Biostimulants with Protective Effects: A Tryptamine-Enriched Fraction from Neltuma nigra and its Impact on Catalase Activity, Lipid Hydroperoxides and Total Antioxidant Activity in Soybean Seedlings
摘要
Biostimulants with protective effects include plant extracts, which are considered a sustainable alternative to synthetic fungicides. In this study, we evaluated the effects of an alkaloid fraction obtained from the leaves of Neltuma nigra on soybean seedlings. Soybean seedlings were grown in the greenhouse. Catalase activity was assessed in vitro by adding the alkaloid fraction to enzyme extracts, whereas in a separate greenhouse assay seedlings were treated with the alkaloid fraction at 50, 150, or 600 µg leaf⁻1 and lipid hydroperoxides, and total antioxidant capacity were measured in the treated tissues. The antifungal efficacy of the alkaloid fraction was evaluated based on the percentage of seedling lesion inhibition. Results showed that the alkaloid fraction inhibited catalase activity in a dose-dependent manner, similar to the effect observed with the known catalase inhibitor hydroxylamine. In addition, total antioxidant capacity decreased compared to the control, whereas lipid hydroperoxide levels remained unchanged. These findings suggest that the alkaloid fraction may serve as a potential ingredient for phytogenic pesticides, offering an environmentally friendly complement to synthetic fungicides. Overall, this study contributes to a better understanding of the role of the biostimulants with protective effects in crops protection.