ABIOTIC STRESS EFFECTS ON PHYTOCHEMICALS AND ANTIOXIDANTS OF C. SPECIOSUS, AND BIOACTIVITY PROFILING (ANTIDIABETIC AND ANTIBIOTIC) IN HEALTHY PLANTS

Abstract

Abiotic stress refers to unfavourable environmental conditions that affect plant growth and survival by disrupting physiological processes, causing oxidative damage and cellular dysfunction. Plants respond to abiotic stress via adaptive mechanisms, such as altering metabolic pathways and producing stress-related proteins. This study explores the morphological changes and quantitative and qualitative evaluation of phytochemical composition of C. speciosus under abiotic stress conditions, including drought, high salinity, flood and nutrient deficiency, to investigate its adaptive mechanisms, while also investigating the antibacterial and anti-diabetic properties of C. speciosus to evaluate its potential medicinal applications. The stress-induced plants exhibited stress-specific symptoms such as leaf senescence, yellowing, and curling, resulting from oxidative stress and disrupted metabolic pathways. The qualitative analysis of the aqueous extract of C. speciosus revealed changes in phytochemicals such as alkaloids, phenols, flavonoids, coumarins, saponins, cardiac glycosides, tannins, terpenoids and steroids under varying stress conditions compared to the control plants. In the quantitative analysis, the moisture content was high in control plants (92.80%), whereas plants subjected to high salinity stress showed the lowest moisture content (58.99%). Flooding stress (29.58 mgGAEg-1) significantly increased the total phenolic content compared to control plants and other stress conditions. Flooding (5.119 mgQEg-1), high salinity (7.335 mgQEg-1) and nutrient deficiency (9.73 mgQEg-1) conditions elevated total flavonoid content compared to the control plant. Total antioxidant capacity increased under flooding and drought (3.233 mgAAEg-1) but decreased with nutrient deficiency compared to the control plant. Flooding, high salinity and nutrient deficiency caused a decrease in total protein content. The change in the phytochemical composition highlights the plant’s strategies to combat oxidative stress and maintain homeostasis. The methanolic extract of C. speciosus exhibited selective antibacterial activity, forming 10 mm inhibition zones, inhibiting the growth of Escherichia coli, but it was found to be ineffective against Staphylococcus aureus. Additionally, the extract (3.62 mg/mL) showed promising antidiabetic potential (60.674 %), with α-amylase inhibition comparable to that of standard acarbose (62.068%), suggesting its effectiveness in managing hyperglycaemia. The outcomes provide a foundation for exploring C. speciosus as a source of bioactive compounds for pharmaceutical and agricultural applications.