Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Energy and electron transfer in porphyrin-phthalocyanin-porphyrin heterotrimers

Diese Dissertation leistet einen Beitrag zum Verständnis des Energie- und Elektronentransfers innerhalb von neuartigen supramolekularen Strukturen, die aus einem zentralen Phthalocyanin und zwei axial angekoppelten Porphyrinen bestehen. Zwei solcher Trimere, welche die koordinative Ankopplung von Porphyrinen über ein Silizium-Zentralatom des Phthalocyanins nutzen, wurden im Rahmen der Arbeit zum ersten Mal quantitativ bezüglich auftretender innermolekularer Transferprozesse charakterisiert. Ziel war die Beantwortung der Frage, ob diese Substanzklasse die wunschgemässe Vereinigung von Lichtsammlung und Ladungstrennung ermöglicht. Aus der Kombination der Messdaten, aufgenommen mit einer Vielzahl von Messverfahren, konnten für die beiden untersuchten Trimere in zwei unterschiedlich polaren Lösungsmitteln die Ratenkonstanten der Energie- und Ladungstransferkanäle ermittelt werden. In allen Fällen findet ein effizienter Ladungstransfer von den Porphyrinen zum Phthalocyanin und ein Lochtransfer vom Phthalocyanin zu einem der beiden Porphyrine statt. Dieses Ergebnis bestätigt die Erwartung, dass Lichtsammlung und Ladungstrennung in diesem Molekül vereint auftreten. Zusätzlich zu den beiden oben erwähnten Prozessen findet je nach Lösungmittelpolarität und Struktur der Porphyrine ein dem Energietransfer paralleler Elektronentransfer und ein Ladungsrücktransfer statt. Allerdings zerfällt der ladungsseparierte Zustand zu schnell, was eine praktische Nutzung der untersuchten Verbindungen in Solarzellen noch verhindert und ihre Weiterentwicklung erfordert.This thesis contributes to the comprehension of energy and electron transfer within novel supra-molecular structures, denominated triads, consisting of a central phthalocyanine axially-coupled to two porphyrins. In the course of this thesis, two of the trimers, were quantitatively characterized regarding their intramolecular transfer processes. Both feature a dative bond between the porphyrins and the phthalocyanine via the central silicium atom of the latter. These investigations aimed at answering whether this class of compounds allows the desired combination of light harvesting and charge separation. The rate constants of both investigated trimers in two solvents with different polarity were determined by the combination of data from a variety of measurement methods. An efficient charge transfer from the porphyrins to the phthalocyanine and a hole transfer from the phthalocyanine to one of the porphyrins occurs in all investigated cases. This result confirms the prospect that light harvesting and charge separation can occur combined in one molecule. Depending on solvent polarity and the structure of the porphyrines, electron transfer parallel to the energy transfer and a charge back transfer takes place in addition to both above-mentioned processes. However, the charge-separated state of the investigated substances decays to fast, still preventing a practical utilization of these compounds in solar cells and necessitating further developments

Solid-Solution Mixed-Linker Synthesis of Isoreticular Al-Based MOFs for an Easy Hydrophilicity Tuning in Water-Sorption Heat Transformations

The solid-solution mixed-linker approach, where a linker is partially replaced by a similar one under retention of the isoreticular metal–organic framework (MOF) structure, offers an easy and inexpensive way to fine-tune MOF properties to design tailored compounds. A total of 10 aluminum mixed-linker MOFs, [Al(OH)(X)a(Y)1–a] (X = IPA, isophthalate; Y = FDC, 2,5-furandicarboxylate) spanning between the isostructural MOFs CAU-10-H (a = 1) and MIL-160 (a = 0), were synthesized by employing different ratios of the aforementioned linkers. CAU-10-H and MIL-160 have been reported as highly promising materials for cycling water sorption for heat transformation applications. A detailed characterization with a focus on the changes in the sorption properties for water vapor showed that the hydrophilicity is readily and easily tuned through the mixed-linker approach between the limits of MIL-160 and CAU-10-H. An increasing fraction of IPA shifts the steep increase in the S-shaped water adsorption isotherm in small steps from p/p0 = ∼0.05 for MIL-160 to p/p0 = ∼0.18 for CAU-10-H. Higher coefficient of performance (COPH) values for the mixed-linker materials over MIL-160 illustrate the well-balanced hydrophobicity/hydrophilicity of the former under the exemplary calculation conditions