Antioxidant Activity and Phytopathogenic Control of Extracts and Fraction from Struthanthus calophyllus A.C.Sm. (Loranthaceae)

Abstract

Phytopathogenic microorganisms cause oxidative stress in host plants, thus affecting agricultural crops. Such stress could be controlled by antioxidant compounds from parasitic plants, given their antioxidant power. This article reports an evaluation of Struthanthus calophyllus antimicrobial activity and antioxidant mechanism by testing different polarity extracts. Antimicrobial activity was evaluated against phytopathogens bacteria (e. g., Erwinia, Pectobacterium, Xanthomonas) using the agar diffusion method. Pectobacterium and Xanthomonas presented growth inhibition zones similar to streptomycin control. Antioxidant activity was determined by measuring total phenol content, DPPH⋅, and ABTS⋅+ radicals‐scavenging inhibition percentage (IP). Most polar extracts presented 76,9–95,9 % IP, which correlates with its phenolic content. Besides, Nuclear Magnetic Resonance in a V14‐1 sub‐fraction from stem ethanolic extract, chose one for highest yield percentage, highest metabolites presence, and antimicrobial activity, showed triterpenic compounds mixture (α‐amyrin, β‐amyrin and 24‐methylenecycloartanol). Findings in this study are among the first reports for S. calophyllus, even the chemical characterization, that confirm its strong antioxidant and antibacterial activities. Further molecular composition research about parasitic plants could show how unknown compounds may combat pathogenic microorganisms.

Targeted metabolite profiling of Salvia rosmarinus Italian local ecotypes and cultivars and inhibitory activity against Pectobacterium carotovorum subsp. carotovorum

“…The activity of the tested antibiotic ampicillin against the same strain was several orders of magnitude higher than extracts and pure compounds with a concentration activity value below 1 μg/mL. This result, compared with literature data ( Ashmawy et al., 2014 ; Shaheen and Issa, 2020 ; Suaza-Gaviria et al., 2023 ), led to the assessment of a low antimicrobial activity of the selected extracts and pure compounds against the strain of P. carotovorum subsp. carotovorum .…”

“…Plant extracts and compounds with the potential to prevent soft rot damage were reported ( Yangui et al., 2013 ; Ashmawy et al., 2014 ; Sánchez-Hernández et al., 2023 ; Suaza-Gaviria et al., 2023 ). Among them, essential oils are well-known for their antimicrobial activity, and their possible application as coatings in storage and as preventive treatments against soft rot was evaluated ( Zheng et al., 2013 ; Purnavab et al., 2015 ; Hajian-Maleki et al., 2019 ).…”