3-Aminofurostane Alkaloids from Solanum paniculatum (“Jurubeba Verdadeira”) Roots

Tania Silva,Celso Camara,Maria Agra,Telma Silva

doi:10.21577/0103-5053.20190269

Abstract

The roots of Solanum paniculatum (Solanaceae) have extensively been used in folk medicine to treat liver infections and as a diuretic. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) were used for the profiling and structural characterization of alkaloids from the roots of S. paniculatum. Sixteen 3-aminofurostane alkaloids were characterized as novel compounds. In this study, three principal alkaloids were isolated in mixture, and their structures were established by different spectroscopic methods, including 1D, 2D nuclear magnetic resonance (NMR) experiments, and the high-resolution electrospray ionization (HR-ESI)-MS analysis. The isolated alkaloids were used to explore fragmentation pathways. Compound identification was based on the exact mass and fragmentation behaviors. Two compounds were identified as new natural compounds as: (25R)-3β-amino-furost-5-en-22α,26-diol O(26)-β-D-glucopyranoside (fatimagraine) and (25R)-3β-amino-furost-22-en,26-ol O(26)-β-D-glucopyranoside (bhattacharyyaine). The unambiguous assignments of 1H and 13C NMR data and chemical correction of the structure alkaloid jurubine are reported for the first time.

Highlights

Solanum paniculatum (Solanaceae) is popularly known in Brazil as “jurubeba verdadeira”, and “jurubeba roxa”.1 This species is exclusive to South America, found in Brazil, Paraguay, and Argentina.[2]
S. paniculatum roots resulted in the characterization of 17 3-aminofurostane alkaloids by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS/MS)
Compounds 11, 12, and 17 were isolated, and their structures were established by different spectroscopic methods including 1D nuclear magnetic resonance (NMR) (1H, attached proton test (APT)), 2D NMR experiments (correlation spectroscopy (COSY), heteronuclear single quantum correlation (HSQC), and heteronuclear multiple bond correlation (HMBC)), and the high-resolution electrospray ionization (HR‐electrospray ionization interface (ESI))‐MS analysis

Summary

Introduction

Solanum paniculatum (Solanaceae) is popularly known in Brazil as “jurubeba verdadeira”, and “jurubeba roxa”.1 This species is exclusive to South America, found in Brazil, Paraguay, and Argentina.[2]. Solanum paniculatum (Solanaceae) is popularly known in Brazil as “jurubeba verdadeira”, and “jurubeba roxa”.1. S. paniculatum roots resulted in the characterization of 17 3-aminofurostane alkaloids by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS/MS). Milli-Q water (Billerica, USA) was used for the UPLC-QTOF-MS (ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry) analysis. The XEVO-G2XSQTOF mass spectrometer (Waters, Manchester, UK) was connected to the ACQUITY UPLC system (Waters, Milford, MA, USA) via an electrospray ionization interface (ESI). The MS analysis was performed on a Xevo G2 QTOF (Waters MS Technologies, Manchester, UK), a quadrupole time-of-flight tandem mass spectrometer coupled with an electrospray ionization source in positive ion mode. The aqueous acid filtrate was basified with NH4OH and left standing overnight This solution was extracted with butanol and concentrated to produce 12.8 g of the BuOH fraction. Fractions 19-21 were eluted with 80% MeOH, and 35‐42 with 100% MeOH resulting in the isolation of the compounds mixture 11/12 (7.8 mg), and 12/17 (43.7 mg)

Results and Discussion

27 Glucose 1’ 2’ 3’ 4’ 5’ 6’

Conclusions