EFFECT OF Nicotiana sylvestris (Speg. and Comes) LEAF EXTRACT ON THE GROWTH of Aspergillus niger on Allium cepa L. in vitro

Abstract

This study evaluated Nicotiana sylvestris (Speg. & Comes) leaf extract as a potential bio-control agent against Aspergillus niger infestation on Allium cepa L. in vitro. Nicotiana sylvestris was screened for vitamins, phytochemicals, proximate, and mineral composition. Aqueous extracts were prepared from fresh N. sylvestris at 20%, 40%, 60% and 80% concentrations, respectively.  Fungal inhibition experiments were done using these doses of N. sylvestris leaf extract to examine its influence on A. niger growth.  The study showed that N. sylvestris contain higher (17.30%) percentage of fat soluble vitamins compared to water soluble vitamins at 2.06% while the phytochemicals varied as follows: total alkaloids profile (15.673 g/100g), total flavonoids profile (74.247 g/100g),  total phenolic profile (42.665 g/100g), total glycosides profile (14.358 g/100g), total organic acid profile (6.831 g/100g), total fatty acid profile (87.403 g/100g), phytate (7.207%), trypsin-inhibitor (6.265%), oxalate (5.509%), saponin (3.434%) and tannin (2.641%). The proximate compostion and minerals of N. sylvestris varied. The 80% concentration of N. sylvestris leaf extract achieved 75.42% mean growth percentage inhibition of A. niger while the lowest concentration 20% exhibited 100%, indicating no growth or inhibition at all. This suggests that the phytochemical constituents of N. sylvestris may likely be responsible for the antifungal properties observed. The data demonstrates promising anti-fungal capabilities of N. sylvestris as anti-fungal agent against A. niger on onions for a short-term preservation. These findings demonstrate the potential of N. sylvestris as a phyto-fungicide and highlight its use for limited control of fungal pathogens in onion cultivation.