Phytochemical and biological properties of the water extract from roots and leaves of Lactuca longidentata, an endemic phytoalimurgic (food) species of Central Sardinia (Italy)

Lactuca longidentata is an endemic species present in Sardinia (Italy). The present study aimed to investigate the phytochemical composition and biological properties of leaf and root water extracts obtained from L. longidentata. Phenolic composition, scavenging/reducing, and enzyme inhibition properties were investigated. In vitro studies, namely allelopathy assay, brine shrimp and Daphnia magna toxicity tests, and viability assay on C2C12 myocytes were also conducted for defining the limits of biocompatibility. Antimicrobial properties were studied against Gram + and Gram − bacteria, yeasts, dermatophytes, and fungi isolated as contaminants of public swimming pools. Colorimetric analyses indicated that leaves are richer than roots in total phenols and flavonoids, whereas chromatographic analyses confirmed that leaves are richer in catechins and chicoric acid. The leaf extract was also the most effective as antiradical agent. Within the limits of biocompatibility (concentration <200 µg/mL), the leaf extract was particularly effective in reducing the growth of Escherichia coli and Trichophyton tonsurans (MIC < 10 µg/mL). However, a similar potency was showed by the root extract against the swimming pool fungal species Rhodotorula, Auxarthron ostraviense, and Trichothecium roseum. Overall, the present study suggested new scenarios for this botanical resource, traditionally used as a food, but underestimated as a health-promoting agent.