Characterization and fragmentation mechanism of 3-aminospirostane alkaloids from roots of Solanum paniculatum L. with hepatoprotective activity.

Abstract

RATIONALE\nSolanum paniculatum L., popularly known as jurubeba, has traditionally been used in brazilian folk medicine for liver diseases, however there is a lack about the chemical characterization, particularly of 3-aminospirostanes alkaloids. This work aimed to characterize the alkaloids by LC/MS/MS supported by molecular-network and theoretical calculations as well as evaluate its contribution in hepatoprotective activity.\n\n\nMETHODS\nS. paniculatum roots were collected and macerated with MeOH/H2 O (8:2) obtaining the crude extract (SP-CE). From this, partition using EtOAc with pH variation yielded the alkaloidic fraction (SP-AF). Both were evaluated in the acute liver injury model (100 and 200 mg/kg), after intraperitoneal administration of carbon tetrachloride (CCl4 ) in mice. AST (aspartate transaminase) and ALT (alanine transaminase) serum levels were investigated, as well as the histopathological characteristics. SP-CE and SP-AF were analyzed by LC/MS/MS, using a quadrupole/time-of-flight and ion-trap systems. The alkaloids annotated by the GNPS molecular network had their structures defined by gas-phase ionization and fragmentation reaction supported by theoretical calculations.\n\n\nRESULTS\nThe SP-CE and SP-AF decreased the ALT serum levels compared with the negative control. The group treated with SP-CE (at the highest dose) demonstrated a significant decrease of ALT. Hepatic cell degeneration decrease was observed mainly at the highest dose of the treatment. Detailed ESI-MS/MS data allowed us to identify alkaloids not previously reported, propose their gas-phase reactions and to redefine the initial open ring fragmentation mechanism of the steroidal alkaloids with the jurubidine moiety.\n\n\nCONCLUSION\nThese results allowed us to identify seven steroidal alkaloids from jurubeba (Solanum paniculatum L.) and redefine the initial mechanism of fragmentation. A significant hepatoprotective effect was also demonstrated, corroborating its traditional use.