Triterpenoids from the Leaves of Cyclocarya paliurus and Their Glucose Uptake Activity in 3T3-L1 Adipocytes.

Four new dammarane triterpenoid saponins cypaliurusides Z1-Z4 (1-4) and eight known analogs (5-12) were isolated from the leaves of Cyclocarya paliurus. The structures of the isolated compounds were determined using a comprehensive analysis of 1D and 2D NMR and HRESIMS data. The docking study demonstrated that compound 10 strongly bonded with PTP1B (a potential drug target for the treatment of type-II diabetes and obesity), hydrogen bonds, and hydrophobic interactions, verifying the importance of sugar unit. The effects of the isolates on insulin-stimulated glucose uptake in 3T3-L1 adipocytes were evaluated and three dammarane triterpenoid saponins (6, 7 and 10) were found to enhance insulin-stimulated glucose uptake in 3T3-L1 adipocytes. Furthermore, compounds 6, 7, and 10 exhibited potent abilities to promote insulin-stimulated glucose uptake in 3T3-L1 adipocytes in a dose-dependent manner. Thus, the abundant dammarane triterpenoid saponins from C. paliurus leaves exhibited stimulatory effects on glucose uptake with application potential as a antidiabetic treatment.

α-Glucosidase inhibitory and anti-inflammatory activities of dammarane triterpenoids from the leaves of Cyclocarya paliurus.

Diabetes mellitus is caused by chronic inflammation and affects millions of people worldwide. Cyclocarya paliurus leaves have been widely used in traditional folk tea as a remedy for diabetes, but the antidiabetic constituents remain to be further studied. The α-glucosidase inhibitory and anti-inflammatory activities were examined to evaluate their effects on diabetes mellitus, and bioassay-guided separation of C. paliurus leaves led to the identification of twenty dammarane saponins, including eleven new dammarane saponins (1-11). The structures of the isolates were elucidated by spectroscopic methods. Bioactivity assay results showed that compounds 1 and 2 strongly inhibited α-glucosidase activity, with IC50 values ranging from 257.74 µM, 282.23 µM, and strongly inhibited the release of NO, with IC50 values of 9.10 µM, 9.02 µM. Moreover, compound 2 significantly downregulated the mRNA expression of iNOS, COX-2, IL-1ß, NF-κB, IL-6 and TNF-α in LPS-mediated RAW 264.7 cells and markedly suppressed the protein expression of iNOS, NF-κB/p65, and COX-2. Dammarane glucoside 2 exhibited the strongest α-glucosidase inhibitory and anti-inflammatory activities. In addition, the structure-activity relationships (SARs) of the dammarane saponins were investigated. In summary, C. paliurus leaves showed marked α-glucosidase inhibitory and anti-inflammatory activities, and dammarane saponins are responsible for regulating α-glucosidase, inflammatory mediators, and mRNA and the protein expression of proinflammatory cytokines, which could be meaningful for discovering new antidiabetic agents.

Cytotoxic Activity and Related Mechanisms of Prenylflavonoids Isolated from Mallotus conspurcatus Croizat.

Five prenylflavonoids, 6-prenylnaringenin (1), 8-prenylnaringenin (2), 7-O-methyl-8-prenylnaringenin (3), 7-O-methyl-6-prenylnaringenin (4), and 4'-O-methyl-6-prenylnaringenin (5), were isolated from the traditional herb Mallotus conspurcatus Croizat (Euphorbiaceae). Compounds 1-5 revealed cytotoxic activity against cervical cancer (HeLa) cells with IC50 values ranging from 10.08 to 60.16 µm by MTT method, and interestingly, these prenylflavonoids were less toxic to normal HL-7702 cells. Furthermore, compounds 1 and 5 could inhibit the c-myc expression and telomerase activity and cause mitochondrial dysfunction. These findings might contribute to a better understanding of the biological activities of prenylflavonoids and lay the foundation for further studies on the cytotoxic activity of natural products isolated from M. conspurcatus.

Structural Characterization and Assessment of the Cytotoxicity of 2,3-Dihydro-1H-indene Derivatives and Coumarin Glucosides from the Bark of Streblus indicus.

A pair of enantiomers and a pair of 2,3-dihydro-1H-indene epimers, rac-indidene A (rac-1), indidenes B and C (2, 3); four new coumarin glucosides (4-7); and four known coumarin glucosides (8-11) were isolated from the bark of Streblus indicus (Bur.) Corner. The structures of 1-11 were defined by physical data analyses, including MS, NMR, and single-crystal X-ray diffraction. The absolute configurations of the 2,3-dihydro-1H-indene derivatives were defined via experimental and calculated ECD data. rac-Indidene A and indidenes B and C showed inhibitory activity against A549 and MCF-7 tumor cells with IC50 values in the range of 2.2 ± 0.1 to 7.2 ± 0.9 µM.

Tandem mass spectrometric fragmentation behavior of lignans, flavonoids and triterpenoids in Streblus asper.

RATIONALE: An unambiguous identification of compounds can be achieved by comparison of known fragmentation patterns. While the literature about fragmentation mechanisms of lignans, flavonoids and triterpenoids is few. So the present study analyses the fragmentation mechanisms of these compounds isolated from Streblus asper. METHODS: Electrospray ionization ion trap mass spectrometry (ESI-ITMS) and atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-ITMS) were used to obtain the MS(n) spectra of the compounds. By analyzing the differences between the ions, the fragmentation mechanisms of these compounds were explored. RESULTS: Of the 29 compounds detected, 17, 7, and 5 were lignans, flavonoids and triterpenoids, respectively. The majority of lignans were found to give [M - H](-) ions of sufficient abundance for MS(n) analyses. The flavonoids were prone to the loss of CO and H2O. The triterpenoids always lost one formic acid molecule and two hydrogens, or one H2O from [M - H](-) to form the most abundant product ion in the MS(n) spectrum. CONCLUSIONS: ESI/APCI-ITMS were demonstrated to be fast, effective and practical tools to characterize the structures of flavonoids, triterpenoids and lignans. Results of the present study can help identify the analogous constituents by analyzing their MS(n) spectra.

Anti-hepatitis B virus lignans from the root of Streblus asper.

Four new lignans, strebluslignanol F (1), (7'R,8'S,7″R,8″S)-erythro-strebluslignanol G (2), isomagnaldehyde (3) and isostrebluslignanaldehyde (4), along with 12 known lignans (5-16) were isolated from the ethyl acetate-soluble part of MeOH extract of the root of Streblus asper. Their structures were elucidated through various spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC and NOESY) and HRMS. The stereochemistry at the chiral centers was determined using CD spectra, as well as analyses of coupling constants and optical rotation data. The isolated lignans were evaluated for their anti-HBV activities in vitro using the HBV transfected HepG2.2.15 cell line. The most active lignans, (7'R,8'S,7″R,8″S)-erythro-strebluslignanol G, magnolol, isomagnolol and isolariciresinol, exhibited significant anti-HBV activities with IC50 values of 1.58, 2.03, 10.34 and 3.67 µM, respectively, for HBsAg with no cytotoxicity, and of 3.24, 3.76, 8.83 and 14.67 µM, respectively, for HBeAg with no cytotoxicity. (7'R,8'S,7″R,8″S)-erythro-Strebluslignanol G and magnolol showed significant anti-HBV activities to inhibit the replication of HBV DNA with the IC50 values of 9.02 and 8.67 µM, respectively.

Cytotoxic cardiac glycosides from the root of Streblus asper.

Bioassay-guided separation of the root of Streblus asper led to the identification of six undescribed cardiac glycosides, including a rare cardiac glycoside dimer, along with twelve previously reported analogues. Their structures were determined on the basis of analyses of spectroscopic methods (1D and 2D-NMR spectroscopy), high-resolution electrospray ionization mass spectrometry (HRESIMS), circular dichroism (CD), and comparison of their spectroscopic data with previously reported data. Regarding their cytotoxic activities, microculture tetrazolium assays showed that all isolated cardiac glycosides strongly inhibited MCC-803, T24, SKOV-3, HepG2, Wi-38, and A549 cancer cell lines, with IC50 values ranging from 0.075 µM to 0.752 µM. One cardiac glycoside, a rare cardiac glycoside dimer, exhibited the strongest activity against the six cancer cell lines, with IC50 values ranging from 0.075 µM to 0.214 µM. In addition, the structure-activity relationships (SARs) of cardiac glycosides were investigated. In summary, S. asper showed marked cytotoxicity to several cancer cell lines, which could be meaningful for discovering new anticancer agents.

Bioactivity-guided isolation of anti-inflammatory constituents from the bark of Streblus zeylanicus.

Based on anti-inflammatory activity to evaluate the effects to the release of NO, bio-assay guided separation of the bark of Streblus zeylanicus led to identify fifteen compounds, including four new terpenes (1, 2, 9, and 10), one new pentanoid glycoside (12), one new rumenic ester (13), together with nine known compounds (3-8, 11, 14, and 15). Their structures were elucidated using extensive NMR and HRESIMS spectroscopic data analyses. The stereochemistry of compound 10 was established by comparing the calculated and experimental ECD spectroscopic data. Compounds 1 and 2 showed moderate inhibition on nitric oxide (NO) production, with IC50 values of 10.21 µM and 15.53 µM, respectively.

3,4-seco-Dammarane Triterpenoid Saponins with Anti-Inflammatory Activity Isolated from the Leaves of Cyclocarya paliurus.

Cyclocarya paliurus is commonly used for the prevention and treatment of hypertension, diabetes, and inflammation in South China. Although research on the anti-inflammatory effects of C. paliurus leaves has been reported, no active anti-inflammatory compounds have been identified. In the present study, RAW 264.7 cells were used to establish a bioactivity-guided identification model to verify the inhibitory effects of C. paliurus leaves on inflammation and identify the anti-inflammatory constituents. The active fraction was isolated to yield 18 dammarane triterpenoid saponins, including 11 new 3,4-seco-dammarane triterpenoid saponins (1-11), the structures of which were identified on the basis of analyses of nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) and comparison with literature data. Compounds 7, 8, 10, and 11 showed strong inhibition on nitric oxide (NO) productions, with IC50 values ranging from 8.23 to 11.23 µM. These four compounds significantly decreased the secretion of tumor necrosis factor-alpha (TNF-α), prostaglandin E2 (PGE2), and interleukin 6 (IL-6) in lipopolysaccharide-activated RAW 264.7 cells. Furthermore, compound 7 decreased the expression of the proteins cyclooxygenase-2 (COX-2), inducible nitric-oxide synthase (iNOS), and nuclear factor kappa-B (NF-κB/p65). In addition, the structure-activity relationships of the isolates were investigated. The results suggest that 3,4-seco-dammarane triterpenoid saponins may be used as potential anti-inflammatory drugs and warrant further investigation.

Discovery of anti-inflammatory terpenoids from Mallotus conspurcatus croizat.

ETHNOPHARMACOLOGICAL RELEVANCE: Mallotus conspurcatus croizat (Euphorbiaceae), a plant native to Jinxiu in Guangxi, is popularly used in folk medicine to treat pelvic inflammatory disease. The anti-inflammatory activities of the compounds obtained from M. conspurcatus root were evaluated in this study. AIM OF THE STUDY: This study explored the major anti-inflammatory components of this plant. MATERIALS AND METHODS: The ethyl acetate fraction of the ethanol extract from M. conspurcatus was separated using chromatographic techniques. The structures of the isolates were elucidated from NMR, MS and X-ray data as well as from ECD. The anti-inflammatory activities of the isolates from M. conspurcatus were evaluated using LPS-stimulated RAW 264.7 cell models. The production of NO, TNF-α and PGE-2 was determined by ELISA and Griess tests. The expression levels of COX-2, NF-κB/p65 and iNOS were measured by western blotting. RESULTS: Two new diterpenoids, malloconspur A (1) and malloconspur B (2), and sixteen known terpenoids (3-18) were identified by comprehensive spectroscopic analyses and comparison with literature data. Malloconspur B (2) and 17-hydroxycleistantha-12,15-dien-3-one (3) substantially inhibited the release of NO with IC50 values of 10.47 µM and 9.32 µM, respectively. Compounds 1, 2 and 3 markedly decreased the secretion of PGE2 and TNF-α (P < 0.01) by LPS-induced RAW264.7 cells. Compounds 2 and 3 markedly decreased iNOS, NF-κB/p65 and COX-2 protein expression. CONCLUSIONS: Our identification of these diterpenoids provides strong evidence for the use of M. conspurcatus among the Yao people as a medicinal plant for the treatment of inflammation. The dramatic differences in the chemical structures of the active diterpenoids of this plant from those on the market suggest these compounds have potential as anti-inflammatory lead compounds for follow-up research.

Anti-inflammatory lignans and phenylethanoid glycosides from the root of Isodon ternifolius (D.Don) Kudô.

Five undescribed lignans, three undescribed phenylethanoid glycosides and eight known compounds were isolated from the root of Isodon ternifolius (D.Don) Kudô (Lamiaceae). The structures of all of the isolated constituents were characterized by physical data analyses including NMR, MS and ECD. The anti-inflammatory activities of the isolates were evaluated based on their ability to inhibit NO, PGE2 and TNF-α production in LPS-induced RAW 264.7 macrophage cells. Six phenyl-naphthalene lignans, ternifoliuslignan A, ternifoliuslignan B, ternifoliuslignan C, ternifoliuslignan D, ternifoliuslignan E and 3-carboxy-6,7-dihydroxy-1-(3',4'-dihydroxyphenyl) -naphthalene, can substantially inhibit the release of NO with IC50 values in the range of 9.98-29.14 µM, which are better than the positive reference. These phenyl-naphthalene lignans could markedly decrease the secretions of PGE2 and TNF-α in LPS-induced RAW264.7 cells. Ternifoliuslignan C and ternifoliuslignan D decreased iNOS, COX-2 and NF-κB/p65 protein expression. A preliminary structure-activity relationship among the phenyl-naphthalene lignans for the anti-inflammatory activity was discussed.

Two new coumarins from the bark of Streblus indicus (Bur.) Corner.

Two new coumarins 7-O-(6-O-(5-O-3,4,5-tri-methoxycinnamate-ß-d-apiofuranosyl-ß-d-glucopyranosyl)-6-methoxy coumarin (1) and 7-O-(6-O-(4-(2-hydroxy-1-hydroxymethyl-ethoxy)-3-methoxy-cinnamyl)-ß-d-glucopyranosyl)-6-methoxy coumarin (2), along with 10 known metabolites, were isolated from the bark of Streblus indicus, their structures were identified by comparison of experimental and published spectroscopic data. (S)-marmesinin (6) and scoparone (7) exhibited moderate antimicrobial activity in vitro against Staphylococcus aureus strain with the MIC values of 62.5 and 125.0 µg/mL, respectively. Betulinic acid showed inhibitory activity in vitro against MCF-7 cell with IC50 value of 9.5 ± 0.1 µM.

Benzofuran glycosides and coumarins from the bark of Streblus indicus (Bur.) Corner.

Two pairs of rare benzofuran glucoside epimers, indicuses A and B and indicuses C and D, three biogenetically related compounds indicuses E-G, and one coumarin indicus H, as well as 11 known compounds, were isolated from the bark of Streblus indicus (Bur.) Corner. The structures of indicuses A-H were elucidated by NMR and MS data, as well as by CD. (S)-Marmesinin exhibited moderate antimicrobial activity in vitro against Bacillus subtilis and Saccharomyces cerevisiae. 7,8-Dihydroxy-3-(3-methyl-2-butenyl) coumarin, umbelliferone, and scopoletin displayed strong cytotoxic activity in vitro against human bladder carcinoma cell line EJ. The structure-activity relationships indicate that hydroxylation at C-7 in the cytotoxic compounds is crucial to their activities.

A new flavane acid from the fruits of Illicium verum.

A new compound, illiciumflavane acid (1), along with 13 known compounds (2-14), were isolated from the fruits of Illicium verum Hook. F. Their structures were elucidated through various spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC and NOESY) and HRMS. The stereochemistry at the chiral centres was determined using CD spectrum as well as analyses of coupling constants and optical rotation data. Cytotoxicity evaluation of four compounds showed that illiciumflavane acid and (E)-1,2-bis(4-methoxyphenyl)ethene exhibited potential against A549 activities with IC50 values of 4.63 µM and 9.17 µM, respectively.

A new chromone from the twig of Mallotus apelta.

A new chromone, 7-hydroxy-2-hydroxymethyl-8-methoxy-4-oxo-4H-chromene-6-carboxylic acid, named melachromone, along with 13 known compounds (2-14), including chromones, flavonoids, coumarins and phenylpropane derivatives, were isolated from the twig of Mallotus apelta. Their chemical structures were elucidated by using various spectroscopic methods. Anti-tumour evaluation of the compounds suggested that compound 1 exhibited medium cytotoxic activity against KB and HeLa Cells, with IC50 values of 9.50 and 9.23 µg mL(-1), respectively.

Lignans from the heartwood of Streblus asper and their inhibiting activities to hepatitis B virus.

Three new lignans, erythro-strebluslignanol (1), threo-7'-methoxyl strebluslignanol (2) and erythro-7'-methoxyl strebluslignanol (3), together with twelve known compounds were isolated from the n-butanol and chloroform fractions of the heartwood of Streblus asper. Their structures were elucidated through extensive spectroscopic methods, including MS and 2D NMR experiments (HMQC and HMBC). The stereochemistry at the chiral center was determined using CD spectra, as well as analysis of coupling constants and optical rotation data, respectively. Primary bioassays showed that 6-hydroxyl-7-methoxyl-coumarin (5) and ursolic acid (10) showed anti-HBV activities, with IC(50) values of 29.60 µM and 89.91 µM for HBsAg at no cytotoxicity, and IC(50) values of 46.41 µM and 97.61 µM for HBeAg at no cytotoxicity, respectively.

Water-soluble constituents of the heartwood of Streblus asper.

A new lignan, (7'R,8'R)-threo-strebluslignanol-2-O-beta-D-glucopyranoside, along with 8 known compounds (2-9) were isolated from the water-soluble part of the MeOH extract of the heartwood of Streblus asper. Their structures were elucidated through various spectroscopic methods, including 1D NMR (1H NMR, 13C NMR), 2D NMR (HMQC, HMBC, and NOESY), and HRMS. The stereochemistry at the chiral centers was determined using the CD spectrum, as well as analyses of coupling constants and optical rotation data. In the preliminary bioassay, the isolated compounds did not show anti-HBV activities in vitro using the HBV transfected HepG2.2.15 cell line.

Anti-HBV activities of Streblus asper and constituents of its roots.

The extracts from leaves, heartwood, barks and roots of the Streblus asper were investigated for anti-HBV activities, separately. The results suggested that the MeOH extracts of the heartwood, barks, and roots exhibited good anti-HBV activities. Further investigations displayed that ethyl acetate and n-butanol soluble parts of their MeOH extracts showed more significant anti-HBV activities. Moreover, a new lignan, together with 11 known compounds, was isolated from n-butanol-soluble part of MeOH extract of the roots of S. asper. The structures were elucidated by spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC) and HR-EI-MS experiments. Compounds 1-3 were evaluated for their anti-HBV activities. Honokiol showed significant anti-HBV activity with IC(50) values of 3.14µM and 4.74µM for HBsAg and HBeAg with no cytotoxicity respectively, while lamivudine (3TC, positive control) exhibited weak anti-HBV activity with IC(50) values of 11.81µM and 25.80µM for HBsAg and HBeAg respectively.

Anti-hepatitis B virus constituents from the stem bark of Streblus asper.

Seven compounds, (7'S,8'S)-trans-streblusol A, (7'R,8'S)-erythro-streblusol B, (7'S,8'S)-threo-streblusol B, 8'R-streblusol C, streblusquinone, (8R,8'R)-streblusol D, and streblusol E, along with 15 known compounds (8-22) were isolated from the n-butanol-soluble part of the MeOH extract of stem bark of Streblus asper. Their structures were elucidated through application of extensive spectroscopic methods, including ESI-MS and 2D NMR spectroscopy (HMQC and HMBC). The stereochemistry at the chiral centers was determined using CD spectra, as well as analyses of coupling constants and optical rotation data. The isolated lignans and allylbenzene derivatives were evaluated for their anti-HBV activities in vitro using the HBV transfected Hep G2.2.15 cell line. The most active compounds, magnolol and 9-ß-xylopyranosyl-isolariciresinol, exhibited significant anti-HBV activities with IC(50) values of 2.03 and 6.58µM for secretion of HBsAg, with no cytotoxicity, and of 3.76 and 24.86µM for secretion of HBeAg, with no cytotoxicity.

Hypoglycemic effects and constituents of the barks of Cyclocarya paliurus and their inhibiting activities to glucosidase and glycogen phosphorylase.

The various fractions of the barks of Cyclocarya paliurus were systematically tested for hypoglycemic effects in alloxan-induced diabetic rats. The results showed that the chloroform fraction of the 75% EtOH extract of the barks of this plant exhibited significant blood sugar reducing activity, most of which were significantly higher than that of positive-drug metformin hydrochloride. A new compound, together with nine known compounds, was isolated from the most active fraction. The structure elucidation was based on spectroscopic methods, including two-dimensional NMR experiments (¹H-¹H COSY, HMQC, and HMBC). All of the isolates were evaluated for their α-glycosidase and glycogen phosphorylase inhibitory activities.