New cytotoxic dihydrochalcone and steroidal saponins from the aerial parts of Sansevieria cylindrica Bojer ex Hook

A new dihydrochalcone, 2‘,4‘-dihydroxy-3‘-methoxy-3,4-methylenedioxy-8-hydroxymethylene dihydrochalcone 1 and two new steroidal saponins, (25S)-ruscogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside 2, (25S)-ruscogenin-3-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranoside 3, together with three known steroidal saponins (25S)-ruscogenin-3-O-β-d-glucopyranoside 4, (25S)-ruscogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 3)]-α-l-arabinopyranoside 5 and (25R)-26-O-β-d-glucopyranosyl-furost-5-ene-1β,3β,22α,26-tetrol-1-O-α-L-rhamnopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 3)]-α-l-arabinopyranoside 6 were isolated from the aerial parts of Sansevieria cylindrica. The structures of the new compounds were established by UV, IR, EI-MS, HR-ESI–MS as well as 1D (¹H,¹³C and DEPT-135) and 2D (HSQC, HMBC and TOCSY) NMR spectral analysis. The isolated compounds 1-6 were assayed for in vitro cytotoxicities against the three human tumor cell lines HT116, MCF7 and HepG2. Compound 1 showed a moderate cytotoxicity against MCF7. Compounds 2, 3 and 6 exhibited moderate cytotoxicities against the three used cell lines and compound 5 showed marked cytotoxicities against all used cell lines.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.     

An easy and stereoselective rearrangement of an abietane diterpenoid into a bioactive microstegiol derivative

Parvifloron D was isolated from Plectranthus ecklonii together with sugiol and mixtures of β-sitosterol and stigmasterol and ursolic and oleanolic acids. Treatment of parvifloron D [2α-(4-hydroxy)benzoyloxy-11-hydroxy-5,7,9(11),13-abietatetraen-12-one] with acid-washed molecular sieves gave the microstegiol derivative 2β-(4-hydroxy)benzoyloxy-11β-hydroxy-4(5 → 11),20(10 → 5)diabeo-5(10),6,8,13-abietatetraen-12-one in a moderate yield (26%). The new microstegiol derivative inhibited the growth of some Staphylococcus and Enterococcus species with significant MIC values ranging from 3.91 to 7.81 μg/ml.     

An antibacterial cytochalasin derivative from the marine-derived fungus Diaporthaceae sp. PSU-SP2/4

A new pentacyclic cytochalasin (diaporthalasin, 1) and a new ethyl trihydroxytridecatrienoate (diaporthacol, 2) together with five known compounds, R-mevalonolactone (4), dothiorelone C (5), (4S,7S,13S)-4,7-dihydroxy-1,3-tetradeca-1,5-dienolide (6), 4β-acetoxy-9β,10β,15α-trihydroxyprobotrydial (7) and O-methyldihydrobotrydial (8) were isolated from the marine-derived fungus Diaporthaceae sp. PSU-SP2/4. The structures were established by spectroscopic techniques. Compound 1 displayed significant antibacterial activity against both Staphylococcus aureus and methicillin-resistant S. aureus with equal MIC values of 2 μg/mL.     

A new complex triterpenoid saponin from Samanea saman with haemolytic activity and adjuvant effect

A new complex triterpenoid saponin was isolated from the stem bark of Samanea saman by using chromatographic methods. Its structure was established as 3-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]-2,23-dihydroxy-(2β,3β,4α)-olean-12-en-28-oic acid O-β-d-glucopyranosyl-(1 → 3)-O-[O-β-d-glucopyranosyl-(1 → 4)]-O-6-deoxy-α-l-mannopyranosyl-(1 → 2)-6-O-[4-O-[(2E,6S)-2,6-dimethyl-1-oxo-2,7-octadienyl]-6-deoxy-α-l-mannopyranosyl)oxy]-β-d-glucopyranosyl ester (1). Structural elucidation was performed using detailed analyses of ¹H and ¹³C NMR spectra including 2D NMR spectroscopic techniques and chemical conversions. The haemolytic activity of the saponin was evaluated using in vitro assays, and its adjuvant potential on the cellular immune response against ovalbumin antigen was investigated using in vivo models.     

Steroidal saponins from Tribulus terrestris

Five new steroidal saponins were isolated from the fruits of Tribulus terrestris. Their structures were fully established by spectroscopic and chemical analysis as (23S,25S)-5α-spirostane-24-one-3β,23-diol-3-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside} (1), (24S,25S)-5α-spirostane-3β,24-diol-3-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside} (2), 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-2α,3β,22α,26-tetraol-3-O-{β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside} (3), 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-20(22)-en-2α,3β,26-triol-3-O-{β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside} (4), and 26-O-β-d-glucopyranosyl-(25S)-5α-furostan-12-one-22-methoxy-3β,26-diol-3-O-{α-l-rhamnopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside} (5). The isolated compounds were evaluated for cytostatic activity against HL-60 cells.     

Three new flavonoid glycosides from the aerial parts of Graptophyllum grandulosum Turril (Acanthaceae)

Grandulosides A-C, three new flavonoid glycosides, were isolated from the aerial parts of Graptophyllum grandulosum Turill and identified as chrysoeriol-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (1), chrysoeriol-7-O-[4′′′-O-acetyl-β-d-apiofuranosyl-(1 → 2)]-β-d-xylopyranoside (2) and 7-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-(4′′-Sodium hydrogeno sulfate) glucopyranoside (3). Four known compounds, chrysoeriol-7-O-β-d-xyloside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (5), luteolin-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (6) and sucrose (7) were also obtained. The structures of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D-NMR (¹H, ¹³C) and 2D-NMR (COSY, NOESY, HSQC and HMBC) and by comparison with the literature data.     

Gynostemosides A–E,megastigmane glycosides from Gynostemma pentaphyllum

Megastigmane glycosides (1–5) together with seven (6–12) related known compounds were isolated from the whole plants of Gynostemma pentaphyllum. The structures were elucidated by means of spectroscopic methods, including 2D NMR, HR-ESIMS, and circular dichroism (CD), as well as chemical transformations to be (3R, 4R, 5S, 6S, 7E)-3,4,6-trihydroxymegastigmane-7-en-9-one-3-O-β-d-glucopyranoside (gynostemoside A, 1), (3S, 4S, 5R, 6R, 7E, 9R)-3,4,6,9-tetrahydroxymegastigmane-7-en-3-O-β-d-glucopyranoside (gynostemoside B, 2), (3S, 4S, 5S, 6S, 7E, 9R)-3,4,9-trihydroxymegastigmane-7-en-9-O-β-d-glucopyranoside (gynostemoside C, 3), (3S, 4S, 5S, 6S, 7E, 9R)-3,4,9-trihydroxymegastigmane-7-en-3-O-β-d-glucopyranoside (gynostemoside D, 4), and (3S, 4S, 5S, 6S, 7E, 9R)-3,4,9-trihydroxymegastigmane-7-en-4-O-β-d-glucopyranoside (gynostemoside E, 5), respectively.     

Novel dammarane saponins from Gynostemma pentaphyllum and their cytotoxic activities against HepG2 cells

Two new dammarane saponins, 2α,3β,12β-trihydroxydammar-20(22),24-diene-3-O-[β-d-glucopyranoxyl(1→2)-β-d-6″-O-acetylglucopyranoside (1, namely damulin C) and 2α,3β,12β-trihydroxydammar-20(21),24-diene-3-O-[β-d-glucopyranoxyl(1→2)-β-d-6″-O-acetylglucopyranoside (2, namely damulin D), were isolated from the ethanol extract of Gynostemma pentaphyllum, which had been heat processed by steaming at 125 °C. The NMR spectroscopic data of the novel saponins were completely assigned by using a combination of 2D NMR experiments including ¹H–¹H COSY, HSQC, and HMBC. Their cytotoxic activities of human liver adenocarcinoma HepG2 cells were evaluated in vitro. They showed cytotoxicities against HepG2 cell line with IC₅₀ of 40 ± 0.7 and 38 ± 0.5 μg/ml, respectively.     

Triterpenoid saponins and C-glycosyl flavones from stem bark of Erythrina abyssinica Lam and their cytotoxic effects.

Six new compounds including two oleanane-type triterpenoid saponins (1, 2) and four C-glycosyl flavones (3–6), along with a known saponin (7), three di-C-glycosyl flavones (8–10) and a glycosyl auronol (11), were isolated from the stem bark of Erythrina abyssinica Lam. The structures of the new compounds, identified as 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (1), 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (2), 6-C-β-glucopyranosyl-8-C-β-quinovopyranosyl apigenin (3), 6-C-β-quinovopyranosyl-8-C-β-glucopyranosyl apigenin (4), 8-C-[6″-O-α-l-rhamnopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (5) and 8-C-[6″-O-β-d-xylopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (6), were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry and acid hydrolysis. These new compounds together with the known saponins 7 were evaluated for their cytotoxic activity against MCF-7 (estrogen dependent) and MDA-MB-231 (estrogen independent) cell lines. The new saponin 2 exhibited the highest cytotoxic activity among tested compounds, exerting a selective inhibitory effect against the proliferation of MCF-7 cells, with lower IC₅₀ value (12.90 μM) than that of the positive control, resveratrol (13.91 μM). Structure–activity relationship of these compounds is also discussed.     

New cytotoxic steroidal saponins from Cestrum parqui

Two new steroidal saponins, 25(R)-3β [(O-β-d-glucopyranosyl-(1 → 3)-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranosyl)oxy]-5α, 15β, 22R, 25R-spirostan-3,15-diol (1, named parquispiroside) and 25R-26-[(β-d-glucopyranosyl)Oxy]-(3β [(O-β-d-glucopyranosyl-(1 → 3)-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranosyl)oxy], 5α, 15β, 22R, 25R)-furostane-3,15,22-triol (2, named parquifuroside), along with the known saponins, capsicoside D (3) and 22-OMe-capsicoside D (4) and the known glycoside, benzyl primeveroside (5), were isolated from the leaves of Cestrum parqui. The structures of these compounds were elucidated by careful analysis of 1D and 2D NMR spectra and ESIMS data. Parquispiroside (1) exhibited moderate inhibition of Hela, HepG2, U87, and MCF7 cell lines with IC₅₀ values in the range of 3.3–14.1 μM.     

Cycloartane-type glycosides from Astragalus schottianus

Three new cycloartane-type triterpene glycosides were isolated from the roots of Astragalus schottianus Boiss. Their structures were established as 20(R),25-epoxy-3-O-β-d-xylopyranosyl-24-O-β-d-glucopyranosyl-3β,6α,16β,24α-tetrahydroxycycloartane (1), 20(R),25-epoxy-3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl-24-O-β-d-glucopyranosyl-3β,6α,16β,24α-tetrahydroxycycloartane (2), 3-O-β-d-xylopyranosyl-3β,6α,16β,20(S),24(S),25-hexahydroxycycloartane (3) by the extensive use of 1D and 2D-NMR techniques and mass spectrometry.     

Triterpenoid saponins from Astragalus wiedemannianus Fischer

Three cycloartane-type triterpene glycosides were isolated from Astragalus wiedemannianus together with eight known secondary metabolites namely cycloastragenol, cycloascauloside B, astragaloside IV, astragaloside VIII, brachyoside B, astragaloside II, astrachrysoside A, and astrasieversianin X. The structures were established mainly by a combination of 1D and 2D-NMR techniques as 3-O-[α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl]-25-O-β-D-glucopyranosyl-20(R),24(S)-epoxy-3β,6α,16β,25-tetrahydroxycycloartane, 3-O-[α-L-rhamnopyranosyl-(1 → 2)-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-24-O-α-(4’-O-acetoxy)-L-arabinopyranosyl-16-O-acetoxy-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3-O-[α-L-rhamnopyranosyl-(1 → 2)-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-24-O-α-L-arabinopyranosyl-16-O-acetoxy-3β,6α,16β,24(S),25-pentahydroxycycloartane. To the best of our knowledge, the presence of an arabinose moiety on the acyclic side chain of cycloartanes is reported for the first time.     

Aginoside saponin,a potent antifungal compound,and secondary metabolite analyses from Allium nigrum L.

The HPLC and spectral analyses of cysteine sulfoxides (CSOs), total polyphenols (TP), and total saponins revealed quantitative variations within the different organs of Allium nigrum L. A large accumulation of CSOs was detected in the bulb (0.367 mg/g fw), of TP in the leaf (116.05 mg CE/100 g fw), and of saponins in the root (19.38 mg/g dw). Phytochemical and chromatographical investigations of A. nigrum root extract led to the isolation of a spirostane-type glycoside or aginoside. The structure was elucidated by spectroscopic analysis (2D NMR, FABMS, HR-ESI-MS). The structure of the aginoside was identified as 25(R,S)-5α-spirostan-2α,3β,6β-trio1-3-O-β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside. The highest content of aginoside, 2.9 mg/g dw, was detected in the root. The in vitro and in vivo antifungal activity of aginoside was evaluated for the first time against phytopathogens. This compound showed significant (P < 0.05) antifungal activity depending on the concentration.     

Triterpenoid saponins from Eryngium yuccifolium ‘Kershaw Blue’

Phytochemical investigation on the root of Eryngium yuccifolium ‘Kershaw Blue’ resulted in the isolation and identification of two new polyhydroxyoleanene saponins, named eryngioside M and eryngioside N, together with 15 known triterpenoid saponins eryngiosides A-L, 21β-angeloyloxy-3β-[β-d-glucopyranosyl-(1 → 2)]-[β-d-xylopyranosyl-(1 → 3)]-β-d-glucuronopyranosyloxyolean-12-ene-15α,16α,22α,28-tetrol, saniculasaponin III, and saniculasaponin II. Their structures were established by extensive spectroscopic and chemical analyses. Eryngioside M and saniculasaponin II showed week cytotoxicity against human non-small cell lung tumor cells (A549) with GI₅₀ values of 37.5 ± 1.59 μM and 35.5 ± 1.11 μM, respectively.     

Dianthus erinaceus var. erinaceus: Extraction,isolation, characterization and antimicrobial activity investigation of novel saponins

A phytochemical analysis of Dianthus erinaceus Boiss. var. erinaceus (Caryophyllaceae) has led to the isolation of two novel triterpenoid saponins, containing an oleane type skeleton, named dianosides K and L (1, 2), along with six known triterpenoid saponins (3–8). On the basis of chemical and spectrometric data, the structures of the new compounds were elucidated as 3-O-[β-d-glucopyranosyl (1 → 3)]–[β-d-glucopyranosyl (1 → 6)]-β-d-glucopyranosyl-olean-12-ene-23α,28-β–dioic acid 28-O-β-d-glucopyranosyl ester (1) and 3-O-[β-d-glucopyranosyl (1 → 3)]–[β-d-glucopyranosyl(1 → 6)]-β-d-glucopyranosyl-olean-12-ene-23α,28-β-dioic acid 28-O-α-l-mannopyranosyl (1 → 6)-β-d-glucopyranosyl ester (2). All isolated natural compounds were structurally characterized by 1D- (¹H, ¹³C, DEPT); 2D- (COSY, HMQC, HMBC) NMR and HR-ESI/MS methods. The antimicrobial activity of compounds 1 and 2 were tested against four Gram-negative, three Gram-positive bacteria and the yeast Candida albicans by the MIC method.     

Chemical constituents from Saussurea cordifolia

Thirty-six naturally occurring compounds, including four C₁₀-acetylenic glycosides and a lignan, were isolated from the whole plants of Saussurea cordifolia. Their structures were elucidated by means of spectroscopic and chemical methods to be 4,6-decadiyne-1-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (1), 4,6-decadiyne-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (2), (8E)-decaene-4, 6-diyn-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (3), (8Z)-decaene-4,6-diyn-1-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (4), and (2R, 3S, 4S)-4-(4-hydroxy-3-methoxybenzyl)-2-(5-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-tetrahydrofuran-3-ol (5).     

Triterpene glycosides from Astragalus icmadophilus

Six cycloartane-type triterpene glycosides were isolated from Astragalus icmadophilus along with two known cycloartane-type glycosides, five known oleanane-type triterpene glycosides and one known flavonol glycoside. The structures of the six compounds were established as 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-3-acetoxy-α-L-arabinopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3-O-[α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-(1 → 2)-O-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy cycloartane, 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-3,4-diacetoxy-α-L-arabinopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-3-acetoxy-α-L-arabinopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),24(S)-epoxycycloartane, 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24α-tetrahydroxy-20(R),25-epoxycycloartane, 3-O-[α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-(1 → 2)-O-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24α-tetrahydroxy-20(R),25-epoxycycloartane by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis.The first four compounds are cyclocanthogenin and cycloastragenol glycosides, whereas the last two are based on cyclocephalogenin as aglycone, more unusual in the plant kingdom, so far reported only from Astragalus spp.     

New immunomodulatory steroidal alkaloids from Sarcococa saligna

Two new steroidal alkaloids, (20 S)-(bennzamido)-3β-(N,N-dimethyamino)-pregnane (1), and (20 S)-(bennzamido)-pregnane-3-one- (2), and two known steroidal alkaloids, pachysanaximine A (3) and 3β, 20α-diacetamido-5α-pregnane (4) were isolated from the whole plant of Sarcococca saligna. The structures of these compounds were identified with the help of spectroscopic techniques while spectra for known compounds were compared with spectra reported in literature. The immunomodulatory potential of the new compounds were found to be significant and dose dependent. Compound 1 showed inhibition of T cells proliferation at 10 μg/mL (95%), and inhibition of IL-2 production with an IC50 = 1.6 μg/mL.