Showing papers on "Triterpene published in 2009"

Pentacyclic triterpene distribution in various plants - rich sources for a new group of multi-potent plant extracts.

Abstract: Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark. In particular the lupane-, oleanane-, and ursane triterpenes display various pharmacological effects while being devoid of prominent toxicity. Therefore, these triterpenes are promising leading compounds for the development of new multi-targeting bioactive agents. Screening of 39 plant materials identified triterpene rich (> 0.1% dry matter) plant parts. Plant materials with high triterpene concentrations were then used to obtain dry extracts by accelerated solvent extraction resulting in a triterpene content of 50 - 90%. Depending on the plant material, betulin (birch bark), betulinic acid (plane bark), oleanolic acid (olive leaves, olive pomace, mistletoe sprouts, clove flowers), ursolic acid (apple pomace) or an equal mixture of the three triterpene acids (rosemary leaves) are the main components of these dry extracts. They are quantitatively characterised plant extracts supplying a high concentration of actives and therefore can be used for development of phytopharmaceutical formulations.

Pentacyclic triterpenes of the lupane, oleanane and ursane group as tools in cancer therapy.

Abstract: Today cancer treatment is not only a question of eliminating cancer cells by induction of cell death. New therapeutic strategies also include targeting the tumour microenvironment, avoiding angiogenesis, modulating the immune response or the chronic inflammation that is often associated with cancer. Furthermore, the induction of redifferentiation of dedifferentiated cancer cells is an interesting aspect in developing new therapy strategies. Plants provide a broad spectrum of potential drug substances for cancer therapy with multifaceted effects and targets. Pentacyclic triterpenes are one group of promising secondary plant metabolites. This review summarizes the potential of triterpenes belonging to the lupane, oleanane or ursane group, to treat cancer by different modes of action. Since Pisha et al. reported in 1995 that betulinic acid is a highly promising anticancer drug after inducing apoptosis in melanoma cell lines in vitro and in vivo, experimental work focused on the apoptosis inducing mechanisms of betulinic acid and other triterpenes. The antitumour effects were subsequently confirmed in a series of cancer cell lines from other origins, for example breast, colon, lung and neuroblastoma. In addition, in the last decade many studies have shown further effects that justify the expectation that triterpenes are useful to treat cancer by several modes of action. Thus, triterpene acids are known mainly for their antiangiogenic effects as well as their differentiation inducing effects. In particular, lupane-type triterpenes, such as betulin, betulinic acid and lupeol, display anti-inflammatory activities which often accompany immune modulation. Triterpene acids as well as triterpene monoalcohols and diols also show an antioxidative potential. The pharmacological potential of triterpenes of the lupane, oleanane or ursane type for cancer treatment seems high; although up to now no clinical trial has been published using these triterpenes in cancer therapy. They provide a multitarget potential for coping with new cancer strategies. Whether this is an effective approach for cancer treatment has to be proven. Because various triterpenes are an increasingly promising group of plant metabolites, the utilisation of different plants as their sources is of interest. Parts of plants, for example birch bark, rosemary leaves, apple peel and mistletoe shoots are rich in triterpenes and provide different triterpene compositions.

Biological and pharmacological activities of squalene and related compounds: potential uses in cosmetic dermatology.

Abstract: Squalene is a triterpene that is an intermediate in the cholesterol biosynthesis pathway. It was so named because of its occurrence in shark liver oil, which contains large quantities and is considered its richest source. However, it is widely distributed in nature, with reasonable amounts found in olive oil, palm oil, wheat-germ oil, amaranth oil, and rice bran oil. Squalene, the main component of skin surface polyunsaturated lipids, shows some advantages for the skin as an emollient and antioxidant, and for hydration and its antitumor activities. It is also used as a material in topically applied vehicles such as lipid emulsions and nanostructured lipid carriers (NLCs). Substances related to squalene, including β-carotene, coenzyme Q10 (ubiquinone) and vitamins A, E, and K, are also included in this review article to introduce their benefits to skin physiology. We summarize investigations performed in previous reports from both in vitro and in vivo models.

Pentacyclic triterpenoids from the medicinal herb, Centella asiatica (L.) Urban.

Abstract: Centella asiatica accumulates large quantities of pentacyclic triterpenoid saponins, collectively known as centelloids. These terpenoids include asiaticoside, centelloside, madecassoside, brahmoside, brahminoside, thankuniside, sceffoleoside, centellose, asiatic-, brahmic-, centellic- and madecassic acids. The triterpene saponins are common secondary plant metabolites and are synthesized via the isoprenoid pathway to produce a hydrophobic triterpenoid structure (aglycone) containing a hydrophilic sugar chain (glycone). The biological activity of saponins has been attributed to these characteristics. In planta, the Centella triterpenoids can be regarded as phytoanticipins due to their antimicrobial activities and protective role against attempted pathogen infections. Preparations of C. asiatica are used in traditional and alternative medicine due to the wide spectrum of pharmacological activities associated with these secondary metabolites. Here, the biosynthesis of the centelloid triterpenoids is reviewed; the range of metabolites found in C. asiatica, together with their known biological activities and the chemotype variation in the production of these metabolites due to growth conditions are summarized. These plant-derived pharmacologically active compounds have complex structures, making chemical synthesis an economically uncompetitive option. Production of secondary metabolites by cultured cells provides a particularly important benefit to manipulate and improve the production of desired compounds; thus biotechnological approaches to increase the concentrations of the metabolites are discussed.

Dual biosynthetic pathways to phytosterol via cycloartenol and lanosterol in Arabidopsis.

Abstract: The differences between the biosynthesis of sterols in higher plants and yeast/mammals are believed to originate at the cyclization step of oxidosqualene, which is cyclized to cycloartenol in higher plants and lanosterol in yeast/mammals. Recently, lanosterol synthase genes were identified from dicotyledonous plant species including Arabidopsis, suggesting that higher plants possess dual biosynthetic pathways to phytosterols via lanosterol, and through cycloartenol. To identify the biosynthetic pathway to phytosterol via lanosterol, and to reveal the contributions to phytosterol biosynthesis via each cycloartenol and lanosterol, we performed feeding experiments by using [6-13C2H3]mevalonate with Arabidopsis seedlings. Applying 13C-{1H}{2H} nuclear magnetic resonance (NMR) techniques, the elucidation of deuterium on C-19 behavior of phytosterol provided evidence that small amounts of phytosterol were biosynthesized via lanosterol. The levels of phytosterol increased on overexpression of LAS1, and phytosterols derived from lanosterol were not observed in a LAS1-knockout plant. This is direct evidence to indicate that the biosynthetic pathway for phytosterol via lanosterol exists in plant cells. We designate the biosynthetic pathway to phytosterols via lanosterol “the lanosterol pathway.” LAS1 expression is reported to be induced by the application of jasmonate and is thought to have evolved from an ancestral cycloartenol synthase to a triterpenoid synthase, such as β-amyrin synthase and lupeol synthase. Considering this background, the lanosterol pathway may contribute to the biosynthesis of not only phytosterols, but also steroids as secondary metabolites.

Triterpene acids isolated from Lagerstroemia speciosa leaves as α-glucosidase inhibitors.

Abstract: The potential antidiabetic activity of ethyl acetate extract of the leaves of Lagerstroemia speciosa (LSL) was investigated by alpha-amylase and alpha-glucosidase inhibition assay. Six pentacyclic triterpenes (oleanolic acid, arjunolic acid, asiatic acid, maslinic acid, corosolic acid and 23-hydroxyursolic acid) were isolated from LSL. Their structures were determined by spectroscopic analysis and their alpha-glycosidase and alpha-amylase inhibitory activities were investigated. They exhibited no or weak inhibitory activity against alpha-amylase and middle alpha-glucosidase inhibitory activities. Corosolic acid, which shows best bioactivity against alpha-glucosidase (IC(50) = 3.53 mu g/mL), contributes most to the alpha-glucosidase inhibitory activity of EtOAc extract. The kinetics of inhibition of corosolic acid was also discussed. Results from this study might provide the scientific evidence for LSL for the treatment of diabetes in traditional medicine. Copyright (C) 2008 John Wiley & Sons, Ltd.

Squalene emulsions for parenteral vaccine and drug delivery.

Abstract: Squalene is a linear triterpene that is extensively utilized as a principal component of parenteral emulsions for drug and vaccine delivery. In this review, the chemical structure and sources of squalene are presented. Moreover, the physicochemical and biological properties of squalene-containing emulsions are evaluated in the context of parenteral formulations. Historical and current parenteral emulsion products containing squalene or squalane are discussed. The safety of squalene-based products is also addressed. Finally, analytical techniques for characterization of squalene emulsions are examined.

Upregulation of ginsenoside and gene expression related to triterpene biosynthesis in ginseng hairy root cultures elicited by methyl jasmonate.

Abstract: In this study, methyl jasmonate (MJ)-induced changes of triterpene saponins in ginseng (Panax ginseng C.A. Meyer) hairy roots and expression profiling of relevant responsive genes were analyzed. The transcription of PgSS (squalene synthase), PgSE (squalene epoxidase), and PNA (dammarenediol synthase-II) genes in hairy root cultures elicited by MJ treatment increased as compared with the controls, whereas that of PNX (cycloartenol synthase) decreased slightly. In order to select candidate genes encoding for cytochrome P450-dependent hydroxylase or glucosyltransferase associated with triterpene biosynthesis, RT-PCR analysis was conducted following MJ elicitation. No differences were observed in any expression among the five genes associated with the cytochrome P450 family, when compared to that of control. For candidates of the glucosyltransferase gene,expression of EST IDs PG07020C06, PG07025D04, and PG07029G02 was upregulated. In an effort to assess the effects of MJ elicitation on the biosynthesis of triterpene saponin, protopanaxadiol saponin (Rb group) and protopanaxatriol saponin (Rg group) contents in hairy roots were evaluated by HPLC analysis. With 7 days of MJ elicitation, levels of all ginseonsides of the two-groups increased much higher than that observed in the control. In particular, protopanaxadiol-type saponin contents increased by 5.5–9.7 times that of the control, whereas protopanaxatriol-type saponin contents were increased by 1.85–3.82-fold. In the case of Rg1 ginsenoside after MJ elicitation, the content was affected negatively in ginseng hairy root cultures.

Squalene: A natural antioxidant?

Abstract: Squalene (see left) is a triterpene and an intermediate in the biosynthesis of sterols in the plant and animal world [1]. The richest known source of squalene is shark liver oil. In vegetable oils, squalene is found over broad ranges [2]. For example, in flaxseed, grape seed, and soybean oils it is not detected, but is quite prominent in peanut (1.28 g/kg), pumpkin (3.53 g/kg), and olive oils (5.99 g/kg). Squalene is the main component of skin surface polyunsaturated lipids and shows some advantages for the skin as an emollient and antitumor compound [3]. The triterpene has also been found to have protective activity against several carcinogens. Conforti et al. [4] reported an antioxidant effect of squalene in a model of lipid peroxidation of liposomes; the IC50 value for squalene was 0.023 mg/mL. An ethyl acetate extract of Amaranthus caudatus examined using the same method was 20-fold less active. The regeneration of a-tocopherol by squalene in photo-oxidation studies was suggested by Psomiadou and Tsimidou [5]. This is in line with the hypothesis of Kohno et al. [6]. Squalene showed slight antioxidant activity when assayed by the crocin bleaching method [7]. In the same study, squalene demonstrated a synergistic effect with a-tocopherol and bsitosterol. The authors suggested that squalene could act as a competitive compound in the crocin bleaching reaction, thereby reducing the rate of oxidation. Results of Dessi et al. [8] showed that during temperature-dependent autoxidation and UVA-mediated oxidation, squalene acts mainly as a peroxyl radical scavenger. Yet, no radical scavenging activity was observed using the DPPH radical in 2-propanol [1]. Pure squalene assayed by the L-ORACFL method exhibited an antioxidant activity of 0.74 mmol Troloxequivalents/g [9]. The rate constant (ko) of quenching of singlet oxygen by squalene is reported to be similar to that of butylated hydroxytoluene (BHT) [6]. The electron donating characteristics of the methyl groups of squalene are essential to the large observed ko. Squalene, subjected to accelerated oxidation in a Rancimat apparatus at 1007C, showed a negligible antioxidant effect [10]. From experiments of Psomiadou and Tsimidou [1], a concentration-dependent moderate antioxidant activity of squalene – when stored at 40 and 627C in the dark – was evident, which was stronger then the case of olive oil compared to that found for sunflower oil and lard. The authors concluded that the weak antioxidant efficacy of squalene in olive oil may be explained by competitive oxidation of the various lipids present, which leads to a reduction in the rate of oxidation. In the study of Dessi et al. [8], the oxidative stability of polyunsaturated fatty acids was affected by squalene. This natural compound at a molar ratio to PUFA as 1:7 inhibited the oxidation of arachidonic and docosahexaenoic acids by 50%. The inhibition of oxidation of linoleic acid was determined to be 22%. Furthermore, squalene exerted a significant antioxidant activity in mild UVA-mediated PUFA oxidation. In experiments with rats, the combined administration of squalene and a PUFA concentrate resulted in a significant (P ,0.05) reduction in the level of lipid peroxidation in the heart tissue [11]. According to Haus et al. [12] squalene – since being a highly lipophilic compound – can readily pass across the PUFA-rich lipid bilayer into intracellular compartments; this is believed to aid in its capabilities as a potent antioxidant. Squalene was found to be a much stronger scavenger of hydroxyl radicals than endogenous reduced glutathione (GSH) [13]. During storage and in technological processes, squalene exhibited great stability. The losses of squalene during 6 months of dark storage of virgin olive oils at room temperature ranged from 26 to 47% [14]. However, contrasting findings were reported by Psomiadou and Tsimidou [15]. In their study an insignificant decrease of squalene content was observed in virgin olive oils stored in the dark at room temperature for 24 months. In photo-oxidation studies, squalene loss has been confirmed (4-12%) [5]. Under accelerated storage conditions (607C), squalene showed high stability in extra virgin olive oil. A loss of ,20% was observed within the induction period [16]. The processing stability of squalene in amaranth was investigated by Tikekar et al [9]. These authors reported that squalene was stable during all processing operations with a maximum loss of only 12% during roasting (20 min at 1507C). Squalene was also stable during pan-frying of French fries in different edible oils [17]. Chemical structure of squalene

Steroids and triterpenes from the fruit bodies of Ganoderma lucidum and their anti-complement activity

Abstract: To determine the anti-complement activity of natural triterpenes, chromatographic separation of the EtOAc-soluble fraction from the fruiting body of Ganoderma lucidum led to the isolation of three steroids and five triterpenoids. They were identified as ergosterol peroxide (1), ergosterol (2), genoderic acid Sz (3), stella sterol (4), ganoderic aic C1 (5), ganoderic acid A (6), methyl ganoderate A (7), and lucidenic acid A (8) based on spectroscopic evidence and physicochemical properties. These compounds were examined for their anti-complement activity against the classical pathway of the complement system. Compounds 2 and 3 showed potent anti-complement activity with IC50 values of 52.0 and 44.6 microM, respectively. Compound 1 exhibited significant inhibitory activity with an IC50 value of 126.8 microM, whereas compounds 4-8 were inactive. Our findings suggested that in addition to the ketone group at C-3, the delta7(8), delta9(11)-lanostadiene type triterpene also plays an important role in inhibiting the hemolytic activity of human serum against erythrocytes.

Biological activities and chemistry of saponins from Chenopodium quinoa Willd.

Abstract: Chenopodium quinoa Willd. is a valuable food source which has gained importance in many countries of the world. The plant contains various bitter-tasting saponins which present an important antinutritional factor. Various triterpene saponins have been reported in C. quinoa including both monodesmosidic and bidesmosidic triterpene saponins of oleanolic acid, hederagenin, phytolaccagenic acid, and serjanic acid as the major aglycones and other aglycones as 3β-hydroxy-23-oxo-olean-12-en-28-oic acid, 3β-hydroxy-27-oxo-olean-12-en-28-oic acid, and 3β, 23α, 30β-trihydroxy-olean-12-en-28-oic acid. A tridesmosidic saponin of hederagenin has also been reported. Here we review the occurrence, analysis, chemical structures, and biological activity of triterpene saponins of C. quinoa. In particular, the mode of action of the mono- and bidesmosidic triterpene saponins and aglycones are discussed.

Triterpenoid Saponins from Rubus ellipticus var. obcordatus

Abstract: Ten new triterpenoid saponins (1-10), named rubusides A-J, and 21 known saponins (11-31) were isolated from the roots of Rubus ellipticus var. obcordatus. The structures of 1-10 were established on the basis of spectroscopic analyses, mainly NMR and MS, and chemical degradations. The compounds demonstrated inhibitory activities against alpha-glucosidase with IC50 values in the range 0.65-3.09 mM.

Triterpene glycosides from Antarctic sea cucumbers. 2. Structure of Achlioniceosides A(1), A(2), and A(3) from the sea cucumber Achlionice violaecuspidata (=Rhipidothuria racowitzai).

Abstract: Three new triterpene glycosides, achlioniceosides A(1) (1), A(2) (2), and A(3) (3), have been isolated from the Antarctic sea cucumber Achlionice violaecuspidata. The glycoside structures were elucidated using extensive NMR spectroscopic analysis including one-dimensional (1)H and (13)C spectra, (1)H-(1)H-COSY, HMBC, HMQC, and NOESY and mass spectrometry. Gycosides 1-3 are disulfated pentaosides that are branched at the first xylose residue. The sulfates are attached to C-6 of the glucose residues. Glycosides 1-3 are the first triterpene glycosides isolated from a sea cucumber belonging to the order Elasipodida.

Enhanced triterpene saponin biosynthesis and root nodulation in transgenic barrel medic (Medicago truncatula Gaertn.) expressing a novel beta-amyrin synthase (AsOXA1) gene.

Abstract: Triterpene saponins are a group of bioactive compounds abundant in the genus Medicago, and have been studied extensively for their biological and pharmacological properties. In this article, we evaluated the effects of the ectopic expression of AsOXA1 cDNA from Aster sedifolius on the production of triterpene saponins in barrel medic (Medicago truncatula Gaertn.). AsOXA1 cDNA encodes beta-amyrin synthase, a key enzyme involved in triterpene saponin biosynthesis. One of the four transgenic lines expressing AsOXA1 accumulated significantly larger amounts of some triterpenic compounds in leaf and root than did control plants. In particular, the leaf exhibited significantly higher levels of bayogenin, medicagenic acid and zanhic acid. The amounts of medicagenic acid and zanhic acid, which represent the core of the M. truncatula leaf saponins, were 1.7 and 2.1 times higher, respectively, than the amounts extracted from the control line. In root, the production of bayogenin, hederagenin, soyasapogenol E and 2beta-hydroxyoleanolic acid was increased significantly. The increase in the total amounts of triterpenic compounds observed in the leaves of transgenic lines correlated with the AsOXA1 expression level. Interestingly, the plants expressing AsOXA1 showed, under different growth conditions, improved nodulation when compared with the control line. Nodulation enhancement was also accompanied by a significant change in the soyasapogenol B content. Our results indicate that the ectopic expression of AsOXA1 in barrel medic leads to a greater accumulation of triterpene saponins and enhanced root nodulation.

Current synthesis of triterpene saponins.

Abstract: Triterpene saponins are a structurally and biologically diverse class of glycoconjugates of triterpenes that are widely distributed in terrestrial plants and some marine organisms. Current synthesis of these complex glycoconjugates has been discussed, whereupon the stereocontrolled glycosylation, global protection/deprotection, and the total synthesis of four unusual triterpene saponins are highlighted.

Acylated Oleanane-Type Triterpene Saponins with Acceleration of Gastrointestinal Transit and Inhibitory Effect on Pancreatic Lipase from Flower Buds of Chinese Tea Plant (Camellia sinensis)†

Abstract: The MeOH extract and its BuOH-soluble fraction (crude saponin fraction) from the flower buds of Chinese tea plant (Camellia sinensis (L.) O. KUNTZE; Fujian Province) were found to exhibit accelerating effects on gastrointestinal transit in mice and inhibitory effects against pancreatic lipase. From the BuOH-soluble fraction, three new acylated oleanane-type triterpene oligoglycosides, chakasaponins I, II, and III (1-3, resp.), were isolated together with 13 known compounds. The chemical structures 1-3 were elucidated on the basis of chemical and physicochemical evidence. Compounds 1-3 showed accelerating effects on gastrointestinal transit in mice and inhibitory effects against porcine pancreatic lipase (IC(50)=150-530 microM).

Brazilian natural medicines. III. structures of triterpene oligoglycosides and lipase inhibitors from mate, leaves of ilex paraguariensis.

Abstract: The methanolic extract from the leaves of Ilex paraguariensis (Aquifoliaceae) was found to show an inhibitory activity on porcine pancreatic lipase. From the methanolic extract, three new triterpene oligoglycosides, mateglycosides A, B, and C, were isolated together with 18 known compounds. The chemical structures of new oligoglycosides were elucidated on the basis of chemical and physicochemical evidence. Several constituents showed inhibitory activities on pancreatic lipase.

Cucurbitane-type triterpenoids from the stems of Cucumis melo.

Abstract: Phytochemical investigation of the stems of Cucumis melo led to the isolation and identification of 21 cucurbitane-type triterpenoids, including nine new compounds (1-9) and 12 known compounds. Their structures were determined on the basis of spectroscopic analyses, chemical methods, and comparison with spectroscopic data in the literature. Two known compounds, cucurbitacin B (10) and cucurbitacin A (11), showed significant cytotoxic activity against the proliferation of A549/ATCC and BEL7402 cells in vitro. Of the new compounds, only compound 7 was weakly cytotoxic. The inhibitory effects of all compounds on the Jak-Stat3 signaling pathway were evaluated, but only cucurbitacin B (10) showed significant inhibitory activity of phosphotyrosine STAT3.

Cytotoxic Oleanane Triterpene Saponins from Albizia chinensis

Abstract: Three new oleanane-type triterpene saponins, albizosides A−C (1−3), were isolated from the stem bark of Albizia chinensis. Their structures were established by 1D and 2D NMR experiments and chemica...

Antifungal Triterpene Glycosides from the Sea Cucumber Bohadschia marmorata

Abstract: Four new holostan-type triterpene glycosides, marmoratoside A ( 1), 17 alpha-hydroxy impatienside A ( 2), marmoratoside B ( 3), 25-acetoxy bivittoside D ( 4), together with two known triterpene glycosides, impatienside A ( 5) and bivittoside D ( 6), were isolated from the sea cucumber Bohadschia Marmorata Jaeger. On the basis of spectroscopic analyses, including two-dimensional NMR techniques, and chemical reactions, the structures of the new triterpene glycosides were elucidated. Compounds 1, 2, 5, and 6 exhibited significant antifungal activity against six strains (0.70 < or = MIC (80) < or = 2.81 microM).