Solanum incanum and S. heteracanthum as sources of biologically active steroid glycosides: confirmation of their synonymy

A new spirostanol saponin (1), along with four known saponins, dioscin (2), protodioscin (3), methyl-protodioscin (4), and indioside D (5), and one known steroid glycoalkaloid solamargine (6) were isolated from the two synonymous species, Solanum incanum and S. heteracanthum. The structure of the new saponin was established as (23S,25R)-spirost-5-en-3β,23-diol 3-O-{β-D-xylopyranosyl-(1→2)-O-α-L-rhamnopyranosyl-(1→4)-[O-α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside}, by using a combination of 1D and 2D NMR techniques including (1)H, (13)C, COSY, TOCSY, NOESY, HSQC and HMBC experiments and by mass spectrometry. The compounds 1, 3, 4 and 5 were evaluated for cytotoxicity against five cancer cell lines and for antioxidant and cytoprotective activity.     

Two new cytotoxic triterpenoid saponins from the roots of Clematis argentilucida

Bioassay-guided fractionation of the n-BuOH extract of the roots of Clematis argentilucida led to the isolation of two new triterpenoid saponins along with a known one, cussonside B (3). By extensive spectral analysis and chemical evidences, the structures of the two new saponins were determined to be 3β-O-[β-D-ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] hederagenin-11,13-dien-28-oic acid (1) and 3β-O-{β-D-ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-xylopyranosyl} oleanolic acid (2), respectively. Saponin 1 is the first example of triterpenoid saponins with two double bonds located at C-11 and C-13 in the aglycone from the genus Clematis. The two new saponins exhibited significant cytotoxicity against human leukemia HL-60 cell lines, human hepatocellular carcinoma Hep-G2 cell lines and human glioblastoma U251MG cell lines with a range of IC(50) values from 2.74 to 25.40μM, while 3 showed inactivity against all of the three cancer cell lines.     

Steroidal saponins from Smilacina japonica

Three new steroidal saponins, japonicoside A (1), japonicoside B (2) and japonicoside C (3) were isolated from the dried rhizomes and roots of Smilacina japonica A. Gray. Their structures were elucidated as (25S)-5α-spirostan-9(11)-en-3β-ol 3-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside (1), (25S)-5α-spirostan-9(11)-en-3β,17α-diol 3-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside (2) and (25S)-5α-spirostan-9(11)-en-3β,17α,24α-triol 3-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside (3) on the basis of chemical methods and detailed spectroscopic analysis, including 1D, 2D NMR and HR-ESI-MS. The cytotoxicity of isolated compounds was evaluated in vitro for cytotoxic properties against human hepatocellular carcinoma cells (SMMC-7221) and human colorectal adenocarcinoma cells (DLD-1), respectively.     

New antibacterial triterpenoid saponin from Lactuca scariola

A new antibacterial triterpenoid saponin, 3beta-O-[alpha-L-rhamnopyranosyl]-30-norolean-12,19-diene-28-oic acid 28-O-[beta-D-glucopyranosyl-(1-->4)-O-beta-D-galactopyranosyl]-ester (1); has been isolated from the stems of Lactuca scariola. Its structure was determined by chemical degradations and spectral analysis.     

Cytotoxic triterpene saponins from the leaves of Aralia elata

Phytochemical investigation of the leaves of Aralia elata has led to the isolation of four new compounds, 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl oleanolic acid (1), 3-O-[β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)]-[β-D-glucopyranosyl (1→2)]-β-d-glucopyranosyl hederagenin 28-O-β-D-glucopyranoside (2), 3-O-{[β-D-glucopyranosyl (1→2)]-[β-d-glucopyranosyl (1→3)-β-d-glucopyranosyl (1→3)]-β-D-glucopyranosyl} oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-[β-D-glucopyranosyl (1→2)]-[β-D-glucopyranosyl (1→3)]-β-d-glucopyranosyl caulophyllogenin (4) and two known compounds, 3-O-[β-D-glucopyranosyl (1→3)-α-l-arabinopyranosyl]-echinocystic acid (5) and 3-O-α-L-arabinopyranosyl echinocystic acid (6). The structural determination was accomplished with spectroscopic analysis, in particular (13)C-NMR, 2D-NMR and HR-ESI-MS techniques. Compounds 1-6 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. Compound 1 showed significant cytotoxic activity against HL60 and A549 cancer cells with IC(50) values of 6.99μM and 7.93μM respectively. In addition, compounds 5 and 6 showed significant cytotoxic activity against HL60 cancer cells with IC(50) values of 5.75μM and 7.51μM, respectively.     

Iridoid, phenylethanoid and flavonoid glycosides from Sideritis trojana

From the MeOH extract of Sideritis trojana, a new iridoid glycoside, 10-O-(E)-feruloylmelittoside (1) was obtained in addition to four known iridoid glycosides [melittoside (2), 10-O-(E)-p-coumaroylmelittoside (3), stachysosides E (4) and G (5)]. Moreover, five phenylethanoid glycosides [verbascoside (6), isoacteoside (7), lamalboside (8), leonoside A (9), isolavandulifolioside (10), three flavone glycosides (isoscutellarein 7-O-[6'-O-acetyl-β-allopyranosyl-(1→2)]-β-glucopyranoside (11), 4'-O-methyisoscutellarein 7-O-[6'-O-acetyl-β-allopyranosyl-(1→2)]-β-glucopyranoside (12), 3'-hydroxy-4'-O-methyisoscutellarein 7-O-[6'-O-acetyl-β-allopyranosyl-(1→2)]-β-glucopyranoside (13) and a benzylalcohol derivative (di-O-methylcrenatin) were obtained and identified. The structures were elucidated on the basis of NMR and HRMS data. All compounds were tested for their antioxidant activity by in vitro TEAC assay and some of them exhibited moderate activity (0.97-1.44 mM) when compared with the reference compound (quercetin 1.86 mM). Glycosides 6-13, the most active compounds in the TEAC assay, were also tested by flow cytometry to evaluate their ability to affect the levels of reactive oxygen species (ROS) in human prostate cancer cells (PC3).     

Triterpenoid saponins from the roots of Silene cucubalus

A new triterpenoid saponin was isolated from the roots of Silene cucubalus and its structure was determined on the basis of one- and two-dimensional NMR spectroscopy as gypsogenin 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside. A known saponin, quillaic acid 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside, was also isolated.     

Antifungal activity of Agapanthus africanus extractives

The ethanolic extract of the rhizomes of Agapanthus africanus showed antifungal activity. In bioassay guided fractionation, n-butanol fraction exhibited significant activity against human pathogens. A saponin, (25R)-spirost-7-en-2alpha,3beta,5alpha-triol-3-O-[alpha-L-rhamnopyranosyl(1-->2)-[beta-D-galactopyranosyl (1-->3)] beta-D-glucopyranoside (1), responsible for the antifungal activity and having MIC value of 15.6 microg/ml against Trychophyton mentagrophytes and Sporothrix schenekii, was isolated and identified as active constituent of the plant.     

Acylated flavonol glycoside from Platanus orientalis

The ethylacetate and n-butanol fractions of ethanolic extract of Platanus orientalis leaves led to the isolation of new acylated flavonol glycoside as 3',5,7-trihydroxy-4'-methoxyflavonol 3-[O-2-O-(2,4-Dihydroxy)-E-cinnamoyl-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl (1→2)]-β-D-glucopyranoside, along with seven known compounds. All the compounds were characterized by NMR including 2D NMR techniques. The isolates were evaluated for NF-κB, nitric oxide (NO), aromatase and QR2 chemoprevention activities and some of them appeared to be modestly active.     

Steroidal saponins from the leaves of Agave macroacantha

A new monodesmosidic spirostanol saponin, along with three known saponins was isolated from Agave macroacantha Zucc leaves. The structure of the new saponin was established as hecogenin-3-O-α-l-rhamnopyranosyl (1→4) β-d-xylopyranosyl (1→3)[β-d-glucopyranosyl (1→2)] β-d-glucopyranosyl (1→4) β-d-galactopyranoside. The ¹H and ¹³C resonances of the four compounds were assigned using a combination of 1D and 2D NMR techniques including ¹H, ¹³C, COSY, TOCSY, ROESY, HSQC and HMBC NMR and confirmed by mass spectrometry.     

Phenolics from Bidens bipinnata and their amylase inhibitory properties

A new chlorinated flavonoid, 3, 6, 8-trichloro-5, 7, 3', 4'-tetrahydroxyflavone (1), a new biscoumaric acid derivative, 4-O-(2″, 3″-O-diacetyl-6″-O-p-coumaroyl-β-d-glucopyranosyl)-p-coumaric acid (2), and 8, 3', 4'-trihydroxyflavone-7-O-β-d-glucopyranoside (3) together with twenty-four known compounds (4-27) were isolated from the whole plant of Bidens bipinnata. All chemical structures were established on the basis of UV-, MS- and NMR ((1)H, (13)C, (1)H-(1)H COSY, HMQC and HMBC) spectroscopic data. Some of the isolated compounds were tested for the inhibition of α-amylase. The result showed that isookanin (6) was a potent inhibitor of α-amylase (IC(50)=0.447mg/ml).     

A new steroidal saponin from the dried stems of Asparagus officinalis L

Yamogenin II (1), a new steroidal saponin with a unique aglycone moiety, and (25S)-spirostan-5-ene-3β-ol-3-O-α-l-rhamnopyranosyl-(1,2)-[α-l-rhamnopyranosyl-(1,4)]-β-d-glucopyranoside (2), were isolated from the dried stems of Asparagus officinalis L. The structure of 1 was assessed by spectroscopial analysis as (25S)-spirostan-5-ene-3β,21-diol-3-O-α-l-rhamnopyranosyl-(1,2)-[α-l-rhamnopyranosyl-(1,4)]-β-d-glucopyranoside.     

A new triterpene saponin from Androsace integra

A new triterpene saponin, androsacin (1), along with two known compounds, ardisiacrispin A (2) and saxifragifolin A (3), were isolated from the whole plants of Androsace integra. The chemical structure of the new compound was elucidated as 3β-O-{β-D-glucopyranosyl-(1 → 4)-O-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-[O-β-D-glucopyranosyl-(1 → 2)]-α-L-arabinopyranosyl}-16α-hydroxy-13β,28-epoxy-olean-30-al on the basis of spectral evidence. Ardisiacrispin A (2) was cytotoxic toward HepG2 cancer cell with the GI₅₀ value of 1.56 μM.     

Structure elucidation and complete NMR spectral assignment of two triterpenoid saponins from Radix Hedysari

A new oleanane-type triterpenoid saponin with a carbonyl group at C-15, named polybosaponin A (1), together with a known triterpenoid saponin, dehydrosoyasaponin I (2), were isolated from Radix Hedysari. On the basis of one- and two-dimensional NMR and high resolution electrospray ionization mass spectrometry, the structure of 1 were elucidated and the ¹H and ¹³C NMR spectral signals were assigned totally. In addition, the complete assignment of ¹H NMR signals and revision of incorrect assignment of ¹³C NMR signals for 2 were also achieved based on one- and two-dimensional NMR spectrometry.     

Cytotoxic triterpene glycosides from the sea cucumber Pseudocolochirus violaceus

A new triterpene glycoside (1) along with the known intercedenside B (2) was isolated from the sea cucumber Pseudocolochirus violaceus. Glycoside 1 was elucidated as 3-O-{6-O-sodiumsulfate-3-O-methyl-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[beta-D-xylopyranosyl(1-->2)]-beta-D-quinovopyranosyl-(1-->2)-4-O-sodiumsulfate-beta-D-xylopyranosyl}-16beta-acetoxy-holosta-7, 24-diene-3beta-ol on the basis of extensive spectral studies and chemical evidence. Both the glycosides exhibited significant cytotoxicity against cancer cell lines MKN-45 and HCT-116.     

New antioxidant and antiglycation active triterpenoid saponins from the root bark of Aralia taibaiensis

Four new oleanane type triterpenoid saponins (1-4) and a known saponin (5) were isolated from the root bark of Aralia taibaiensis Z.Z. Wang et H.C. Zheng. The structures of the four new compounds were elucidated as 3-O-{β-d-glucopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 3)]-β-d-glucurono-pyranosyl}-olean-11,13(18)-diene-28-oic acid 28-O-β-d-glucopyranosyl ester (1), 3-O-{β-d-gluco-pyranosyl-(1 → 3)-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl}-olean-11,13(18)-diene-28-oic acid 28-O-β-D-glucopyranosyl ester (2), 3-O-{β-d-glucopyranosyl-(1 → 2)-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl}-oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-{β-d-glucopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 3)]-β-d-glucuronopyranosyl}-oleanolic acid 28-O-β-d-glucopyranosyl ester (4), on the basis of extensive spectral analysis and chemical evidence. Compounds 1-5 exhibited moderate effects on antioxidant and antiglycation activities, which correlated with treatment of diabetes mellitus.     

Three drimane sesquiterpene glucoside from the aerial parts of Dryopteris fragrans (L.) schot

Sesquiterpene glucoside was isolated from the aqueous extract of the aerial parts of Dryopteris fragrans (L.) schot. Three new sesquiterpene glucoside xianglinmaojuesides A–C (1–3), 3β,11-dihydroxy-drim-8 (12)-en-11-O-β-d-glucopyranoside (1), 3β,11-dihydroxy-drim-8(12)-en-3-O-β-d-glucopyranoside (2), and 11,14-dihydroxy-drim-8(12)-en-11-O-β-d-glucopyranoside (3) were finally obtained by reversed-phase HPLC and their structures were elucidated by HRESIMS and 1D, 2D NMR analyses.     

Dammarane-type glycosides and long chain sesquiterpene glycosides from Gynostemma yixingense

A new dammarane-type glycoside and a new long chain sesquiterpene glycoside, along with nine known compounds 20(S)-ginsenoside Rh1 (3), 20(R)-ginsenoside Rh1 (4), ginsenoside F1 (5), amarantholidoside IV (6), ginsenoside Rc (7), 20(S)-ginsenoside Rg2 (8), 20(R)-ginsenoside Rg2 (9), ginsenoside Rd (10) and gypenoside XLVI (11) were isolated from Gynostemma yixingense. The structures of the new compounds were determined on the basis of spectroscopic analysis, including 1D-, 2D-NMR and ESI-MS techniques as well as by comparison of the spectral data with those of related compounds as 2α,3β,20(S)-trihydroxydammar-24-ene-3-O-[β-d-glucopyranosyl((1 → 2)-β-d-glucopyranosyl]-20-O-[β-d-xylopyranosyl((1 → 6)-β-d-glucopyranoside] (1) (2E,6E)-10-β-d-glucopyranosyl-1,10,11-trihydroxy-3,7,11-trimethyldodeca-2,6-diene (2).     

Cytotoxic steroidal glycosides from Allium flavum

Three new spirostane-type glycosides (1–3) were isolated from the whole plant of Allium flavum. Their structures were elucidated mainly by 2D NMR spectroscopic analysis and mass spectrometry as (20S,25R)-2α-hydroxyspirost-5-en-3β-yl O-β-d-xylopyranosyl-(1 → 3)-[β-d-galactopyranosyl-(1→2)]-β-d-galactopyranosyl-(1→4)-β-d-galactopyranoside (1), (20S,25R)-2α-hydroxyspirost-5-en-3β-yl O-β-d-xylopyranosyl-(1 → 3)-[β-d-glucopyranosyl-(1→2)]-β-d-galactopyranosyl-(1→4)-β-d-galactopyranoside (2), and (20S,25R)-spirost-5-en-3β-yl O-α-l-rhamnopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1→2)]-β-d-glucopyranoside (3). The three saponins were evaluated for cytotoxicity against a human cancer cell line (colorectal SW480).     

Three triterpenoid saponins from the roots of Polygala japonica Houtt

Three new triterpenoid saponins polygalasaponins LI-LIII (1-3) with two acylation groups in oligosaccharide chain, together with three known saponins were isolated from the roots of Polygala japonica Houtt. (4-6). The neuroprotective effects of these compounds on neuron-like PC12 cells were evaluated in vitro. Compounds 5 and 6 show neuroprotective effects in Aβ(25-35) model at the concentration of 10μM.