Preliminary Study on Supercritical Extract of Aspergillus Niger Inhibiting Alternaria
The mechanism of inhibition of Alternaria alternata by supercritical extraction (SE) from Aspergillus Niger mycelium was studied. Sample SE was extracted from Aspergillus Niger mycelium by supercritical fluid extraction, and its extract was separated and identified by gas chromatography-mass spectrometry (GC-MS). The antimicrobial mechanism of SE was studied by cell membrane permeability test, nucleic acid and total protein content determination, 4′, 6-diimidine-2-phenylindole (DAPI) fluorescence staining, reactive oxygen species (ROS) content determination and respiratory metabolic pathway. The results of nucleic acid and protein showed that SE could affect the integrity of cell membrane of Alternaria alternata. After 4.5 h of SE treatment, the conductivity increased by 37.2% compared with the negative control, and the content of extracellular nucleic acid protein increased significantly. DAPI staining showed that DAPI could bind to nucleic acid in Alternaria alternata. After 30 minutes of SE treatment, SE could cause abnormal dispersion of nuclear chromatin. The results of ROS test showed that SE could stimulate the bacteria to produce excessive reactive oxygen species. The ROS content increased by 79.67% when SE acted on Alternaria for 40 minutes compared with the negative control. Respiratory metabolic test showed that SE could inhibit the activity of succinate dehydrogenase in tricarboxylic acid cycle (TCA), and the inhibition rate was 35.4%. SE has strong bacteriostatic activity. Its bacteriostatic mechanism is achieved by affecting the normal function of cell membrane, damaging cell structure and inhibiting the respiratory metabolism of fungi.
Tags: guggul supercritical co2 extract, liquid co2 extraction thc, seyting up a supercritical co2 extraction sustem