Chemical Composition and Bioactivities of Sideritis libanotica Labill subsp. Libanotica: LC–HRMS Phytochemical Profiling, Mineral Content, Antioxidant, Antibacterial, and Neuroprotective–Antidiabetic Enzyme Inhibitory Potentials

Sideritis libanotica Labill. subsp. libanotica (SLL) is an herbal tea used for colds, coughs, and digestive system disorders. SLL has higher antioxidant activity in methods (µg/mL) like 1,1-diphenyl-2-picrylhydrazyl (DPPH•) (40.912 ± 0.170), ABTS•+ (14.61 ± 0.331) scavenging activity, and Fe3+ (0.872 ± 0.052) and Cu2+ (0.840 ± 0.013) reduction capacity compared to other Sideritis species. It is rich in essential minerals, such as Ca, Mg, and P, with the highest content of mineral K (14 203.97 mg/kg). Zone values in the range of 9–11 mm were obtained from Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Pseudomonas putida, and Klebsiella pneumoniae strains, which is an indicator that the plant has antibacterial activity. Among 33 secondary metabolites, sinapinic acid, rutin, and hispidulin have high values, whereas the one with the highest value is verbascoside (274 483 mg/kg), a pharmacologically active compound. It showed an inhibitory effect (mg/mL) on some enzymes targeting neurodegenerative and metabolic disorders. (IC50; acetylcholinesterase [AChE]: 0.065, butyrylcholinesterase [BChE]: 0.086, α-glucosidase: 0.014).