Morushalunin D, a tri-O-bridged Diels-Alder type adduct from Morus alba var. shalun root cultures and the related precursors.

Three Diels-Alder type adducts (1-3) along with their precursors, including one 2-arylbenzofuran (4) and one stilbene (5), were isolated from the MeOH extract of M. alba var. shalun root cultures. Among them, 1 is a new Diels-Alder type adduct named morushalunin D. The molecular structures of 1-5 were elucidated based on spectroscopic data and comparison with the literatures. Cytotoxic properties of compounds 1-5 were evaluated against murine leukemia P-388 cells. Morushalunin D (1), mulberrofuran T (2), sorocein A (3), moracin M (4), and oxyresveratrol (5) were active, significantly inhibiting the growth of P-388 cells with IC50 values of 0.5, 1.0, 0.6, 2.0, and 3.3 µg/ml, respectively.

Two New Enantiomers of Phenylethanoid and Their Anti-Inflammatory Activities.

In this phytochemical investigation, two pairs of new phenylethanoid derivative enantiomers (1a/1b and 2a/2b), a new phenylethanoid derivative 3b, and seven known compounds (3a, 4-9) were isolated from the leaves of Picrasma quassioides. Spectroscopic techniques were used for the elucidation of their chemical structures, and the absolute configurations were determined by a comparison between the experimental and calculated ECD data, as well as the application of Snatzke's method. Compounds (1a/1b-3a/3b) were measured for their production of NO levels in LPS-induced BV-2 microglial cells. The results showed that all compounds exhibited potential inhibitory effects, and compound 1a showed stronger activity than the positive control.

Aromatic diglycosides from Sophora tonkinensis and a multi-step conformer filtering procedure for TDDFT calculation of flexible glycoside.

Three previously undescribed aromatic diglycosides (1, 5, and 8) and six known analogs (2-4, 6, 7, and 9) were isolated from the roots and rhizomes of Sophora tonkinensis Gagnep. Their structures were elucidated by detailed spectroscopic analysis. The absolute configuration of compound 8 was determined by comparing the experimental and TDDFT calculated ECD spectra of 8 and aglycone 8a. Furthermore, a multistep conformer filtering procedure for TDDFT calculation of flexible glycoside was proposed, which afforded high accuracy with acceptable computing cost in determining the absolute configuration of glycosides using quantum calculated ECD.

Termitomenins F and G, Two New Lignan Glucosides from Terminalia chebula var. tomentella (Kurz) C. B. Clarke.

The extensive chemical investigation on the branches and leaves of Terminalia chebula var. tomentella (Combretaceae) led to the isolation of two new lignan glucosides with a furofuran skeleton, termitomenins F (1) and G (2). In addition, 19 known compounds including five lignan glucosides (3-7), six hydrolyzable tannins (8-13) and eight simple phenolics (14-21) were also identified. Their structures were determined by comprehensive spectroscopic analyses. It is noted that 8 and 9 were C-glycosidic hydrolyzable tannins with one hexahydroxydiphenoyl and one gallagyl group linked to an open-chain glucosyl C-1/O-2/O-3 and O-4/O-6, respectively, which were rarely found in plants. Nine known compounds, 6-9, 13, and 18-21, were procured from the titled plant for the first time, while 3-5, 10-12 and 14-17 were also found in the fruits. Notably, the known hydrolyzable tannins 8-13 exhibited stronger α-glucosidase inhibitory activities with IC50 values ranging from 0.10 to 3.12 µM, than the positive control, quercetin (IC50 = 9.38 ± 0.33 µM).

Termitomenins A-E: Five new lignans from Terminalia chebula var. tomentella (Kurz) C. B. Clarke.

An elaborated phytochemical study on the fresh fruits of Terminalia chebula var. tomentella (Combretaceae) led to the isolation of five new lignans, including three tetrahydrofuran (1-3) and two furofuran (4 and 5) derivatives, namely termitomenins A-E (1-5), along with 10 known ones. All of them were obtained from the titled plant for the first time. Their structures were determined by extensive spectroscopic analysis, including 1D/2D NMR, MS, UV, IR, electronic circular dichroism (ECD), time-dependent density functional theory (TDDFT) calculation of ECD spectra, and single crystal X-ray diffraction in case of 3. Compounds 1-15 exhibited certain anti-inflammatory activities. Interestingly, compounds 6 (IC50 = 18.17 ± 0.57  µM) and 7 (IC50 = 13.66 ± 0.38 µM) which contain an aldehyde group displayed stronger NO inhibitory activity than the positive control L-NMMA (IC50 = 42.34 ± 0.66 µM).

Dihydro-ß-agarofuran sesquiterpenoid derivatives with neuroprotective activity from the leaves of Tripterygium wilfordii.

A phytochemical investigation on the leaves of Tripterygium wilfordii Hook. F. was conducted, leading to the isolation of five undescribed dihydro-ß-agarofuran sesquiterpenoids (1-5) and one known analogue (6). Their structures were determined by comprehensive spectroscopic analyses. The absolute configurations of the compounds were determined by comparison of the experimental ECD with the calculated data. In addition, all the compounds were evaluated for their neuroprotective activities against H2O2-induced cell injury in human neuroblastoma SH-SY5Y cells, and 3 showed the better protective effect with 76.63% cell viability comparing with the positive control Trolox (69.84%) at 12.5 µM.

Isolation of macrocarpene-type sesquiterpenes from stigma maydis with neuroprotective activities.

Five undescribed macrocarpene-type sesquiterpenes (1-5), along with a known analogue (6) were isolated from the crude extract of stigma maydis. The structures of these compounds were elucidated based on comprehensive spectroscopic analyses together with quantum chemical calculations of 13C NMR data and electronic circular dichroism (ECD) curves. All isolated compounds were tested for their neuroprotective effects against the injury of human neuroblastoma SH-SY5Y cells induced by H2O2. Among them, compounds 3 (65.89%) and 5 (64.38%) showed moderate neuroprotective activity at 50 µM.

Enantiomeric 8,4'-type oxyneolignans from the root barks of Ailanthus altissima (Mill.) Swingle and their neuroprotective effects against H2O2-induced SH-SY5Y cells injury.

Ailanthus altissima Swingle is a deciduous tree, belonging to the Simaroubaceae family. Phytochemical investigation of the root barks of A. altissima showed the presence of eight pairs of enantiomeric 8,4'-type oxyneolignans (1a/1b-8a/8b) including nine undescribed compounds (1b, 2a, 3a/3b, 4a/4b, 5b, 7b, 8a). Their structures were elucidated by comprehensive spectroscopic analyses, and their absolute configurations were determined by comparison of the experimental and quantum chemical calculations of electronic circular dichroism (ECD) curves. In addition, their neuroprotective effects against H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells were investigated. Among them, 4a, 4b, and 8b exhibited moderate neuroprotective activity.

Sesquiterpenoids from the herbs of Solanum lyratum and their cytotoxicity on human hepatoma cells.

Eleven sesquiterpenoids including four new eudesmane sesquiterpenoids, solanoids A-D (1-4), and seven known compounds (5-11) were isolated from the herbs of Solanum lyratum. By analyzing the UV, MS and NMR data, the gross structures of all isolates were established. The absolute configurations of these new compounds were determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. The in vitro cytotoxicity of all isolates against the hepatocellular carcinoma Hep3B and HepG2 cell lines was evaluated. Among them, compounds 7 and 11 exhibited moderate cytotoxicity against two cell lines.

Assignment of the stereostructures of sesquiterpenoids from the roots of Daphne genkwa via quantum chemical calculations.

Five new guaiane-type sesquiterpenoids were obtained from the roots of Daphne genkwa. Their gross structures were established by extensive spectroscopic analyses. Attempts on the assignment of the relative configurations were unsuccessful when based on the NOESY correlations. Therefore, NMR chemical shift calculations based on the gauge independent atomic orbital (GIAO) method in combination with the statistical method DP4+ were employed to establish their relative configurations. Furthermore, the absolute configurations were determined by comparing the experimental and calculated electronic circular dichroism (ECD) using time-dependent density functional theory (TDDFT). The isolated compounds were screened for their cytotoxicity in vitro against two human hepatocellular carcinoma, HepG2 and Hep3B cell lines.

Absolute structure assignment of an iridoid-monoterpenoid indole alkaloid hybrid from Dipsacus asper.

Iridoid-monoterpenoid indole alkaloid hybrids (IMIAHs) represent a rare class of natural products reported from only several plants of Rubiaceae and Dipsacaceae families, while their structural assignments remain a very challenging work due to complexity and flexibility. In the current study, a new IMIAH (1) was isolated from the roots of Dipsacus asper and its structure with absolute configuration was unambiguously established by a combination of spectroscopic analyses, chemical degradation and ECD calculation. A new oleanane-type triterpenoid saponin (2) and 15 known co-metabolites were also obtained and structurally characterized. Our biological evaluations showed that compound 2 exhibited moderate inhibition against acetylcholine esterase (AChE) with an IC50 value of 15.8 ±â€¯0.56 µM, and compound 15 displayed potent cytotoxicity selectively against human A549 and H157 lung cancer cells with IC50 values of 6.94 ±â€¯0.24 and 9.06 ±â€¯0.12 µM, respectively.

Isolation of enantiomeric furolactones and furofurans from Rubus idaeus L. with neuroprotective activities.

A phytochemical study on the fruits of Rubus idaeus L. (Rosaceae) yielded eight pairs of enantiomeric lignans, including one undescribed furolactone named (-)-idaeusinol A and six undescribed furofuran derivatives named (+/-)-idaeusinol B-D. The structures of these isolated compounds were elucidated by spectroscopic analyses and a combination of computational techniques including gauge-independent atomic orbital (GIAO) calculation of 1D NMR data and TD-DFT calculation of electronic circular dichroism (ECD) spectra. Bioactivity screenings suggested that (+)-idaeusinol D exhibited the most significant protective effect against H2O2-induced neurotoxicity at the concentration of 25 µM. In contrast, (-)-idaeusinol D, as the enantiomer of (+)-idaeusinol D, showed no effect against H2O2-induced neurotoxicity at both 25 and 50 µM concentration.

Renoprotective phenolic meroterpenoids from the mushroom Ganoderma cochlear.

Twelve previously undescribed phenolic meroterpenoids, cochlearols N-Y, along with two known analogs, ganocochlearins B and C, were isolated from the fruiting bodies of Ganoderma cochlear. Most of these substances were isolated as racemic mixtures. The structures of cochlearols N-Y were assigned based upon spectroscopic data and theoretical calculations. The renoprotective activities of these compounds were evaluated using normal and diseased rat renal interstitial fibroblast cells (NRK-49F). The results show that ganocochlearins S, U, X and Y display potent inhibitory activities against fibronectin overproduction in TGF-ß1-induced NRK-49F cells.

Antiproliferative ent-kaurane diterpenoids isolated from the roots of Zea mays L.

Four new ent-kaurane diterpenoid maizediterpenes A-D (1-4), along with fourteen known compounds were isolated from the roots of Zea mays (maize). Compounds 7, 15, 16 were isolated from this genus for the first time. The planar structures of the new compounds were determined by extensive analysis of their NMR and HR-ESI-MS spectra, and the absolute configurations were established on the basis of specific rotation in association with calculated ECD spectra. Compounds 2, 6 and 18 showed significant antiproliferative effects against five human cancer cell lines (A549, MDA-MB-231, SK-Hep-1, SNU638, HCT116) with IC50 values ranging from 1.99 ±â€¯0.41 µM to 15.18 ±â€¯1.17 µM.

A pair of humulane sesquiterpenoid enantiomers from Syringa pinnatifolia.

Two humulane-type sesquiterpenoids, namely (+)-alashanoid I (1a) and (-)-alashanoid I (1b), were isolated as a pair of enantiomers from the peeled stems of Syringa pinnatifolia. Their structures were elucidated by extensive spectroscopic data (1 D and 2 D NMR, UV, and IR), and the absolute configurations were resolved by X-ray diffraction and experimental and calculated ECD data analysis.

Asprenols A-H, phenolic constituents from the stems of Ilex asprella.

Encouraged by the in vivo anti-inflammatory effect of aqueous extract of Ilex asprella stems, a further phytochemical investigation on I. asprella stems oriented by the in vitro NO production inhibition in RAW264.7 cells was conducted, which led to the isolation of eight new phenolic constituents, namely asprenols A-H (1-8), together with 12 known ones (9-20). The structures of the new compounds were established by extensive spectroscopic data analyses of HR-ESI-MS, IR, UV, and 1D and 2D NMR, and the absolute configurations were determined by comparison of experimental and calculated ECD analyses. All isolated were evaluated for the inhibition against NO production in RAW 264.7 cells, and several compounds showed moderate inhibitory effect.

A Tri-O-Bridged Diels-Alder Adduct from Cortex Mori Radicis.

Sanggenon X, an unusual tri-O-bridged Diels-Alder adduct, was isolated from Cortex Mori Radicis. Its structure was established by spectroscopic analysis, including NMR and HR-MS (High Resolution Mass Spectrometry). Sanggenon X contained three O-bridged rings, where the oxygenated bridgeheads were all quaternary carbons. Chemical methylation was carried out to deduce the linkages of the three O-bridges. The absolute configuration was determined by calculating the ECD (Electronic Circular Dichroism) using the TDDFT (Time-Dependent Density Functional Theory) method. Sanggenon X showed significant antioxidant activity against Fe2+-Cys-induced lipid peroxidation in rat liver microsomes, and was as effective as the positive control, curcumin.

Noralashinol B, a norlignan with cytotoxicity from stem barks of Syringa pinnatifolia.

One new norlignan, noralashinol B (1), and one new natural product, proposed noralashinol C (2), were isolated in a continuous phytochemical investigation on the stem barks of Syringa pinnatifolia. Their structures were elucidated based on the analysis of spectroscopic data, including mass spectrometry and 1D and 2D NMR spectroscopies, and the absolute configuration was determined by experimental and calculated electronic circular dichroism. Compound 1 showed a weak cytotoxicity against HepG2 hepatic cancer cells with its IC50 value of 31.7 µM. Furthermore, 1 induced apoptosis of HepG2 cells in a dose-dependent manner at concentrations of 0-80.0 µM.

Alashinols F and G, two lignans from stem bark of Syringa pinnatifolia.

Two new lignans, alashinols F and G (1 and 2), together with two known analogues (-)-secoisolariciresinol (3) and meso-secoisolariciresinol (4) were isolated from the stem bark of Syringa pinnatifolia, a Mongolian folk medicine with anti-myocardial ischaemic effects. Their structures were elucidated on basis of spectroscopic data analyses, including MS and 1D and 2D NMR, and their absolute configurations were elucidated on the basis of experimental and calculated electronic circular dichroisms. The in vitro anti-inflammation and anti-hypoxia evaluations were also discussed.

Antiviral glycosidic bisindole alkaloids from the roots of Isatis indigotica.

Seven new glycosidic bisindole alkaloids, isatindigobisindolosides A-G (1-7), were isolated from an aqueous extract of the Isatis indigotica roots. Their structures including absolute configurations were determined by spectroscopic and chemical methods, together with calculations of electronic circular dichroism (ECD) spectra based on the quantum-mechanical time-dependent density functional theory. In the NMR spectra of 1-3, it is found that integration of H-2 and intensity of C-2 are affected not only by a substitution group at C-2 but also by solvents. Influences of the glucopyranosyloxy on the calculated ECD spectra of the glycosidic bisindole alkaloids are discussed. Compounds 2, 5, and 6 showed antiviral activity against both the influenza virus A/Hanfang/359/95 (H3N2) and Coxsackie virus B3 with IC50 values of 8.4-100.0 µM.