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.
