Pin-Yi Gao

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.

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.

Cytotoxic clerodane diterpenoids from Croton crassifolius

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, and treatment options for HCC are limited. In addition, the discovery of new natural compounds with anti-hepatocarcinoma activity is attracting increasing attention. For this reason, phytochemical investigation of Croton crassifolius led to the isolation of 17 diterpenoids, including three new clerodane diterpenoids, named crassifolius A-C (1-3), along with 14 known ones (4-17). Their structures were established by 1D, 2D NMR, HR-ESI-MS, detailed calculated electronic circular dichroism (ECD) spectra and the assistance of quantum chemical predictions (QCP) of 13C NMR chemical shifts. The cytotoxicities of all these compounds against human liver cancer lines (HepG2 and Hep3B) were determined. Among them, compound 1 exhibited good cytotoxicity with IC50 value of 17.91μM against human liver tumor cells Hep3B. Following further studies of the anti-tumor mechanism of compound 1-induced cell growth inhibition, we found that compound 1 caused apoptotic cell death in Hep3B cells by detecting morphologic changes and Western blotting analysis.

Neogenkwanines A–H: daphnane-type diterpenes containing 4,7 or 4,6-ether groups from the flower bud of Daphne genkwa

Neogenkwanines A–H (1–8), eight daphnane-type diterpenes possessing new skeletons with 4,7- or 4,6-ether groups, along with seven known ones (10–16), were isolated from Daphne genkwa. Their structures and absolute configurations were established by analysis of their NMR, X-ray crystallography, CD exciton chirality data and hydrolysis experiments. In addition, an MTT assay was used to examine the growth-inhibitory effects of all the new isolates on HL-60, Hep3B, and U87 cells; compounds 3, 4 and 5 exhibited significant inhibitory effects against Hep3B cell lines with IC50 values of 7.61, 8.16 and 8.35 μM, respectively.

Synthesis and biological evaluation of novel sarsasapogenin derivatives as potential anti-tumor agents

Based on the fact that timosaponin A-III (TA-III) exhibits potent cytotoxic effects and has been considered as a potential anti-tumor agent, a range of novel sarsasapogenin derivatives 1, 2a-2g, 3, 4, 5, 6a-6g have been synthesized by a simple and facile synthetic route. The in vitro cytotoxic activity of these synthetic compounds has been evaluated against ten human cancer cell lines. The pharmacological results showed that most of the sarsasapogenin derivatives displayed excellent selective cytotoxicity toward the cancer cell lines. An amino group at C-3 or C-26 position of the sapogenin had a profound influence on the cytotoxic activity. In particular, compound 6c exhibited significantly inhibitory activity against A375-S2 (IC50=0.56μM) and HT1080 (IC50=0.72μM) cells. However, introducing a bromo or morpholinyl substituent at the C-3 and C-26 position of the sapogenin generally rendered it inactive against the human cancer cell lines. This research provides a theoretical reference for the exploration of new anti-tumor drugs.

Two new compounds from Crataegus pinnatifida and their antithrombotic activities

One new sesquiterpene, (1α,4aβ,8aα)-1-isopropanol-4a-methyl-8-methylenedecahydronaphthalene (1), with one new phenylpropanoid, threo-2-(4-hydroxy-3,5-dimethoxyphenyl)-3-(4-hydroxy-3-methoxyphenyl)-3-ethoxypropan-1-ol (2), along with four known phenylpropanoids were isolated from Crataegus pinnatifida. The structures of compounds 1 and 2 were elucidated on the basis of 1D, 2D NMR analyses, and HR-ESI-MS. The antithrombotic activity in vitro of all isolates was assayed, and only compound 1 exhibited potent antithrombotic activity by inhibiting platelet aggregation in rat plasma by 81.4% at 1 mg/ml.

Triterpenes from the fruits of Rosa laevigata with acetylcholinesterase and Aβ-aggregation inhibitory activities

A lupane-type triterpene (1) featuring a rare 2-hemiacetal moiety in its A ring and aromatic ester derivatives (2–6) were isolated from the fruits of R. laevigata and evaluated to possess acetylcholinesterase and Aβ-aggregation inhibitory activities. Their structures were determined by multi-spectroscopic methods, chemosynthesis and CD analysis.

Natural terpenoid glycosides with in vitro/vivo antithrombotic profiles from the leaves of Crataegus pinnatifida

Two norditerpenoids (1–2) with unique carbon skeletons, four sesquiterpenoids (3–6) and nine nor-sesquiterpenoids (7–15) were isolated from the leaves of Crataegus pinnatifida and evaluated as possessing antithrombotic activities in vitro/vivo. Their structures with absolute configurations were determined via a combination of spectroscopic data, chemical methods, and quantum-chemical calculations (ECD, NMR, and OR data). Compound 3 showed an inhibitory effect on ADP induced platelet aggregation in vitro, which is mediated through the response to the specific receptor of P2Y12 by docking results. Compound 3 also clearly prolonged the time to form thrombocytes induced by FeCl3, in the caudal vessels of zebrafish.