PHYTOCHEMICAL PROFILING AND IN VITRO ANTIFUNGAL ACTIVITY OF EUCALYPTUS GLOBULUS LEAF EXTRACTS AGAINST FISH PATHOGENIC FUNGI

Abstract

The present investigation was carried out to evaluate the in-vitro antifungal potential of Eucalyptus globulus leaf extract against fish associated fungal isolates i.e. Aspergillus flavus (PP980959, PP980962), Aspergillus fumigatus (PP956955, PP980961), Alternaria alternata (PP980717), Aspergillus spp. refer to (PP980956) and Alternaria spp. (PP980711) from different aquaculture systems of Hisar district, Haryana; which were identified by using morphological, microscopic and molecular methods. E. globulus leaf extracts of aqueosus, hydroethanol and absolute ethanol consists of phytochemical viz. tannins, saponins, alkaloids, glycosides, steroids, terpenoids and anthraquinones with variable intensity among the solvents. Among all the extracts, hydroethanol extract had the highest total phenolic content (86.35 ± 2.21 mg GAE/g) and total flavonoid content (24.68 ± 0.92 mg QE/g). Subsequently, absolute ethanol and aqueous next. According to FTIR result, the presence of functional groups like phenols, alcohols, esters, ethers, carbonyl compounds, and aromatic functional groups indicates the antifungal activity. The antifungal test results revealed that the inhibition was found to be concentration-dependent as 8% and 16% extracts exhibited stronger activity as compared to 2% and 4%. The aqueous extract showed an antifungal activity with zone of inhibition values from 7-15 mm which is lower than other extracts (absolute ethanol and hydroethanol). The MIC values were lowest for absolute ethanol extract at 30-75 mg/ml, followed hydroethanol (40-90 mg/ml) and aqueous extract (45-115 mg/ml). As a whole, the finding of the study reveals that Eucalyptus globulus extract, especially absolute ethanol extract, demonstrated better antifungal activity against fish-associated fungal isolates, which may be an antifungal agent for aquaculture health management after in vivo assessment.