Isolation and Characterization of Flavonoid C‑glycosides from Prosopis glandulosa Torr. Leaves

Background: Prosopis glandulosa Torr. (Fabaceae) is native to Africa, America, and Asia. In India, it is abundantly found in southern parts. The plant is reported to contain polyphenols, flavonoids, mesquitol‑catechin dimers, indolizidine alkaloids, and triterpenes, imparting antitumor, antimicrobial, anti‑infective, and anti‑parasitic activities. Aim: The present study deals with the isolation and characterization of flavonoid C‑glycosides from P. glandulosa Torr. leaves. Materials and Methods: P. glandulosa leaves were subjected to hot aqueous extraction at 90°C–100°C to yield crude aqueous extract (PGA). PGA was fractionated and then subjected to chromatography over Diaion® HP‑20 column and semi‑preparative high‑performance liquid chromatography to provide flavonoid C‑glycosides. Results: We have identified and characterized vicenin‑2/isomer and schaftoside (s) from P. glandulosa leaves through liquid chromatography‑electron spray ionization‑mass spectrometry/ mass spectrometry (LC‑MS/MS) and nuclear magnetic resonance. LC‑MS/MS chromatogram displayed peaks at retention time of 9.69 and 10.37 with m/z 594 and major fragments at m/z 473 [M‑H‑120]− (loss of glucose unit) for “vicenin‑2/isomer.” Interestingly, five major peaks were observed with retention times of 10.75, 11.17, 11.92 (major), 12.92, and 13.32 corresponding to the same mass of m/z 564 with major fragments at m/z 473 [M‑H‑90]− (loss of arabinose unit) and 443 [M‑H‑120]− (loss of glucosyl unit), together termed as “schaftosides.” Conclusion: To the best of our knowledge, this is the first report on flavonoid C‑glycosides (vicenin‑2/isomer and Schaftosides) from P. glandulosa leaves which may act as chemomarker(s) for the standardization and quality control of this plant.