Caspicaosides E-K, triterpenoid saponins and cytotoxic acylated saponins from fruits of Gleditsia caspica Desf.

Seven bisdesmosidic triterpenoid saponins named caspicaosides E-K, were isolated from the methanolic fruit extract of Gleditsia caspica Desf. Their structures were determined by 1D and 2D NMR spectroscopy as well as high resolution mass spectrometry and acid hydrolysis. The saponins comprised echinocystic acid or oleanolic acid as the aglycone and saccharide moieties at C-3 and C-28. Like most Gleditsia saponins, the oligosaccharide moiety at C-3 was identified as ß-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-(1→6)-ß-D-glucopyranosyl. The common oligosaccharide moiety linked to C-28 was determined as ß-D-xylopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranosyl with the presence of additional ß-D-galactopyranose unit and/or another α-L-rhamnopyranose moiety. The C-28 saccharide moiety was acylated with a monoterpenic acid unit or a monoterpenic acid linked to a monoterpene-arabinoside unit at the ester-ß-D-glucopyranose C-6. Esterification of C-2 and C-3 hydroxyl groups of the terminal α-L-rhamnopyranose unit with a monoterpenic acid and epoxy-monoterpenic acid units, respectively, or with two identical monoterpenic acid units, was also shown. The acylated saponins caspicaosides G-K were assayed for their in vitro cytotoxicities against the three cell lines HCT116, HepG2 and MCF7. The tested saponins showed moderate to strong activities.

Cytotoxic triterpenoid saponins acylated with monoterpenic acids from fruits of Gleditsia caspica Desf.

Four bisdesmosidic triterpenoid saponins named caspicaosides A-D, were isolated from the fruits of Gleditsia caspica Desf. Their structures were determined by NMR spectroscopy including HOHAHA, ¹H-¹H COSY, ROE, HMQC, HMBC experiments and HRFAB-MS as well as acid hydrolysis. The four 3,28-O-bisdesmosidic triterpenoid saponins comprised echinocystic acid as the aglycone and common oligosaccharide moieties at C3 and C28. The saccharide moiety at C-3 was identified as ß-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-(1→6)-ß-D-glucopyranosyl while that at C-28 was determined as ß-D-xylopyranosyl-(1→3)-ß-d-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)-]ß-D-glucopyranosyl. The pentasaccharide moiety linked to C-28 was acylated with monoterpenic acid and or monoterpene-arabinoside moieties at C-2 or C-2 and C-3 of the terminal rhamnose unit. The isolated saponins were assayed for their in vitro cytotoxicities against the three human tumor cell lines HepG2, A549 and HT29 using MTT method. The results showed that caspicaosides B and C bearing two and three monoterpene units, respectively, exhibited significant cytotoxic activities against the used cell lines with IC50 values 1.5-6.5 µM. Caspicaosides A and D with one monoterpene unit exhibited significant cytotoxic activities on HepG2 cell line with IC50 values equal to 4.5 and 5.4 µM, respectively, and IC50 values > 10 µM against the other two cell lines. The number of monoterpene units seems to play a main role in determining the activity.

Echinocystic acid 3,16-O-bisglycosides from Albizia procera.

Three triterpene glycosides and two known ones were isolated from the bark of Albizia procera by using chromatographic techniques. The structures of the compounds were determined to be 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 16-O-beta-D-glucopyranoside, 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 16-O-beta-D-glucopyranoside and 3-O-alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 16-O-beta-D-glucopyranoside. Their structures were determined by NMR techniques including HOHAHA, (1)H-(1)H COSY, ROE, HMQC and HMBC experiments together with FABMS as well as acid hydrolysis. To the best of our knowledge, the new compounds are considered the first examples of echinocystic acid 3,16-O-bisglycosides. In contrast to other cytotoxic echinocystic acid glycosides with N-acetyl glucosamine unit, the new glycosides were found inactive when assayed by MTT method for their cytotoxicities against the human tumor cell lines HEPG2, A549, HT29 and MCF7. The results showed the importance of the free hydroxyl group at the aglycone C-16 for exhibiting cytotoxic properties.

Triterpenoid saponins with N-acetyl sugar from the bark of Albizia procera.

Three (1,2,4) and one known (3) triterpenoid saponins were isolated from the bark of Albizia procera. The saponins were characterized as 3-O-[beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl] echinocystic acid (1), 3-O-[alpha-L-arabinopyranosyl-(1-->2)-beta-D-fucopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl] echinocystic acid (2) and 3-O-[beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl] acacic acid lactone (4). Their structures were elucidated by 1D and 2D NMR experiments, FABMS as well as chemical means. Saponins 1 and 3 exhibited cytotoxicity against HEPG2 cell line with IC50 9.13 microg/ml and 10 microg/ml, respectively.

Saponins and acylated saponins from Dizygotheca kerchoveana.

Four new triterpenoid saponins were isolated from the leaves and stem of branches of Dizygotheca kerchoveana along with seven known ones. The new saponins were respectively characterized as 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid, 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-3-O-trans-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester and 3-O-[beta-d-3-O-cis-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester. Their structures were elucidated by 1D and 2D NMR experiments, FAB-MS as well as chemical means.

Further saponins from Meryta lanceolata.

Five new oleanane-type saponins along with 11 known ones were isolated from the leaves and stems of Meryta lanceolata. The new saponins were characterised by spectroscopic analysis including FAMS, 1 and 2D NMR experiments and the results of hydrolysis as 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] hederagenin 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl] ester, 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] oleanolic acid 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl]ester, 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] oleanolic acid 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-6-O-acetyl glucopyranosyl-(1-->6)-beta-d-glucopyranosyl]ester, 3-O-[beta-d-glucopyranosyl-(1-->3)-beta-d-glucopyranosyl-(1-->3)-alpha-l-arabinopyranosyl] oleanolic acid 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl] ester and 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] hederagenin, respectively.

Triterpenoid saponins from Schefflera arboricola.

Nine triterpenoid saponins were isolated from the leaves and stems of Schefflera arboricola. The saponins were characterised, on the basis of chemical and spectral evidence, as 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid, 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] echinocystic acid, 3-O-[beta-D-apiofuranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-ramnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-beta-D-apiofuranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid and 3-O-beta-D-apiofuranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester.

Triterpenoid saponins from Meryta lanceolata.

Four new oleanane-type saponins and a known one were isolated from the leaves and stems of Meryta lanceolata. The new saponins were characterised by spectroscopic means and chemical hydrolysis as 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl]oleanolic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D- glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl]oleanolic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-6-O-acetyl glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]oleanolic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester and 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester. The NMR assignments were made by means of HOHAHA, 1H-1H COSY, HMQC, HMBC and NOE difference studies.

New steroidal saponins from Agave lophantha Schiede and their pharmacological evaluation.

The structures of one new monodesmosidic spirostanoside and one new bisdesmosidic furanostanol glycoside isolated from leaves of Agave lophantha Schiede have been determined by means of spectroscopic and chemical methods as (25R)-5 beta-spirostan-3 beta-ol-3-O-(beta-D-apiofuranosyl(1-->4)beta-D -glucopyranosyl(1-->3)[beta-D-glucopyranosyl(1-->2)]beta-D -galactopyranoside) and 26-O-beta-D-glucopyranosyl(25R)-5 beta-furost-20(22)-ene-3 beta, 26-diol-3-O-(beta-D-xylopyranosyl(1-->3)-[beta-D-glucopyranosyl(1--2)] beta-D-galactopyranoside), respectively. The 1H and 13C NMR resonances of the two compounds were assigned by NMR (1H, 13C, HOHAHA, 1H-1H COSY, HMQC, HMBC, NOE difference) studies. The pharmacological activities of the saponin containing fraction are discussed.

Triterpenoid saponins from Oreopanax guatemalensis.

Seven oleanane-type saponins were isolated from the leaves and stems of Oreopanax guatemalensis, together with ten known saponins of lupane and oleanane types. The new saponins were respectively characterized as 3-O-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha- L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-beta-D-glucopyranosyl 3beta-hydroxy olean-11,13(18)-dien-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta- D-glucopyranosyl]ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]3beta-hydroxy olean-11,13(18)-dien-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]3beta, 23 dihydroxy olean-18-en-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-6-O-acetyl glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl] hederagenin 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-[beta-D-xylopyranosyl-(1-->2 )-]beta-D-glucopyranosyl]ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]hederagenin 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1-->2)-]beta-D-glucopyranosyl] ester and 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl] hederagenin 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-[alpha-L-arabinofuranosyl-(1-->2)]-beta-D-glucopyranosyl] ester. The structures were determined by spectral analyses. The NMR assignments were made by means of HOHAHA, 1H-1H COSY, HMQC, HMBC spectra and NOE difference studies.

Further saponins from Fagonia cretica.

Three triterpenoid saponins including two new ones were isolated and identified from the aerial parts of Fagonia cretica. The new saponins were characterized as 3-O-[beta-D-xylopyranosyl(1-->2)alpha-L-arabinopyranosyl]27-hydroxyoleanolic acid 28-O-[beta-D-glucopyranosyl(1-->6)beta-D-glucopyranosyl]ester and 3 beta-O-[beta-D-xylopyranosyl(1-->2)alpha-L-arabinopyranosyl] olean-12-en-27-al-28-oic acid 28-O-[beta-D-glucopyranosyl(1-->6)beta-D-glycopyranosyl] ester. The structures were determined by spectral analyses. The NMR assignments were made by means of HOHAHA, 1H-1H COSY, HMQC, HMBC spectra and NOE studies.

Saponins from Fagonia glutinosa.

Twelve triterpenoid saponins, including six new, were isolated and identified from the aerial parts of Fagonia glutinosa. The new saponins were characterised as 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl(1-->3)]-alpha-L - arabinopyranosyl-27-hydroxy oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-[beta-D-glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl ursolic acid, 3-O-alpha-L-arabinopyranosyl ursolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-[beta-D-xylopyranosyl(1-->2)][beta- D-glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl ursolic acid, 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D- glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl ursolic acid 28-O-beta-D-glucopyranosyl ester and 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl(1-->3)]-alpha-L - arabinopyranosyl-27-hydroxy ursolic acid 28-O-beta-D-glucopyranosyl ester. The structures of the saponins were established by spectral and chemical evidences. The assignments of the NMR signals were performed by means of HOHAHA, 1H-1H COSY, ROE, HMQC and HMBC experiments.

Triterpenoid saponins from Fagonia cretica.

Four new triterpenoid saponins were isolated and identified from the aerial parts of Fagonia cretica. They were characterized as 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] hederagenin 28-O-beta-D-glucopyranosyl ester, 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] oleanolic acid 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] 27-hydroxy oleanolic acid 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] ester and 3beta-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl] olean-12-en-27-al-28-oic acid 28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] ester. The structures of the saponins were assigned by spectral analyses (FABMS, 1H, 13C NMR, 1H-1H COSY, TOCSY, HMQC and HMBC spectra) and NOE experiments. To the best of our knowledge the genin 3beta hydroxy olean-12-en-27-al-28-oic acid is new.

Saikosaponin homologues from Verbascum spp. The structures of mulleinsaponins I-VII.

From the aerial parts of Verbascum (V.) sinaiticum, V. thapsiforme, V. fruticulosum and Celsia roripifolia, seven new saikosaponin homologues, called mulleinsaponins I-VII, having 13,28-epoxy-olean-11-ene skelton were isolated together with eight known saikosaponin homologues, 3-O-beta-D-fucopyranosyl saikogenin F, saikosaponin a, desrhamnosylverbascosaponin, songarosaponins C, D, mimengoside A and buddlejasaponins I, IV. The structures of mulleinsaponins I-VII were characterized as 3-O-beta-D-glucopyronosyl-(1-->3)-beta-D-fucopyranosyl-6-deoxy- saikogenin F, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)-beta-D - fucopyranosyl-16-deoxysaikogenin F, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)-beta-D - fucopyranosyl-saikogenin F, 3-O-alpha-L-rhamnopyranosyl- (1-->4)-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-be ta -D-fucopyranosyl-21 beta-hydroxysaikogenin F, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)-[beta- D- glucopyranosyl-(1-->2)]-beta-D-fucopyranosyl-21 beta-acetoxysaikogenin F, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D- glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-beta-D- fucopyranosyl-16 beta-acetoxysaikogenin F and 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl- (1-->3)-[beta-D-glucopyranosyl-(1-->2)]-beta-D-fucopyranosylsaikogeni n F 16-O-beta-D-glucopyranoside, respectively, from chemical and spectroscopic evidence.

Saponins from Fagonia arabica.

Seven new triterpenoid saponins were isolated and identified from the aerial parts of Fagonia arabica. They were characterized as 3-O-beta-D-xylopyranosyl(1-->2)-[beta-D-glucopyranosyl(1-->3)]-alpha-L- arabinopyranosyl oleanolic acid 28-O-beta-D-glucopyranoside, 3-O-beta-D-glucopyranosyl(1-->2)-[beta-D-glucopyranosyl(1-->3)]-alpha-L- arabino pyranosyl oleanolic acid 28-O-beta-D-glucopyranoside, 3-O-beta-D-xylopyranosyl(1-->2)-[beta-D-glucopyranosyl (1-->3)]-alpha- L-arabinopyranosyl oleanolic acid, 3-O-beta-D-glucopyranosyl(1-->2)-[beta-D-glucopyranosyl(1-->3)]-alpha-L- arabino pyranosyl oleanolic acid, 3-O-beta-D-xylopyranosyl(1-->2)-[beta-D-glucopyranosyl (1-->3)]-alpha-L-arabinopyranosyl 27-hydroxyoleanolic acid, 28-O-beta-D-glucopyranoside, 3-O-beta-D-xylopyranosyl(1-->2)-[beta-D-glucopyranosyl(1-->3)]-alpha-L- arabinopyranosyl ursolic acid 28-O-beta-D-glucopyranoside and 3-O-beta-D-xylopyranosyl (1-->2)-[beta-D-glucopyranosyl (1-->3)-alpha-L-arabinopyranosyl 27-hydroxyursolic acid 28-O-beta-D-glucopyranoside. The structures of the saponins were established by analyses of their 1H and 13C NMR spectra with the aid of 2D experiments. The two genins, 27-hydroxyoleanolic acid and 27-ursolic acid, are new.