Medicinal plants are rich in nutrients and phytochemicals which prevent and treat a wide range of ailments. Accumulating experimental studies exhibit that some bioactive ingredients extracted from medicinal plants have suitable therapeutic effects on hepatic and renal injuries. This review focuses on the hepato- and reno-protective effects of thymoquinone, crocin, and carvacrol. The relevant literature was retrieved from PubMed, Scopus, Web of Science, and Google Scholar databases from the beginning of 2015 until the end of November 2021. According to the scientific evidence, the considered phytochemicals in this review have been applied with useful therapeutic effects on hepatic and renal damage. These therapeutic effects were mainly mediated through the amelioration of oxidative stress, suppression of inflammatory responses, and inhibition of apoptosis. Intracellular signaling pathways linked to nuclear factor kappa B (NF-κB), adenosine monophosphate-activated protein kinase, c-jun N-terminal kinase, and extracellular signal-regulated kinase 1/2 and Toll-like receptors are the most important pathways targeted by these phytochemicals. Up-regulation of transcription factor Nrf2 and down-regulation of transforming growth factor-beta 1 by these natural compounds also contribute to the alleviation of hepatic and renal injuries.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a novel coronavirus identified at the end of 2019. It is recognized as the causative agent of coronavirus disease 2019 (COVID-19). Flavonoids have been shown to exhibit therapeutical effect on complications related to COVID-19. The present study reviews possible therapeutic benefits of flavonoids on SARS-CoV-2. The Web of Science, PubMed, Scopus, and Google Scholar were searched using keywords: 'COVID-19', 'SARS-CoV-2', 'Kaempferol' and 'Quercetin' in the Title/Abstract. Relevant published articles in the English language until August 2020 were considered. Kaempferol and quercetin showed antiviral properties such as inhibition of protein kinase B and phosphorylation of protein kinase and blocking effects on a selective channel (3a channel) expressed in SARS-CoV infected cells. They also reduced the level of reactive oxygen species, expression of inducible nitric oxide synthase, pro-inflammatory mediators including TNF-α, IL-1α, IL-1β, IL-6, IL-10, and IL-12 p70, and chemokines. Kaempferol and quercetin might exert beneficial effects in the control or treatment of COVID-19 because of their antiviral, antioxidant, anti-inflammatory, and immunomodulatory effects.

Objective: To explore the effect of ethyl acetate gum resin extract of Boswellia serrata on lipopolysaccharide (LPS) induced inflammation and oxidative damage in hepatic and renal tissues of rats. Methods: The rats were divided into four groups: control, LPS, LPS+Boswellia serrata extracts (100 mg/kg and 200 mg/kg). LPS (1 mg/kg) and the extract (100 and 200 mg/kg, 30 min before LPS) were administered intraperitoneally for 3 weeks. The levels of liver enzymes, albumin, total protein, creatinine, blood urea nitrogen (BUN), interleukin (IL)-6, malondialdehyde (MDA), and total thiol groups and superoxide dismutase (SOD) and catalase (CAT) activities were measured. Results: The levels of liver enzymes, creatinine, and BUN, IL-6, MDA in the LPS group were markedly increased (P<0.001) while albumin, total protein, and total thiol concentration, as well as SOD and CAT activities, were decreased compared with the control group (P<0.05 or 0.01). Boswellia serrata extracts diminished the levels of liver enzymes, creatinine, BUN, IL-6, and MDA (P<0.01 and P<0.001), and elevated the concentration of total protein and total thiol and SOD and CAT activities (P<0.05 or 0.01). Conclusions: The ethyl acetate gum resin extract of Boswellia serrata reduces LPS-induced inflammatory reactions and oxidative damage, thus ameliorating hepatic and renal function.