Contribution of Constituents in Rosemary-Magnolia Compound Essential Oil to Antibacterial, Antioxidant and Cytotoxicity Bioactivities Revealed by Grey Correlation Analysis.

The compound of essential oils (EOs) is a key approach to achieving the superimposed efficacy of plant EOs. In this article, grey correlation analysis was applied for the first time to explore the compound ratios and contribution between constituents and the bioactivity of the compound EOs. There were 12 active constituents shared in rosemary and magnolia EOs prepared by negative pressure distillation. With different proportions, these two EOs were blended and analyzed for the antioxidant, bacteriostatic and antitumor effects. According to the results of the inhibition circle, minimum bactericidal and inhibitory concentration, the most obvious inhibition effect of the compound EOs on different strains of bacteria was shown in Staphylococcus aureus. The results of antioxidant test showed that single EO from rosemary had the best antioxidant effect, and its EO content was directly proportional to the antioxidant effect. The cytotoxicity results showed that, there was a significant difference in the lethality of the compound EOs between tumor cells Mcf-7 (human breast cancer cells) and SGC-7901 cells (human gastric cancer cells). Furthermore, single EO from magnolia had an obvious inhibitory effect on the growth of Mcf-7 cells and SGC-7901 cells, and the cell lethality rate was as high as 95.19 % and 97.96 %, respectively. As the results of grey correlation analysis, the constituents with the maximal correlation of inhibitory effects on bacteria were as follows: S. aureus - Terpinolene (0.893), E. coli - Eucalyptol (0.901), B. subtilis - α-Pinene (0.823), B. cereus - Terpinolene (0.913) and Salmonella - α-Phellandrene (0.855). For the ABTS and DPPH scavenging effects, the constituents with the maximal correlation were (-)-Camphor (0.860) and ß-Pinene (0.780), respectively. In terms of the effects of the active constituents of compound EOs on the inhibitory activities of tumor cells Mcf-7 and SGC-7901, the three active constituents of γ-Terpinene, (R)-(+)-ß-Citronellol and (-)-Camphor were in the top three, and their correlation were Mcf-7 (0.833, 0.820, 0.795) and SGC-7901 (0.797, 0.766, 0.740). Our study determined the contribution degree of active constituents in the antibacterial, antioxidant, and antitumor bioactivities of rosemary-magnolia compound EOs, and also provided new insights for the research of EOs combination formulations.

Direct MYD88L265P gene detection for diffuse large B-cell lymphoma (DLBCL) via a miniaturised CRISPR/dCas9-based sensing chip.

Traditional methods for single-nucleotide variants based on amplification and fluorescence signals require expensive reagents and cumbersome instruments, and they are time-consuming for each trial. Here, a porous anodised aluminium (PAA)-based sensing chip modified with deactivated Cas9 (dCas9) proteins and synthetic guide RNA (sgRNA) as the biorecognition receptor is developed, which can be used for the label-free sensing of the diffuse large B-cell lymphoma (DLBCL) MYD88L265P gene by integrating with electrochemical ionic current rectification (ICR) measurement. The sgRNA that can specifically identify and capture the MYD88L265P gene was screened, which has been proved to be workable to activate dCas9 for the target MYD88L265P. In the sensing process, the dCas9 proteins can capture the genome sequence, thus bringing negative charges over the PAA chip and correspondingly resulting in a variation in the ICR value due to the uneven transport of potassium anions through the ion channels of the PAA chip. The whole sensing can be finished within 40 min, and there is no need for gene amplification. The CRISPR/dCas9-based sensor demonstrates ultrasensitive detection performance in the concentration range of 50 to 200 ng µL-1 and it has been proved to be feasible for the genome sequence of patient tissues. This sensor shows the potential of targeting other mutations by designing the corresponding sgRNAs and expands the applications of CRISPR/dCas9 technology to the on-chip electrical detection of nucleic acids, which will be very valuable for rapid diagnosis of clinically mutated genes. This makes the hybrid CRISPR-PAA chip an ideal candidate for next-generation nucleic acid biosensors.