ABSTRACT
The extract of the whole plant of Carpesium abrotanoides L. yielded five new sesquiterpenes including four eudesmanes (1-4) and one eremophilane (5). The new compounds were characterized by spectroscopic analysis especially 1D and 2D NMR spectroscopy and HRESIMS data. Structurally, both compounds 1 and 2 were sesquiterpene epoxides and 2 owned an epoxy group at C-4/C-15 position to form a spiro skeleton. Compounds 4 and 5 were two sesquiterpenes without lactones and 5 possessed a carboxy group in the molecule. Additionally, all the isolated compounds were preliminarily evaluated for the inhibitory activity against SARS-CoV-2 main protease. As a result, compound 2 showed moderate activity with an IC50 value of 18.79 µM, while other compounds were devoid of noticeable activity (IC50 > 50 µM).
ABSTRACT
Therapeutic mRNAs and vaccines are being developed for a broad range of human diseases, including COVID-19. However, their optimization is hindered by mRNA instability and inefficient protein expression. Here, we describe design principles that overcome these barriers. We develop an RNA sequencing-based platform called PERSIST-seq to systematically delineate in-cell mRNA stability, ribosome load, as well as in-solution stability of a library of diverse mRNAs. We find that, surprisingly, in-cell stability is a greater driver of protein output than high ribosome load. We further introduce a method called In-line-seq, applied to thousands of diverse RNAs, that reveals sequence and structure-based rules for mitigating hydrolytic degradation. Our findings show that highly structured "superfolder" mRNAs can be designed to improve both stability and expression with further enhancement through pseudouridine nucleoside modification. Together, our study demonstrates simultaneous improvement of mRNA stability and protein expression and provides a computational-experimental platform for the enhancement of mRNA medicines.