| Summary: | 博士 === 國立中興大學 === 食品科學系 === 92 === The research reported herein was to first study various methods for production of Ling chih (Ganoderma tsugae Murrill), including the use of polypropylene bag for cultivation of Ling chih and baby Ling chih and the utilization of submerged culture for production of mycelia and fermentation filtrate. Furthermore, the research was emphasized on the comparison of taste quality of mature and baby Ling chih, mycelia and filtrate and the analysis of constituents and structure of their hot-water-extracted polysaccharides. Finally, the research was focused on the physiological properties of water extracts and hot-water extracted polysaccharides from Ling chih, mycelia and filtrate, including antioxidant and antimutagenic properties and cytotoxicity on cancer cells.
In polypropylene bag cultivation, Ling chih was preferably inoculated after March and harvested during May to November in Mid-Taiwan region. With regards to the biological efficiency in fruiting body cultivation, baby Ling chih was evidently higher than Ling chih (1.05 > 0.56). In shaken flask culture, the relationship of dry mycelial biomass and pH value, residual sugar content, laccase activity and polysaccharide concentration indicated that at day 12 the highest amount of dry biomass (18.74 g/L) was obtained with the highest amount polysaccharide concentration (1.38 g/L). The contents of taste components were found in descending order of filtrate, mycelia, baby Ling chih and Ling chih.
With regard to the hot-water or hot alkali extraction, the yield was the highest for mycelial polysaccharides. However, the highest sugar content was found in hot-water extracted polysaccharides from filtrate. The protein contents of hot alkali extracted polysaccharides from Baby ling chih, mycelia and filtrate were higher than that of their hot-water extracted polysaccharides. The hot-water and hot alkali extracted polysaccharides comprised mainly of mannitol. Using gel filtration, the molecular weights of hot-water extracted polysaccharides were in the descending order of baby Ling chih > Ling chih > mceylia > filtrate and in the range of 2.8 104∼1.8 105 Da. The profiles of infrared spectra were similar for hot-water extracted polysaccharides from four forms of G. tsugae. All of them exhibited the absorption characteristics of sugar functional groups whereas only that from filtrate showed the -glucosidal bonding.
Cold-water extract from Ling chih showed the best antioxidant properties, especially the antioxidant activity, scavenging ability in free radicals and chelating ability on ferrous ions. Using the conjugated diene method, hot-water extracted polysaccharides from four forms of G. tsugae were good in antioxidant properties. With regard to reducing power, scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals and chelating ability on ferrous ions, hot-water extracted polysaccharides from mature and baby Ling chih were superior over the hot alkali extracted. The hot alkali extracted polysaccharides from mycelia and filtrate were better than the hot-water extracted in reducing power, scavenging ability and chelating ability. Regardless of hot-water or hot alkali extracted polysaccharides, four forms of G. tsugae were good in antioxidant properties.
No toxicity or mutagenicity was found in Salmonella typhimurium TA98 and TA100 was observed at 0.05-5 mg/plate of Ling chih, mycelia and filtrate from the submerged culture. The water extracts from Ling chih, mycelia and filtrate were good in antimutagenic effect against NQNO. The hot water extracts from baby Ling chih and mycelia showed the excellent effect against NQNO toward TA98 and TA100. The water extracts and hot extracted polysaccharide from G. tsugae showed excellent effect against B[a]P toward S. typhimurium TA100. The cold water extracts and hot-alkali-extracted polysaccharide from baby Ling chih showed excellent effect against B[a]P.
In the anti-tumor activity test, the inhibitory effects on IMR32 and Hep G2 tumor cell lines were studied using MTT test. At 10 mg/ml, hot-water extracts from Ling chih showed stronger cytotoxicity on IMR32 cells, with a survival of 29.03∼30.93%. Cold-water extracts and hot-water extracted polysaccharides from four forms of G. tsugae exhibited better cytotoxicity on MR32 cellswith the increased concentrations. Only hot-water extracts from Ling chih showed the cytotoxic effect on Hep G2 cells. The cytotoxicity of hot-water extracted polysaccharides on Hep G2 cells were in the descending order of Ling chih > baby Ling chih > filtrate > mycelia.
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