Antiproliferative constituents from Umbelliferae plants VI. New ursane-type saikosaponin analogs from the fruits of Bupleurum rotundifolium

The MeOH extract of the fruits of Bupleurum rotundifolium showed inhibitory activity against human gastric adenocarcinoma (MK-1) cell growth (GI(50): 6.25 microg/ml). From this extract, 10 new ursane-type triterpene glycosides viz. three 3-O-triosides (called rotundifoliosides A, I, and J) of 13beta,28-epoxy-3beta,16alpha-dihydroxyurs-11-ene, two (G and H) of 13beta,28-epoxy-3beta,16alpha,23-trihydroxyurs-11-ene, two (E and F) of 13beta,28-epoxy-3beta,16alpha,21beta-trihydroxyurs-11-ene, two (B and C) of 3beta,11alpha,16alpha,28-tetrahydroxyurs-12-ene, and one (D) of 3beta,11alpha,28-trihydroxy-15alpha,16alpha-epoxyurs-12-ene were isolated in addition to 16 new oleanane-type triterpene glycosides (rotundiosides J-Y), echinocystic acid 3-O-sulfate and 3 known oleanane-type triterpene glycosides (rotundiosides A, F and G). The isolation, structures and antiproliferative activity of the new ursane-type triterpene glycosides against MK-1, human uterus carcinoma (HeLa), and murine melanoma (B16F10) cell lines are described with some comments on the structural requirements for their activity.     

Four New Triterpenes from Anchusa azurea var. azurea

Four new triterpene glycosides, named oleanazuroside 1 ( 1 ), oleanazuroside 2 ( 2 ), ursolazuroside 1 ( 3 ), and ursolazuroside 2 ( 4 ), together with the seven known compounds 5 – 11 , were isolated from the MeOH extract of the aerial parts of Anchusa azurea Miller var. azurea. Their structures were elucidated by means of spectroscopic evidence (UV, IR, MALDI‐MS, and 1D‐ and 2D‐NMR). The radical‐scavenging activities against 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) of the BuOH extract and of 8 and 10 were very strong (Table 5).     

Cytotoxic lupane-, secolupane-, and oleanane-type triterpenes from Viburnum awabuki

Bioassay-guided fractionation of the methanolic extract of Viburnum awabuki afforded two new lupane triterpene derivatives; 6 beta-hydroxyl-3,20-dioxo-30 norlupane-28-oic acid (1) and 3,4-secolup-4,20-dihydroxy-3,28-dioic acid-3-oic acid methyl ester (2), along with seven known lupane and oleanane-type triterpenes (3-9). The structure of the isolated compounds was assigned using different spectroscopic techniques including 1D and 2D NMR. The 13CNMR data of compounds 5 and 9 is reported for the first time. Triterpenes 1, 2, and 7-9 showed in vitro cytotoxic activity against several tumor cell lines.     

Triterpenes and flavonol glucuronides from Oenothera cheiranthifolia

A new ursane-type triterpene, named as cheiranthic acid (1), was isolated from the MeOH extract of whole plants of Oenothera cheiranthifolia (Onagraceae) along with an isomeric pair of known oleanane- and ursane-type triterpenes (arjunolic acid and asiatic acid) and three flavonol glucuronide analogues (quercetin 3-O-glucuronide, its n-butyl ester, and myricetin 3-O-glucuronide). Their structures were elucidated based on spectroscopic evidence.     

Tareciliosides H-M: further cycloartane glycosides from leaves of Tarenna gracilipes

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Tarenna gracilipes, collected in Okinawa, six further new cycloartane glycosides, named tareciliosides H-M (1-6), were isolated. Their structures were established through a combination of spectroscopic analyses.     

Cytotoxicity of triterpenes isolated from Aceriphyllum rossii

Bioassay-guided fractionation of a MeOH extract of the whole plant of Aceriphyllum rossii (Saxifragaceae) led to the isolation of two new triterpenes, 3alpha,23-isopropylidenedioxyolean-12-en-27-oic acid (1) and 23-hydroxy-3-oxoolean-12-en-27-oic acid (2), together with six known triterpenes, 3-oxoolean-12-en-27-oic acid (3), 3alpha-hydroxyolean-12-en-27-oic acid (4), beta-peltoboykinolic acid (5), aceriphyllic acid A (6), oleanolic acid (7), and gypsogenic acid (8). The structures of these compounds were elucidated on the basis of physicochemical and spectroscopic analyses. These compounds were evaluated for in vitro cytotoxicity against the K562 and HL-60 cell lines. Olean-12-en-27-oic acid derivatives (1-6) exhibited considerable cytotoxicity against K562 and HL-60 cell lines with IC(50) values ranging from 12.2 to 28.7 microM and from 12.1 to 25.8 microM, respectively.     

Tareciliosides A--G: Cycloartane glycosides from leaves of Tarenna gracilipes (HAY.) OHWI

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Tarenna gracilipes, collected in Okinawa, seven new cycloartane glycosides, named tareciliosides A--G (4--10), were isolated together with three known compounds, D-mannitol (1), (R)-linalool 6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside (2), and mussaenoside (3). Their structures were elucidated through a combination of spectroscopic analyses.     

Myrseguinosides A-E, five new glycosides from the fruits of Myrsine seguinii

Chemical investigation of the 1-BuOH soluble fraction of the dried fruits of Myrsine seguinii (Myrsinaceae) led to the isolation of five new glycosides, named myrseguinosides A-E (1-5), together with eight known compounds (6-13). The absolute structures of the new glycosides were elucidated by spectroscopic and chemical analyses to be a monoterpene glucoside (1), two flavonol glycosides (2, 3), and two oleanane-type triterpene saponins (4, 5). Myrseguinosides B (2), D (4), and E (5) exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and growth inhibitory activity toward human cancer cells, respectively.     

New triterpene constituents, foliasalacins A(1)-A(4), B(1)-B(3), and C, from the leaves of Salacia chinensis

Four dammarane-type, three lupane-type, and an oleanane-type triterpenes named foliasalacins A(1) (1), A(2) (2), A(3) (3), A(4) (4), B(1) (5), B(2) (6), B(3) (7), and C (8) were isolated from the leaves of Salacia chinensis LINN. collected in Thailand. The structures of new triterpene constituents (1-8) were characterized on the basis of chemical and physiochemical evidence.     

Medicinal flowers. XXI. Structures of perennisaponins A, B, C, D, E, and F, acylated oleanane-type triterpene oligoglycosides, from the flowers of Bellis perennis

Six new acylated oleanane-type triterpene oligoglycosides, perennisaponins A (1), B (2), C (3), D (4), E (5), and F (6), were isolated from the flowers of Bellis perennis (Daisy flower) together with 14 saponins, nine flavonoids, and two glycosides. The structures of 1-6 were elucidated on the basis of chemical and physicochemical evidence.     

Two novel triterpenoids from Dysoxylum hainanense

Two novel rearranged oleanane-type triterpenes, dysoxyhainanin A ( 1) possessing a unique 1,3- cyclo-2,3- seco A ring with a formamido-containing appendage and dysoxyhainanin B ( 2) featuring an unprecedented 1,2-dinor-3,10:9,10- bisseco skeleton, were isolated from Dysoxylum hainanense. Dysoxyhainanin A ( 1) exhibited significant antibacterial activity against Gram-positive bacteria.     

Anti-oxidative activity of glycosides from Ligustrum sinense

Three active glycosides that afford protection to red blood cell membrane to resist hemolysis induced by a peroxyl radical initiator, 2,2'-azo-bis-(2-amidinopropane) dihydrochloride (AAPH) were isolated from the MeOH extract of Ligustrum sinense. The compounds are 10-hydroxyl-oleuropein (1), 3-O-alpha-L-rhamnopyranosyl-kaempferol-7-O-beta-D-glucopyranoside (4), and 8'-alpha-hydroxyl-lariciresinol-4'-O-beta-D-glucopyranoside (6). The structures of these glycosides were determined by 1D and 2D NMR spectral analysis.     

Novel illudalane sesquiterpenes from Encephalartos villosus Lehm. antimicrobial activity

Phytochemical investigation of Encephalartos villosus Lehm. leaves afford two new illudalane sesquiterpenes namely Encephaldiene 1 and Encephaldiene 2 together with four known flavone glycosides, Luteolin-7-rutinoside, Luteolin-7-glucoside, Luteolin-7-rhamnoside and Apigenin-7-glucoside. The structures of the isolated compounds were elucidated by means of spectroscopic methods including 1D and 2D NMR experiments along with HRESIMS spectrometry. Antimicrobial activity of CHCl₃ and MeOH extracts was investigated. Both extracts showed antibacterial activity against Gram-positive bacteria Streptococcus pneumonia and Bacillus subtilis, and antifungal activity against Aspergillus fumigatus. While CHCl₃ extract showed additional activity against Gram-negative bacteria Escherichia coli.     

Tricalysionoside A, a megastigmane gentiobioside, sulfatricalysines A-F, and tricalysiosides X-Z, ent-kaurane glucosides, from the leaves of Tricalysia dubia

Further isolation work on the water-soluble fraction of a MeOH extract of Tricalysia dubia afforded one new megastigmane gentiobioside, named tricalysionoside A (1), and three sulfates, named sulfatricalysines A-C (2-4). Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of T. dubia yielded sulfatricalysines D-F (5-7) and three new ent-kaurane glucosides, named tricalysiosides X-Z (8-10). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute stereochemistry of tricalysionoside A (1) was established by modified Mosher's method.     

Constituents from the roots of Taraxacum platycarpum and their effect on proliferation of human skin fibroblasts

A MeOH extract from the roots of Taraxacum platycarpum has shown significant effects on the proliferation of normal human skin fibroblasts. Chemical analysis of the extract resulted in the isolation of 26 compounds, including eight new triterpenes, one new sesquiterpene glycoside, and seventeen known compounds. The structure of each new compound was established using NMR spectroscopy. Some triterpenes had a significant effect on the proliferation of normal human skin fibroblasts.     

Studies on differentiation-inducing activities of triterpenes.

Differentiation-inducing activity of over 180 extracts of crude drugs and plants was tested using mouse myeloid leukemia cell line (M1). The methanol extracts of clove (Syzygium aromaticum Merrill et Perry, Myrtaceae) showed remarkable induction of differentiation of M1 cells into macrophage-like cells. From the extract, oleanolic acid (1) and crategolic acid (2) were isolated as the active components. We also tested other triterpenes, such as oleananes, ursanes and dammaranes, to investigate the structure-activity relationship. Some triterpene aglycones showed differentiation-inducing activity, but triterpene glycosides showed little activity. Furthermore, the differentiation-inducing activity of these triterpene compounds was tested against human acute promyelocytic leukemia cell line (HL-60).     

Antiplasmodial prenylated flavanonols from Tephrosia subtriflora

The CH₂Cl₂/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodium falciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC₅₀ values 1.4–4.6 μM without significant cytotoxicity against Vero and HEp2 cell lines (IC₅₀ > 100 μM). The new compound (1) showed weak antiplasmodial activity, IC₅₀ 12.5–24.2 μM, but also showed selective anticancer activity against HEp2 cell line (CC₅₀ 16.9 μM).     

New lignan glycosides from Glehnia littoralis

From the roots ethanol extract of Glehnia littoralis, two new lignan glycosides, named glehlinoside E (1) and F (2), were obtained. Their structures were determined to be (-)-secoisolariciresinol 4-O-β-D-(6-O-feruloyl) glucopyranoside (1) and (-)-secoisolariciresinol 4-O-β-D-(6-O-caffeloyl) glucopyranoside (2) by analysis of their spectral data, respectively.     

Two new polyacetylene glycosides from the roots of Codonopsis tangshen Oliv.

Two new polyacetylene glycosides, tangshenyne A (1) and tangshenyne B (2), along with six known polyacetylenes were isolated from an 85% MeOH extract of the roots of Codonopsis tangshen Oliv. The chemical structures of the new compounds were determined on the basis of extensive spectroscopic analyses, including UV, IR, 1D and 2D NMR (¹H–¹H COSY, HSQC and HMBC) and HR-ESI-MS.     

New Triterpenoid N-Acetylglycosides with Molluscicidal Activity from Tetrapleura tetraptera TAUB

Activity-guided fractionation of the MeOH extract of the fruits of Tetrapleura tetraptera TAUB. (Mimosaceae) afforded 4 saponins 1 – 4 , which exhibited strong molluscicidal properties against the schistosomiasis-transmitting snails Biomphalaria glabrata. Chemical, enzymatic, and spectral methods (DCI-MS, ¹H-NMR, ¹³C-NMR) showed that they were N-acetylglycosides of oleanolic acid and of echinocystic acid. Apart from saponin 1 (aridanin), previously isolated from this plant, glycosides 2 – 4 are new naturally occurring compounds.