Evaluation of the effect of Cassia surattensis Burm. f., flower methanolic extract on the growth and morphology of Aspergillus niger.

BACKGROUND AND AIM Cassia (C.) surattensis Burm. f. (Leguminosae), a medicinal herb native to tropical equatorial Asia, was commonly used in folk medicine to treat various diseases. The aim of the present study is to investigate the effects of methanolic flower extract of C. surattensis against Aspergillus (A.) niger. MATERIALS AND METHODS Antifungal activity of C. surattensis flower extract was studied by using agar disc diffusion method, broth dilution method, percentage of hyphal growth inhibition and scanning electron microscopy (SEM) observation. RESULTS The extract exhibited good antifungal activity with zone of inhibition 15 mm and minimum inhibitory concentration (MIC) 6.25 mg/ml. The flower extract exhibited considerable antifungal activity against A. niger with a IC50 of 2.49 mg/ml on the hyphal growth. In scanning electron microscopy (SEM) squashed, collapsed, empty and deformation of hyphae were the major changes observed. Shrunken conidiophores were the obvious alteration on the spores. Morphological alterations observed on A. niger caused by the flower extract could be the contribution of chemical compounds present in the Cassia flower. Phytochemical screening reveals the presence of carbohydrate, tannins, saponins and phenols in the extract. The amount of tannin, total phenolics and flavonoids were estimated to be 55.14 ± 3.11 mg/g, 349.87 ± 5.41 mg/g gallic acid equivalent and 89.64 ± 3.21 mg/g catechin equivalent respectively. CONCLUSIONS C. surattensis flower extract potently inhibited the growth of A. niger and are, therefore, excellent candidates for use as the lead compounds for the development of novel antifungal agents.