Impact of Chitosan and Folic Acid on Growth, Leaf Qualities, and Antioxidant Compounds of Purslane (Portulaca oleracea L.)

Purslane (<em>Portulaca oleracea</em> L.) is a nutrient-rich leafy vegetable valued for its nutritional and medicinal properties. Improving its quality and bioactive compounds through eco-friendly inputs is essential for sustainable production. This study evaluated the effects of foliar-applied chitosan and folic acid on growth, leaf quality, and antioxidant compounds of purslane. A field experiment was conducted in a randomized complete block design with chitosan (0, 50, and 100 mg l⁻¹) and folic acid (0, 25, and 50 mg l⁻¹), applied singly or in combination. The combined treatment of 100 mg l⁻¹ chitosan and 50 mg l⁻¹ folic acid was the most effective, producing plant height of 36.7 cm, leaf area of 17.8 cm², and 92 leaves plant⁻¹, representing 27 to 30% increases over the control. Fresh weight reached 91.2 g plant⁻¹, a 26% improvement. Leaf quality improved as total chlorophyll (33.2 mg 100 g⁻¹ FW) and carotenoids (5.46 mg 100 g⁻¹ FW) rose by 13% and 10%, respectively. Antioxidant levels were also enhanced: phenols (41.12 mg GAE g⁻¹ DW), flavonoids (15.91 mg RE g⁻¹ DW), tannins (20.11 mg TAE g⁻¹ DW), saponins (40.65 mg g⁻¹ DW), and ascorbic acid (55.82 mg 100 g⁻¹ FW), with 8 to 22% increases over single treatments and 12 to 31% over the control. DPPH radical scavenging activity reached 77.32%, 54% higher than the control (50.11%) and greater than single applications of chitosan (62.33%) or folic acid (69.58%), confirming a synergistic effect. These results suggest that chitosan and folic acid can serve as cost-effective and eco-friendly biostimulants to enhance purslane production and nutritional value under sustainable agriculture.