ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
Phytochemical investigation of the ethanol extract of the stem bark of Hypericum lanceolatum Lam. (Guttifereae)afforded eight known compounds including 2,2ʹ,5,6ʹ-tetrahydroxybenzophenone (1), 5-hydroxy-3-methoxyxanthone(2), 3-hydroxy-5-methoxyxanthone (3), betulinic acid (4), hydroquinone (5) 6,7-dihydroxy-1,3-dimethoxyxanthone(6), calophyllumin A (7), and 1,3,5,6-tetrahydroxy-4-prenylxanthone (8). Compound 1 was submitted to acetylationreaction to give 5-acetoxy-2,2ʹ,6ʹ-trihydroxybenzophenone (9), a new hemisynthetic derivative. Compounds 5 and8 were isolated for the first time from this plant. The structures were established by extensive analysis of their massspectrometry and nuclear magnetic resonance (NMR) spectroscopic data and comparison with those from the literature.The isolated compounds (1, 2, 4, 5, and 8) and the derivative of benzophenone (9) were tested for their antipromastigoteand cytotoxic activities against visceral leishmaniasis parasite Leishmania donovani and macrophage RAW 264.7 cellline, respectively. Compound 9 was the most active with an IC50 value of 6.1 µg/ml, while compounds 1, 2, 4, and 8were moderately active with IC50 values ranging from 11.4 to 34.8 µg/ml against L. donovani and were not cytotoxicexcept compound 5 that was very toxic and not active. The findings of the present study suggested that compounds 1,2, 4, and 8 could be considered as a potential source of therapeutic medicine for the treatment of leishmaniasis.
ABSTRACT
The present research evaluated the antidiabetic and antioxidant properties of M. lucida stem bark [50 and 500mg/kg] and glibenclamide [25mg/kg, standard drug] in acute [Oral glucose tolerance test] and sub-acute [Streptozotocin 60mg/kg, i.p. diabetic model] administration. A group of healthy rats constituted the normal control. The sub-acute experiment lasted 28 days during which water, food intake and weight gain were measured and biochemical parameters analyzed in both plasma and erythrocytes at the end of the experiment. The chemical substances present in M. lucida bark extract were determined. In the Oral glucose tolerance test, the reduction of blood glucose level was statistically significant for both M. lucida extracts and glibenclamide. However, in the diabetic rats acute administration of 500mg/kg extract had better blood sugar lowering effect than glibenclamide, which was better than 50mg/kg extract. Streptozotocin diabetic animal model was characterized by a decrease in weight gain, erythrocyte SOD and CAT activities and an increase in water and food consumption, lipid peroxidation, cholesterol, triglycerides, plasma glucose, creatinine and urea concentrations, and transaminases activities. M. lucida extract and glibenclamide significantly prevented the alteration of these parameters, thus indicating a corrective effect on diabetes and its complications. This study justifies the traditional claim and provides a rationale for the use of M. lucida to treat diabetes. Its antioxidant properties may serve to curb oxidative stress and hence prevent the diabetic complications related to oxidative stress. Chemical substances, which may be accountable for the antidiabetic and antioxidant properties of M. lucida were detected in the aqueous extract of M. lucida bark