Antifungal Activity and In Silico Study of Phyllanthus Amarus Ethanolic Leaf Extract against Pests of Stored Grains. Nigerian Journal of Post-Harvest Research, 3(4), 60-76

The persistence of synthetic pesticides in the environment and their toxic residues in food pose significant health risks, necessitating the pursuit of safe and eco-friendly green alternatives in postharvest management of stored grains. The antifungal efficacy of Phyllanthus amarus ethanolic leaf extract against Aspergillus flavus, Fusarium spp., and Penicillium spp. in stored maize and cowpea was evaluated in this report. The extract was screened for the presence of phytoconstituents. The results revealed the presence of phenols, tannins, flavonoids, alkaloids, and other bioactive compounds, while the GC-MS analysis identified 18 specific compounds. Antifungal activity was assessed using an in vitro food poisoning assay and in vivo storage studies. The results of the in vitro assay showed 85.3% inhibition against A. flavus, 83.7% against Fusarium spp., and 81.5% for Penicillium spp. The positive control demonstrated significantly lower inhibition, confirming the efficacy of P. amarus bioactive compounds. In vivo storage studies showed that the extract maintained fungal counts at 1.2–1.8 × 10⁶ cfu/g, whereas untreated samples reached 8.5 × 10⁶ cfu/g for A. flavus. Four phytoconstituents from the GC-MS result of the ethanolic extract of the Phyllanthus amarus leaves were docked against lanosterol 14-alpha demethylase (4LXJ), with Propiconazole as the standard ligand. Hinokinin was identified as the hit ligand, exhibiting the highest binding affinity compared to the other ligands. The outcome of this study suggests that P. amarus is a promising bio-preservative for grain storage, and its antifungal activity is attributed to the activity of the phytoconstituents, with hinokinin serving as the lead compound.