Enhancement of Antioxidant Potential in Musa Accuminata using Humic Acid

Humic Acid is the most important constituent of a completely decomposed organic matter. Leonardite is found to be the best source for Humic Acid and it is extracted by using alkali solution. Humic Acid scientifically proves to be a free radical scavenger. The study determines that Humic Acid (HA) is used to enhance stress tolerance in plant tissue culture. The induction of the antioxidant system [polyphenol, Catalase (CAT), Superoxide dismutase (SOD),Ascorbate peroxidase (APX) and Glutathione S Transferase (GST)] and also the elevation of the content of the enzymes show that the noted changes provoked the treatment of Humic Acid to Musa accuminata. Humic acid exposed plants (GWO4 –HU) were found to exhibit only 55 µg of GAE g/dw while native plant (GWO4 – NA) exhibited 147.5 µg of GAE g/dw. The increase of polyphenols in the native may be due to the exposure of roots to the heavy metals that are present in activated charcoal used in rooting medium or due to metal ions in water used. Superoxide anion is one of the most representative free radicals. Both the ethanolic extracts of GWO4-HU and GWO4-NA showed the maximum decolourization at 41.75% and 30.94% at a maximum concentration of 1600 µg/ml with the IC50 value 334±0.001 and 247.52±0.050 respectively. In this work, a slight increase in the CAT activity is observed in humic acid exposed plants than native plants. GWO4-HU exhibited 0.042 and GWO4-NA exhibited only 0.038. The raised GST activity is suggested to be a marker for the enhanced antioxidant activity in HA exposed plants. Increased GST activity is found in GWO4-HU of about 557.06 U/mg GST while GWO4-HU exhibit a specific activity of 583.2U/mg GST. APX activity found in GWO4-HU showed higher specific activity of about 408.58 U.mg-1 APX while GWO4-NA showed only 379.6 U.mg-1 APX.