Amomum tsao-ko essential oil, a novel anti-COVID-19 Omicron spike protein natural products: A computational study.

Since the outbreak of COVID-19, this virus has been constantly mutating. The latest mutant Omicron has been identified as VOC by WHO. The main reason for its concern is the mutation of 46 amino acids in spike protein, which has brought the global epidemic prevention into another difficulty. Herbal aromatic plant Amomum tsao-ko was excavated from formula 1 and 2 for the treatment of COVID-19 in China, and its active components were extracted and identified. Molecular dynamics simulation and Fpocket were applied to find the key sites on RBDOmicron, and molecular docking was also used to reveal the interaction between A. tsao-ko essential oil (AEO) and RBDOmicron. The AEO components were analyzed and identified by GC/Q-TOF MS. There were 20 kinds of AEO with a relative area percentage of more than 1%, and they were related to the three active centres of RBDOmicron. In this study, virtual screening was used to mine the essential oil components of medicinal plants, and it was found that the components could interact with the spike protein RBD in aerosol to block the interaction of RBD and hACE2, thus cutting off the transmission route and protecting the host. This study has certain guiding significance in the modernization of Traditional Chinese medicine and the prevention of COVID-19.

Rapid extraction of Amomum tsao-ko essential oil and determination of its chemical composition, antioxidant and antimicrobial activities.

A simple, green and efficient extraction method named modified-solvent free microwave extraction (M-SFME) was employed for the extraction of essential oils (EOs) from Amomun tsao-ko. The process of M-SFME was optimized with the prominent preponderance of such higher extraction yield (1.13%) than those of solvent free microwave extraction (SFME, 0.91%) and hydrodistillation (HD, 0.84%) under the optimal parameters. Thirty-four volatile substances representing 95.4% were identified. The IC50 values of EOs determined by DPPH radical scavenging activity and ß-carotene/linoleic acid bleaching assay were 5.27 and 0.63mg/ml. Furthermore, the EOs exhibited moderate to potent broad-spectrum antimicrobial activity against all tested strains including five gram-positive and two gram-negative bacteria (MIC: 2.94-5.86mg/ml). In general, M-SFME is a potential and desirable alternative for the extraction of EOs from aromatic herbs, and the EOs obtained from A. tsao-ko can be explored as a potent natural antimicrobial and antioxidant preservative ingredient in food industry from the technological and economical points of view.

Efficient extraction and preparative separation of four main isoflavonoids from Dalbergia odorifera T. Chen leaves by deep eutectic solvents-based negative pressure cavitation extraction followed by macroporous resin column chromatography.

In this study, green and efficient deep eutectic solvent-based negative pressure cavitation-assisted extraction (DES-NPCE) followed by macroporous resin column chromatography was developed to extract and separate four main isoflavonoids, i.e. prunetin, tectorigenin, genistein and biochanin A from Dalbergia odorifera T. Chen leaves. The extraction procedure was optimized systematically by single-factor experiments and a Box-Behnken experimental design combined with response surface methodology. The maximum extraction yields of prunetin, tectorigenin, genistein and biochanin A reached 1.204, 1.057, 0.911 and 2.448mg/g dry weight, respectively. Moreover, the direct enrichment and separation of four isoflavonoids in DES extraction solution was successfully achieved by macroporous resin AB-8 with recovery yields of more than 80%. The present study provides a convenient and efficient method for the green extraction and preparative separation of active compounds from plants.