ng-Zhi Li

Anti-inflammatory triterpenes from the leaves of Rosa laevigata.

Bioassay-guided fractionation of an EtOAc extract of the leaves of Rosa laevigata afforded two new 19-oxo-18,19-seco-ursane-type triterpenes (1 and 3), a new ursane-type nortriterpene (2), a new ursane-type triterpene lactone saponin (4), and two new oleanane-type triterpenoids (5 and 6), together with eight known triterpenoids (7-14). Compound 1, a 19-oxo-18,19-seco-28-norursane, possesses a conjugated diene between C-12 and C-17. Several of the isolated compounds (1, 5, 7, 11, and 13) exhibited moderate activities in anti-inflammatory assays in vitro.

Daphnane-type diterpenes with inhibitory activities against human cancer cell lines from Daphne genkwa.

Four new daphnane-type diterpenes, genkwadanes A-D (1-4), together with 19 known ones, were isolated from ethanol extract of the flower buds of Daphne genkwa. Their structures were determined on the basis of extensive spectroscopic data. Among them, daphnane-type diterpene with a 1,10-double bond (1) was isolated from this plant for the first time. The cytotoxicity of all compounds 1-23 against the 10 selected human cancer cell lines was assayed. A number of compounds exhibited significant activities against the 10 cancer cell lines (IC50<9.56 μM). and most interestingly, all the compounds revealed preferred cytotoxicities on the HT-1080 cell line and displayed much stronger inhibitory activities (IC50<29.94 μM) compared with positive control 5-fluorouracil (IC50=35.62 μM), particularly, compounds 9-11, 13, 16 and 19 exhibited the strongest cytotoxicity activities against the HT-1080 cell line (IC50<0.1 μM).

Studies on cytotoxic triterpene saponins from the leaves of Aralia elata

Aralia elata has long been used as a tonic, anticancer and antidiabetic agent in China and Japan, and is widely consumed as food. Phytochemical investigation of the leaves of A. elata has led to the isolation of four new compounds, 3-O-[β-D-glucopyranosyl(1 → 3)-β-D-glucopyranosyl] echinocystic acid 28-O-β-D-glucopyranosyl ester (congmuyenoside I, 1), 3-O-[β-D-glucopyranosyl(1 → 2)-β-D-glucopyranosyl] hederagenin 28-O-β-D-glucopyranosyl ester (congmuyenoside II, 2), 3-O-{[β-D-glucopyranosyl(1 → 2)]-[β-D-glucopyranosyl(1 → 3)-β-D-glucopyranosyl(1 → 3)]-β-D-glucopyranosyl} echinocystic acid 28-O-β-D-glucopyranosyl ester (congmuyenoside III, 3) and 3-O-β-D-glucopyranosyl caulophyllogenin 28-O-β-D-glucopyranosyl ester (congmuyenoside IV, 4), and eight known triterpene saponins (5-12). The structural determination was accomplished with spectroscopic analysis, in particularly (13)C NMR, 2D NMR and HR-ESI-MS techniques. In addition, compounds 5–10 were found for the first time in the genus Aralia. Compounds 1-12 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. In addition, compound 8 showed significant cytotoxic activities against HL60, A549 and DU145 cancer cells with IC(50) values of 15.62, 11.25 and 7.59 μM, respectively.

Rapid determination of eight bioactive alkaloids in Portulaca oleracea L. by the optimal microwave extraction combined with positive-negative conversion multiple reaction monitor (+/-MRM) technology.

A rapid and reliable microwave extraction and the triple quadrupole-linear ion trap mass spectrometry method was developed and validated for the determination of eight alkaloids in Portulaca oleracea L. The optimal microwave extraction (MWE) condition was performed at 60 °C for 12 min with ethanol-water (70:30, v/v) as the extracting solvent, and the solvent to solid ratio was 30:1. The alkaloids were first detected simultaneously by electrospray ionization tandem mass spectrometry under positive-negative conversion multiple reaction monitor ((+/-)MRM) technique. With investigating three different columns, samples were separated in only 8 min on a Waters ACQUITY UPLC HSS T3 (50 × 2.1 mm(2), 1.8 μm) column using acetonitrile and formic acid-water solution as a mobile phase with a flow rate at 0.2 mL/min. All calibration curves showed good linearity (r>0.999) within the test ranges. The method developed was validated with acceptable sensitivity, intra- and inter-day precision, reproducibility, and extraction recoveries. It was successfully applied to the determination of eight alkaloids in Portulaca oleracea L. from different sources and different harvest periods. The method also provide a reference for extraction and determination of alkaloids in other complex systems.

Two new alkaloids from Portulaca oleracea and their cytotoxic activities

Two new alkaloids named (3R)-3,5-bis(3-methoxy-4-hydroxyphenyl)-2,3-dihydro-2(1H)-pyridinone (1) and 1,5-dimethyl-6-phenyl-1,2-dihydro-1,2,4-triazin-3(2H)-one (2), together with two known compounds (7′R)-N-feruloyl normetanephrine (3) and N-trans-feruloyl tyramine (4) were isolated from the air-dried aerial parts of Portulaca oleracea L. Their structures and configurations were elucidated by spectroscopic methods including 1D NMR, 2D NMR, and HR-MS techniques. In addition, compounds 1–4 were tested for in vitro cytotoxic activities against human lung (K562 and A549) and breast (MCF-7 and MDA-MB-435) cancer cell lines.

Cytotoxic triterpenoid glycosides (saikosaponins) from the roots of Bupleurum chinense.

As a part of our ongoing studies on cytotoxic triterpenoid saponins from herbal medicines, phytochemical investigation of the roots of Bupleurum chinense DC. afforded four new saikosaponins (1-4), along with 16 known ones (5-20). Their structures were established by direct interpretation of their spectral data, mainly HR-ESI-MS, 1D NMR and 2D NMR, and by comparison with literature data. Among them, compound 20 was isolated from the natural product for the first time. The cytotoxicities of all compounds against five selected human cancer cell lines (A549, HepG2, Hep3B, Bcap-37 and MCF-7) were assayed. In general, a number of the isolated compounds exhibited potent cytotoxic activities against the five selected human cancer cell lines. In particular, compounds 3, 8-9, 11-13, 16 and 20 showed more potent cytotoxic activities against the HepG2 and A549 cell lines than the positive control 5-fluorouracil. Based on the primary screening results, the preliminary structure-activity relationship (SAR) studies were also discussed. The SAR results suggest that the 13,28-epoxy bridge, the orientation of the hydroxyl group and the type of the sugar units are important requirements for cytotoxicity and selectivity.

Cytotoxic triterpene saponins from the leaves of Aralia elata.

Phytochemical investigation of the leaves of Aralia elata has led to the isolation of four new compounds, 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl oleanolic acid (1), 3-O-[β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)]-[β-D-glucopyranosyl (1→2)]-β-d-glucopyranosyl hederagenin 28-O-β-D-glucopyranoside (2), 3-O-{[β-D-glucopyranosyl (1→2)]-[β-d-glucopyranosyl (1→3)-β-d-glucopyranosyl (1→3)]-β-D-glucopyranosyl} oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-[β-D-glucopyranosyl (1→2)]-[β-D-glucopyranosyl (1→3)]-β-d-glucopyranosyl caulophyllogenin (4) and two known compounds, 3-O-[β-D-glucopyranosyl (1→3)-α-l-arabinopyranosyl]-echinocystic acid (5) and 3-O-α-L-arabinopyranosyl echinocystic acid (6). The structural determination was accomplished with spectroscopic analysis, in particular (13)C-NMR, 2D-NMR and HR-ESI-MS techniques. Compounds 1-6 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. Compound 1 showed significant cytotoxic activity against HL60 and A549 cancer cells with IC(50) values of 6.99μM and 7.93μM respectively. In addition, compounds 5 and 6 showed significant cytotoxic activity against HL60 cancer cells with IC(50) values of 5.75μM and 7.51μM, respectively.

Two new glycosides from the fruits of Forsythia suspense.

Two new glycosides suspensaside C (1) and 2,3,5,6-tetrahydro-jacaranone-4-O-β-d-glucopyranoside (2), together with four known compounds suspensaside A (3), rengynic acid-1′-O-β-d-glucopyranoside (4), forsythoside A (5), and rengynic acid (6), were isolated from the fruits of Forsythia suspense (Thunb.) Vahl. The structures of 1 and 2 were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR analyses and HR-ESI-MS. All isolates were tested for their cytotoxicities against five human cancer cell lines (A549, Colo-205, Hep-3B, HL60, and KB). Compound 3 exhibited cytotoxicity against HL-60, Hep-3B, and A549 cancer cell lines.

Secondary metabolites from the flower buds of Lonicera japonica and their in vitro anti-diabetic activities

Four new compounds (1, 2, 7 and 8) and twenty known compounds were isolated from the flower buds of Lonicera japonica. Their structures were determined by extensive NMR and HR-ESIMS spectroscopic data analyses. Among them, compounds 1 and 2 are a pair of diastereoisomers possessing a rare chemical structure, and their absolute configurations were determined by comparing their experimental and calculated ECD spectra. Furthermore, all the isolates were evaluated for their inhibitory effects on α-glucosidase and protein tyrosine phosphatase 1B (PTP1B), especially 1 and 2, which displayed both significant inhibitions. In addition, the possible action mechanism of the active compounds was also explored by using molecular docking studies.

Steroidal saponins from Anemarrhena asphodeloides

Two new steroidal saponins, named anemarnoside A (1) and anemarnoside B (2), along with three known compounds, timosaponin J (3), timosaponin B II (4), and timosaponin B (5), have been isolated from Anemarrhena asphodeloides. Their structures were established by spectroscopic techniques (IR, MS, 1D NMR, and 2D NMR) and by comparison with published data.