Previously undescribed pyridyl-steroidal glycoalkaloids and 23S,26R-hydroxylated spirostanoid saponin from the fruits of Solanum violaceum ortega and their bioactivities.

Three previously undescribed pyridyl-steroidal glycoalkaloids, solanindiosides A‒C, one rare 23 S ,26 R -hydroxylated spirostanoid saponin, and two steroidal alkaloid aglycones, solanindins A and B, derived from the acid hydrolysis of solanindiosides A‒C, were isolated from the fruits of Solanum violaceum , together with five known analogues, including two rare steroidal glycosides, two lignans and a diterpene. Structurally, they comprise a 16 β -methoxy-23-deoxy-22,26-epimino-cholest-type skeleton moiety, and a 16 β -methoxy-3,23-dideoxy-22,26-epimino-cholest-3,5-dien derivative. The hitherto undescribed structures were established on the basis of extensive spectroscopic analyses. Configurations of sugar moieties were resolved by chemical derivations. Solanindiosides A‒C, (22 R ,23 S ,25 R ,26 R)-spirost-5-ene-3 β ,23,26-triol3- O - β - d -xylopyranosyl-(1→3)- β - d -glucopyranoside, solanindins A and B, and (1 S ,2 S)-1-(4-hydroxy-3-methoxyphenyl)-2-[2-methoxy-4-[(2 S ,3 R ,4 R)-tetrahydro-4-[(4-hydroxy-3-methoxyphenyl)methyl]-3-(hydroxymethyl)-2-furanyl]phenoxy]-1,3-propanediol were evaluated for their cytotoxic and antibacterial activities. (1 S ,2 S)-1-(4-hydroxy-3-methoxyphenyl)-2-[2-methoxy-4-[(2 S ,3 R ,4 R)-tetrahydro-4-[(4-hydroxy-3-methoxyphenyl)methyl]-3-(hydroxymethyl)-2-furanyl]phenoxy]-1,3-propanediol showed the most potent cytotoxic activity against MCF-7 cells (IC 50 = 4.386 ± 0.098 μM), while solanindin B displayed some inhibitory effects against Staphylococcus aureus Rosenbach with MIC 50 value of 37.32 ± 0.793 μM. In addition, (1 S ,2 S)-1-(4-hydroxy-3-methoxyphenyl)-2-[2-methoxy-4-[(2 S ,3 R ,4 R)-tetrahydro-4-[(4-hydroxy-3-methoxyphenyl)methyl]-3-(hydroxymethyl)-2-furanyl]phenoxy]-1,3-propanediol induced dose dependent apoptosis effect in MCF-7 cells. [Display omitted] • Three undescribed pyridyl-steroidal glycoalkaloids, solanindiosides A-C were isolated. • One rare 23S,26R-hydroxylated spirostanoid saponin was obtained. • Acid hydrolysis gave two undescribed aglycones, solanindins A and B. • A known lignan showed cytotoxicity on MCF-7 cells (IC 50 = 4.39 ± 0.10 μM). • Solanindin B showed inhibitory effects on Staphylococcus aureus. [ABSTRACT FROM AUTHOR]