Antimicrobial and antioxidant activities of selected Malaysian Basidiomycetes grown in solid substrate

M. Rajalingam, Pavalamalar (2008) Antimicrobial and antioxidant activities of selected Malaysian Basidiomycetes grown in solid substrate. Masters thesis, University of Malaya.

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Secondary metabolites are known to contribute to the biological properties such as antimicrobial and antioxidant activities in fungi. In this study, twenty Basidiomycetes selected from the families Agaricaceae, Coprinaceae,Lentinaceae and Tricholomataceae were grown on rice as the solid substrate to obtain mycelial biomass. The methanolic extracts of the mycelial biomass were analysed for antimocrobial and antioxidant properties. The Basidiomycetes exhibited varying degrees of inhibitory effect on the Gram positive and Gram negative bacteria. In the inhibition against Gram positive bacteria the biggest zone was observed in Lentinus squarrosulus(KUM50016) with a diameter of 23.0 ± 1.0 mm from family Lentinaceae for Staphylococcus aureus, Mycena sp. (KUM50071) with 20.0 ± 0.2 mm from Tricholomataceae against Bacillus subtilis and Trogia sp. with 22.0 ± 0.3 mm inhibition against Bacillus cereus. As for Gram negative bacteria the highest inhibition was seen in Marasmiellus sp. (KUM50064) with 26.0 ± 0.0 mm from the family Tricholomataceae against Pseudomonas aeruginosa, Leucocoprinus fragillissimus (KUM50074) inhibited Proteus vulgaris with a zone of 16.0 ± 0.0 mm and Escherichia coli was inhibited by Trogia sp. (KUM50056) and Psathyrella sp. (KUM50069) with a zone of 19.0 ± 0.0 mm. Most fungal biomass from the family Tricholomataceae showed inhibition against the fungal species tested. Marasmiellus sp. (KUM50064) gave the biggest inhibition zone of 19.0 ± 0.0 mm against all three fungal species that were the Saccharomyces pombe, Candida albicans and Candida parapsilosis. Their antioxidant activities were determined using the ferric reducing antioxidant power (FRAP) assay and the inhibition of lipid peroxidation reaction given in malondialdehyde assay (MDA) and the total phenolic content (TPC) were measured. The highest value in the FRAP assay was given by L. squarrosulus (KUM50016) with a value of 1040.42 ± 66.64 7mol/g. The malondialdehyde-thiobarbituric acid (MDA-TBA) assay showed inhibition against lipid peroxidation by L. squarrosulus (KUM50016) with a value of 1.32 ± 0.14 7mol/L. The highest value for total phenolic content was shown by Psathyrella sp. (KUM50007) with 324.25 ± 40.43 DW mg/g and L. squarrosulus (KUM50016) gave a value of 196.78 ± 5.99 DW mg/g. All twenty Basidiomycetes mycelia biomass extracts were put through a preliminary brine shrimp toxicity bioassay. All mycelia extracts tested were found to be non-toxic as the high extract concentration of 50 mg/ml to 600 mg/ml were needed to cause more than 50% mortality in the Artemia salina nauplii. L. squarrosulus (KUM50016) which exhibited excellent antimicrobial and antioxidant properties was found to be non-toxic and was further optimized. Different types of rice such as white polished rice, parboiled rice and brown rice were further supplemented with nitrogen sources such as yeast and rice bran. The mycelia biomass grown on brown rice added with yeast and bran gave the highest value of 1240.00 ± 80.50 7mol/g of FRAP, 1.31± 0.0.65 7mol/L of MDA value and 332.50 ± 6.90 DW mg/g of total phenolic content. Analysis of the nutritional composition of the extract gave good values of magnesium which was 1893ppm compared to the uninoculated substrate with 412ppm. Iron was increased 865.71%, zinc increased 1383.33% and manganese increased 1103.13%. There were also increase in the quantity of Vitamin B1, Protein, Fiber, calcium and selenium. Thus, the mycelia of L. squarrosulus (KUM50016) is suitable to be used as an additive in the food, cosmetic and pharmaceutical products. It may have broad impact as a biocatalyst, therapeutic product as well as prophylactic product.

Item Type: Thesis (Masters)
Subjects: Q Science > Q Science (General)
Date Deposited: 31 Jul 2013 03:13
Last Modified: 31 Jul 2013 03:13

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