A three-step optimization strategy which includes one-factor-at-a-time classical method and different statistical approaches (Plackett-Burman design and response surface methodology) that were applied to optimize the antioxidant potential of Penicillium granulatum. Antioxidant activity was assayed by different procedures and compared with total phenolic content. Primarily, different carbon and nitrogen sources were screened by classical methods, which revealed sucrose and NaNO3 to be the most suitable. In second step, Plackett-Burman design also supported sucrose and NaNO3 to be the most significant. In third step, response surface analysis showed 4.5% sucrose, 0.1% NaNO3, and incubation temperature of 25°C to be the optimal conditions. Under these conditions, the antioxidant potential assayed through different procedures was 78.2%, 70.1%, and 78.9% scavenging effect for DPPH radical, ferrous ion, and nitric oxide ion, respectively. The reducing power showed an absorbance of 1.6 with 68.5% activity for FRAP assay. 1. Introduction Antioxidants are the compounds that scavenge or neutralize free radicals. These are produced constantly in human body during normal physiological processes and are responsible for various pathological process like aging, cardiovascular diseases, diabetes, cancer, Alzheimer’s disease, neurodegenerative disorders, atherosclerosis, cataracts, and inflammation [1]. Filamentous fungi are historically important sources of pharmacologically relevant secondary metabolites, and this group continues to provide new structures with novel biological activities [2]. The discovery of pharmaceutically significant novel product through screening of microbial secondary metabolites is an attraction in the pharmaceutical and biotechnological industry and is also becoming increasingly beneficial. There is widespread acceptance that fungi are virtually unlimited source of novel structures with many potential therapeutic applications including antibacterial, anticancer, anti-inflammatory, immunostimulatory, and antioxidant [3]. Recently, fungi have emerged as an important source of antioxidant compounds [4, 5]. Phenolic compounds are considered to be the main secondary metabolites in plants, mushrooms, and fungi responsible for their antioxidant activity [6–8]. Physiochemical and nutritional conditions greatly influence the growth as well as the activities of the microorganisms. Hence, optimization of such parameters is an important step for the enhancement of activity. Optimization is a tedious process due to involvement of multivariable parameters.
References
[1]
N. Gursoy, C. Sarikurkcu, M. Cengiz, and M. H. Solak, “Antioxidant activities, metal contents, total phenolics and flavonoids of seven Morchella species,” Food and Chemical Toxicology, vol. 47, no. 9, pp. 2381–2388, 2009.
[2]
A. L. Demain, “Pharmaceutically active secondary metabolites of microorganisms,” Applied Microbiology and Biotechnology, vol. 52, no. 4, pp. 455–463, 1999.
[3]
A. Ran？i？, M. Sokovi？, A. Karioti, J. Vukojevi？, and H. Skaltsa, “Isolation and structural elucidation of two secondary metabolites from the filamentous fungus Penicillium ochrochloron with antimicrobial activity,” Environmental Toxicology and Pharmacology, vol. 22, no. 1, pp. 80–84, 2006.
[4]
C. H. Chen, C. Y. Shaw, C. C. Chen, and Y. C. Tsai, “2,3,4-Trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran, a novel antioxidant, from Penicillium citrinum F5,” Journal of Natural Products, vol. 65, no. 5, pp. 740–741, 2002.
[5]
W. Y. Huang, Y. Z. Cai, K. D. Hyde, H. Corke, and M. Sun, “Endophytic fungi from Nerium oleander L (Apocynaceae): main constituents and antioxidant activity,” World Journal of Microbiology and Biotechnology, vol. 23, no. 9, pp. 1253–1263, 2007.
[6]
E. M. Heider, J. K. Harper, D. M. Grant et al., “Exploring unusual antioxidant activity in a benzoic acid derivative: a proposed mechanism for citrinin,” Tetrahedron, vol. 62, no. 6, pp. 1199–1208, 2006.
[7]
R. Yawadio Nsimba, H. Kikuzaki, and Y. Konishi, “Antioxidant activity of various extracts and fractions of Chenopodium quinoa and Amaranthus spp. seeds,” Food Chemistry, vol. 106, no. 2, pp. 760–766, 2008.
[8]
T. Jayakumar, P. A. Thomas, and P. Geraldine, “In-vitro antioxidant activities of an ethanolic extract of the oyster mushroom, Pleurotus ostreatus,” Innovative Food Science and Emerging Technologies, vol. 10, no. 2, pp. 228–234, 2009.
[9]
P. Katapodis, V. Christakopoulou, and P. Christakopoulos, “Optimization of xylanase production by Thermomyces lanuginosus in tomato seed meal using response surface methodology,” World Journal of Microbiology and Biotechnology, vol. 22, no. 5, pp. 501–506, 2006.
[10]
Q. L. Wu, T. Chen, Y. Gan, X. Chen, and X. M. Zhao, “Optimization of riboflavin production by recombinant Bacillus subtilis RH44 using statistical designs,” Applied Microbiology and Biotechnology, vol. 76, no. 4, pp. 783–794, 2007.
[11]
D. S. Arora and P. Chandra, “Assay of antioxidant potential of two Aspergillus isolates by different methods under various physio-chemical conditions,” Brazilian Journal of Microbiology, vol. 41, no. 3, pp. 765–777, 2010.
[12]
G. R. Zhao, Z. J. Xiang, T. X. Ye, Y. J. Yuan, and Z. X. Guo, “Antioxidant activities of Salvia miltiorrhiza and Panax notoginseng,” Food Chemistry, vol. 99, no. 4, pp. 767–774, 2006.
[13]
L. W. Chang, W. J. Yen, S. C. Huang, and P. D. Duh, “Antioxidant activity of sesame coat,” Food Chemistry, vol. 78, no. 3, pp. 347–354, 2002.
[14]
A. Othman, A. Ismail, N. Abdul Ghani, and I. Adenan, “Antioxidant capacity and phenolic content of cocoa beans,” Food Chemistry, vol. 100, no. 4, pp. 1523–1530, 2007.
[15]
S. K. Ki, T. Yokozawa, Y. K. Hyun, and H. P. Jeong, “Study on the nitric oxide scavenging effects of ginseng and its compounds,” Journal of Agricultural and Food Chemistry, vol. 54, no. 7, pp. 2558–2562, 2006.
[16]
V. L. Singleton, R. Orthofer, and R. M. Lamuela-Raventós, “Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent,” Methods in Enzymology, vol. 299, pp. 152–178, 1998.
[17]
P. Chandra and D. S. Arora, “Antioxidant activity of fungi isolated from soil of different areas of Punjab, India,” Journal of Applied and Natural Science, vol. 1, pp. 123–128, 2009.
[18]
D. M. Maron and B. N. Ames, “Revised methods for the Salmonella mutagenicity test,” Mutation Research, vol. 113, no. 3-4, pp. 173–215, 1983.
[19]
G. Ciapetti, E. Cenni, L. Pratelli, and A. Pizzoferrato, “In vitro evaluation of cell/biomaterial interaction by MTT assay,” Biomaterials, vol. 14, no. 5, pp. 359–364, 1993.
[20]
S. A. Sayyad, B. P. Panda, S. Javed, and M. Ali, “Optimization of nutrient parameters for lovastatin production by Monascus purpureus MTCC 369 under submerged fermentation using response surface methodology,” Applied Microbiology and Biotechnology, vol. 73, no. 5, pp. 1054–1058, 2007.
[21]
J. A. Macedo, L. D. Sette, and H. H. Sato, “Optimization of medium composition for transglutaminase production by a Brazilian soil Streptomyces sp.,” Electronic Journal of Biotechnology, vol. 10, no. 4, pp. 618–626, 2007.
[22]
G. C. Yen and Y. C. Chang, “Medium optimization for the production of antioxidants from Aspergillus candidus,” Journal of Food Protection, vol. 62, no. 6, pp. 657–661, 1999.
[23]
R. N. Tandon and J. S. Grewal, “Effect of nitrogen nutrition on growth and sporulation of some pathogenic fungi,” Proceedings of the Indian Academy of Sciences B, vol. 44, no. 2, pp. 61–67, 1956.
[24]
L. Miao, T. F. N. Kwong, and P. Y. Qian, “Effect of culture conditions on mycelial growth, antibacterial activity, and metabolite profiles of the marine-derived fungus Arthrinium c.f. saccharicola,” Applied Microbiology and Biotechnology, vol. 72, no. 5, pp. 1063–1073, 2006.
[25]
R. H. Hassegawa, M. C. M. Kasuya, and M. C. D. Vanetti, “Growth and antibacterial activity of Lentinula edodes in liquid media supplemented with agricultural wastes,” Electronic Journal of Biotechnology, vol. 8, no. 2, pp. 212–217, 2005.
[26]
D. K. Gogoi, H. P. Deka Boruah, R. Saikia, and T. C. Bora, “Optimization of process parameters for improved production of bioactive metabolite by a novel endophytic fungus Fusarium sp. DF2 isolated from Taxus wallichiana of North East India,” World Journal of Microbiology and Biotechnology, vol. 24, no. 1, pp. 79–87, 2008.
[27]
S. Trupkin, L. Levin, F. Forchiassin, and A. Viale, “Optimization of a culture medium for ligninolytic enzyme production and synthetic dye decolourization using response surface methodology,” Journal of Industrial Microbiology and Biotechnology, vol. 30, no. 12, pp. 682–690, 2003.
[28]
B. Sultana, F. Anwar, and R. Przybylski, “Antioxidant activity of phenolic components present in barks of Azadirachta indica, Terminalia arjuna, Acacia nilotica, and Eugenia jambolana Lam. trees,” Food Chemistry, vol. 104, no. 3, pp. 1106–1114, 2007.
[29]
S. Bounatirou, S. Smiti, M. G. Miguel et al., “Chemical composition, antioxidant and antibacterial activities of the essential oils isolated from Tunisian Thymus capitatus Hoff. et Link.,” Food Chemistry, vol. 105, no. 1, pp. 146–155, 2007.
[30]
F. Abas, N. H. Lajis, D. A. Israf, S. Khozirah, and Y. U. Kalsom, “Antioxidant and nitric oxide inhibition activities of selected Malay traditional vegetables,” Food Chemistry, vol. 95, no. 4, pp. 566–573, 2006.
[31]
M. Femenía-Ríos, C. M. García-Pajón, R. Hernández-Galán, A. J. Macías-Sánchez, and I. G. Collado, “Synthesis and free radical scavenging activity of a novel metabolite from the fungus Colletotrichum gloeosporioides,” Bioorganic and Medicinal Chemistry Letters, vol. 16, no. 22, pp. 5836–5839, 2006.
[32]
L. M. Cheung and P. C. K. Cheung, “Mushroom extracts with antioxidant activity against lipid peroxidation,” Food Chemistry, vol. 89, no. 3, pp. 403–409, 2005.
[33]
S. S. Ali, N. Kasoju, A. Luthra et al., “Indian medicinal herbs as sources of antioxidants,” Food Research International, vol. 41, no. 1, pp. 1–15, 2008.
