Oleanane-type triterpenoids from Aceriphyllum rossii and their cytotoxic activity

Bioactive Usual and Unusual Triterpenoids Derived from Natural Sources Used in Traditional Medicine

Triterpenoids are accessible in several terrestrial plants as well as marine organisms, including sponges, algae, fungi, and sea cucumbers are examples of marine creatures. So far, more than 20,000 natural triterpenoids have exhibited several varied bioactivities, including anticancer, antimalarial, anti-HIV, inhibit HIF-1 activation, antibacterial, chemopreventive, anti-inflammatory, antioxidant, cardioprotective, antiviral, neuroprotective, hepatoprotective, insecticidal, antidiabetic, cytotoxic. Several plants are used in folklore medicine to treat numerous ailments, and the preparation or uses of traditional practices have been scientifically validated. Although various structural diversity has been observed in the triterpenoids, this review presents the sources and uses of those triterpenoids that showed significant biological activities which could be accessible and promoted to familiar people in the form of traditional medicine or for industrial, or pharmaceutical applications.

Undescribed abietane-type diterpenoids and oleanane-type triterpenoids from the stem and branch of Tripterygium wilfordii

Six undescribed abietane-type diterpenoids (tripterydinoids A-F) and five undescribed oleanane-type triterpenoids (tripterytrinoids A-E) were obtained and determined from the stem and branch of Tripterygium wilfordii Hook. f. (Celastraceae). Tripterydinoids A-C possessed the abietane-type diterpenoid skeleton with rare 8, 9-epoxy ring. The structures of undescribed compounds were established by extensive spectroscopic studies [HRESIMS, 1D/2D-NMR and electronic circular dichroism (ECD) calculation]. The absolute configurations of tripterydinoids A, B, E and tripterytrinoid A were defined by X-ray crystallographic analyses. Bioactivity screening indicated that tripterydinoids A-C exhibited potent inhibitory effects against NO release in LPS-activated RAW 264.7 macrophages with IC₅₀ values of 6.93, 4.46 and 2.98 μM, respectively. Meanwhile, tripterydinoids A-D and tripterytrinoids B, C showed moderate and selective cytotoxicities against five human tumor cell lines (A375, Huh7, MCF-7, HCT-116 and NCI-H460).

Identification of Cytotoxic Constituents from the Whole Plant of Isodon ternifolius

A new oxygenated spiroketone, isodonspiroketone (1), and 4 known ones (2-5) were isolated from the whole plant of Isodon ternifolius (D.Don) Kudô. The structure of isodonspiroketone (1) was determined by nuclear magnetic resonance, mass spectroscopy, and circular dichroism spectral data. Compound 3 has not been previously isolated from I. ternifolius. Their cytotoxic activities were evaluated against A549, HepG2, and MDA-MB-231 cancer cell lines in vitro. New compound (isodonspiroketone, 1) showed moderate cytotoxic activities against A549, HepG2, and MDA-MB-231 cancer cell lines with half-maximal inhibitory concentration values of 23.84 ± 2.73, 27.77 ± 3.01, and 17.26 ± 1.61 μM, respectively; meanwhile, the others were inactive.

3-Hydroxyolean-12-en-27-oic Acids Inhibit RANKL-Induced Osteoclastogenesis in Vitro and Inflammation-Induced Bone Loss in Vivo

Olean-12-en-27-oic acids possess a variety of pharmacological effects. However, their effects and underlying mechanisms on osteoclastogenesis remain unclear. This study aimed to investigate the anti-osteoclastogenic effects of five olean-12-en-27-oic acid derivatives including 3α,23-isopropylidenedioxyolean-12-en-27-oic acid (AR-1), 3-oxoolean-12-en-27-oic acid (AR-2), 3α-hydroxyolean-12-en-27-oic acid (AR-3), 23-hydroxy-3-oxoolean-12-en-27-oic acid (AR-4), and aceriphyllic acid A (AR-5). Among the five olean-12-en-27-oic acid derivatives, 3-hydroxyolean-12-en-27-oic acid derivatives, AR-3 and AR-5, significantly inhibited receptor activator of nuclear factor-κB ligand (RANKL)-induced mature osteoclast formation by reducing the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, F-actin ring formation, and mineral resorption activity. AR-3 and AR-5 decreased RANKL-induced expression levels of osteoclast-specific marker genes such as c-Src, TRAP, and cathepsin K (CtsK) as well as c-Fos and nuclear factor of activated T cells cytoplasmic 1 (NFATc1). Mice treated with either AR-3 or AR-5 showed significant protection of the mice from lipopolysaccharide (LPS)-induced bone destruction and osteoclast formation. In particular, AR-5 suppressed RANKL-induced phosphorylation of JNK and ERK mitogen-activated protein kinases (MAPKs). The results suggest that AR-3 and AR-5 attenuate osteoclast formation in vitro and in vivo by suppressing RANKL-mediated MAPKs and NFATc1 signaling pathways and could potentially be lead compounds for the prevention or treatment of osteolytic bone diseases.

PTP1B Inhibitory Flavonoids From Orthosiphon stamineus Benth. and Their Growth Inhibition on Human Breast Cancer Cells

In our preliminary screening study on the protein tyrosine phosphatase 1B (PTP1B) inhibitory and cytotoxic activities, an ethyl acetate soluble fraction of the aerial part of Orthosiphon stamineus Benth. was found to inhibit PTP1B activity. Thus, based on assay-guided isolation of this active fraction, ten compounds (1-10) were purified and evaluated for their inhibitory effects on PTP1B and their growth inhibition on MCF7, tamoxifen-resistant MCF7 (MCF7/TAMR), and MDA-MB-231 human breast cancer cell lines. Among the isolates, compounds 5, 6, 9, and 10 showed potencies against PTP1B with IC50 values of 9.76, 10.12, 6.88, and 8.92 μM, respectively, followed by compounds 1 and 4 with IC50 values of 16.92 and 22.25 μM. Kinetic study showed that the active compounds (1, 5, 9, and 10) possessed mixed-competitive inhibition, which was similar to the positive control (ursolic acid, IC50 value of 3.42 μM, mixed-competitive). The others showed noncompetitive inhibition (4 and 6). In addition, all these active compounds (1, 4-6, and 9-10) displayed growth inhibition on three cancer cell lines, especially the most PTP1B inhibitory flavanones (9 and 10) exhibited comparable inhibitory effects on MCF7, MCF7/TAMR, and MDA-MB-231 cancer cells (IC50 values of 11.5 and 15.4, 8.9 and 10.5, and 17.6 and 21.3 μM, respectively) with tamoxifen, the positive control used in this assay (IC50 values of 11.9, 12.1, and 12.7 μM, respectively). The results suggest that these active constituents from O. stamineus might be considered as new natural compounds for the development of anticancer agents via PTP1B inhibition.

Chemical constituents from the fruits of Ligustrum japonicum and their inhibitory effects on T cell activation

A previously undescribed nor-dammarane, 3β,20,23-trihydroxy-24,25,26,27-tetranordammarane; three previously undescribed secoiridoid glycosides, ligujaponosides A-B, and iso-oleonuzhenide; and twenty three known compounds, were isolated from the fruits of Ligustrum japonicum Thunb. Their chemical structures were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR, and HRMS. The isolated compounds were screened for immunosuppressive effects on T activated cells by evaluating interleukin-2 (IL-2) production. Among them, sesamin inhibited IL-2 production in Jurkat T cells with an IC50 value of 38 ± 2 μM. In addition, sesamin inhibited the phosphorylation of extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase (MAPK) family, in phorbol 12-myristate 13-acetate (PMA)/A23187-stimulated T cells. Therefore, sesamin was demonstrated to inhibit T cell activation via regulation of MAPK phosphorylation pathway.

Biologically active xanthones from Codonopsis ovata

Five new xanthones, named coxanthones A-E (1-5), together with 21 known secondary metabolites (6-26) that include seven xanthones, five flavonoids, two steroids and seven triterpenoids were isolated from the chemically unexplored whole plant Codonopsis ovata. The structures of new metabolites were elucidated by HRMS, interpretation of NMR spectra and other spectroscopic techniques. The absolute configuration of the stereogenic centre of coxanthone B (2) was determined by electronic circular dichroism (ECD) spectroscopy. This is the first report of xanthones from the genus Codonopsis. All isolated metabolites were evaluated for cytotoxic activity by SRB assay against six human cancer cell lines A549 (lung), PC-3 (prostate), HCT-116 (colon), MCF-7 (breast), SF-295 (CNS), and MDAMB-435 (melanoma). Among the new compounds, coxanthone B (2) exhibited significant inhibitory activity against SF-295 and MDAMB-435 with IC₅₀ values of 7.0 and 15.0 μM, respectively. Coxanthone A (1) displayed cytotoxicity against A549 cell line at IC₅₀ value of 22.5 μM. Cytotoxic activity of 1-hydroxy-3,5-dimethoxyxanthone (7), swertiperenine (9) and 1,7,8-trihydroxy-3-methoxyxanthone (10) are reported here first time that exhibited the IC₅₀ values of 3.0, 5.0 and 21.0 μM against A549, MDAMB-435, and A549 cell lines, respectively. Kaempferol (13) showed most potent cytotoxic activity with an IC₅₀ values in the 1.0-2.3 μM range against all tested cancer cell lines.

Isolation of a New Homomonoterpene from Madhuca Pasquieri and Effect of Isolated Compounds on NO Production

A new homomonoterpene, l,3,3-trimethyl-7-oxabicyclo[3.1.1]hexa-9-en-10-oic acid, named madhusic acid A (1), together with ten known compounds (2-11) were isolated from the methanolic extract of the dried leaves of Madhuca pasquieri (Dubard) H. J. Lam. The structure of the new compound was elucidated on the basis of ID, 2D NMR (COSY, HMQC, and HMBC) and mass spectral analyses. We examined the effects of the isolated compounds against LPS-induced NO production in macrophage RAW264.7 cells and compound 2 showed effective activity with an IC50 value of 14.5 μM.

Anti-inflammatory Activity of Pyrrolizidine Alkaloids from the Leaves of Madhuca pasquieri (Dubard)

A novel pyrrolizidine alkaloids, madhumidine A (1), and two known alkaloids, lindelofidine benzoic acid ester (2) and minalobine B (3) were isolated from the leaves of Madhuca pasquieri (Dubard) H. J. LAM. The chemical structures of these alkaloids were established mainly by NMR techniques and mass spectrometry. Their anti-inflammatory activity was evaluated against lipopolysaccharide-induced nitric oxide production in macrophage RAW264.7 cell. In addition, the cytotoxic activity of all isolated compounds was tested against a panel of cancer cell lines.

Amino Acid-Derived Metabolites from the Ascidian Aplidium sp

Four new iodobenzene-containing dipeptides (1-4), a related bromotryptophan-containing dipeptide (5), and an iodophenethylamine (6) were isolated from the ascidian Aplidium sp. collected off the coast of Chuja-do, Korea. The structures of these novel compounds, designated as apliamides A-E (1-5) and apliamine A (6) were determined via combined spectroscopic analyses. The absolute configuration of the amino acid residue in 1 was determined by advanced Marfey's analysis. Several of these compounds exhibited moderate cytotoxicity and significant inhibition against Na+/K+-ATPase (4).

Pentacyclic Triterpenoids from Astilbe rivularis that Enhance Glucose Uptake via the Activation of Akt and Erk1/2 in C2C12 Myotubes

Glucose uptake into insulin-sensitive tissues is important for the regulation of blood glucose. This study has investigated whether the pentacyclic triterpenoids substituted with a carboxylic acid at the C-27 position isolated from Astilbe rivularis can enhance glucose uptake and subsequently to also examine their underlying molecular mechanisms. The structure of the new pentacyclic triterpenoid 1 was assigned by spectroscopic data interpretation. To evaluate the activity of compounds 1 and 2, glucose uptake and glucose transporter 4 (GLUT4) translocation were measured in C2C12 myotubes. The C-27-carboxylated triterpenoids 1 and 2 significantly increased basal and insulin-stimulated glucose uptake and GLUT4 translocation to plasma membrane. Both compounds stimulated the phosphorylation of insulin receptor substrate-1 (IRS-1), protein kinase B (Akt), and extracellular signal-regulated kinase 1/2 (Erk1/2). Pretreatment with the Akt inhibitor triciribine or the Erk1/2 inhibitor U0126 decreased the ability of both compounds to enhance basal- and insulin-stimulated glucose uptake and stimulate GLUT4 translocation. These results indicate that compounds 1 and 2 activated both the IRS-1/Akt and Erk1/2 pathways and subsequently stimulated GLUT4 translocation, leading to enhanced glucose uptake. Thus, these observations suggest that C-27-carboxylated-pentacyclic triterpenoids may serve as scaffolds for development as agents for the management of blood glucose levels in disease states such as diabetes.

Bioactive Metabolites from the Fruits of Psoralea corylifolia

Twenty-four metabolites, including seven new compounds (1-7), were isolated from the dried fruits of Psoralea corylifolia. On the basis of combined spectroscopic and chemical analysis, the new compounds were determined to be six flavonoids (1-6) and a meroterpenoid (7). The absolute configurations of the natural products obtained, including the previously undetermined 16 and 17, were assigned by several methods, such as NOE spectroscopy, optical rotation, and CD spectroscopy. Several of these compounds exhibited moderate inhibitory activity toward Staphylococcus mutans-derived SrtA (2, 6, and 16) and significant stimulation of SIRT1 activity (2, 3, and 15).

Antimicrobial activity of oleanolic and ursolic acids: an update

Triterpenoids are the most representative group of phytochemicals, as they comprise more than 20,000 recognized molecules. These compounds are biosynthesized in plants via squalene cyclization, a C30 hydrocarbon that is considered to be the precursor of all steroids. Due to their low hydrophilicity, triterpenes were considered to be inactive for a long period of time; however, evidence regarding their wide range of pharmacological activities is emerging, and elegant studies have highlighted these activities. Several triterpenic skeletons have been described, including some that have presented with pentacyclic features, such as oleanolic and ursolic acids. These compounds have displayed incontestable biological activity, such as antibacterial, antiviral, and antiprotozoal effects, which were not included in a single review until now. Thus, the present review investigates the potential use of these triterpenes against human pathogens, including their mechanisms of action, via in vivo studies, and the future perspectives about the use of compounds for human or even animal health are also discussed.

Constituents of Vigna angularis and their in vitro anti-inflammatory activity

Nine non-phenolic compounds, including four furanylmethyl glycosides, angularides A-D, one ent-kaurane diterpene glycoside, angularin A, and four triterpenoid saponins, angulasaponins A-D, were isolated from seeds of Vigna angularis, together with eight known compounds. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic analysis as well as chemical methods. Angularin A, angulasaponins A-C, and azukisaponins III and VI showed inhibition of nitric oxide production in LPS-activated RAW264.7 macrophages, with IC50 values ranging from 13μM to 24μM.

Amino alcohols from the ascidian Pseudodistoma sp

Seven new amino alcohol compounds, pseudoaminols A-G (1-7), were isolated from the ascidian Pseudodistoma sp. collected off the coast of Chuja-do, Korea. Structures of these new compounds were determined by analysis of the spectroscopic data and from chemical conversion. The presence of an N-carboxymethyl group in two of the new compounds (6 and 7) is unprecedented among amino alcohols. Several of these compounds exhibited moderate antimicrobial activity and cytotoxicity, as well as weak inhibitory activity toward Na+/K+-ATPase.

Saponins with highly hydroxylated oleanane-type aglycones from Silphium asteriscus L

Silphium asteriscus L., commonly known as starry rosinweed, is a plant found in prairies, glades, woodlands and savannas of the southeastern United States. The phytochemical investigation of the methanolic extract of S. asteriscus leaves led to the isolation of eighteen saponins with highly hydroxylated oleanane-type aglycones never reported before. Their structures were elucidated by extensive spectroscopic methods including 1D- ((1)H and (13)C) and 2D-NMR (DQF-COSY, HSQC, HMBC, TOCSY and ROESY) experiments as well as ESIMS analysis. The antiproliferative activity of the isolated compounds was evaluated against three cancer cell lines including Hela (human epitheloid cervix carcinoma), Jurkat cells (leukaemic T-cell line) and DLD-1 (colorectal adenocarcinoma). Compounds 1, 5 and 17 displayed weak activity with IC50 values ranging from 50 to 75 μM.

Cytotoxic triterpenoids from Lysimachia parvifolia

Five new oleanane-type triterpenoids, including two aglycones, 13β-28-epoxy-3β,22α,23-trihydroxyolean-16-one (1) and 13β-28-epoxy-22α,23-dihydroxyolean-3,16-dione (2), and three glycosides, anagalligenone-3-O-α-L-arabinopyranoside (3), anagalligenone-3-O-[β-D-glucopyranosyl(1 → 4)-α-L-arabinopyranoside] (4) and anagalligenone-3-O-[β-D-xylopyranosyl(1 → 2)-β-D-glucopyranosyl(1 → 4)-α-L-arabinopyranoside] (5), were isolated from the aerial parts of Lysimachia parvifolia, together with three known oleanane-type triterpenoid glycosides (6-8). The structures of the new compounds were subsequently elucidated by spectroscopic analysis and their cytotoxicities evaluated against six human cancer cell lines. Compounds 5-8 exhibited significant cytotoxicities against all the cell lines tested, with IC50 values lower than 10 μM. The possible mechanism of action of compound 6 was also studied.

Brominated aromatic furanones and related esters from the ascidian Synoicum sp

Nine new compounds, tris-aromatic furanones (1, 2, 3a, 3b, and 4) and related bis-aromatic diesters (5a, 5b, 6a, and 6b), are described from the ascidian Synoicum sp. collected off the coast of Chuja-do, Korea. The structures of these compounds, designated as cadiolides E and G-I (1-4) and synoilides A and B (5 and 6), were determined by extensive spectroscopic analyses. The absolute configuration at the asymmetric center of cadiolide G (2) was assigned by ECD analysis. Of these new compounds, cadiolide I and the synoilides possess unprecedented carbon skeletons. Several of these compounds exhibited significant inhibition against diverse bacterial strains as well as moderate inhibition against the enzymes sortase A, isocitrate lyase, and Na(+)/K(+)-ATPase.

Anticomplementary activity of oleanane-type triterpenes from the roots of Aceriphyllum rossii

To gain a better understanding of the anticomplement activity of triterpenoids, the complement activity of five unusual oleanane-type triterpenoids, bearing a carboxyl group at the C-29 position, were estimated against the classical pathway of a complementary system. The five triterpenoids were obtained from the roots of Aceriphyllum rossii (Saxifragaceae), and were determined to be aceriphyllic acids B-E (1-4) and K (5). Of the isolated compounds, compounds 1, 2 and 5 showed anticomplement activities, with IC(50) values of 328.4, 77.5 and 348.6 μM, respectively, whereas, compounds 3 and 4 were inactive. This showed that a carboxyl group at the C-23 position and an α-configuration of a hydroxyl group at the C-3 position in the olean-29-carboxylic acid triterpenoids seemed to play an important role in the anticomplement activity of human serum against erythrocytes.

Beta-carboline alkaloids derived from the ascidian Synoicum sp

Six β-carboline alkaloids (1-6) of the eudistomin Y class were isolated from the Korean ascidian Synoicum sp. These compounds were chemically converted to a known compound, eudistomin Y(1) (7) and six new derivatives, designated eudistomins Y(8)-Y(13) (8-13). Several of these natural and synthetic compounds exhibited moderate to significant antimicrobial activity, weak cytotoxic activity, and inhibitory activities toward sortase A, isocitrate lyase, and Na(+)/K(+)-ATPase. Structure-activity relationships were also deduced.

3-O-acetyloleanolic acid induces apoptosis in human colon carcinoma HCT-116 cells

The cytotoxic effect of 3-O-acetyloleanolic acid, an oleanolic acid derivative isolated from the seeds of Vigna sinensis K., was investigated in human colon carcinoma HCT-116 cells. 3-O-acetyloleanolic acid dose-dependently inhibited the viability of HCT-116 cells. Apoptosis was characterized by detection of cell surface annexin V and sub-G1 apoptotic cell populations. The number of immunostained cells with annexin V-FITC was increased after treatment with 3-O-acetyloleanolic acid. The sub-G1 cell population was also increased. Expression of TRAIL-mediated apoptosis signaling-related death receptor DR5 was increased in 3-O-acetyloleanolic acid-treated HCT-116 cells. Activation of caspase-8 and caspase-3, critical mediators of extrinsic apoptosis signaling, was also increased by 3-O-acetyloleanolic acid. The results indicate that 3-O-acetyloleanolic acid induces apoptosis in HCT-116 cells mediated by an extrinsic apoptosis signaling cascade via up-regulation of DR5.

A new ursane-type triterpenoid from Schefflera heptaphylla (L.) Frodin

A new ursane-type triterpenoid (1), together with 15 known compounds (2-16), was isolated from the barks of Schefflera heptaphylla (L.) Frodin. The structure of the new compound was determined on the basis of extensive spectroscopic data including IR, HR-ESI-MS, 1D and 2D NMR, and further confirmed by single-crystal X-ray diffraction. Compounds 2-6 were isolated from Schefflera genus for the first time.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids, including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes and saponins; 278 references are cited.