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Monascus purpureus in relation to statin and sterol production and mutational analysis

Mohan Kumari, H. P. (2009) Monascus purpureus in relation to statin and sterol production and mutational analysis. PhD thesis, University of Mysore.

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Abstract

Fermented products of Monascus purpureus are used as traditional natural dietary supplement in China. It contains monacolins, sterols and unsaturated fatty acids and believed to decrease serum lipids such as triglycerides and cholesterol. M. purpureus and mutants isolated in this study were found to produce various bioactive secondary metabolites like statins, sterols and fatty acids during growth. The metabolites were characterized after preparatory TLC and HPLC. The fermentation conditions were optimised for metabolite production. In solid-state cultures, more quantities of the metabolites were quantitated. The fungi accumulate sterols mainly in shake flask growth. Cultural conditions have a significant influence on the yield of statins. The fungus grown at pH 5.0 at 28º C in a medium made of maltose and peptone as carbon and nitrogen sources resulted in maximum statin production. Among the two statins produced by M. purpureus and mutants lovastatin (Monacolin K) was produced in significant amount. The antioxidant molecule ankaflavin was also characterized by 1H, 13C, 2D HSQC and HMQC NMR, FTIR, MS and UV-visible spectroscopic studies. L-asparaginase and L-glutaminase activities were comparatively more in the mutant CFR 410-11 compared to the wild type MTCC 410 and the mutant CFR 410- 22. CFR 410-11 secreted more red pigment when cultured on rice and in broth. Significant difference in L-asparaginase and L-glutaminase activities in MTCC 410, CFR 410-11 and CFR 410-22 revealed the importance of these enzymes in pigment production. Characterization of compounds that showed applications as functional food resulted in the safety evaluation of M. purpureus. Only low levels of the nephrotocin citrinin were estimated in rice fermented by Monascus (RMR). Feeding acute doses of RMR to rats did not cause any symptoms of toxicity or mortality. Similarly, dietary xii feeding of RMR to rats did not produce any significant changes in food intake or gain in body weight of the experimental animals and they were comparable to the rats fed with normal diet (control). No significant differences in the relative weight of vital organs, hematological parameters, macroscopic and microscopic changes in vital organs and serum clinical enzyme levels between the experimental and control groups were determined. RMR containing lovastatin fed at a concentration of 11.51g/ kg fermented rice reduced total cholesterol (TC), triglyceride (TG), lipoprotein cholesterol (LDL) in high fat diet (HFD) fed rats. The results were similar with reference to serum and liver. There was no significant difference with regard to the food intake, gain in body weight and organ weights of rats in different dietary groups. In addition, histological examinations of liver of hyperlipidemic rats showed decreased lipid accumulation in red mould rice powder fed rats. RMR effectively scavenged 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals (IC50=100μg/ml). RMR affected oxidative stress in male albino rats fed on high fat diet (HFD) by increasing activities of glutathione reductase, glutathione peroxidase, superoxide dismutase and Catalase. It also increases total thiols, glutathione and ascorbic acid (antioxidants) in rats. Lipid peroxidation was significantly inhibited in rats fed with RMR compared to rats fed with HFD. Consumption of RMR by rats induced antioxidant enzymes and molecules to scavenge the reactive oxygen species (ROS) released due to oxidative stress in rats fed on HFD.

Item Type: Thesis (PhD)
Uncontrolled Keywords: Monascus purpureus, Fermented products, secondary metabolites, probiotics
Subjects: 500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 04 Fungi
600 Technology > 08 Food technology > 32 Antioxidants
Divisions: Food Microbiology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 01 Mar 2011 09:36
Last Modified: 22 Dec 2016 13:12
URI: http://ir.cftri.com/id/eprint/9950

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