New and Bioactive Sesquiterpenes from Schisandra sphenanthera

Three new sesquiterpenes, schisansphenins A ( 1 ) and B ( 2 ) and (?)‐γ‐cuparenol ( 3 ), were isolated from an acetone extract of the fruits of Schisandra sphenanthera. The known compound 4 was isolated for the frist time from a natural source. The structures of the isolated compounds were elucidated through extensive spectroscopic analyses, particularly 2D‐NMR experiments (¹H,¹H‐COSY, HMQC, HMBC, and NOESY). A plausible biogenetic pathway for schisansphenin B ( 2 ) is proposed. Compounds 2 and 3 significantly reduced activation of NF‐AT and NF‐κB in the luciferase‐reporter assay.     

Metabolite Profiling of In Vitro Cultured and Field Grown Rhizomes of Acorus calamus from Mongolia Using GC–MS

Acorus calamus (sweet flag) is used in the traditional Chinese and Indian medicines for various ailments. Due to its extensive use in herbal medicine, natural resources from the world’s forests are being depleted at an alarming rate. In the present study, an in vitro cell culture technique is being explored as an alternative to field grown A. calamus with respect to the metabolite profile, antioxidant properties, total phenol, and total flavonoid content. Gas chromatography mass spectrometry (GC–MS) was utilized to compare the metabolite profiling between methanolic extracts of in vitro and field grown rhizome tissues of A. calamus. A statistical analysis indicated an upregulation of α-selinene, which is representative of sesquiterpene ketones, and a cyclic polyol, d-pinitol, which has an insulin mimicking effect in the in vitro cultivated rhizome tissue when compared to field grown rhizomes. Significantly higher free-radical scavenging activity (IC₅₀ 69.32 μg mL⁻¹), total phenolic content (71.60 mg GAE g⁻¹), and total flavonoid content (42.34 mg CE g⁻¹) were observed in in vitro rhizome tissues compared with those from field grown rhizomes. These observations suggest that the in vitro cultivation of Acorus rhizomes could be exploited as an alternative to field grown A. calamus, as it is an endangered medicinal plant. The production of useful metabolites by the in vitro cultured rhizomes can be explored successfully for utilization by various food and drug industries.

     

A facile combinatorial approach to construct a ratiometric fluorescent sensor: application for the real-time sensing of cellular pH changes

Realtime monitoring of the cellular environment, such as the intracellular pH, in a defined cellular space provides a comprehensive understanding of the dynamics processes in a living cell. Considering the limitation of spatial resolution in conventional microscopy measurements, multiple types of fluorophores assembled within that space would behave as a single fluorescent probe molecule. Such a character of microscopic measurements enables a much more flexible combinatorial design strategy in developing fluorescent probes for given targets. Nanomaterials with sizes smaller than the microscopy spatial resolution provide a scaffold to assemble several types of fluorophores with a variety of optical characteristics, therefore providing a convenient strategy for designing fluorescent pH sensors. In this study, fluorescein (CF) and tetramethylrhodamine (CR) were assembled on a DNA nanostructure with controlling the number of each type of fluorophore. By taking advantage of the different responses of CF and CR emissions to the pH environment, an appropriate assembly of both CF and CR on DNA origami enabled a controlled intensity of fluorescence emission and ratiometric pH monitoring within the space defined by DNA origami. The CF and CR-assembled DNA origami was successfully applied for monitoring the intracellular pH changes.

A combinatorial assembly of two types of intensity-based fluorophores on a DNA nanostructure provided a ratiometric pH probe with high emission intensity for monitoring intracellular pH changes.