Biostimulant-induced Phytochemical Changes from Moringa, Neem, Papaya, and Bitter Leaf on Dioscorea bulbifera Mini-setts

Abstract

The use of chemical agents or plant extracts on the exposed surfaces of the minisett to retard fungal, nematode and insect attack is a common practice amongst farmers. As a result, it is important to investigate the effects of these extract on the phytochemical composition of crop, as they can negatively impact it. This study evaluated the effect of aqueous extracts of Moringa oleifera, Azadirachta indica, Carica papaya and Vernonia. Amygdalinaon phytochemical composition of Dioscorea bulbifera using standard techniques. The research was conducted on the research farm at university of Port Harcourt, Port Harcourt, between November 2021 and September 2023 cropping seasons. All analysis were carried out based on standard methods. The phytochemical’s components in the Dioscorea bulbifera mature leaves grown with different treatments at 8 weeks were alkaloids were  Apoatropine 0.77-0.94mg/100g, Caffeine 0.44-0.54mg/100g, cocaine 0.013-0.017mg/100g, quinine 0.012-0.015mg/100g, glycosides were verapamil 0.013-1.47mg/100g, linsinopril 0.006-0.018mg/100g, ameodipine 0.001-0.003mg/100g, flavonoids were didymin4.87-13.01mg/100g, quercertin 0.56-1.54mg/100g, catechin 0.08-0.23mg/100g, phenolics (45) including; caffeic acid 12.4-33.1mg/100g, tannic acid 2.96-7.86mg/100g, cinnamic acid 3.57-9.53mg/100g  and organic acids were formic acid 0.21-0.57mg/100g, citric acid 0.03-0.09mg/100g, oxalic acid 0.04-0.10mg/100g. Increases in studied phytochemicals occurred across all treatments with the studied bio-stimulants. The increased phytochemical contents observed after treatments for eight weeks is suggestive that Dioscorea bulbifera, Moringa oleifera, Azadirachta indica, Carica papaya and Vernonia amygdalina could be potent plant-based bio-stimulants in sustainable agricultural practices. The findings support the use of eco-friendly, plant-based bio-stimulants as an effective strategy to boost the biochemical quality of the extracts, with potential implications for enhanced crop value, health benefits, and reduced dependency on synthetic agrochemicals.