Preliminary investigation of kinetin, polyethylene glycol, iron sulphate, and water priming effects on the phytochemical accumulation and antimicrobial activity of Corchorus trilocularis L

Introduction This study preliminarily investigated how seed priming with kinetin (K), polyethylene glycol (PEG), iron sulphate (FeSO 4 ), and water (W) can modulate phytochemical accumulation, antioxidant capacity, and antibacterial activity of Corchorus trilocularis across vegetative and flowering growth stages. C. trilocularis was selected due to its reported nutritional and medicinal importance. Methods Methanolic leaf extracts were analysed using standard phytochemical, antioxidant, and antibacterial assays. Results Multivariate analysis revealed that both priming treatment and growth stage significantly influenced phytochemical accumulation (p< 0.001). Phytochemical levels were generally higher at the flowering stage. FeSO 4 priming consistently produced the greatest phytochemical accumulation, increasing flavonoids (70%), phenolics (42-50%), and tannins (~40%) relative to the control at flowering. This enhancement may be attributed to priming-induced stress signalling, which stimulates secondary metabolite biosynthesis. FeSO 4 and PEG treatments showed 20-30% greater radical scavenging activity. Significant positive correlations were observed between priming treatments and phytochemical accumulation. A treatment-dependent antibacterial activity against Staphylococcus aureus was observed, with PEG-primed plants showing the strongest activity (MIC 0.14 mg/mL, MBC 1.18 mg/mL), followed by FeSO 4 (MIC 0.16 mg/mL, MBC 1.25 mg/mL), whereas no activity was observed against Pseudomonas aeruginosa . Discussion The lack of activity against P. aeruginosa may be associated with its Gram-negative cell wall structure and intrinsic resistance mechanisms. No antibacterial activity was observed at the vegetative stage. Overall, extracts from the flowering stage exhibited greater bioactivity than those from the vegetative stage. These findings demonstrate that seed priming and plant developmental stage are key determinants of phytochemical accumulation and bioactivity. This highlights seed priming as a strategy to enhance the pharmacological potential through optimised cultivation and harvest management.