Comparative evaluation of phenolic composition, enzymes inhibition, antimicrobial virulence and chemical antioxidant activities of Atriplex halimus L. (Amarthaceae) from mining and non-mining sites in Eastern Algeria.

Abstract

Mining dust can enter plant tissues and impair phytosynthesis, nutrient uptake and production of secondary metabolites. This study investigates a comparative study of phenolic compounds and bioactivities of Atriplex halimus from mining (Ouenza) and non-mining (Tebessa City) sites. Chemical profiling and bioassays suggest that mining-associated environmental stress, including iron dust exposure, influences the plant’s metabolism. HPLC-DAD phenolic profile revealed that amounts of p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and taxifolin decreased with exposure to mining dust while syringic acid, vanillin, ferulic acid, quercetin, rutin, luteolin and catechin increased upon exposure to mining dust. The antimicrobial activity of the samples was low to moderate and varied from 0.3125 to 5 mg/mL.
The plant fractions equally inhibited biofilm formation against S. aureus, E. coli and C. albicans with S. aureus being the most susceptible. All fractions inhibited violacein production in C. violaceum CV12472 at MIC, MIC/2 and MIC/4 and equally showed quorum-sensing inhibition zones against C. violaceum CV026, with the fractions from non-mining sites being more potent. The plant fractions exhibited inhibitory effects varying from 17.95 ± 0.20 to 52.70 ± 0.31% at 200 µg/mL on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), suggesting their potential in relieving symptoms of Alzheimer’s disease. The fractions exhibited a low to moderate inhibition of α-glucosidase and α-amylase ranging from 13.44 ± 0.88 to 49.41 ± 0.65% at 200 µg/mL. Interestingly, the mining iron dust seems to have induced oxidative stress which triggered a compensatory increase in phenolic antioxidants, as confirmed by cyclic voltammetry. This research gives insights into the understanding of plant resilience in polluted environments, and effects on plant metabolism.