No abstract

COVID-19, a global-pandemic binds human-lung-ACE2. ACE2 causes vasodilatation. ACE2 works in balance with ACE1. The vaso-status maintains blood-pressure/vascular-health which is demolished in Covid-19 manifesting aldosterone/salt-deregulations/inflammations/endothelial-dysfunctions/hyper-hypo- tension, sepsis/hypovolemic-shock and vessel-thrombosis/coagulations. Here, nigellidine, an indazole-alkaloid was analyzed by molecular-docking for binding to different Angiotensin-binding-proteins (enzymes, ACE1(6en5)/ACE2(4aph)/receptors, AT1(6os1)/AT2(5xjm)) and COVID-19 spike-glycoprotein(6vsb). Nigellidine strongly binds to the spike-protein at the hinge-region/active-site-opening which may hamper proper-binding of nCoV2-ACE2 surface. Nigellidine effectively binds in the Angiotensin- II binding-site/entry-pocket (−7.54 kcal/mol, −211.76, Atomic-Contact-Energy; ACE-value) of ACE2 (Ki 8.68 and 8.3 μmol) in comparison to known-binder EGCG (−4.53) and Theaflavin-di-gallate (−2.85). Nigellidine showed strong-binding (Ki, 50.93 μmol/binding-energy −5.48 kcal/mol) to mono/multi-meric ACE1. Moreover, it binds Angiotensin-receptors, AT1/AT2 (Ki, 42.79/14.22 μmol, binding-energy, −5.96/−6.61 kcal/mol) at active-sites, respectively. This article reports the novel binding of nigellidine and subsequent blockage of angiotensin-binding proteins. The ACEs-blocking could restore Angiotensin-level, restrict vaso-turbulence in Covid patients and receptor-blocking might stop inflammatory/vascular impairment. Nigellidine may slowdown the vaso-fluctuations due to Angiotensin-deregulations in Covid patients. Angiotensin II-ACE2 binding ( ACE -value −294.81) is more favorable than nigellidine-ACE2. Conversely, nigellidine-ACE1 binding-energy/Ki is lower than nigellidine-ACE2 values indicating a balanced-state between constriction-dilatation. Moreover, nigellidine binds to the viral-spike, closer-proximity to its ACE2 binding-domain. Taken together, Covid patients/elderly-patients, comorbid-patients (with hypertensive/diabetic/cardiac/renal-impairment, counting >80% of non-survivors) could be greatly benefited.

Background Replication of SARS-CoV-2 depends on viral RNA-dependent RNA-polymerase (RdRp). Remdesivir, the broad-spectrum RdRp inhibitor acts as nucleoside-analogues (NAs). Remdesivir has initially been repurposed as a promising drug against SARS-CoV-2 infection with some health hazards like liver damage, allergic reaction, low blood-pressure, and breathing-shortness, throat-swelling. In comparison, theaflavin-3’-O-gallate (TFMG), the abundant black tea component has gained importance in controlling viral infection. TFMG is a non-toxic, non-invasive, antioxidant, anticancer and antiviral molecule. Results Here, we analyzed the inhibitory effect of theaflavin-3’-O-gallate on SARS CoV-2 RdRp in comparison with remdesivir by molecular-docking study. TFMG has been shown more potent in terms of lower Atomic-Contact-Energy (ACE) and higher occupancy of surface area; −393.97 Kcal/mol and 771.90 respectively, favoured with lower desolvation-energy; −9.2 Kcal/mol. TFMG forms more rigid electrostatic and H-bond than remdesivir. TFMG showed strong affinity to RNA primer and template and RNA passage-site of RdRp. Conclusions TFMG can block the catalytic residue, NTP entry site, cation binding site, nsp7-nsp12 junction with binding energy of −6. 72 Kcal/mol with Ki value of 11.79, and interface domain with binding energy of −7.72 and −6.16 Kcal/mol with Ki value of 2.21 and 30.71 µM. And most importantly, TFMG shows antioxidant/anti-inflammatory/antiviral effect on human studies.

COVID-19 is the global-pandemic targets human-lung-ACE2 that converts Angiotensin-II to (1-7) peptide causing vasodilatation. Vasoconstriction caused by Angiotensin-II is produced from Angiotensin-I by ACE1. The vaso-status maintains bloodpressure/vascular-health of the individuals which is demolished in Covid-19 infection manifesting aldosterone/salt-deregulations/inflammations/endo dysfunctions/hyper-hypo-tension, sepsis/hypovolemic-shock and vessel-thrombosis/coagulations. These cause comorbidity patients. Here, nigellidine, an indazole-alkaloid was analyzed by molecular-docking for binding to different Angiotensin-bindingproteins (enzymes, ACE1(6en5)/ACE2(4aph)/receptors, AT1(6os1)/AT2(5xjm)) and COVID-19 spike-glycoprotein(6vsb). Data suggest that nigellidine strongly binds to the spike-protein at the hinge-region/active-site-opening which may hamper properbinding of nCoV2-ACE2 surface. Nigellidine strongly (-7.54 kcal/mol,-211.76, Atomic-Contact-Energy; ACE-value) binds (>known-binderEGCG;-4.53 and Theaflavin-di-gallate;-2.85) in the Angiotensin-II binding-site/entry-pocket at ACE2 with Ki 8.68 and 8.3 μmol. Further, Nigellidine showed strong-binding (best Ki, 50.93μmol/binding-energy-5.48 kcal/mol) to both mono-and multi-meric ACE1-forms. Moreover, this compound binds Angiotensin-receptors, AT1/AT2 (Ki, 42.79/14.22 μmol, binding-energy,-5.96/-6.61 kcal/mol) at active-sites, respectively. Here, we first-time report that nigellidine can block all angiotensin-binding proteins where, the Angiotensin-bonded amino acids were more or less similar/analogous and effec

The recent outbreak of SARS CoV-2 has changed the global scenario of human lives and economy. In this pandemic-outbreak the ratio of infected person is much higher than the death encountered. Most of the dead patients were observed with dysfunction/failure of cardiac and renal systems. Beside this a ‘cytokine storm’ namely TNF-α/IL1 receptors i.e. TNFR1/TNFR2/IL1R over-functioning was reported in the infected-persons. Here, nigellidine, an indazole-alkaloid and key-component of Nigella Sativa L. (NS); black-cumin-seed, has been analyzed for COVID-19 different protein and TNFα receptors TNFR1/TNFR2 and IL1R inhibition through molecular-docking study and biochemical-study of cumin-seed extract exposure to experimental-rat. The NMR, X-ray-crystallographic or Electron-microscopic structures of COVID-19 Main-protease(6LU7), Spike-glycoprotein(6vsb), NSP2(QHD43415_2), N-terminus-protenase (QHD43415_3), Nucleocapsid(QHD43423) and Human IL1R (1itb), TNFR1 (1ncf), TNFR2 (3alq) from PDB were retrieved/analyzed for receptor-ligand interaction in normal condition. Then those structures were docked with nigellidine using Autodock-software and Patchdock-server. Where nigellidine showed highest binding-energy of -7.61 (kcal/mol) and ligand-efficiency value of (-0.35) forming bonds with amino acids THR943/LYS945/MET1556/ALA1557/PRO1558/ILE1559. Highest ACE-value of -356.72 was also observed for nigellidine N-terminal-protease interaction. Nigellidine also showed strong interaction with NSP2 (-6.28) and Mpro/3CLpro_Q (-6.38s). Nigellidine showed affinity to TNFR1 (-6.81), IL1R (-6.23) and TNFR2 (-5.16). In rat experiment 2-groups (vehicle and NS treated) of female Wistar-rats were taken for experiments. The NS treated tissue showed marked decline in ALP/SGPT/ SGOT/MDA level then the basal-levels. From the Western-blot or activity analysis it was observed that Nigellidine, the sulfuryl-group containing drug showed no impact on Phenol-catalyzing ASTIV or Steroid-catalyzing EST expressions/activities and thus have no influence in sulfation-mediated adverse metabolic-processes. Current-results concluded that Nigellidine has hepato/reno-protective; immunomodulatory/anti-inflammatory and antioxidant activities as well as it inhibits important proteins of COVID-19. With steps to further validation/checking nigellidine can be used in COVID-19 infection.