Viruses constitute a significant group of pathogens that have caused numerous fatalities and substantial economic losses in recent years, particularly with the emergence of coronaviruses. While the impact of SARS-CoV-2 appears to be diminishing in daily life, only a limited number of drugs have received approval or emergency use authorization for its treatment. Given the high mutation rate of viral genomes, host-directed agents (HDAs) have emerged as a preferred choice due to their broad applicability and lasting effectiveness. In contrast to direct-acting antivirals (DAAs), HDAs offer several advantages, including broad-spectrum antiviral activities, potential efficacy against future emerging viruses, and a lower likelihood of inducing drug resistance. In our review article, we have synthesized known host-directed antiviral targets that span diverse cellular pathways and mechanisms, shedding light on the intricate interplay between host cells and viruses. Additionally, we have provided a brief overview of the development of HDAs based on these targets. We aim for this comprehensive analysis to offer valuable perspectives and insights that can guide future antiviral research and drug development efforts.

A chemical investigation of secondary metabolites (SMs) from Aspergillus nidulans resulted in the identification of five novel dioxopiperazine (DKP)-diphenyl ether hybrids, designated as diphenylemestrins A-E (1-5). These compounds 1-5 represent the first known dimers combining DKP and diphenyl ether structures, with compound 4 featuring an uncommon dibenzofuran as the diphenyl ether component. The structural elucidation and determination of absolute stereochemistry were accomplished through spectroscopic analysis and electronic circular dichroism (ECD) calculations. Notably, diphenylemestrin C (3) exhibited moderate cytostatic activity against NB4 cells, with a half maximal inhibitory concentration (IC₅₀) value of 21.99 μmol·L^-1, and induced apoptosis at higher concentrations.
Aspergillus nidulans/metabolism* ; Diketopiperazines/pharmacology* ; Molecular Structure ; Phenyl Ethers/pharmacology* ; Humans ; Apoptosis/drug effects* ; Cell Line, Tumor

(±)-Talapyrones A-F (1-6), six pairs of dimeric polyketide enantiomers featuring unusual 6/6/6 and 6/6/6/5 ring systems, were isolated from the fungus Talaromyces adpressus. Their structures were determined by spectroscopic analysis and HR-ESI-MS data, and their absolute configurations were elucidated using a modified Mosher's method and electronic circular dichroism (ECD) calculations. (±)-Talapyrones A-F (1-6) possess a 6/6/6 tricyclic skeleton, presumably formed through a Michael addition reaction between one molecule of α-pyrone derivative and one molecule of C₈ poly-β-keto chain. In addition, compounds 2/3 and 4/5 are two pairs of C-18 epimers, respectively. Putative biosynthetic pathways of 1-6 were discussed.
Polyketides/isolation & purification* ; Talaromyces/chemistry* ; Stereoisomerism ; Molecular Structure ; Circular Dichroism ; Pyrones/chemistry*

Objective: To study the chemical constituents in the barks and leaves of Cinnamomum cassia.Methods: The crude extracts of the barks and leaves of Cinnamomum cassia were extracted by ethanol, the chemical constituents of the crude extracts were separated and purified by chromatographic methods and identified by spectroscopic analysis.Results: Five lignans were separated from the barks and two lignans were separated from the leaves of Cinnamomum cassia as follows: (7S,8R)-dihydrodehydrodiconiferyl alcohol 9'-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranoside (1), 1,2,3-propanetriol,1--3-methoxyphenyl-(1R,2R) (2), (6R,7R,8R)-7a-lyoniresinol (3), (6S,7R,8R)-7a-lyoniresinol (4), (6R,7S,8S)-7a-lyoniresinol (5),(+)-lariciresinol(6), (-)-4-epi-lyoniresinol (7).Conclusion: All the lignans are isolated from Cinnamomum cassia for the first time.

Objective:To simultaneously separate 5 phenylpropanoids from Cinnamomum cassia by semi-preparative HPLC, and explore their immunosuppressive activity. Methods:After extracted by ethanol, the ethyl acetate part of Cinnamomum cassia was isola-ted by semi-preparative HPLC. The separation was conducted on an Ultimate XB-C18 (250 mm × 10 mm, 5μm) semi-preparative chro-matographic column and the mobile phase was acetonitrile-water with gradient elution. The detection wavelength was 330 nm, and the flow rate was 2. 5 ml·min-1 . The sample volume was 0. 3 ml. MS and NMR spectroscopic analysis were used to determine the config-urations. A CCK-8 method was used to detect the immunosuppressive activity of phenylpropanoids. Results: Totally 5 phenylpro-panoids were separated from Cinnamomum cassia by the semi-preparative HPLC, and identified as erythro-guaiacylglycerol, (7R,8S)-syringoylglycerol, (7S,8S)-syringoylglycerol, 3-methoxyphenyl-acrylaldehyde and O-methoxy cinnamaldehyde. The inhibitory rates of T cells and B cells of the compound 3 was more than 20% at the concentration of 800μmol·L-1 . Conclusion:The method is conven-ient with good separation effect, which can simultaneously separate 5 phenylpropanoids from Cinnamomum cassia, and among them, the compound 3 shows immunosuppressive effect to some extent.

We Injecte(?) 12-16 ?l 20—40% HRP in normal sanne into the myocardium orthe anterior wall of the left ventricle in six rats and 10 ?l choleragenoid-horsera-dish peroxidase conjugate(CB-HRP)in three rats.The Th1-3 DRG and the nodoseganglia of both side were removed.The sections of these ganglia were proceeded bythe TMB chromogentic reaction for HRP and immunohistochemical reaction(the firstantibody is the substance P antiserum).There are three types of labeled cells——theHRP labeled cells.Sp-IR cells,and HRP-Sp-IR double labeled cells were observedin the Th1-3 DRG and nodose ganglia of both side.The parts of Sp-IR nerve fib-ers in the heart wall originate from the DRG and nodose ganglia and these neuronsprojecting the HRP-Sp-IR nerve fiber contained substanse P.Their functions may berelated to the pain(nociceptive)sensation of the heart.This study may also be aevidence of the main function of the cardiac sympathetic afferent fiber is the con-duction of the pain sensation.A few of HRP-Sp-IR double labeled cells in thenodose ganglion observed suggest that the cardiac parasympathetic afferent fibermay participate in conduction of the pain sensation.This question requires furtherstudy.