Dimeric ent-kauranoids isolated from Isodon japonica var. Glaucocalyx and their anti-inflammatory activities

The phytochemical investigation of the aerial parts of Isodon japonica var. glaucocalyx afforded four undescribed (glaucocalyxin O-R, 1-4) and six known ent-kauranoids (5-10). Their structures were established using NMR and MS measurements. Compounds 1 and 2 are dimeric ent-kaurane-type diterpenoids. Moreover, the plausible biogenetic pathways for compounds 1 and 2 were proposed as Michael addition between two monomers. Eight compounds were assayed for their anti-inflammatory activity by evaluating NO production in LPS-induced RAW 267.4 cells, and compounds 7, 8 and 9 exhibited relatively remarkable anti-inflammatory activities at 10 μM.

Eighteen iridoids from the roots and rhizomes of Valeriana jatamansi and their protective effects against α-hemolysin

Thirteen previously undescribed iridoids (1-13), together with five known iridoids (14-18) were isolated from the roots and rhizomes of Valeriana jatamansi Jones. Their structures with absolute configurations were elucidated by analysis of MS, NMR, optical rotation and their experimental and calculated electronic circular dichroism spectra. All of the isolated compounds were tested for their protective effects against α-hemolysin-induced cell death in A549 cells. Compounds 14, 16 and 17 showed moderate protective effects, and compounds 15 and 18 showed weak protective effects.

Five undescribed abietane-type diterpenes of Callicarpa macrophylla

A phytochemical investigation of the medicinal plant Callicarpa macrophylla resulted in the characterization of two rare rearrangement abietane-type diterpenoids, macrophypene F-G (1-2), and three abietane diterpenoids, named macrophypene H-J (3-5). Additionally, five known diterpenoids (6-10) were identified. The structures of the newly discovered compounds were fully established through extensive analysis of HRESIMS, 1D and 2D NMR data. The absolute configurations of the isolated compounds were determined using CD comparison, chemical methods, and X-ray crystal diffraction experiments. Subsequently, all isolated diterpenoids were evaluated for their inhibitory effects on extracellular PCSK9 protein levels by PCSK9 AlphaLISA screening. Jiadfenoic acid B (6, 56.80% inhibition at 20 μM) and holophyllin F (10, 43.18% inhibition at 20 μM) significantly decreased PCSK9 protein levels in medium of HepG2 cells.

Calysepins I-VII, Hexasaccharide Resin Glycosides from Calystegia sepium and Their Cytotoxic Evaluation

Seven new hexasaccharide resin glycosides, named calysepins I-VII (1-7), with 27-membered rings, were obtained from the aerial parts of Calystegia sepium. Their structures with absolute configuration were established on the basis of spectroscopic data interpretation analysis and the use of chemical methods. They were defined as hexasaccharides composed of one d-quinovose, four d-glucose, and one l-rhamnose unit, and their sugar moieties were partially acylated by (2S)-methylbutanoic acid in 1-7 and (2R,3R)-nilic acid in 1-5 and 7, which mainly differed at the positions of acylation. Additionally, calysepin IV (4) exhibited cytotoxicity against A549 cells with an IC₅₀ value of 5.2 μM.

Efficient nitrogen-vacancy centers' fluorescence excitation and collection from micrometer-sized diamond by a tapered optical fiber in endoscope-type configuration

Using an optical fiber to both excite the nitrogen-vacancy (NV) center in diamond and collect its fluorescence is essential to build NV-based endoscope-type sensor. Such endoscope-type sensor can reach inaccessible fields for traditional NV-based sensors built by bulky optical components and extend the application areas. Since single NV's fluorescence is weak and can easily be buried in fluorescence from optical fiber core's oxide defects excited by the green laser, fixing a micrometer size diamond containing high-density NVs rather than a nanodiamond containing single NV or several NVs on the apex of an optical fiber to build an endoscope-type sensor is more implementable. Unfortunately, due to small numerical aperture (NA), most of the optical fibers have a low fluorescence collection efficiency, which limits the sensitivity and spatial resolution of the NV-based endoscope-type sensor. Here, using a tapered optical fiber (TOF) tip, we significantly improve the efficiency of the laser excitation and fluorescence collection of the NV ensembles in diamond. This could potentially enhance the sensitivity and spatial resolution of the NV-based endoscope-type sensor. Numerical calculations show that the TOF tip delivers a high NA and has a high NV excitation and fluorescence collection efficiency. Experiments demonstrate that such TOF tip can obtain up to over 7-fold excitation efficiency and over 15-fold fluorescence collection efficiency of that from a flat-ended fiber (non-TOF) tip.

Fast magneto-optical spectrometry by spectrometer

Time efficient measurement of the spectroscopic magneto-optical (MO) activity of materials has always been desirable. In conventional MO systems, the monochromator produces quasi-monochromatic light in a narrow wavelength window. Therefore, to measure the spectroscopic MO activity, a large number of measurements over the full spectra is required to obtain satisfactory wavelength resolution and thus is very time consuming. Here, we develop a novel system that is capable of fast measurement of the MO activity by only one white light source, two polarizers, one achromatic quarter-wave plate, and one spectrometer. This system is flexible from UV to IR region, only depending on the power spectra of light source and sensitivity of the detector at the corresponding wavelengths. As examples, we measured the intriguing optic and MO activity in glass, ferromagnetic thin film, and bulk GaAs in the visible to near infrared region. The results of glass demonstrated a minimum resolvable Faraday rotation angle of 0.004° by the currently equipped system.