Antipathogenic drugs are a potential source of therapeutics, particularly following the emergence of multiple drug-resistant pathogenic microorganisms in the last decade. The inhibition of quorum sensing (QS) is an advanced antipathogenic approach for suppression of bacterial virulence and dissemination. This study aimed to investigate the inhibitory effect of some Egyptian medicinal plants on the QS signaling system of Pseudomonas aeruginosa. Among the tested plants, Mangifera indica exhibited the highest quorum sensing inhibition (QSI) activity against Chromobacterium violaceum ATCC 12472. Four pure compounds were extracted and identified; of these, methyl gallate (MG) showed the most potent QSI. MG had a minimum inhibitory concentration (MIC) of 512 g/mL against P. aeruginosa strains PAO1, PA14, Pa21, Pa22, Pa23, Pa24, and PAO-JP2. The virulence factors of PAO1, PA14, Pa21, Pa22, Pa23, and Pa24 were significantly inhibited by MG at 1/4 and 1/2 sub-MICs without affecting bacterial viability. Computational insights were performed by docking the MG compound on the LasR receptor, and the QSI behavior of MG was found to be mediated by three hydrogen bonds: Trp60, Arg61, and Thr75. This study indicates the importance of M. indica and MG in the inhibition and modulation of QS and QS-related virulence factors in P. aeruginosa.

Nine flavonoids and one saponin were isolated from the aerial parts of Cleome amblyocarpa. Molecular docking of isolated compounds on COVID-19 virus main protease showed variable binding affinities with scores ranging from −8.63 to −6.08 compared to N3 inhibitor (−10.10) and binding modes better than N3 inhibitor in some of the isolated compounds. The descending order of the binding affinity of the tested drugs was as follows: N3 inhibitor (11, docked) > kaempferitrin (6) > isorhamnetin 3,7-O-α-L-dirhamnoside (3) > kaempferol 3-O-β-glucoside-7-O-α-rhamnoside (2) > soysaponin I (1) > isorhamnetin 7-O-α-L-rhamnoside (10) > genistein-8-C-glucoside (8) > tamarixetin 7-O-β-D-glucoside (4) > isoprunetin-7-glucoside (9) > genistin (5) > 5-O-methylgenistein (7). These results could be a good start for fast further examination of the isolated compounds in vitro and in vivo either alone or in combination for the treatment of the COVID-19 virus. Besides, this work gives an explanation of the SAR required for targeting the newly emerged SARS-CoV-2 protease and facilitates the future design and synthesis of new drugs targeting it as well.

Changes in the activities of antimicrobial, antitumor, and antioxidant properties of postbiotics (YCG) are related to changes in the composition of phenolic compounds. Antimicrobial activity was found to be highest in postbiotic (YCG-7) against P. aeruginosa, S. aureus, and E. faecalis with an MIC of 3.1 µg/mL. YCG-7 revealed the most cytotoxicity against LS-174T and PC-3 cell lines with an IC₅₀ of 5.78 and 6.56 µg/mL, respectively. YCG-7 was far more effective for scavenging free radicals in the NO^• and DPPH assays with a scavenging activity of 70.73% and 85.6%, respectively. YCG-7’s total phenolic acid content is up to eightfold higher compared with control. Escherichia coli Nissle 1917 retained high viable counts during refrigerated storage, particularly in YCG (>10⁸ cells g⁻¹) revealing a potential prebiotic activity of Cape gooseberry juice. EcN affected the phenolic profile of the YCG. Pyrogallol, p-coumaric acid, ellagic acid, 4-hydroxybenzoic acid, salicylic acid, gallic acid, vanillic acid, o-coumaric acid, caffeic acid, catechol, syringic acid, and rutin were the predominant phenolic compounds in YCG-7 or YCG-15. Chlorogenic, rosmarinic, cinnamic acid, naringin, and kaempferol were degraded by EcN in YCG-7 and YCG-15. The YCG had significantly higher sensory scores for appearance, smoothness, sourness, mouthfeel, and overall acceptance. These results provide the basis to target the functional benefits of YCG for further human health applications.

Bioassay-guided investigation ofPanicum turgidumextract resulted in the identification of seven steroidal saponins (Turgidosterones 1–7).