Isocoumarins from American cockroach (Periplaneta americana) and their cytotoxic activities

Four new isocoumarins (1–4), along with three known ones (5–7), were isolated from the 70% ethanol extract of the whole body of the traditional Chinese insect medicine, American cockroach (Periplaneta americana). The structures with absolute configurations of new compounds were elucidated by extensive spectroscopic methods in combination with X-ray diffraction experiment and CD analyses. Compounds 3–5 showed significant cytotoxic activities in HepG2 and MCF-7 cells with IC₅₀ values in the ranges 6.41–23.91 μM and 6.67–39.07 μM, respectively.     

Triterpene saponins from the roots of Ilex pubescens

Five new triterpene saponins, Ilexpublesnins N–R (1–5), along with seven known analogs were isolated from the root of Ilex pubescens. Their structures were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments. Ilexpublesnin N (1) possessed a rare 20-hydroxyursolic acid scaffold from natural resource. These compounds were evaluated in vitro for their cytotoxic effects on human cancer cell lines HepG2, HLE, BEL7402, BEL7403, BEL7405, MCF-7, HeLa. Among them, only compounds 5 and 10 showed cytotoxic potentiality against BEl-7403 and HEL cell lines [inhibition (%): 35.38 and 45.12, respectively].     

Phytochemical analysis of the triterpenoids with cytotoxicity and QR inducing properties from the total tea seed saponin of Camellia sinensis

The tea seed triterpene saponin (TS) from Camellia sinensis was found to exhibit better antitumor activity in vivo in S180 implanted ICR mice and QR inducing activity for hepa lclc7 cells respectively compared with the total tea seed saponin (TTS), hydrolysate of the TTS and tea seed flavonoid glycosides (TF). By bioassay-guided isolation, the TS fraction was separated and seven major components were purified and identified as theasaponin E1 (1), theasaponin E2 (2), theasaponin C1 (3), assamsaponin C (4), theasaponin H1 (5), theasaponin A9 (6), and theasaponin A8 (7), among which compounds 4 and 5 were isolated from this genus for the first time. The antitumor bioassay of the isolated compounds showed that compounds 1, 2 and 3 exhibited potential activities against the human tumor cell lines K562 and HL60. Furthermore, compound 1 (the major constituent with a mass content of over 1%) showed significant QR inducing activity with an IR value of 4.2 at 4 μg/ml. So it can be concluded that tea seed especially the compound 1 (theasaponin E1) could be used as an antitumor agent and a chemoprevention agent of cancer. The preliminary structure–activity relationship in the anti-tumor activity and QR inducing activity of tea saponins was discussed briefly.     

Chemical constituents of Aloe barbadensis Miller and their inhibitory effects on phosphodiesterase-4D

Aloe barbadensis Mill has been used as food and medicine for a long time. In order to investigate the chemical constituents of A. barbadensis and their inhibitory activities towards phosphodiesterase-4D (PDE4D), 70% methanol extract of the dried A. barbadensis powder was employed. Phytochemical investigation has led to the isolation of three new chromones, 5-(hydroxymethyl)-7-methoxy-2-methylchromone (4), 5-((4E)-2′-oxo-pentenyl)-2-hydroxymethylchromone (6), and 7-hydroxy-5-(hydroxymethyl)-2-methylchromone (7), together with eighteen known compounds. Their chemical structures were determined based on spectroscopic methods including UV, IR, 1D and 2D NMR, and HRMS spectrometry. In addition, their inhibition against PDE4D was evaluated using tritium-labeled adenosine 3′,5′-cyclic monophosphate (³H-cAMP) as the substrate. Inhibition was calculated by the variation of radioactivity after the reaction, and compounds 1–4, 10, and 21 exhibited certain inhibitory activities towards PDE4D, which can provide an explanation why A. barbadensis can serve as anti-inflammatory agents.     

Bioactive phenolics and terpenoids from Manglietia insignis

Four new compounds, maninsigins A–D (1–4), including two new neolignans (1–2) and two new sesquiterpenes (3–4), as well as ten known compounds (5–14), were isolated from the leaves and stems of Manglietia insignis. Their structures were established on the basis of extensive spectroscopic analyses. In addition, some compounds were tested for their cytotoxic and neurite outgrowth-promoting activities, as well as their antagonistic activity toward FXR ligand.     

Alkyl and phenolic glycosides from Saussurea stella

One alkyl glycoside, saussurostelloside A (1), two phenolic glycosides, saussurostellosides B1 (2) and B2 (3), and 27 known compounds, including eleven flavonoids, seven phenolics, six lignans, one neolignan, one phenethyl glucoside and one fatty acid, were isolated from an ethanol extract of Saussurea stella (Asteraceae). Their structures were elucidated by NMR, MS, UV, and IR spectroscopic analysis. Of the known compounds, (+)-medioresinol-di-O-β-d-glucoside (7), picraquassioside C (10), and diosmetin-3′-O-β-d-glucoside (27) were isolated from the Asteraceae family for the first time, while (+)-pinoresinol-di-O-β-d-glucoside (6), di-O-methylcrenatin (11), protocatechuic acid (14), 1,5-di-O-caffeoylquinic acid (17), formononetin (28), and phenethyl glucoside (29) were isolated from the Saussurea genus for the first time. The anti-inflammatory activities of three new compounds (1–3), five lignans ((−)-arctiin (4), (+)-pinoresinol-4-O-β-d-glucoside (5), (+)-pinoresinol-di-O-β-d-glucoside (6), (+)-medioresinol-di-O-β-d-glucoside (7) and (+)-syringaresinol-4-O-β-d-glucoside (8)), one neolignan (picraquassioside C (10)), and one phenolic glycoside (di-O-methylcrenatin (11)) were evaluated by testing their inhibition of the release of β-glucuronidase from PAF-stimulated neutrophils. Only compound 5 showed moderate inhibition of the release of β-glucuronidase, with an inhibition ratio of 39.1%.     

Hepatoprotective coumarins and secoiridoids from Hydrangea paniculata

Three new coumarin glucosides (1, 3, 4), and a new secoiridoid glucoside (2), together with one known secoiridoid glucoside (5), were isolated from the stems of Hydrangea paniculata. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR, MS and CD spectra. At 10 μM, compounds 1–5 showed hepatoprotective activities against DL-galactosamine-induced toxicity in HL-7702 cells.     

Four new bis-iridoids isolated from the traditional Tibetan herb Pterocephalus hookeri

Pterocenoids A–E (1–4), which Pterocenoids A(1) is one novel dimer containing a pyridine monoterpene alkaloid; and Pterocenoids B–E (2–4) are rare arranged non-glycosidic bis-iridoids were isolated from Pterocephlus hookeri. The structures of the compounds were established by 1D and 2D NMR spectroscopy and mass spectrometry. All bis-iridoids isolated from P. hookeri were found to possess secoiridoid/iridoid subtype skeletons. Hence, bis-iridoids can be regarded as the chemotaxonomic markers of P. hookeri. The origins of the new bis-iridoids (1–4) were postulated and their activities of inhibition of the NF-κB pathway were assayed and compounds 1–3 showed moderate activity in inhibiting NF-κB.     

Phenylethanoid glycosides with anti-inflammatory activities from the stems of Cistanche deserticola cultured in Tarim desert

Five new phenylethanoid glycosides, cistanosides J–N (1–5), together with 15 known ones (6–20) were isolated from the stems of Cistanche deserticola cultured in Tarim desert, China. Their structures were elucidated on the basis of extensive spectroscopic analysis (IR, HR-ESIMS, 1D- and 2D-NMR) and chemical degradation. All the compounds obtained were examined for their inhibitory effect on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse microglial cells (BV-2 cells), and compounds 2 and 8 showed potent inhibition on the NO production with IC₅₀ values of 14.94 μM and 14.32 μM, respectively.     

Bioactivity-guided chemical analysis of Melia azedarach L. (Meliaceae), displaying antidiabetic activity

One new Euphane-type triterpenoid 3β-hydroxytirucalla-5, 24-dien-21-oic acid (1), and ten known compounds (2–11) were isolated from Melia azedarach L. through bioassay-guided chemical analysis. The structures of the isolated compounds were established by means of 1D and 2D NMR spectroscopic (¹H, ¹³C, DEPT, COSY, HSQC and HMBC) and MS spectral analyses. All the fractions and isolated pure compounds were evaluated for antidiabetic activity by determining their inhibitory effects on PTP-1B enzyme as well as glucose uptake stimulation in C₂Cl₂ myoblasts cells. Compounds 4 and 7 showed significant in vitro PTP-1B inhibitory activity with 69.2 and 66.8% inhibition at 10 μg/ml concentrations respectively.     

Characterization of tyrosinase inhibitors in the twigs of Cudrania tricuspidata and their structure–activity relationship study

The twigs of Cudrania tricuspidata were found to show strong tyrosinase inhibitory activity, and further detailed component analysis resulted in the isolation of a new flavanol glucoside, (2S,3S)-2,3-trans-dihydromorin-7-O-β-d-glucoside (1), plus twenty-seven known compounds (2–28). Their structures were elucidated on the basis of ESI-MS and NMR spectral data. Among the isolated compounds, trans-dihydromorin (8), oxyresveratrol (9), and steppogenin (12) were found to exhibit significant tyrosinase inhibition activities. Moreover, the structure–activity relationship of these isolated compounds was also discussed.     

Diphenyl ethers from Aspergillus sp. and their anti-Aβ42 aggregation activities

Two new compounds with the character of diphenyl ether structure, oxisterigmatocystin D (1) and 9-acetyldiorcinol B (6), were isolated from the endolichenic fungal strain Aspergillus sp. (No. 16-20-8-1), along with six known compounds, oxisterigmatocystin A (2), oxisterigmatocystin C (3), sterigmatocystin (4), diorcinol B (5), violaceol-I (7), and violaceol-II (8). The structures of the new compounds were determined by extensive NMR spectroscopic data, and the absolute configuration of 1 was established by single-crystal X-ray diffraction analysis. Moreover, the Aβ₄₂ aggregation inhibitory activities of 5–8 were evaluated by the standard thioflavin T (ThT) fluorescence assay using epigallocatechin gallate (EGCG) as the positive control. Compounds 7 and 8 displayed significant anti-Aβ₄₂ aggregation activity with IC₅₀ values of 5.1 and 2.3 μM, respectively. Preliminary structure–activity relationship of these diphenyl ethers as anti-Aβ₄₂ aggregation inhibitors was proposed.     

8-9′ linked neolignans with cytotoxicity from Alpinia conchigera

Five new 8-9′ linked neolignans conchigeranals A–E (1–5), together with three known compounds galanganal (6), galanganols A (7) and B (8), were isolated from the whole plant of Alpinia conchigera. Their structures were established by spectroscopic analysis, including 2D-NMR spectroscopic techniques. Cytotoxicities of compounds 1–8 were tested against two cancer cell lines A549 and Hela. Results showed that 4, 5, 7 and 8 exhibited cytotoxicity against A549 with the IC₅₀ values of 12.36, 9.72, 10.26, 13.05 μg/ml, respectively, and 1–8 against Hela with the IC₅₀ values from 1.53 to 5.29 μg/ml.     

Sesquiterpenes from the rhizomes of Alpinia japonica and their inhibitory effects on nitric oxide production

A novel norsesquiterpene (1), three new bisabolenes sesquiterpenes (2–4), along with 7 known compounds (5–11), were isolated from the rhizomes of Alpinia japonica. The structures of the new compounds were elucidated by analysis of spectroscopic data. The absolute configuration of C-1 in 3 was deduced via the circular dichroism data of the in situ formed [Rh₂(OCOCF₃)₄] complexes. Inhibitory effects of the isolates on nitric oxide production in lipopolysaccaride-activated RAW264.7 macrophages were evaluated. Compound 6 showed significant inhibitory activity with IC₅₀ value of 5.3 μΜ, and compounds 1, 3, 5 and 7–10 exhibited moderate inhibitory activities with IC₅₀ values between 24.5 and 46.3 μM.     

Chemical constituents of Swertia yunnanensis and their anti-hepatitis B virus activity

Four new triterpenoids, sweriyunnangenin A (1), sweriyunnanosides A (2), B (3) and C (4), along with nineteen known compounds (5–23) were isolated from Swertia yunnanensis. Based on extensive spectroscopic analyses (1D- and 2D-NMR, HRESIMS, UV, IR, [α]_D), the structures of sweriyunnangenin A (1), sweriyunnanosides A (2), B (3) and C (4) were elucidated as taraxer-14-ene-3α,6β-diol, oleanolic acid 28-O-β-d-glucopyranosyl-(1 → 2)-O-β-d-glucopyranoside, 2α,3β-di-hydroxyolean-12-en-28-oic acid 28-O-β-d-glucopyranosyl(1 → 6)-β-d-glucopyranosyl (1 → 6)-β-d-glucopyranosyl(1 → 2)-β-d-glucopyranoside and hederagenin 28-O-β-d-glucopyranosyl(1 → 6)-β-d-glucopyranosyl(1 → 6)-β-d-glucopyranosyl(1 → 2)-β-d-glucopyranoside, respectively. Twenty-two compounds were evaluated for their anti-HBV activities on the HepG 2.2.15 cell line in vitro, of which nine compounds showed potent anti-HBV activities. Compounds 1, 5–6, 14–16 and 19 showed activities against the secretion of HBsAg (IC₅₀ values from 0.10 to 1.76 mM) and HBeAg (IC₅₀ values from 0.04 to 1.41 mM), and compounds 11 and 13–16 exhibited significant inhibition on HBV DNA replication (IC₅₀ values from 0.01 to 0.09 mM).     

Isolation,characterization and acetylcholinesterase inhibitory activity of alkaloids from roots of Stemona sessilifolia

Two new alkaloids, named stenine A (1) and stenine B (2), along with the known compounds neostenine (3), stenine (4) and neotuberostemonine (5), were isolated from the roots of Stemona sessilifolia. Their structures were elucidated by 1D- and 2D-NMR spectra and X-ray single-crystal diffraction experiment. Anti-acetylcholinesterase (AChE) activity of compounds 1–5 were also tested. Compounds 2 and 4 showed significant anti-acetylcholinesterase activities, with IC₅₀ values of 2.1 ± 0.2 μM and 19.8 ± 2.5 μM, resp. The mode of AChE inhibition by Compound 2 (the most potential AChE inhibitor) was reversible and competitive. In addition, molecular modeling was performed to explore the binding mode of compound 2 with AChE.     

Bioassay-guided isolation of urease and α-chymotrypsin inhibitory constituents from the stems of Lawsonia alba Lam. (Henna)

Seven constituents were isolated from the stems of Lawsonia alba Lam., following an activity-guided isolation, which include two new constituents, namely lawsorosemarinol (1) and lawsofructose (2), one known compound 2-(β-d-glucopyranosyloxy)-1, 4-naphthoquinone (3) and four compounds, 4-hydroxy coumarine (4), 3-(4-hyroxyphenyl)-triacontyl-(Z)-propenoate (5), 3-(4-hydroxy-3-methoxyphenyl)-triacontyl-(Z)-propenoate (6) and 7-hydroxy-4-methyl coumarin (7) first time isolated from Lawsonia alba. Their structure elucidation was based on spectroscopic data analyses. Compounds 3 and 7 showed a moderate inhibition of urease activity, while rest of them showed less than 50% inhibition. These compounds did not show any significant inhibition against α-chymotrypsin.     

Two new diterpene derivatives from Euphorbia lunulata Bge and their anti-proliferative activities

A new ent-abietane-type diterpene lactone (1) and a new jatrophane-type diterpenoid (2), together with twelve known compounds including three diterpenes (3–5), five triterpenes (6–10) and four sterides (11–14) were isolated from the ethanol extract of the whole plant of Euphorbia lunulata Bge. The structure of compounds 1 and 2 was elucidated on the basis of 1D and 2D NMR spectra and the HR-ESI-MS data. The structure of compound 2 was further analyzed by an X-ray crystallographic study. The in vitro anti-proliferative activities against MCF-7 and NCI-H460 cell lines for compounds 1–5 (diterpene) were evaluated. The results showed marked activity for compound 1 against the two cell lines with the IC₅₀ values 19.5 (NCI-H460) and 18.6 (MCF-7) μM, while for cis-platinum (a positive cytotoxic control agent) 29.7 (NCI-H460) and 27.7 (MCF-7) μM. Compounds 2–5 exhibited moderate cytotoxic activities for the two cell lines with the IC₅₀ values ranging from 32.1 to 58.2 μM.     

Mangostanaxanthones I and II,new xanthones from the pericarp of Garcinia mangostana

Two new xanthones: mangostanaxanthones I (3) and II (5) were isolated from the pericarp of Garcinia mangostana, along with four known xanthones: 9-hydroxycalabaxanthone (1), parvifolixanthone C (2), α-mangostin (4), and rubraxanthone (6). Their structures were elucidated on the basis of IR, UV, 1D, 2D NMR, and MS spectroscopic data, in addition to comparison with literature data. The isolated compounds were evaluated for their antioxidant, antimicrobial, and quorum-sensing inhibitory activities. Compounds 3 and 5 displayed promising antioxidant activity with IC₅₀ 12.07 and 14.12 μM, respectively using DPPH assay. Compounds 4–6 had weak to moderate activity against Escherichia coli and Staphylococcus aureus, while demonstrated promising action against Bacillus cereus with MICs 0.25, 1.0, and 1.0 mg/mL, respectively. The tested compounds were inactive against Candida albicans. However, they showed selective antifungal potential toward Aspergillus fumigatus. Compounds 3 and 4 possessed quorum-sensing inhibitory activity against Chromobacterium violaceum ATCC 12472.     

Chemical constituents of Morus alba L. and their inhibitory effect on 3T3-L1 preadipocyte proliferation and differentiation

Mulberry leaf, an important traditional Chinese medicine, possesses many biological activities, including effects of anti-obesity. However, which constituents of mulberry leaf are responsible for its anti-adipogenic action is unclear. This study primarily investigated the chemical constituents from mulberry leaf and their bioactivity on the proliferation and differentiation of 3T3-L1 preadipocytes. A new flavane derivative, (2S)-4′-hydroxy-7-methoxy-8-prenylflavan (1), together with twelve known compounds including three flavanes (2–4), three chalcones (5–7), two flavones (8–9), two benzofurans (10–11) and two coumarin (12–13) was isolated from mulberry leaf. The structure of the new compound was elucidated by various spectroscopic methods including UV, HR-ESI-MS, ¹H and ¹³C NMR and CD. The results of activity screening showed that compound 2, 6 and 7 inhibited the proliferation and differentiation of 3T3-L1 preadipocytes.