Purification and properties of a novel phenolic antioxidant from Radix astragali fermented by Aspergillus oryzae M29.

The Chinese herb Radix astragalus (RA) has been widely used as a dietary supplement in Asia, and there are numerous reports on its bioactivities. However, there are no reports to date regarding the use of Aspergillus spp. in the culture medium of the RA plant for the production of phenolic antioxidants. In this study, utilizing the fungus Aspergillus to ferment the native RA has successfully resulted in a significant increase in the phenolic contents of RA, and the fermented RA also revealed much better antioxidant activity toward 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, hydroxyl radical, superoxide radical and peroxyl radical than those of unfermented RA. Among these phenolics, a potent novel antioxidant was isolated and identified as 3,4-di(4'-hydroxyphenyl) isobutyric acid with a molecular weight of 272, by ESI-MS (electrospray ionization mass), ¹H NMR (nuclear magnetic resonance), ¹³C NMR, DEPT (distortionless enhancement by polarization transfer)-NMR, HMQC (heteronuclear multiple quantum coherence), and HMBC (heteronuclear multiple bond correlation) spectra. These data demonstrated that the solid-state bioprocessing strategy could be an innovative approach to enhance the antioxidant activity of RA.

[1]  W. Cho,et al.  In vitro and in vivo anti-tumor effects of Astragalus membranaceus. , 2007, Cancer letters.

[2]  Jun Ren,et al.  Chinese medicinal herb Radix Astragali suppresses cardiac contractile dysfunction and inflammation in a rat model of autoimmune myocarditis. , 2008, Toxicology letters.

[3]  C. Chou,et al.  Enhanced antioxidative activity of soybean koji prepared with various filamentous fungi. , 2006, Food microbiology.

[4]  M. Krucker,et al.  Determination and identification of isoflavonoids in Radix astragali by matrix solid-phase dispersion extraction and high-performance liquid chromatography with photodiode array and mass spectrometric detection. , 2004, Journal of chromatography. A.

[5]  K. Shetty,et al.  Solid-state bioconversion of fava bean by Rhizopus oligosporus for enrichment of phenolic antioxidants and l-DOPA , 2004 .

[6]  G. Yen,et al.  Antioxidant activity and active compounds of rice koji fermented with Aspergillus candidus , 2003 .

[7]  C. S. Yang,et al.  Inhibition of carcinogenesis by dietary polyphenolic compounds. , 2001, Annual review of nutrition.

[8]  B. Chiang,et al.  Anti-tumor activity of the fermentation broth of Cordyceps militaris cultured in the medium of Radix astragali , 2008 .

[9]  Wei Hu,et al.  Identification and Determination of Flavonoids in Astragali Radix by High Performance Liquid Chromatography Coupled with DAD and ESI-MS Detection , 2011, Molecules.

[10]  C. Chou,et al.  Solid-state fermentation with fungi to enhance the antioxidative activity, total phenolic and anthocyanin contents of black bean. , 2008, International journal of food microbiology.

[11]  R. Bauer,et al.  Radix Astragali — Huang Qi , 2011 .

[12]  Florence Lam,et al.  Amelioration of experimental colitis by Astragalus membranaceus through anti-oxidation and inhibition of adhesion molecule synthesis. , 2005, World journal of gastroenterology.

[13]  Xiaoxin Yin,et al.  The antioxidative effects of astragalus saponin I protect against development of early diabetic nephropathy. , 2006, Journal of pharmacological sciences.

[14]  A. Bast,et al.  A new approach to assess the total antioxidant capacity using the TEAC assay , 2004 .

[15]  K. Shetty,et al.  Antimicrobial activity against select food-borne pathogens by phenolic antioxidants enriched in cranberry pomace by solid-state bioprocessing using the food grade fungus Rhizopus oligosporus , 2004 .

[16]  Y. Chan,et al.  Nutrient Physiology , Metabolism , and Nutrient-Nutrient Interactions Differential Effects of Isoflavones , from Astragalus Membranaceus and Pueraria Thomsonii , on the Activation of PPAR a , PPAR g , and Adipocyte Differentiation In Vitro 1 – 3 , 2006 .

[17]  Y. Kuo,et al.  Cytotoxic activities of 9,11-dehydroergosterol peroxide and ergosterol peroxide from the fermentation mycelia of ganoderma lucidum cultivated in the medium containing leguminous plants on Hep 3B cells. , 2009, Journal of agricultural and food chemistry.

[18]  Mei Hui Liu,et al.  Differential effects of isoflavones, from Astragalus membranaceus and Pueraria thomsonii, on the activation of PPARalpha, PPARgamma, and adipocyte differentiation in vitro. , 2006, The Journal of nutrition.

[19]  C. Tsai,et al.  Rapid and specific detection of hydroxyl radical using an ultraweak chemiluminescence analyzer and a low-level chemiluminescence emitter: application to hydroxyl radical-scavenging ability of aqueous extracts of Food constituents. , 2001, Journal of agricultural and food chemistry.

[20]  H. Boon,et al.  Counseling cancer patients about herbal medicine. , 1999, Patient education and counseling.

[21]  J. Chiou,et al.  Improved superoxide-generating system suitable for the assessment of the superoxide-scavenging ability of aqueous extracts of food constituents using ultraweak chemiluminescence. , 2003, Journal of agricultural and food chemistry.

[22]  R. Kwakkel,et al.  In vitro fermentation characteristics of two mushroom species, an herb, and their polysaccharide fractions, using chicken cecal contents as inoculum. , 2003, Poultry science.

[23]  T. Jørgensen.  Identification and toxigenic potential of the industrially important fungi, Aspergillus oryzae and Aspergillus sojae. , 2007, Journal of food protection.

[24]  A. Pihlanto.  Antioxidative peptides derived from milk proteins , 2006 .

[25]  Z. Hong,et al.  Astragaloside IV protects against ischemic brain injury in a murine model of transient focal ischemia , 2004, Neuroscience Letters.

[26]  A. Dávalos,et al.  Extending applicability of the oxygen radical absorbance capacity (ORAC-fluorescein) assay. , 2004, Journal of agricultural and food chemistry.

[27]  S. Sinclair,et al.  Chinese herbs: a clinical review of Astragalus, Ligusticum, and Schizandrae. , 1998, Alternative medicine review : a journal of clinical therapeutic.

[28]  T. Dong,et al.  Chemical analysis of Radix Astragali (Huangqi) in China: a comparison with its adulterants and seasonal variations. , 2002, Journal of agricultural and food chemistry.

[29]  B. Chiang,et al.  Effect of Bacillus subtilis natto–fermented Radix astragali on collagen production in human skin fibroblasts , 2009 .

[30]  R. Pomerantz,et al.  Antiviral potentials of medicinal plants , 2007, Virus Research.

[31]  Guangyong Chen,et al.  Suppressive effect of Astragalus membranaceus Bunge on chemical hepatocarcinogenesis in rats , 2002, Cancer Chemotherapy and Pharmacology.