Can phytotherapy with polyphenols serve as a powerful approach for the prevention and therapy tool of novel coronavirus disease 2019 (COVID-19)?

Much more serious than the previous severe acute respiratory syndrome (SARS) coronavirus (CoV) outbreaks, the novel SARS-CoV-2 infection has spread speedily, affecting 213 countries and causing ∼17,300,000 cases and ∼672,000 (∼+1,500/day) deaths globally (as of July 31, 2020). The potentially fatal coronavirus disease (COVID-19), caused by air droplets and airborne as the main transmission modes, clearly induces a spectrum of respiratory clinical manifestations, but it also affects the immune, gastrointestinal, hematological, nervous, and renal systems. The dramatic scale of disorders and complications arises from the inadequacy of current treatments and absence of a vaccine and specific anti-COVID-19 drugs to suppress viral replication, inflammation, and additional pathogenic conditions. This highlights the importance of understanding the SARS-CoV-2 mechanisms of actions and the urgent need of prospecting for new or alternative treatment options. The main objective of the present review is to discuss the challenging issue relative to the clinical utility of plants-derived polyphenols in fighting viral infections. Not only is the strong capacity of polyphenols highlighted in magnifying health benefits, but the underlying mechanisms are also stressed. Finally, emphasis is placed on the potential ability of polyphenols to combat SARS-CoV-2 infection via the regulation of its molecular targets of human cellular binding and replication, as well as through the resulting host inflammation, oxidative stress, and signaling pathways.

Plasma Lactoferrin Levels Positively Correlate with Insulin Resistance despite an Inverse Association with Total Adiposity in Lean and Severely Obese Patients

Context

Lactoferrin (Lf) is an important protein found on mucosal surfaces, within neutrophils and various cells, and in biological fluids. It displays multiple functions, including iron-binding as well as antimicrobial, immunomodulatory and anti-inflammatory activities. Although Lf ingestion has been suggested to cause adiposity reduction in murine models and humans, its relationship with insulin resistance (IR) has not been studied thoroughly.

Objective

To establish the association between circulating Lf levels, glucose status and blood lipid/lipoprotein profile.

Methods

Two independent cohorts were examined: lean to moderately obese women admitted for gynecological surgery (n = 53) and severely obese subjects undergoing biliopancreatic diversion (n = 62).

Results

Although body mass index (BMI) and total body fat mass were negatively associated with Lf, IR (assessed by the HOMA-IR index) was positively and independently associated with plasma Lf concentrations of the first cohort of lean to moderately obese women. These observations were validated in the second cohort in view of the positive correlation between plasma Lf concentrations and the HOMA-IR index, but without a significant association with the body mass index (BMI) of severely obese subjects. In subsamples of severely obese subjects matched for sex, age and BMI, but with either relatively low (1.89 ± 0.73) or high (13.77 ± 8.81) IR states (according to HOMA-IR), higher plasma Lf levels were noted in insulin-resistant vs insulin-sensitive subjects (P<0.05). Finally, Lf levels were significantly higher in lean to moderately obese women than in severely obese subjects (P<0.05).

Conclusion

Our findings revealed that plasma Lf levels are strongly associated with IR independently of total adiposity, which suggests an intriguing Lf regulation mechanism in conditions of obesity and IR.