Detection, Isolation, and 1H NMR Quantitation of the Nitrile Glycoside Sarmentosin from a Bryophyllum pinnatum Hydro-Ethanolic Extract

Bryophyllum pinnatum (Lam) Pers. (Crassulaceae) is widely used in folk medicine as leaf juice, aqueous, or hydroethanolic extracts. It is also listed as a medicinal plant in several countries such as France and Brazil. The main reported constituents are flavone glycosides, especially those with the rare 3-O-alpha-L-arabinopyranosyl-(1 -> 2)-alpha-L-rhamnopyranoside moiety. Despite several phytochemical screenings indicating the presence of cyanide derivatives or alkaloids, there are no reports of nitrogenous metabolite characterization from this plant species. Nevertheless, the occurrence and the type of such compounds are of particular interest, as they may account for some of the numerous biological activities and ethnomedicinal uses described for B. pinnatum and could be regarded as chemical/taxonomic markers. Consequently, a hydro-ethanolic extract of B. pinnatum was investigated by using UHPLC-HRMS/MS and the nitrile glucoside sarmentosin was detected for the first time within the genus Bryophyllum/Kalanchoe. Considering the wide use of B. pinnatum and its closely related species for health purposes, the target metabolite was isolated by a combination of centrifugal partition chromatography in elution/extrusion mode and MPLC in order to confirm its structure. A linear, selective, precise, fast, and reliable H-1 NMR quantitation method was then developed and validated and may become a tool for easy quality assessment of the plant species. The amount of sarmentosin was determined as 2.07% of the examined sample. Sarmentosin was also detected in Kalanchoe laciniata, confirming the occurrence of this compound within the genus.

Automated summary

Bryophyllum pinnatum is commonly used in folk medicine, with flavone glycosides as its main constituents. The nitrile glucoside sarmentosin was detected for the first time in the genus Bryophyllum/Kalanchoe, indicating a potential link to the plant's biological activities and ethnobotanical uses. Sarmentosin was also found in Kalanchoe laciniata, confirming its occurrence within the genus.