Hydroxytyrosol and Arginine as Antioxidant, Anti-Inflammatory and Immunostimulant Dietary Supplements for COVID-19 and Long COVID.

Phytochemicals from plant extracts are becoming increasingly popular in the world of food science and technology because they have positive effects on human health. In particular, several bioactive foods and dietary supplements are being investigated as potential treatments for chronic COVID. Hydroxytyrosol (HXT) is a natural antioxidant, found in olive oil, with antioxidant anti-inflammatory properties that has been consumed by humans for centuries without reported adverse effects. Its use was approved by the European Food Safety Authority as a protective agent for the cardiovascular system. Similarly, arginine is a natural amino acid with anti-inflammatory properties that can modulate the activity of immune cells, reducing the production of pro-inflammatory cytokines such as IL-6 and TNF-α. The properties of both substances may be particularly beneficial in the context of COVID-19 and long COVID, which are characterised by inflammation and oxidative stress. While l-arginine promotes the formation of •NO, HXT prevents oxidative stress and inflammation in infected cells. This combination could prevent the formation of harmful peroxynitrite, a potent pro-inflammatory substance implicated in pneumonia and COVID-19-associated organ dysfunction, as well as reduce inflammation, improve immune function, protect against free radical damage and prevent blood vessel injury. Further research is needed to fully understand the potential benefits of HXT and arginine in the context of COVID-19.

Investigation and quantification of the potential antioxidant, inflammatory, and antibacterial bioactive molecules of the extracts of Algerian black and green table olive brine

The table olive industry produces a large amount of wastewater that can be expensive to be treated and harmful to the environment. This study aimed to find a way to reuse brine water from the production of black and green table olive brines from Bejaia and Mascara of the Sigoise cultivar in order to create a valuable byproduct and con-tribute to sustainable development. In this context, the high-performance liquid chromatography–diode-array detection (HPLC-DAD) analysis revealed the highest concentration of hydroxytyrosol (4-(2-dihydroxy phenyl ethanol);69.67 mg/100 mg) for green table olive brines of Mascara (EOGM) and tyrosol (Ty) (28.8 mg/100 mg) for black table olive brines of Bejaia (EOBB). Presence of polyphenols and ortho-diphenols could be responsible for their antioxidant, anti-inflammatory, and antibacterial properties. To assess antioxidant activity, the scavenging effects of DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,20-Azinobis[3-ethylbenzothiazoline-6-sulfonate]) radicals as well as hydrogen peroxide (H2O2) radicals were used. The antimicrobial activity showed that the black olive extract exhibited the best inhibitory effect, with a minimum inhibitory concentration (MIC) ranging from 0.625 mg/mL to 0.31 mg/mL. The anti-inflammatory activity of tested extracts of black olives of Bejaia (EOBB) and green of olives Mascara (EOGM) was 20.06 µg/mL and 20.21 µg/mL, respectively, which demonstrated the anti-inflammatory effect of these extracts on human beings.

In vitro and clinical studies on the efficacy of alpha-cyclodextrin and hydroxytyrosol against SARS-CoV-2 infection

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus responsible for the current pandemic of coronavirus disease 2019 (COVID-19). This virus attacks cells of the airway epithelium by binding transmembrane angiotensin-converting enzyme 2 (ACE2). Hydroxytyrosol has anti-viral properties. Alpha-cyclodextrin can deplete sphingolipids and phospholipids from cell membranes. The aim of the present experimental study was to evaluate the efficacy of alpha-cyclodextrin and hydroxytyrosol in improving defenses against SARS-CoV-2 infection in in vitro cell models and humans. PATIENTS AND METHODS: For in vitro experiments on Vero E6 cells, RNA for RT-qPCR analysis was extracted from Caco2 and human fibroblast cell lines. For study in humans, the treatment group consisted of 149 healthy volunteers in Northern Cyprus, considered at higher risk of SARS-CoV-2 infection than the general population. The volunteers used nasal spray containing alpha-cyclodextrin and hydroxytyrosol for 4 weeks. The control group consisted of 76 healthy volunteers who did not use the spray. RESULTS: RT-qPCR experiments on targeted genes involved in endocytosis showed a reduction in gene expression, whereas cytotoxicity and cytoprotective tests showed that the compounds exerted a protective effect against SARS-CoV-2 infection at non-cytotoxic concentrations. None of the volunteers became positive to SARS-CoV-2 RT-qPCR assay during the 30 days of treatment. CONCLUSIONS: Treatment with alpha-cyclodextrin and hydroxytyrosol nasal spray improved defenses against SARS-CoV-2 infection and reduced synthesis of viral particles.

The SARS-CoV-2-Inactivating Activity of Hydroxytyrosol-Rich Aqueous Olive Pulp Extract (HIDROX®) and Its Use as a Virucidal Cream for Topical Application.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally. Although measures to control SARS-CoV-2, namely, vaccination, medication, and chemical disinfectants are being investigated, there is an increase in the demand for auxiliary antiviral approaches using natural compounds. Here we have focused on hydroxytyrosol (HT)-rich aqueous olive pulp extract (HIDROX®) and evaluated its SARS-CoV-2-inactivating activity in vitro. We showed that the HIDROX solution exhibits time- and concentration-dependent SARS-CoV-2-inactivating activities, and that HIDROX has more potent virucidal activity than pure HT. The evaluation of the mechanism of action suggested that both HIDROX and HT induced structural changes in SARS-CoV-2, which changed the molecular weight of the spike proteins. Even though the spike protein is highly glycosylated, this change was induced regardless of the glycosylation status. In addition, HIDROX or HT treatment disrupted the viral genome. Moreover, the HIDROX-containing cream applied on film showed time- and concentration-dependent SARS-CoV-2-inactivating activities. Thus, the HIDROX-containing cream can be applied topically as an antiviral hand cream. Our findings suggest that HIDROX contributes to improving SARS-CoV-2 control measures.