Phytochemical profiling, in vitro biological properties and in silico studies on Caragana ambigua stocks (Fabaceae): A comprehensive approach

Plant from Caragana genus have interesting potential in folklore medicines and have been explored for various pharmacological activities. The aim of this study was to probe into the chemical and biological effects of different extracts of Caragana ambigua Stocks (Fabaceae). Total phenolic and total flavonoids contents were determined using standard spectrophotometric methods, whereas, the secondary metabolites composition was established by ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) analysis. Antioxidant potential was estimated via 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging, ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), phosphomolybdenum and metal chelating assays and the enzyme (cholinesterases, α-amylase, α-glucosidase and tyrosinase) inhibition potential were also assessed. Moreover, in silico docking studies were performed to highlight possible interactions between three major secondary metabolites and the tested enzymes. The ethyl acetate extract exhibited higher phenolic (85.87 ± 2.96 mg GAE/g) and flavonoid (66.45 ± 0.37 mg RE/g) contents, which, we propose, are responsible for its higher radical scavenging, reducing power, total antioxidant capacity and tyrosinase inhibition. The n-hexane extract showed stronger anti-cholinesterase and anti-diabetic property. Similarly, UHPLC-MS profiling of methanol and ethyl acetate extracts identified the presence of flavonoids, phenolics, alkaloids, and coumarin derivatives. Three of the dominant compounds (isobergaptene, jujubasaponin IV and phellodensin D), were docked against all enzymes and their affinity were compared. Among these compounds, phellodensin D showed highest affinity towards all the studied enzymes. It is therefore, concluded that extracts from C. ambigua showed potent antioxidant and enzyme inhibition potential with potent bioactive molecules which could open new industrial applications.