From parasitism to bioactivity: Metabolomic profiling and biological activity evaluation of Cuscuta campestris haustoria and flowers

This study was designed to investigate the phytochemical composition, antioxidant and enzyme inhibitory activities of the haustoria and flowers of Cuscuta campestris (Convolvulaceae). Ethyl acetate, methanol and aqueous extracts were prepared. Results revealed that the highest total phenolic and flavonoids contents were accumulated in the aqueous (43.41 mg GAE/g) and methanol (73.31 mg RE/g) extracts of the haustorium. Chemical analysis by UPLC-ESI-QToF-MS revealed that the extracts, mainly those of the haustorium, were predominantly composed of 3-p-coumaroylquinic acid, chlorogenic acid, 4-feruloylquinic acid, 1-O-caffeoyl-O-rutinose ester, cuscuta propenamide 1, luteolin glucoside isomer, kaempferol, and isoquercitrin. The best antioxidant activity was mainly recorded from the haustorium (DPPH = 48.63 and 47.12 mg TE/g, p ≥ 0.05 from the methanol and aqueous extracts; ABTS = 82.78 mg TE/g from the latter; CUPRAC and FRAP = 163.64 and 87.36 mg TE/g from the methanol extract; PBD = 1.23 mmol TE/g from the ethyl acetate extract), while the flower aqueous extract displayed the highest chelating capacity (50.19 mg EDTAE/g). The highest anti-acetylcholinesterase (2.90 mg GALAE/g) and anti- butyrylcholinesterase (1.53 mg GALAE/g) activities were recorded from the ethyl acetate of the flower while the best anti-tyrosinase activity was obtained from its methanolic extract (54.70 mg KAE/g). The aqueous and ethyl acetate extracts of the haustorium showed the best inhibitory effect against the ⍺-glucosidase (1.79 mmol ACAE/g) and ⍺-amylase (0.58 mmol ACAE/g) respectively. Molecular docking and molecular dynamics simulations showed that isoquercitrin and isorhamnetin strongly interacted with cholinesterases and carbohydrate-hydrolyzing enzymes, whereas caffeoyl-syringoylquinic acid derivatives preferentially bound to butyrylcholinesterase and α-glucosidase. This work represents the first in-depth study on C. campestris and the results indicated that it may represent a promising source of bioactive compounds with potential utility in the prevention or management of oxidative stress–related disorders.