Phenolic Composition, Antioxidant Capacity, and Antibacterial Activity of Hydroalcoholic Extracts from Cupressus sempervirens L. and Cupressus arizonica L. Against Pseudomonas savastanoi pv. Savastanoi
DOI:
https://doi.org/10.64252/vjakn717Keywords:
Cupressus arizonica ; cupressus sempervirens; pseudomonas savastanoi ; polyphenols ; antioxidant activity ; antibacterial activity ; biocontrol ; bioproducts.Abstract
The growing demand for environmentally friendly alternatives to synthetic pesticides has. intensified interest in plant-derived bioactive compounds for sustainable disease management. In this context, the present study investigated the antioxidant and antibacterial properties of hydroalcoholic leaf extracts obtained from Cupressus sempervirens L. and Cupressus arizonica L. against the phytopathogenic bacterium Pseudomonas savastanoi pv. savastanoi ; the causal agent of olive knot disease.
Hydroalcoholic extraction (70% methanol) yielded 15.34% and 11.31% for C. sempervirens and C. arizonica, respectively. Quantification of total phenolic compounds using the folin-ciocalteu method revealed high polyphenol contents in both species, reaching 2.128 and 2.114 mg gallic acid equivalents (GAE)/g extract for C. sempervirens and C. arizonica, respectively, with no significant difference between them.
The antoxidant activity was evaluated using the DPPH radical scavenging assay. Both extracts exhibited strong antiradical activity, which increased as concentration decreased. At 0.115 g/ml, DPPH reduction percentages reached 78.36% for C. sempervirens and 91.09% for C. arizonica. Probit analysis estimated IC values of 0.297 and 0.512 g/ml for C. sempervirens and C. arizonica, respectively.
Antibacterial activity was assessed using the agar disc diffusion method. Both extracts effectively inhibited the growth of P. savastanoi pv. Savastanoi, with inhibition zones increasing proportionally to extract concentration. Probit regression analysis estimated LD50 values of 3.44 g/mL and 1.88 g/Ml and LD99 values of 62.72 g/mL and 14.15 g/mL for C. Sempervirens and C. arizonica, respectively.
Overall, the results demonstrate that both cypress species represent promising natural sources of bioactive compounds with antioxidant and antibacterial properties. Considering extraction yield and lethal dose requirements, C.arizonica appears to be the more economically advantageous species for the developement of plant-based bioproducts targeting olive knot disease management.
