Pentacyclic Triterpenoid Compound Research Articles

Identification of d-friedoolean-13-en-3-one (Taraxerone) as an antioxidant compound from sedom (Sedum sarmentosum)

A pentacyclic triterpenoid compound was isolated from the ethyl acetate extract of sedum (Sedum sarmentosum) and identified as d-friedoolean-13-en-3-one (taraxerone) by GC-MS and crystallographic analysis. The extraction yield of taraxerone was 74.12±0.57 mg/kg sedum (dry weight). The IC50 values of taraxerone were 102.34±1.53 μM and 1,763.81±12.63 μM/mL (Trolox equivalent) by the DPPH and ferric reducing ability of plasma (FRAP) assays, respectively. Taraxerone exhibited comparable antioxidant capacities with butylated hydroxytoluene (BHT) by the DPPH (p=0.117) and FRAP (p= 0.179) assays. The production of inducible nitric oxide in lipopolysaccharide-stimulated murine macrophage was inhibited by taraxerone (IC50=38.49±3.77 μM) via downregulation of inducible nitric oxide synthase (iNOS) expression at the transcriptional level. The inhibitory effect of taraxerone on nitric oxide generation was significantly more effective than that of caffeic acid and/or gallic acid.

Oleanolic acid

Oleanolic acid (3β-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpenoid compound with a widespread occurrence throughout the plant kingdom. In nature, the compound exists either as a free acid or as an aglycone precursor for triterpenoid saponins, in which it can be linked to one or more sugar chains. Oleanolic acid and its derivatives possess several promising pharmacological activities, such as hepatoprotective effects, and anti-inflammatory, antioxidant, or anticancer activities. With the recent elucidation of its biosynthesis and the imminent commercialization of the first oleanolic acid-derived drug, the compound promises to remain important for various studies. In this review, the recent progress in understanding the oleanolic acid biosynthesis and its pharmacology are discussed. Furthermore, the importance and potential application of synthetic oleanolic acid derivatives are highlighted, and research perspectives on oleanolic acid are given.

Ursolic acid induces HL60 monocytic differentiation and upregulates C/EBPβ expression by ERK pathway activation

Ursolic acid (UA), a pentacyclic triterpenoid compound, is widely distributed in the plant kingdom and has a broad range of biological effects. This study was carried out for the first time to investigate the potential role of UA in the differentiation of human leukemia HL60 cells and the underlying mechanisms in it. UA could induce differentiation of HL60 cells into the monocytic lineage, as assessed by the morphological change, nitroblue tetrazolium reduction assay, and expression of CD14 and CD11b surface antigens. Moreover, UA activated the extracellular signal-regulated kinase (ERK) pathway in both dose-dependent and time-dependent manners. Inhibiting ERK pathway activation with PD98059 could significantly block the differentiation induced by UA. Consistent with the induced differentiation, the upregulation of CCAAT/enhancer-binding protein β by UA was also eliminated by PD98059. Taken together, the results reported here show that UA can promote the monocytic differentiation of HL60 cells and increase the expression of CCAAT/enhancer-binding protein β by activating the ERK pathway, suggesting that UA could be a potential candidate as a differentiation-inducing agent for the therapeutic treatment of leukemia.

Ursolic acid induces PC‐3 cell apoptosis via activation of JNK and inhibition of Akt pathways in vitro

Ursolic acid (UA), a pentacyclic triterpenoid compound, has been demonstrated to have an antiproliferative effect in various tumors. We investigated the cell killing effects of UA in the human hormone refractory prostate cancer cell line, PC-3 cells. Also, the molecular mechanisms underlying its antigrowth effect were explored. We found that UA treatment in vitro can effectively inhibit PC-3 cell viability in a dose-dependent manner by inducing apoptosis, demonstrated by annexin V-FITC/propidium iodide staining. Both extrinsic and intrinsic apoptotic pathways appear to be triggered by UA treatment, because inhibiting activation of both caspase-8 and -9 could prevent UA-induced apoptosis in PC-3 cells. The c-Jun N-terminal kinase (JNK) was found to be activated, followed by Bcl-2 phosphorylation and activation of caspase-9. On the other hand, UA inhibited the Akt pathway, subsequently upregulating the expression of Fas ligand (FasL), which initiates death receptor-mediated apoptosis in PC-3 cells. Importantly, experimentally lowering FasL expression by siRNA significantly inhibited UA-induced caspase-8 activation and at least partly attenuated the consequent apoptosis, suggesting an involvement of FasL and its regulating pathway in the cell killing effect of UA. UA also inhibited cell invasion by downregulating matrix metalloproteinase-9 via inhibition of Akt in PC-3 cells. Although further evaluation of the UA effects in vivo is needed, the present results suggest the potential utility of UA as a novel therapeutic agent in advanced prostate cancer.

In vitro Anti-Leishmanial and Anti-Tumour Activities of a Pentacyclic Triterpenoid Compound Isolated from the Fruits of Dregea volubilis Benth Asclepiadaceae

Purpose: Dregea volubilis Benth, commonly known as Jukti in Bengal, is used in the treatment of boils and abscesses from ancient times. The purpose of this study is to elucidate the active compounds and as well as their anti-leishmanial and anti-tumour activities. Methods: Dried and crushed fruits of Dregea volubilis were extracted by petroleum ether (40 - 60°C); the best solvent system had first been verified by analytical Thin Layer Chromatography (TLC). The extract was subjected to TLC and column chromatography (CC) to isolate the pure compounds. Spectra data were obtained by Infra Red pectroscopy, Mass Spectroscopy and Nuclear Magnetic Resonance - Proton Magnetic Resonance (PMR), Carbon Magnetic Resonance (CMR) and Distortionless Enhancement by Polarization Transfer (DEPT) - for structure elucidation of the isolated compound(s). One of the compounds isolated was screened for anti-leishmanial activity against promastigotes of Leishmania donovani and anti-tumour activity on K562 leukemic cell line. Results: A pentacyclic triterpenoid compound was isolated and designated as taraxerone, and then characterized as d-friedoolean-14-en, 3 one together with s-sitosterol and a long chain lipid fraction. This compound showed in vitro anti-leishmanial activity against promastigotes of Leishmania donovani (strain AG 83) and anti-tumour activity on K562 leukemic cell line. Conclusion: A pentacyclic triterpenoid compound designated as taraxerone and characterized as Dfriedoolean- 14-en, 3 one together was successfully isolated. The structure was determined on the basis of spectral analysis (IR, MASS, NMR (PMR, CMR and DEPT) and the compound demonstrated in vitro anti-leishmanial and anti-tumour activities.

Phosphorylation of Bcl-2 and activation of caspase-3 via the c-Jun N-terminal kinase pathway in ursolic acid-induced DU145 cells apoptosis

There is currently no successful therapy for androgen-independent prostate cancer. Ursolic acid (UA), a pentacyclic triterpenoid compound, has been shown to have an anti-proliferative effect on various tumors. We investigated the effect of UA on cell viability in the human hormone-refractory prostate cancer cell line DU145, as well as the molecular mechanisms underlying its growth inhibiting effect. We demonstrated that UA induces apoptosis and the activation of caspase-3 in DU145 cells. UA also causes the activation of c-Jun N-terminal kinase (JNK), but has no effect on extracellular signal-regulated protein kinases (ERK1/2) and p38 MAP kinases (p38). UA-induced JNK activation could result in Bcl-2 phosphorylation (Ser70) and degradation in DU145 cells, which may be one of the molecular mechanisms by which it induces apoptosis. Although further evaluation, such as in vivo testing, is clearly needed, the present results suggest the potential utility of UA as a novel therapeutic agent in advanced prostate cancer.

Synthesis and NO Production Inhibitory Activities of Ursolic Acid and Oleanolic Acid Derivatives

Ursolic acid and oleanolic acid are pentacyclic triterpenoid compounds with 30 carbon atoms, biosynthetically derived from the cyclization of squalene. Since these triterpenes are widely distributed in food, medicinal herbs and other plants, these compounds can be integral part of the human diet.

Ursolic Acid and Oleanolic Acid Suppress Preneoplastic Lesions Induced by 1,2-Dimethylhydrazine in Rat Colon

Ursolic acid (UA) and oleanolic acid (OA) are pentacyclic triterpenoid compounds found in plants used in the human diet and in medicinal herbs, in the form of aglycones or as the free acid. These compounds are known for their hepatoprotective, anti-inflammatory, antimicrobial, hypoglycemic, antimutagenic, antioxidant, and antifertility activities. In the present study, we evaluated the effects of UA and OA on the formation of 1,2-dimethyl-hydrazine (DMH)-induced aberrant crypt foci (ACF) in the colon of the male Wistar rat. The animals received subcutaneous (sc) injections of DMH (40 mg/kg body weight) twice a week for two weeks to induce ACF. UA, OA and a mixture of UA and OA were administered to the rats five times a week for four weeks by gavage at doses of 25 mg/kg body weight/day each, during and after DMH treatment. All animals were sacrificed in week 5 for the evaluation of ACF. The results showed a significant reduction in the frequency of ACF in the group treated with the triterpenoid compounds plus DMH when compared to those treated with DMH alone, suggesting that UA and OA suppress the formation of ACF and have a protective effect against colon carcinogenesis.

Endogenous reverse transcriptase as a mediator of ursolic acid’s anti-proliferative and differentiating effects in human cancer cell lines

Ursolic acid (UA) is a pentacyclic triterpenoid compound that is widely distributed in the plant kingdom and has a broad range of biological effects. Here, we examined the effects of UA on the proliferation and differentiation of human tumor cell lines from melanoma (A375), glioblastoma (U87) and thyroid anaplastic carcinoma (ARO), and on the proliferation of a non-transformed human fibroblast cell line (WI-38). The results show that UA inhibits tumor cell proliferation in a dose- and time-dependent manner. Consistent with this finding, UA treatment promotes differentiation of all of the analyzed tumor cell lines. Interestingly, we found that UA inhibits the endogenous reverse transcriptase (RT) activity in tumor cells, which has recently been shown to be involved in the control of proliferation and differentiation of neoplastic cells. Considering these findings, we suggest that the observed anti-proliferative and differentiating effects of UA may be related to this target.

Differential involvement of mitochondria during ursolic acid-induced apoptotic process in HaCaT and M4Beu cells

Ursolic acid (UA) is a pentacyclic triterpenoid compound which exists widely in nature and is known to have a pleitropic biological activity profile. For the last few decades, extensive work has been carried out to establish its biological activities and pharmacological actions. It is described as a promising chemopreventive agent with an antiproliferative effect on cancer cells that stems from its ability to induce apoptosis. We investigated and compared the role played by mitochondria during the apoptotic process induced by UA in human HaCaT-derived keratinotic cells and M4Beu human melanoma cells. In both cell lines, UA induced significant caspase-3 activation, the downstream central effector of apoptosis. Subsequent JC-1/TOTO-3 double staining clearly demonstrated that UA induces strong mitochondrial-transmembrane potential collapse in M4Beu cells, while mitochondria from HaCaT-treated cells remain largely unstimulated. This was confirmed by Western blot analysis, which revealed a Bax/Bcl-2-balance change in favor of Bax, the proapoptotic member, in UA-treated M4Beu cells. It can be concluded that UA induces apoptosis in M4Beu through the mitochondrial pathway, while other mechanisms are activated in the case of HaCaT cells.

ISOLATION OF PENTACYCLIC TRITERPENOID COMPOUNDS FROM LITHOCARPUS ELEGANS (BL.) HATUS. EX SOEP. BY ELECTROCOAGULATION

ISHS III WOCMAP Congress on Medicinal and Aromatic Plants - Volume 3: Perspectives in Natural Product Chemistry ISOLATION OF PENTACYCLIC TRITERPENOID COMPOUNDS FROM LITHOCARPUS ELEGANS (BL.) HATUS. EX SOEP. BY ELECTROCOAGULATION

Ursolic acid induces Bax-dependent apoptosis through the caspase-3 pathway in endometrial cancer SNG-II cells

The goal of this study was to examine the effect of ursolic acid, a pentacyclic triterpenoid compound, on growth of the endometrial cancer cell line SNG-II. We found that ursolic acid strongly inhibited the growth of SNG-II cells in a dose- and time-dependent manner. Morpholgical changes characteristic of apoptosis were observed in treated cells, such as the presence of apoptotic bodies and fragmentation of DNA into oligonucleosomal-sized fragments. We also investigated the active forms of caspase-3, -8 and -9 in ursolic acid-treated SNG-II cells. At 25 and 50 microM strength, ursolic acid induced marked increases in caspase-3 activity to approximately 5-fold that of control cells. Levels of cleaved caspase-3 increased in a time- and dose-dependent manner. Activation of caspases also led to the cleavage of target proteins, such as PARP. Ursolic acid treatment also resulted in a cleavage of poly (ADP-ribose) polymerase in a dose-dependent manner. Testing whether caspase-3 activation and DNA polymerase activity were inhibited by addition of Ac-DEDV-HCO during ursolic acid treatment showed that 50 microM Ac-DEDV-HCO inhibited caspase-3 activity in treated cells. Although DNA fragmentation was observed after ursolic acid treatment, DNA fragmentation did not occur in SNG II cells treated with both Ac-DEDV-HCO and ursolic acid. Because some researchers have suggested that mitochondrial pathways are involved in ursolic acid-induced apoptosis secondary to induction of mitochondrial cytochrome c release, we studied mitochondrial events in ursolic acid-induced apoptosis in these cell lines. After ursolic acid treatment, the anti-apoptotic Bcl-2 protein decreased and Bax expression was enhanced. Our results indicated that ursolic acid induced apoptotic processes in the endometrial cancer SNG-II cell line through mechanisms involving mitochondrial pathways and Bcl-2 family proteins.

Anti-AIDS Agents. Part 57: Actein, an anti-HIV principle from the rhizome of Cimicifuga racemosa (black cohosh), and the anti-HIV activity of related saponins

Actein (1), a tetracyclic triterpenoid from the rhizome of Cimicifuga racemosa (black cohosh), and 82 related triterpenoid and steroidal saponins isolated from higher plants were evaluated for anti-HIV activity as a continuing study to discover potential anti-AIDS agents from natural products. Actein showed potent activity and another twelve saponins showed moderate activity. The active compounds included two steroidal, seven tetracyclic triterpenoid, and four pentacyclic triterpenoid compounds.

Chemistry and cancer preventing activities of ginseng saponins and some related triterpenoid compounds.

More than 25 dammarane-type tetracyclic triterpenoid saponins have been isolated from ginseng, the root and rhizome of Panax ginseng C.A. Meyer (Araliaceae). The genuine sapogenins of those saponins, 20(S)-protopanaxa-diol and -triol, were identified as 20(S) 12beta-hydroxy-and 20(S) 6alpha,12beta-dihydroxy-dammarenediol-II, respectively. There are two types of preparations from ginseng: white ginseng prepared by drying after peelling off and red ginseng prepared by steaming and drying. Some partly deglycosylated saponins such as ginsenoside Rh-1, Rh-2, and Rg-3 are obtained from red ginseng as artifacts produced during steaming. Several workers studied the metabolic transformation by human intestinal bacteria after oral administration of ginsenoside Rb-1 and Rb-2 and found that the stepwise deglyco-sylation yielded compound K and finally 20(S)-protopanaxadiol. Ginsenoside Rg-1 was converted into 20(S)-protopanaxatriol via ginsenoside Rh-1. Yun et al. in Korea conducted the epidemiological case-control studies of ginseng and suggested its cancer preventing activities. Kitagawa et al. demonstrated in vitro that ginsenosides, especially 20(R)-ginsenoside Rg-3, specifically inhibited cancer cell invasion and metastasis. Azuma et al. found that ginsenoside Rb-2 inhibited tumor angiogenesis, and Kikuchi et al. reported that ginsenoside Rh-2 inhibited the human ovarian cancer growth in nude mice. Recently, ginsenoside Rg-3 was produced as an anti-angiogenic anti-cancer drug in China. The aforementioned reports suggest that less glycosylated protopanaxadiol derivatives are effective in cancer prevention. Apart from Ginseng tetracyclic triterpenoid saponins, some oleanane-type pentacyclic triterpenoid compounds showed the anti-carcinogenic activity in the two-stage anti-cancer-promotion experiments in vitro and in vivo.

Ursolic acid triggers calcium-dependent apoptosis in human Daudi cells.

Ursolic acid (UA) is a pentacyclic triterpenoid compound which occurs naturally in a large variety of vegetarian foods, medicinal herbs and plants. In the present study, ursolic acid was found to decrease cell viability in human lymphoma Daudi cells in a dose-dependent manner. UA also induced morphological changes in cells as well as loss of membrane asymmetry, DNA fragmentation and nuclei condensation, indicating that the mechanism by which UA induced cell death was through apoptosis. Treatment with UA increased intracellular Ca2+ levels. Use of Ca2+ channel inhibitors like verapamil blocked this Ca2+ influx and also the triggering of apoptosis. We hypothesized that the binding of UA to glucocorticoid receptors and the Ca2+ currents induced constituted the first steps of apoptosis.

Myricadiol and Other Taraxerenes fromScaevola spinescens

Scaevola spinescens R. Br. (Goodeniaceae), a West Australian semi-arid native plant, has been found to contain a number of pentacyclic triterpenoid compounds of the taraxerene type in high yield compared with other species in which these compounds are known to occur. Isolation of these molecules, which are potential lead compounds for synthetic anti-cancer drugs, was achieved by partitioning the diethyl ether-soluble fraction, of the methanol Soxhlet extract, between hexane and aqueous methanol, followed by base extraction of minor components from the methanol isolate and recrystallisation or column chromatography. The major component isolated from the extract, and main subject of this report, is the pentacyclic triterpenoid, 14-taraxerene-3,28-diol (1; myricadiol).

Novel extended side-chain-unsaturated hopenes released from the kerogen macromolecules under artificial conditions

A novel family of hopanoids present in pyrolysates of solvent-extracted peat from Caohai Basin, Southwest China, has been tentatively identified on the basis of GC-MS data as C 32C 35 extended side-chain-unsaturated hopenes. These unsaturated pentacyclic triterpenoid compounds are produced by laboratory thermal decomposition of kerogen. The results of our pyrolysis experiments suggest that these structures result from thermal release of bound C 35 bacteriohopanepolyols which are bonded to the kerogen macromolecule via polyether or polyester linkages. The finding of these new hopenes indicates that pyrolysis can provide information about the types of linkings and sites of bonding of hopane units to the macromolecular network. Meanwhile, this study also provides valuable information on the way that these hopane skeletons are released from a kerogen structure under thermal stress. These novel extended side-chain-unsaturated hopenes may act as intermediates in the transformation of bound C 35 hopanoid precursors to free C 27C 35 hopanes under artificial conditions.

IDENTIFICATION OF AN ADHESIVE USED TO REPAIR A ROMAN JAR

A combination of micro‐analytical techniques, including thin layer chromatography (TLC), gas chromatography (GC), and combined gas chromatography/mass spectrometry (GC/MS), was employed to study the lipid composition of an adhesive used to repair an Ecton ware jar, recovered from Roman sediments of the River Nene at West Cotton (Rounds, Northamptonshire, U.K.). GC of the total lipid extract of the adhesive showed a complex pattern which was difficult to interpret. TLC was used to fractionate the extract. The fractions were then trimethylsilylated and submitted to GC and GC/MS. Betulin, lupeol, lupenone, allobetul‐2‐ene, and several other pentacyclic triterpenoid compounds were shown to be present in the ancient material. The similarities between the lipid compositions of the adhesive and of contemporary birch bark tar and a birch bark total lipid extract led to the conclusion that the adhesive was derived largely from birch bark, thus providing the first firm evidence for the use of birch bark tar in ancient Britain.

Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara

Lantadene A (22 beta-angeloyloxy-3-oxo-olean-12-en-28-oic acid), a pentacyclic triterpenoid compound from lantana (Lantana camara) leaves has been obtained in two polymorphic forms I and II. Form I had white, fluffy, and rod-shaped uniform crystals. Form II particles were irregular, shining, and polyhedral. The two forms differed in melting behavior. The powder x-ray diffraction of form I showed sharp peaks whereas from II did not contain distinct peaks. From single-crystal three-dimensional x-ray structure determination, the molecular structure of form I has been established. A/B and B/C rings of the molecule are trans fused while D/E rings are cis fused. The packing of the molecule is stabilized by hydrogen bonding. Form I of lantadene A was non-toxic to guinea pigs on oral administration. Form II induced ictericity and toxicity associated with decrease in feed intake and fecal output, hepatomegaly, increase in plasma bilirubin, and acid phosphatase activity.

Pentacyclic triterpenes from the fungus, Leptosphaeria maculans

Fermented broth of the fungus, Leptosphaeria maculans gave two pentacyclic triterpenoid compounds. Based on spectral analysis these compounds were identified as maculaniol and 3α-hydroxy-urs-18,20-dien-28-oic acid.