Treatment of COVID-19 patients with quercetin: a prospective, single center, randomized, controlled trial

Abstract

Scientific research continues on new preventive and therapeutic strategies against severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2). So far, there is no proven curative treatment, and a valid alternative therapeutic approach needs to be developed. This study is designed to evaluate the effect of quercetin in COVID-19 treatment. This was a single-centre, prospective randomized controlled cohort study. Routine care versus QCB (quercetin, vitamin C, bromelain) supplementation was compared between 429 patients with at least one chronic disease and moderate-to-severe respiratory symptoms. Demographic features, signs, laboratory results and drug administration data of patients were recorded. The endpoint was that QCB supplementation was continued throughout the follow-up period from study baseline to discharge, intubation, or death. The most common complaints at the time of hospital admission were fatigue (62.4%), cough (61.1%), anorexia (57%), thirst (53.7%), respiratory distress (51%) and chills (48.3%). The decrease in CRP and ferritin levels was higher in the QCB group (all Ps were < 0.05). In the QCB group, the increase in platelet and lymphocyte counts was higher (all Ps were < 0.05). QCB did not reduce the risk of events during follow-up. Adjustments for statistically significant parameters, including the lung stage, use of favipiravir and presence of comorbidity did not change the results. While there was no difference between the groups in terms of event frequency, the QCB group had more advanced pulmonary findings. QCB supplement is shown to have a positive effect on laboratory recovery. While there was no difference between the groups in terms of event frequency, QCB supplement group had more advanced pulmonar findings, and QCB supplement is shown to have a positive effect on laboratory recovery/results. Therefore, we conclude that further studies involving different doses and plasma level measurements are required to reveal the dose/response relationship and bioavailability of QCB for a better understanding of the role of QCB in the treatment of SARS CoV-2.

Flavonoids for Treating Viral Acute Respiratory Tract Infections: A Systematic Review and Meta-Analysis of 30 Randomized Controlled Trials

“…The risk of bias data for the included 30 RCTs was presented in Figure 2 . The randomization process was rated at high risk in 3 (10%) RCTs ( 30 , 45 , 48 ) because concealment of allocation sequence was not presented or open-label design. Besides, 2 (6.7%) RCTs ( 34 , 42 ) were rated at some concerns for the lack of details of the concealment and the difference in baseline data between groups; the remaining 25 (83.3%) RCTs were rated at low risk.…”

“…Regarding the basis of missing outcome data, 4 (13.3%) studies ( 27 , 35 , 36 , 49 ) were considered as high risk for more than 5% of missing outcome data which could have made a negative impact on the estimated effect of the intervention. Regarding the bias of measurement of the outcome was rated at high risk in 4 (13.3%) RCTs ( 30 , 46 – 48 ) for that the outcome assessors were aware of the interventions. Regarding the bias of selection of the reported result, 10 (33.3%) RCTs ( 24 , 25 , 27 , 28 , 36 , 38 , 43 , 45 , 48 , 49 ) were rated at some concerns for no protocols or registrations.…”

Oral Co-Supplementation of Curcumin, Quercetin, and Vitamin D3 as an Adjuvant Therapy for Mild to Moderate Symptoms of COVID-19—Results From a Pilot Open-Label, Randomized Controlled Trial

“…Several clinical trials, in particular, have investigated the anti-inflammatory and immunomodulatory pharmacological effects of curcumin in patients with COVID-19 and revealed improvement in serum CRP levels, a significant reduction in the gene expression, and/or serum levels of IFN-γ, IL-1β, IL-6, IL-10, IL-17, IL-21, IL-23, IL-35, retinoic acid-related orphan receptor-C, forkhead box P3, transforming growth factor beta, granulocyte-macrophage colony-stimulating factor, and frequency of T helper 17 cells ( Salehi et al, 2020 ; Ahmadi et al, 2021 ; Tahmasebi et al, 2021a ; Tahmasebi et al, 2021b ; Hassaniazad et al, 2021 ; Asadirad et al, 2022 ). Similarly, several randomized clinical trials involving patients with COVID-19 have also revealed multiple treatment benefits for quercetin adjuvant therapy, including faster negativization of the SARS-CoV-2, early amelioration of the acute symptoms, reduction in the serum levels of inflammatory markers such as CRP, LDH, ferritin, and alkaline phosphatase ( Kamel et al, 2020 ; Di Pierro et al, 2021a ; Di Pierro et al, 2021b ; Onal et al, 2021 ; Shohan et al, 2022 ). Moreover, with vitamin D3 adjuvant supplementation, early negativization of the SARS-CoV-2 and improvement in the acute symptoms have also been reported in patients with early-stage of COVID-19 ( Opko Press Release, 2021 ; Sabico et al, 2021 ; Sanchez-Zuno et al, 2021 ; Rastogi et al, 2022 ).…”

Beneficial effect of polyphenols in COVID‐19 and the ectopic F1FO‐ATP synthase: Is there a link?

“…Evidence supports the potential applicability of polyphenols in the prevention and treatment of COVID‐19, 36 due to their antioxidant, anti‐inflammatory, and potential antiviral properties 37–41 . Moreover, some polyphenols, have been recently approved in clinical trials for COVID‐19 prevention and/or therapy 41,42 . Quercetin has been extensively studied for the treatment of COVID‐19 patients 43–48 .…”