Antifungal Compound Isolated from Leaf of Cassia fistula L. (Ngu Shwe Wah)

In the investigation of antifungal compound against rice plantpathogenic fungus Magnaporthe grisea, five kinds of plants grown in Pathein area were utilized. These plant parts such as leaves, barks and stems were extracted with ethanol, methanol, and acetone solvents and tested the antifungal activity on M. grisea by paper diffusion assay. In this study, methanol extract of leaf of Cassia fistula L. (Ngu Shwe Wah) showed highly activity on Magnaporthe grisea (24.1 rom inhibitory zone). Therefore, methanol extract of leaf Cassia fistula L. was selected for further investigations such as isolation, purification and biological properties. In the isolation and purification, silica gel column chromatography, CIS gel column chromatography, silica gel column rechromatography and Sephadex LH-20 gel chromatography were undertaken with using suitable ratios of organic solvents. MICs of this compound is 0.156 µg/ml on M grisea, 0.3125 µg/ml on Cladosporium sp. and Alternaria alterna, and 0.625 µg/ml on Aspergillus flavus, A. fumigatus, Curvularia oryzae, and Fusarium oxysporum, This compound affects on the growth of M grisea at a concentration of 0.156 µg/ml; any further increase in its concentration above 0.156 µg/ml resulted in a more suppressive effect on growth. At a concentration of 0.6.25 µg/ml, cell lysis was observed that indicating that this plant compound cut acts as a fungicidal agent