Sesquiterpene lactones from Carpesium abrotanoides L. and their activity in inducing protective autophagy.

Fourteen sesquiterpene lactones were isolated from the whole plant of Carpesium abrotanoides L. Their structures were determined on the basis of comprehensive spectroscopic data analysis. All compounds were screened for their cytotoxic activity, and compound 6 showed the strongest activity (IC50 2.73 - 7.21 µM) against five human cancer cell lines, including A549, HepG2, HCT116, MDA-MB-231, and CNE2. Compound 6 was further investigated. Compound 6 effectively induced G2/M cell cycle arrest and ROS accumulation in a dose-dependent manner, which further led to apoptosis in cancer cells. Interestingly, compounds 1 and 6 could also activate protective autophagy, which was reported for the first time in sesquiterpene isolated from Carpesium abrotanoides. In addition, compounds 1 and 6 could induce lysosomal biogenesis by 173.2% and 163.7%, respectively. In sum, sesquiterpene lactones from Carpesium abrotanoides could induce apoptosis and protective autophagy in cancer cells, which provide a serial of compounds with potential clinical applications.

Ten new nortriterpenes from Euphorbia resinifera and their anti-tomato yellow leaf curl virus activities.

Ten new nortriterpenes, euphorbiumrins A-J (1-10), together with three known analogues (11-13) were isolated from the latex of Euphorbia resinifera. Their structures were established on the basis of extensive spectroscopic analyses (IR, UV, HRESIMS, 1D and 2D NMR). Their inhibitions on tomato yellow leaf curl virus (TYLCV) were evaluated and compound 5 exhibited significant anti-TYLCV activity with an inhibition rate of 71.7% at concentration of 40 µg/mL.

Two New C21 Steroidal Glycosides from the Roots of Cynanchum paniculatum.

Two new C21 steroidal glycosides, paniculatumosides H and I, together with four known ones were isolated from the roots of Cynanchum paniculatum (Bge.) Kitag. Their structures were identified by spectroscopic methods including extensive 1D and 2D NMR techniques. All compounds were subjected to detect the anti-tobacco mosaic virus (TMV) activities and their cytotoxities against three human tumor cell lines (SMMC-7721, MDA-MB-231 and A549). The results showed that compounds 1 and 5 exhibited potent protective activities against TMV, while 2, 4 and 6 had moderate effects on the SMMC-7721 cancer cells viability.

Spoof localized surface plasmons in corrugated ring structures excited by microstrip line.

We have investigated the fundamental and high-order spoof localized surface plasmons (LSPs) modes in the proposed corrugated ring resonator printed on a thin dielectric substrate with or without ground plane. An efficient and ease-of-integration method to excite spoof LSPs in the textured ring resonator has been adopted to suppress unwanted high-order modes and enhance fundamental modes. A multi-band-pass filter has been proposed and numerically demonstrated. Experimental results at the microwave frequencies verify the high performances of the corrugated ring resonator and the filter, showing great agreements with the simulation results. We have also shown that the fabricated device is sensitive to the variation of the refraction index of materials under test, even when the material is as thin as paper.

Planar spoof plasmonic ultra-wideband filter based on low-loss and compact terahertz waveguide corrugated with dumbbell grooves.

Although subwavelength planar terahertz (THz) plasmonic devices can be implemented based on planar spoof surface plasmons (SPs), they still suffer from a little high propagation loss. Here the dispersion and propagation characteristics of the spoof plasmonic waveguide composed of double metal strips corrugated with dumbbell shaped grooves have been investigated. It has been found that much lower propagation loss and longer propagation length can be achieved based on the waveguide compared with the conventional spoof plasmonic waveguide with rectangular grooves. Moreover, the waveguide can implement a decrease in size of about 22%. An ultra-wideband THz plasmonic filter for planar circuits has been demonstrated based on the proposed waveguide. The experimental verification at the microwave frequency has been conducted by scaling up the geometry size of the filter.

A 4-way wavelength demultiplexer based on the plasmonic broadband slow wave system.

We propose a broadband slow wave system based on the thin metal-insulator-metal (MIM) graded grating structure composed of two corrugated metal strips with periodic array of grooves on a thin dielectric substrate. The guided spoof surface plasmon polaritons (SSPPs) at different frequencies can be localized at different positions along the ultrathin MIM grating. By introducing specially designed non-corrugated MIM branches with specific lengths at the locations where the EM waves are trapped, the trapped EM waves can be released and propagate along these branches. A 4-way wavelength demultiplexer based on such plasmonic broadband slow wave system is then demonstrated and fabricated. To improve the isolations between different branches at lower frequencies, band-reject filters are inserted at the front of some MIM branches. The measurements and the simulation results have shown very good agreements, which validate the feasibility of the 4-way wavelength demultiplexer.