Novel 2-arylbenzofuran dimers and polyisoprenylated flavanones from Sophora tonkinensis

Two novel 2-arylbenzofuran dimers, shandougenines A (1) and B (2), and two new polyisoprenylated flavanones 3 (shandougenine C) and 4 (shandougenine D) were isolated from the 95% EtOH extract of Sophora tonkinensis, together with 18 known compounds. Their structures were determined on the basis of spectral data interpretation and by comparing the spectral data with that reported previously for known compounds. Shandougenine A (1) is a unique dimeric 2-arylbenzofuran with a C-3C-5‴ bond linkage. Shandougenine B (2) is the first naturally occurring dimeric 2-arylbenzofuran with a novel C-3C-3″ bond linkage. Compound 1 showed moderate DPPH free radical scavenging capacity, whereas 2 has stronger DPPH free radical and ABTS cation radical scavenging capacity than Vc. Compounds 12, 19, and 20 showed parallel DPPH free radical scavenging capacity with Vc. Compounds 1, 3, 4, 19, 20, and 22 have parallel ABTS cation radical scavenging capacity to Vc. Compounds 1, 3, 4, and 18 showed slightly stronger superoxide anion radical scavenging capacity than the known flavanone luteolin. The antioxidant activities of shandougenines A (1) and B (2) indicated that compounds 1 and 2 may represent novel scaffolds for the development of new antioxidants.     

Two new anthraquinone dimers from the fruit bodies of Bulgaria inquinans

Two new dimeric anthraquinone derivatives, bulgareone A(1) and bulgareone B(2), were isolated from the fruit bodies of Bulgaria inquinans. Their structures were elucidated on the basis of extensive spectroscopic analysis. The in vitro cytotoxic activity of compounds 1 and 2 was assayed. They displayed inhibitive activities against human cancer cell lines HL60 and K562.     

Indole alkaloids from the roots of Isatis indigotica and their inhibitory effects on nitric oxide production

Three rare indole-2-S-glycosides, indole-3-acetonitrile-2-S-β-D-glucopyranoside (1), indole-3-acetonitrile-4-methoxy-2-S-β-D-glucopyranoside (2) and N-methoxy-indole-3-acetonitrile-2-S-β-D-glucopyranoside (3), together with 11 known indole alkaloids were isolated from the roots of Isatis indigotica Fort. (Cruciferae). The structures of 1–3 were elucidated on the basis of mass spectrometry and extensive 1D and 2D NMR spectroscopy. All of the isolated compounds were tested for inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages. A plausible biosynthesis pathway of 1–3 is also proposed.     

Novel indole C-glycosides from Isatis indigotica and their potential cytotoxic activity

Two novel indole C-glycosides, which were the first reported alkaloids C-glycosides from Isatis indigotica, together with five known alkaloids were isolated. The novel alkaloids were elucidated to be indole-3-acetonitrile-4-methoxy-2-C-β-D-glucopyranoside (1) and N-methoxy-indole-3-acetonitrile-2-C-β-D-glucopyranoside (2) on the basis of spectroscopic analysis. 1 exhibited significant cytotoxic activities against human myeloid leukemia HL-60 and human liver cancer HepG2 cells with the IC₅₀ of 1.3 ± 0.1 and 2.1 ± 0.3 μM, respectively. 2 showed potential cytotoxic activities against HL-60 and human myeloid leukemia Mata cells with the IC₅₀ of 5.1 ± 0.4 and 12.1 ± 0.8 μM, respectively.     

NO inhibitory guaianolide-derived terpenoids from Artemisia argyi

An unusual dimeric guaianolide, artemilinin A (1) and a sesquiterpene–monoterpene lactone, isoartemisolide (2), were isolated from the leaves of Artemisia argyi. Their structures were elucidated on the basis of extensive spectroscopic analysis (IR, HR-ESIMS, 1D- and 2D-NMR), and the absolute configurations were determined by CD spectra and quantum chemical ECD calculation. Furthermore, in in vitro assay, compound 2 exhibited pronounced inhibition on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cells with an IC₅₀ value of 4.00 μM.     

A new indole alkaloid from Ervatamia yunnanensis

The stems of Ervatamia yunnanensis have afforded a new indole alkaloid, ervataine (1), whose structure was determined by spectroscopic analysis. Five known compounds, ibogaine (2) coronaridine (3), heyneanine (4), voacangine hydroxyindolenine (5) and coronaridine hydroxyindolenine (6), were also isolated.     

Japonicones Q–T,four new dimeric sesquiterpene lactones from Inula japonica Thunb.

Four new dimeric sesquiterpene lactones (japonicones Q–T, 1–4) were isolated from the aerial part of Inula japonica Thunb., together with two known ones. Their structures were determined mainly by 1D and 2D NMR spectroscopic techniques including HSQC, ¹H–H COSY, HMBC, and NOESY. Herein, the inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages of 1–6 were evaluated; IC₅₀ values were tested as 8.5, 8.9, 4.3, 4.3, 4.2, and 9.2 μM, respectively.     

Antibacterial dihydrobenzopyran and xanthone derivatives from Garcinia cowa stem barks

Two new compounds, garciniacowol (1) and garciniacowone (2) along with 15 known compounds were isolated from the stem barks of Garcinia cowa. Their structures were determined by intensive spectroscopic methods. The structure of 1 was a symmetrical dimeric dihydrobenzopyran derivative, whereas the framework of 2 was a triprenyl caged-xanthone precursor. The antibacterial activities against Escherichia coli TISTR 780, Salmonella typhimurium TISTR 292, Staphylococcus aureus TISTR 1466, and methicillin-resistant S. aureus (MRSA) SK1 of the isolated compounds were also evaluated. Compounds 2 and 9 exhibited good antibacterial activity against MRSA SK1 with the same minimum inhibitory concentration (MIC) value of 2 μg/mL. Moreover, compound 2 also showed good antibacterial activity against S. aureus with an MIC value of 2 μg/mL.     

Axially chiral biscarbazoles and biological evaluation of the constituents from Murraya koenigii

Chemical investigation of the fruit pulp of Murraya koenigii resulted in the identification of two new dimeric carbazole alkaloids, bisgerayafoline D (1) and bismahanimbinol (2) along with four known alkaloids, bispyrayafoline (3), O-methyl mahanine (4), O-methyl mukonal (5), and mahanine (6). Structures of 1–6 were determined with the aid of UV, IR, Mass and extensive NMR spectroscopic studies. Absolute configurations of biaryls in 1 and 2 were assigned using a combination of computational Circular Dichroism (CD) and experimental electronic CD spectroscopic data. Compounds 1–6 were evaluated for anti-oxidant, anti-α-glucosidase, DNA binding, protein interactions and cytotoxic activities. Among all the isolates, mahanine (6) was found to exhibit significant radical scavenging and α-glucosidase inhibitory activities. Compound 6 was also found to be active in cytotoxicity assay against three human cancer cell lines HeLa, HCT116, AGS and this compound was weakly active against normal mouse embryonic fibroblasts (NIH3T3).     

Novel dinorcassane- and cassane-type diterpenes from the seeds of Caesalpinia minax

Two novel diterpenes, norcaesalpinin I (1) featuring an unusual ring C-contracted dinorcassane and caesalpinin U (2) possessing a highly oxygenated furanocassane skeleton were isolated from the seeds of Caesalpinia minax. Their structures were determined by different spectroscopic methods. A plausible biosynthetic pathway of 1 was proposed. The cytotoxic activity of compounds 1 and 2 against HepG2 and HeLa human tumor cell lines was evaluated.     

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.     

Japodagricanones A and B,novel diterpenoids from Jatropha podagrica

Two novel diterpenoids, japodagricanones A (1) and B (2), along with their biogenetically related diterpenoid 15-epi-4E-jatrogrossidentadion (3), were isolated from the leaves and twigs of Jatropha podagrica. Japodagricanones A (1) and B (2) are the first C-5-nor lathyrane-type diterpenoids. Their structures were established using spectroscopic data, including MS, NMR and ECD data. A plausible biosynthetic pathway for their generation was also proposed.     

Four new coumarinolignoids from seeds of Solanum indicum

Activity-guided fractionation of seeds of Solanum indicum for anti-HBV activity led to the isolation of two novel coumarinolignoid alkaloids (indicumines A–B, 1–2) and two new coumarinolignoids (indicumines C–D, 3–4), together with four known coumarins (5–8). Their structures were established on the basis of spectroscopic data. The two novel coumarinolignoid alkaloids shows anti-HBV activities through specifically inhibiting the secretion of HBsAg in HepG2.2.15.     

Norcassane- and cassane-type furanoditerpenoids from the seeds of Caesalpinia sappan

Three novel furanoditerpenoids, norcaesalpinin J (1) featuring an unusual 20-norcassane hydroperoxide and phangininoxys B (2) and C (3) possessing cassane hemiketal skeletons, were isolated from the seeds of Caesalpinia sappan. Their structures were elucidated by extensive spectroscopic methods. All isolates were evaluated for the cytotoxic activities on three human cancer cell lines.     

Caesappin A and B,two novel protosappanins from Caesalpinia sappan L.

Two novel protosappanins, named Caesappin A (1) and B (2), along with three known protosappanins were isolated from Caesalpinia sappan L. Caesappin A is a new type protosappanin with a seven-membered ring fusing an acetal-type section. Compound 4 was isolated from the genus Caesalpinia for the first time. The structures were elucidated on the basis of spectral analysis and the absolute configuration was determined by the ECD experiment coupled with calculated ECD spectra. Their cytotoxic activities were evaluated using MTT assay.     

Chemical constituents from the fibrous root of Ophiopogon japonicus,and their effect on tube formation in human myocardial microvascular endothelial cells

In an effort to identify novel active constituents on the cardiovascular system, a systematic study on macroporous resin adsorption of extracts from the fibrous root of Ophiopogon japonicus was performed in a human myocardial microvascular endothelial cell line (HMMEC) based assay. One novel spirostan, named ophiogenin (1), together with six known spirostans (4–8, 10), and one new sesquiterpene glycoside, named ophioside A (2), together with one known monoterpene glycoside (9) were isolated from the active fractions, and the aglycone of compound 2 that was a new natural compound was obtained from the acid hydrolysis of 2, named ophiopogonol (3). Their structures were determined by spectral and chemical analyses. Furthermore, their effect on HMMEC tube formation was also determined. Our results indicated that compounds 4 and 8 could significantly improve the tube formation and 2 showed moderate increasing effect, while compound 5 exhibited potent inhibitory effect.     

Glomexanthones A–C,three xanthonolignoid C-glycosides from Polygala glomerata Lour

Three novel xanthonolignoid C-glycosides, glomexanthones A–C, with a trans-dihydrobenzofuran on B ring and a 2-hydroxymethyl-5-hydroxyl-2-pentenoic acid moiety in the sugar chain were isolated from an ethanol extract of Polygala glomerata. Their structures and absolute configurations were characterized by extensive NMR, MS, and CD spectroscopic studies. Screening results indicated that compounds 1–3 showed moderate neuroprotective effects on l-Glutamic acid-induced cellular damage in human neuroblastoma SK-N-SH cells.     

Simonols A and B,two novel sesqui-neolignans from the fruits of Illicium simonsii

Two new sesqui-neolignans with novel conjugation way, simonol A (1), featuring a unique motif of a 5,5-dihydro-pyran with a hemiketal carbon, while simonol B (2) possessing two dihydronfuran rings in the same direction, were isolated from the ethanol extract of the fruits of Illicium simonii. Their structures were elucidated by spectroscopic methods including 1D and 2D NMR, HRESIMS, and calculation of electronic circular dichroism (ECD) using density functional theory (DFT). The two isolates were evaluated for their inhibitory activities against the growth of four lines of human cancer cells (NCI-H460, SMMC-7721, MCF-7, BGC-823): 1 showed strong activities comparable to 5-Fluorouracil, and 2 to a less content. In addition, plausible biosynthetic routes for the two compounds were also proposed.     

Cytotoxic and apoptotic effects of constituents from Millettia pachycarpa Benth

The aim of this study is to investigate the cytotoxic and apoptotic effects of constituents from the seeds of Millettia pachycarpa Benth. Fourteen compounds (1–14) including one novel chalcone (10) were isolated as active principles from Chinese herbal medicine M. pachycarpa Benth. Their structures were identified by using spectroscopic methods. All isolates were then evaluated for their cytotoxic effects against several cancer cell lines (HepG2, C26, LL2 and B16) with cisplatin as a positive control. And their apoptosis-inducing effects were tested against HeLa-C3 cells with taxol as a positive control. Both studies showed that compounds 1, 2, 7 and 10 demonstrated significant cytotoxic and apoptotic effects against cancer cells. Moreover, in the apoptosis assay the novel chalcone (10) showed strong apoptosis inducing effects at a concentration of 2 μM within 36 h. It was found to be the most potent apoptotic inducer of the compounds isolated from M. pachycarpa Benth.     

Occurrence of stilbene oligomers in Cyperus rhizomes

Investigation of the chemical constituents of Rhizoma Cyperi (Cyperus rotundus Linneus) resulted in the isolation of novel enantiomeric and meso-stilbene trimers [i.e., (+)- and (−)-(E)-cyperusphenol A (1, 2 respectively) and (E)-mesocyperusphenol A (3)], a trimer bearing a novel hexacyclic ring system [cyperusphenol B (5)], as well as known stilbenoids (cyperusphenols C (4) and D (6), scirpusins A (7) and B (8), and piceid (9)) and luteolin. HPLC was used for the optical resolution of 1 and 2 as well as for the identification of cooccurrence of enantiomers of 7. The structures of the isolates were established by spectroscopic analyses, including a detailed NMR spectroscopic investigation. The isolates were evaluated in terms of their antiproliferative activity employing the Jurkat cell line (human T-cell leukemia cells), while the IC₅₀ potencies of a racemate of 1 and 2, 3, 5, and 6 were estimated as 27.4, 40.5, 26.4, and 26.3 μM, respectively. The suppression of cell growth by 6 was due to the induction of apoptosis, which was characterized by nuclear changes and PARP-1 cleavage determined by western blotting. We also evaluated the free radical scavenging activity of the isolates.