Cycloartane-type Triterpene Research Articles

Hepatoprotective effects of Astragalus kahiricus root extract against ethanol-induced liver apoptosis in rats

The hepatoprotective activity of the ethanol extract of Astragalus kahiricus (Fabaceae) roots against ethanol-induced liver apoptosis was evaluated and it showed very promising hepatoprotective actions through different mechanisms. The extract counteracted the ethanol-induced liver enzymes leakage and glutathione depletion. In addition, it demonstrated anti-apoptotic effects against caspase-3 activation and DNA fragmentation that were confirmed by liver histopathological examination. Moreover, the phytochemical study of this extract led to the isolation of four cycloartane-type triterpenes identified as astrasieversianin II (1), astramembrannin II (2), astrasieversianin XIV (3), and cycloastragenol (4). The structures of these isolates were established by HRESI-MS and 1D and 2D NMR experiments. The antimicrobial, antimalarial, and cytotoxic activities of the isolates were further evaluated, but none of them showed any activity.

Anti-Inflammatory Cycloartane-Type Saponins of Astragalus membranaceus

A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-β-(2'-O-acetyl)-d-xylopyranosyl-6-O-β-d-glucopyranosyl-(24S)-3β,6α,24α,25-tetrahydroxy-9,19-cyclolanostane, by means of spectroscopic methods, including HR-FAB/MS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. Four known cycloartane glycosides, namely, agroastragaloside I (2), agroastragaloside II (3), isoastragaloside II (4) and astragaloside IV (5) were also isolated. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.

Oleanane glycosides from Astragalus tauricolus: Isolation and structural elucidation based on a preliminary liquid chromatography-electrospray ionization tandem mass spectrometry profiling

As a part of our ongoing research for bioactive compounds from Turkish Astragalus species, the investigation of Astragalus tauricolus has been carried out. An approach based on HPLC-ESIMS(n) experiments has been used to profile the triterpene glycosides occurring in the butanol extract of the whole plant. On the basis of the results of the online screening by HPLC-ESIMS(n), 22 oleanane-type triterpene glycosides, including ten compounds never reported before, were isolated, and their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Noteworthy, cycloartane-type triterpene glycosides, the main constituents of Astragalus spp., were not found. This peculiar feature characterizes a very limited group of Astragalus spp. The antiproliferative activity of the isolated compounds 1-12, 15, 17-19 was evaluated against a small panel of cancer cell lines. Only compound 11 showed an IC(50) of 22 μM against human leukemia cell line (U937). The other tested compounds, in a range of concentrations between 1 and 50 μM, did not cause any significant reduction of the cell number.

Cycloartane-type Triterpene Glycosides from the Rhizomes of Cimicifuga heracleifolia and Their Anticomplementary Activity

Seven known triterpene glycosides, 23-O-acetylshengmanol 3-O-α-L-arabinopyranoside (1), 23-O-acetylshengmanol 3-O-β-D-xylopyranoside (2), 24-epi-24-O-acetylhydroshengmanol 3-O-β-D-xylopyranoside (3), cimiaceroside B (4), (23R,24S)-cimigenol 3-O-β-D-xylopyranoside (5), (23R,24R)-25-O-acetylcimigenol 3-O-β-D-xylopyranoside (6) and (23R,24S)-25-O-anhydrocimigenol 3-O-β-D-xylopyranoside (7) were isolated from the rhizomes of Cimicifuga heracleifolia. Their chemical structures were determined on the basis of spectroscopic analyses including 2D NMR. All isolates were investigated for their inhibitory effects on the classical pathway of the complement system. Among them, compound 6 showed strong inhibitory activity with an IC₅₀ value of 7.7 µM while compound 3 was moderately active with an IC₅₀ value of 195.6 µM.

Cycloartane-Type Triterpenes from the Leaves of Homonoia riparia with VEGF-Induced Angiogenesis Inhibitory Activity

Six new cycloartane-type triterpenes (1-6), 24-methylenecycloartane-3β,6β,7β-triol (1), 24-methylenecycloartane-3β,6β,7β,16β-tetraol (2), 24-methylenecycloartane-3β,6β,16β-triol (3), 24-methylenecycloartane-3β,7β,16β-triol 3-O-β-d-xylopyranoside (4), 24-methylenecycloartane-3β,6β,16β-triol 3-O-β-d-xylopyranoside (5), and 24-methylenecycloartane-3β,6β,7β-triol 3-O-β-d-xylopyranoside (6), were isolated from the leaves of Homonoia riparia, together with one known compound, 24-methylenecycloartane-3β,6β,7β,16β-tetraol 3-O-β-d-xylopyranoside (7). The structures of the new triterpenes were established by spectroscopic studies and from chemical evidence, and the inhibitory effects of compounds 1 and 3-7 on VEGF-induced vascular permeability were examined in vivo in rats using the Miles assay. In addition, the inhibitory effect of 7 on VEGF-induced tube formation by HUVECs in vitro was investigated.

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.

Phytochemical study and anti-inflammatory, antidiabetic and free radical scavenger evaluations of Krameria pauciflora methanol extract.

The plant Krameria pauciflora MOC et. Sessé ex DC. is used as an anti-inflammatory and antidiabetic in traditional medicine. The aim of this study was to evaluate the in vivo anti-inflammatory and antidiabetic effects of a methanol extract from the roots of K. pauciflora. Dichloromethane and ethyl acetate extracts obtained by partitioning the methanol extract were also evaluated. Complete methanol and dichloromethane extracts showed anti-inflammatory effects at 3 mg/kg. An anti-inflammatory effect similar to indomethacin (10 mg/kg) was observed when the methanol and dichloromethane extracts, which contain a cycloartane-type triterpene and an sterol, were administered orally at several doses (3, 10, 30 and 100 mg/kg), whereas no anti-inflammatory effect was observed at any dose for the ethyl acetate extract, which contains catechin-type flavonoids. The antidiabetic effect of each extract was also determined. An antihyperglycaemic effect was observed in diabetic rats, but no effect in normoglycaemic animals was observed when the methanol extract was administrated at 30 mg/kg. All of the extracts exhibited radical scavenger activity. Additionally, constituents from all of the extracts were identified by NMR. This article supports the use of K. pauciflora as an anti-inflammatory because it exhibits a similar effect to indomethacin. However, its antidiabetic effect is not completely clear, although it could be useful for preventing diabetic complications.

Cycloartane glycosides from Astragalus stereocalyx Bornm.

Six cycloartane-type triterpene glycosides were isolated from Astragalus stereocalyx along with six known cycloartane-type glycosides. Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Three compounds are based on an aglycon characterized by the occurrence of an unusual hydroxyl group at position 20, whereas three other compounds are based on cycloasgenin C as aglycon, so far reported from Astragalus spp. All the compounds were tested for their cytotoxic activity against a number of cancer cell lines. One compound exhibited activity versus human cervical cancer (Hela) with an IC 50 value = 10 μM.

Unusual Cycloartane Saponins with Cytotoxic Activity from Astragalus stereocalyx Bornm.

The genus Astragalus L., which is included 10 subgenera and approximately 150 sections, today it contains about 2500–3000 species and subspecies according to some sources (1–2). In Turkish folk medicine, the aqueous extracts of some Astragalus species (declared by the healer) are used to treat leukaemia as well as for wound healing (3). Six new cycloartane-type triterpene glycosides (1–6) were isolated from Astragalus stereocalyx Bornm. along with six known cycloartane-type glycosides (Figure). Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Compounds 1-3 are based on a new aglycon characterized by the occurrence of an unusual hydroxyl group at position 20, whereas compounds 4-6 are based on cycloasgenin C as aglycon, so far reported from Astragalus spp. All of the compounds tested for their cytotoxic activities against a number of cancer cell lines. Among the compounds, only 10 exhibited activity versus human cervical cancer (Hela) at 10µM concentration.

Cycloartane glycosides from Astragalus aureus

Eight cycloartane-type triterpene glycosides ( 1– 8) were isolated from Astragalus aureus Willd along with ten known cycloartane-type glycosides ( 9– 18). Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. Compounds 1– 5 are cyclocanthogenin glycosides, whereas compounds 6– 8 are based on cyclocephalogenin as aglycon, more unusual in the plant kingdom, so far reported only from Astragalus spp. Moreover, for the first time monoglycosides of cyclocanthogenin ( 5) and cyclocephalogenin ( 7, 8) are reported. All of the compounds tested for their cytotoxic activities against a number of cancer cell lines. Among the compounds, only 8 exhibited activity versus human breast cancer (MCF7) at 45 μM concentration.

Indonesian propolis: chemical composition, biological activity and botanical origin

From a biologically active extract of Indonesian propolis from East Java, 11 compounds were isolated and identified: four alk(en)ylresorcinols (obtained as an inseparable mixture) (1–4) were isolated for the first time from propolis, along with four prenylflavanones (6–9) and three cycloartane-type triterpenes (5, 10 and 11). The structures of the components were elucidated based on their spectral properties. All prenylflavanones demonstrated significant radical scavenging activity against diphenylpicrylhydrazyl radicals, and compound 6 showed significant antibacterial activity against Staphylococcus aureus. For the first time Macaranga tanarius L. and Mangifera indica L. are shown as plant sources of Indonesian propolis.

Cycloartane-type glycosides from the roots of Astragalus caspicus Bieb.

Two new cycloartane-type glycosides, caspicuside I and caspicuside II, were isolated along with two known saponins, cycloastragenol and astragaloside IV, from the roots of Astragalus caspicus. As the aglycon group, caspicuside I possesses 3β,6α,16β,(24S),25-pentahydroxycycloartane (cyclocanthagenol), while caspicuside II owns (20R, 24S)-epoxy-3β, 6α,16β, 25-tetrahydroxycycloartane (cycloastragenol). The chemical structures of these new cycloartane-type glycosides were established as 3-O-α-L-rhamnopyranosyl-16-O-β-D-xylopyranosyl-cyclocanthogenol and 3-O-[β-D-xylopyranosyl(1 → 3)-β-D-glucopyranosyl]-6-O-β-xylopyranosyl-cycloastragenol, respectively. These findings add to a growing body of literature demonstrating the high variation of cycloartane-type triterpene glycosides in different species of Astragalus.

Triterpene glycosides from Astragalus and their genins. LXXXV. Structure of cyclomacroside E

The structure of a new cycloartane-type triterpene glycoside, cyclomacroside E, which was isolated from roots of Astragalus macropus Bunge (Leguminosae), was established as 3-O-α-L-rhamnopyranoside,24-O[(β-D-xylopyranosyl)(1→2)-β-D-xylopyranoside]-24R-cycloartan-1α,3β,7β,24,25-pentaol.

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.

Gastroprotective effect of Astragaloside IV: role of prostaglandins, sulfhydryls and nitric oxide

This investigation evaluated the gastroprotective activity of Astragaloside IV, a cycloartane-type triterpene glycoside isolated from Astragalus zahlbruckneri. Gastric mucosal damage was induced in rats by intragastric ethanol (1 mL/rat). Rats treated orally with Astragaloside IV suspended in Tween 80 at 3, 10 and 30 mg kg(-1), showed 15, 37 and 52% gastroprotection, respectively. The gastroprotection observed at 30 mg kg(-1) for this compound was attenuated in rats pretreated with N(G)-nitro-L arginine methyl ester (70 mg kg(-1), i.p), a nitric oxide (NO)-synthase inhibitor, suggesting that the gastroprotective mechanism of this glycoside involves, at least in part, the participation of NO. The gastroprotective effect of Astragaloside IV was not affected by the inhibition of prostaglandin synthesis with indometacin (10 mg kg(-1), s.c.) nor by the block of endogenous sulfhydryls with N-ethylmaleimide (NEM, 10 mg kg(-1), s.c.). Carbenoxolone was used as a gastroprotective model drug and showed a dose-dependent gastroprotective effect (25, 43 and 88% of gastroprotection, at 3, 10 and 30 mg kg(-1), respectively). The partial participation of prostaglandins, sulfhydryls and NO was observed in the gastroprotective mechanism of carbenoxolone.

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-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-25-O-beta-D-glucopyranosyl-20(R),24(S)-epoxy-3beta,6alpha,16beta,25-tetrahydroxycycloartane, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-24-O-alpha-(4'-O-acetoxy)-L-arabinopyranosyl-16-O-acetoxy-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-24-O-alpha-L-arabinopyranosyl-16-O-acetoxy-3beta,6alpha,16beta,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.

Chemical Constituents of Propolis from Myanmar and Their Preferential Cytotoxicity against a Human Pancreatic Cancer Cell Line

A methanolic extract of propolis obtained in Myanmar was found to inhibit PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions (NDM), with a PC(50) value of 9.3 microg/mL. Bioactivity-guided fractionation of the extract led to the isolation of two new cycloartane-type triterpenes, (22Z,24E)-3-oxocycloart-22,24-dien-26-oic acid (1) and (24E)-3-oxo-27,28-dihydroxycycloart-24-en-26-oic acid (2), together with 13 cycloartanes (3-13) and four known prenylated flavanones (14-17). Among these, compound 1 exhibited the most potent preferential cytotoxicity (PC(50) 4.3 microM) in a concentration- and time-dependent manner. Furthermore, 1 induced apoptosis-like morphological changes of PANC-1 cells within 24 h of treatment.

Wound healing effects of cycloartane-type triterpenes isolated from Astragalus species

Wound healing effects of cycloartane-type triterpenes isolated from Astragalus species

A new cycloartane-type glycoside from Astragalus schottianus Boiss.

Astragalus L., the largest genus in the family Leguminosae, is represented by 380 species in the flora of Turkey [1]. The roots of Astragalus species represent a very old and well-known drug in traditional medicine for its usage as an antiperspirant, diuretic and tonic drug [2]. In the district of Anatolia, located in South Eastern Turkey, an aqueous extract of the roots of Astragalus is traditionally used against leukemia and for its wound-healing properties. Known biologically active constituents of Astragalus roots represent two major classes of chemical compounds, polysaccharides and saponins [2]. In our continuing search on Turkish Astragalus species, we have isolated a new cycloartane-type triterpene glycoside from methanolic extract of A. schottianus together with three known compounds by combined chromatografies on reverse phase C-18 and silica gel. The structure of the new compound (1) was determined as 20(R),25-epoxy-3-O-[α-L-arabinopyranosyl(1→2)-β-D-xylopyranosyl]-24-O-β-D-glucopyranosyl-3β,6α,16β,24α-tetrahydroxy-cycloartane by a combination of one- and two-dimensional NMR techniques.

SU3, an oxocycloartane diglucoside from Sutherlandia humilis

The structure of a new cycloartane-type triterpene glycoside was determined as 24,25- O-β - d-diglucopyranosyl-6α-hydroxycycloart-3-one (SU3) by spectroscopic methods. This is the first cycloartane diglycoside reported from the genus Sutherlandia (an important South African traditional medicine and general tonic known as cancer bush). It was isolated from a dwarf form of S. frutescens, currently known as Sutherlandia humilis.