[Jurubin, a nitrogen containing steroidsaponin of a new structural type from Solanum paniculatum L; concerning the structure of paniculidin]

Steroidal Glycoalkaloids: Isolation, Structure, Analysis, and Biosynthesis

In recent years, the steroidal glycoalkaloids have emerged as an important class of bioactive compounds. Their occurrence in a number of foods and their diverse biological activities has encouraged the development of more efficient procedures for their isolation, purification and analysis, and more sensitive methods of detection and structure determination. This review is mainly concerned with new approaches for the characterization of these metabolites. The formation of artifacts of isolation and purification is discussed. The limited information on their biosynthesis is summarized.

New Polyhydroxylated Steroidal Saponins from Solanum paniculatum L. Leaf Alcohol Tincture with Antibacterial Activity against Oral Pathogens

Solanum paniculatum L. is widely used in Brazilian folk medicine for the treatment of liver and gastrointestinal disorders as well as for culinary purposes and beverage production. Fractionation of hydroalcoholic [ethanol (EtOH) 70%] tincture from S. paniculatum leaves led to the isolation of six new spirostanic saponins which included 6- O-α-l-rhamnopyranosyl-(1''→3')-β-d-quinovopyranosyl-(22 S,23 R,25 S)-3β,6α,23-trihydroxy-5α-spirostane (1), 6- O-β-d-xylopyranosyl-(1''→3')-β-d-quinovopyranosyl-(22 S,23 R,25 R)-3β,6α,23-trihydroxy-5α-spirostane (4), 3- O-α-l-rhamnopyranosyl-(1''→3')-β-d-quinovopyranosyl-(22 S,23 S,25 R)-3β,6α,23-trihydroxy-5α-spirostane (5), 3- O-β-d-xylopyranosyl-(1''→3')-β-d-quinovopyranosyl-(22 S,23 S,25 R)-3β,6α,23-trihydroxy-5α-spirostane (6), 6- O-α-l-rhamnopyranosyl-(1''→3')-β-d-quinovopyranosyl-(22 S,25 S)-1β,3β,6α-trihydroxy-5α-spirostane (7), and 6- O-β-d-xylopyranosyl-(1''→3')-β-d-quinovopyranosyl-(22 S,25 S)-3β,4β,6α-trihydroxy-5α-spirostane (8) together with two known spirostanic saponins (2, 3). The structures of these compounds were determined by one-dimensional (1D) and two-dimensional (2D) NMR experiments in addition to high-resolution electrospray ionization mass spectrometry (HRESIMS) analyses. The 70% alcohol tincture, used as phytomedicine, exhibited promising activities against oral pathogens, including, Steptococcus sanguinis, St. oralis, St. mutans, St. mitis, and Lactobacillus casei with minimal inhibitory concentration (MIC) values ranging from 6.25 to 50 μg/mL. The saponin fraction, nonetheless, showed lower activity against all the strains tested (from 100 to >400 μg/mL).

Solanum paniculatum L. (Jurubeba): potent inhibitor of gastric acid secretion in mice

Solanum paniculatum L. is used commonly in Brazilian folk medicine for the treatment of liver and gastrointestinal disorders. The freeze-dried aqueous extracts (WEs) obtained from distinct parts of the plant (flowers, fruits, leaves, stems and roots) were tested to determine their antiulcer and antisecretory gastric acid activities using mice. The aqueous extracts of roots, stems and flowers inhibited gastric acid secretion in pylorus-ligated mice with ED50 values of 418, 777 and 820 mg/kg body wt. (i.d.), respectively. Extracts of leaves (0.5-2 g/kg body wt., i.d.) did not affect gastric secretion, whereas fruit extracts (0.5-2 g/kg body wt., i.d.) stimulated gastric acid secretion. The stimulatory effect of the fruit extract was inhibited by pretreatment with atropine (5 mg/kg body wt., i.m.) but not with ranitidine (80 mg/kg body wt., i.p.) suggesting that the fruit extract activates the muscarinic pathway of gastric acid secretion. In contrast, administration of the root extract into the duodenal lumen inhibited histamine- and bethanechol-induced gastric secretion in pylorus-ligated mice. In addition, the aqueous extract of roots (ED50 value, 1.2 g/kg body wt., p.o.) protected the animals against production of gastric lesions subsequent to the hypersecretion induced in mice by stress following cold restraint. This effect was not reproduced when the lesions were induced by blockade of prostaglandins synthesis via subcutaneous injection of indomethacin. Thus, antiulcer activity of the plant extracts appears to be related directly to a potent anti-secretory activity. No toxic signs were observed following administration of different extracts up to 2 g/kg body wt., p.o. Collectively, the results validate folk use of Solanum paniculatum L. plant to treat gastric disorders.

Furostanosides from Asparagus filicinus roots

Two furostanosides have been isolated from an ethanolic extract of the roots of Asparagus filicinus and identified as 3-O-beta-D-glucopyranosyl-26-O-beta-D-glucopyranosyl-22-alpha-methoxy-(2 5S), 5 beta-furostan-3 beta, 26-diol (filicinoside-A) and 3-O-beta-D-glucopyranosyl-26-O-beta-D-glucopyranosyl-25S), 5 beta-furostan-3 beta, 22 alpha, 26-triol (filicinoside-B).

Isolation and characterization of an intermediate steroid metabolite in diosgenin biosynthesis in suspension cultures of Dioscorea deltoidea cells

The aglycon form of the steroidal sapogenin furost -5-ene-3 beta, 22,26-triol, 3 beta- chacotrioside 26 beta-D-glucopyranoside was isolated from cell suspension cultures of Dioscorea deltoidea and its molecular structure was determined by mass spectrometry and 1H and 13C n.m.r. spectroscopy. From kinetic studies and incorporation experiments with [1-14C]acetate it was concluded that the steroidal compound (in the glycoside form) is an intermediate in vivo in diosgenin biosynthesis. It accumulated in growing cells of D. deltoidea and was metabolized to diosgenin (in the glycoside form, i.e. dioscin ) in non-dividing cells.