial cell from the fermentation liquid following by concentration and cold ethanol precipitation of the supernatant. The polysaccharide material was purified by gel permeation chromatography on a Sephacryl S-300HR column and characterized using chemical and spectral methods. The results show that WSEPS is protein-bound polysaccharide, and it is composed of arabinose, glucose galactose and gulcuronic acid in the molar ratio of 1.0:2.2:2.8:0.9. Their antioxidant activities in vitro were studied by various antioxidant assays, including hydroxyl radical scavenging, superoxide radical scavenging and antilipid peroxidation. The results show that the WSEPS extracted had a high antioxidant activity in a concentration-dependent manner (except the activity of antilipid peroxidation). WSEPS quenched hydroxyl radicals, superoxide radicals at low amounts, the IC(50) of which were 0.07 and 0.15 mg/ml, respectively. These results indicate that the protective effect of WSEPS against UV radiation is most likely to be due to the free radicals-scavenging ability.
Two new sesquiterpenoid aromatic esters, armillarin and armillaridin, have been isolated from the artificially cultured mycelium of Armillaria mellea (Vahi. ex Fr.) Quel. (Tricholometaceae). On the basis of spectral (UV, IR, 'H-NMR, '3C-NMR and MS) analysis and chemical degradation as well as X-ray crystallography, their structures were identified as (1) and (2), respectively.
From the petroleum ether extracts of the artificially cultured mycelium of ARMILLARIA MELLEA, a novel sesquiterpenoid aromatic ester named armillaricin has been isolated by silica gel column chromatography. Its structure was deduced from spectral data and confirmed by single-crystal X-ray analysis.
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