Industrial Distillation Fractions of Garlic Essential Oil, Design, Synthesis, and Antifungal Activity Evaluation of Aliphatic Substituted Trisulfide Derivatives

Garlic oil has a wide range of biological activities, and its broad-spectrum activity against phytopathogenic fungi still has the potential to be explored. In this study, enzymatic treatment of garlic resulted in an increase of approximately 50 % in the yield of essential oil, a feasible GC-MS analytical program for garlic oil was provided. Vacuum fractionation of the volatile oil and determination of its inhibitory activity against 10 fungi demonstrated that garlic oil has good antifungal activity. The antifungal activity levels were ranked as diallyl trisulfide (S-3)>diallyl disulfide (S-2)>diallyl monosulfide (S-1), with an EC50 value of S-3 against Botrytis cinerea reached 8.16 mg/L. Following the structural modification of compound S-3, a series of derivatives, including compounds S-4~7, were synthesized and screened for their antifungal activity. The findings unequivocally demonstrated that the compound dimethyl trisulfide (S-4) exhibited exceptional antifungal activity. The EC50 of S-4 against Sclerotinia sclerotiorum reached 6.83 mg/L. SEM, In vivo experiments, and changes in mycelial nucleic acids, soluble proteins and soluble sugar leakage further confirmed its antifungal activity. The study indicated that the trisulfide bond structure was the key to good antifungal activity, which can be developed into a new type of green plant-derived fungicide for plant protection.

Kinetics of Trisulfide-to-Disulfide Conversion of Therapeutic IgG1 Monoclonal Antibodies Under Physiological Conditions: A Case Study of Casirivimab And Imdevimab

The percentage of trisulfide variants is a product quality metric that is monitored during the manufacture of monoclonal antibody (mAb)-based therapeutics. Results from earlier preclinical studies revealed that trisulfide linkages in mAbs are rapidly converted to disulfides in circulation. In this study, casirivimab and imdevimab, which are both IgG1 subclass mAbs that target the non-overlapping epitopes in SARS-CoV2 Spike protein, are used as models to study the kinetics of trisulfide-to-disulfide conversion in vivo in human circulation. To determine the percentage of trisulfide variants in systemic circulation immediately after intravenous injection, both mAbs were immunoprecipitated from serum samples collected from COVID-19 patients that received this cocktail antibody treatment as part of a first-in-human study. The immunoprecipitated mAbs were then digested under non-reducing conditions and evaluated by liquid-chromatography-mass spectrometry (LC-MS). Significant reductions in the percentages of trisulfide variants were observed in serum samples as early as 1 hr after completion of the intravenous infusion. A flow-through dialysis model designed to mimic the redox potential of blood revealed a plausible chemical mechanism for the rapid trisulfide-to-disulfide conversion of IgG1 subclass mAbs under physiological conditions.

Thiol-responsive lyotropic liquid crystals exhibit triggered phase re-arrangement and hydrogen sulfide (H2S) release

Hydrogen sulfide (H₂S) is an important signalling molecule with potential pharmaceutical applications. In pursuit of a suitable delivery system for H₂S, herein we apply an amphiphilic trisulfide to concomitantly alter the mesophase behaviour of dispersed lipid particles and enable triggered H₂S release. Amperometric release studies indicate the trisulfide acts as a sustained H₂S donor, with inclusion into the mesophase attenuating release vs neat dispersed trisulfide. Taken together the results highlight the potential for including trisulfide-based additives in stimuli-responsive drug delivery vehicles.

Sulfur transformation and bacterial community dynamics in both desulfurization-denitrification biofilm and suspended activated sludge

Types of microbial aggregates have essential effects on bacterial communities' characteristics, thus affecting the pollutants removal. An up-flow biofilm reactor was used to study the different performances of S^2-/NO₂^- removal and functional genes in suspended sludge and biofilms. The metabolic pathways of sulfurous and nitrogenous pollutants in the desulfurization-denitrification process were proposed. The results showed that S⁰ formation dominated the reactor with a high S^2- concentration. Autotrophic Sulfurovum responsible for S^2-/S⁰ oxidation was the only dominant bacteria in suspended sludge. Heterotrophic Desulfocapsa responsible for SO₄^2- reduction coexisted with Sulfurovum and dominated in biofilms. S^2- oxidation to S⁰ was catalyzed via fccA/B and sqr genes in suspended sludge. S₃^2-/S⁰ oxidation to SO₄^2- was catalyzed via dsrA/B gene in biofilms. SO₄^2- and NO₂^- were removed via the dissimilatory sulfate reduction and denitrification pathway, respectively. This work provides a fundamental and practical basis for optimizing suspended sludge/biofilm systems for S^2-/NO₂^- removal.

Cysteine trisulfide oxidizes protein thiols and induces electrophilic stress in human cells

The cellular effects of hydrogen sulfide (H₂S) signaling may be partially mediated by the formation of alkyl persulfides from thiols, such as glutathione and protein cysteine residues. Persulfides are potent nucleophiles and reductants and therefore potentially an important endogenous antioxidant or protein post-translational modification. To directly study the cellular effects of persulfides, cysteine trisulfide (Cys-S₃) has been proposed as an in situ persulfide donor, as it reacts with cellular thiols to generate cysteine persulfide (Cys-S-S^-). Numerous pathways sense and respond to electrophilic cellular stressors to inhibit cellular proliferation and induce apoptosis, however the effect of Cys-S₃ on the cellular stress response has not been addressed. Here we show that Cys-S₃ inhibited cellular metabolism and proliferation and rapidly induced cellular- and ER-stress mechanisms, which were coupled to widespread protein-thiol oxidation. Cys-S₃ reacted with Na₂S to generate cysteine persulfide, which protected human cell lines from ER-stress. However this method of producing cysteine persulfide contains excess sulfide, which interferes with the direct analysis of persulfide donation. We conclude that cysteine trisulfide is a thiol oxidant that induces cellular stress and decreased proliferation.