ABSTRACT
The study aims to identify the bioactive secondary metabolites from the leaves of Papuacedrus papuana that have not been reported yet so far. Two main antibacterial compounds, ferruginol, and trans-communic acid were isolated from the leaves of the plant through several chromatography techniques, including a TLC-direct bioautography technique. The antibacterial activity of abietane and labdane diterpenes were categorized as strong. The values of MIC were 16 and 4 µg/mL for ferruginol and 8 and 16 for trans-communic acid against E. coli (InaCC B5) and S. aureus (InaCC B4), respectively. In addition, only ferruginol showed a moderate antioxidant activity with an IC50 value of 116.12 μg/mL. By docking studies, both compounds showed their more stable interaction with structural SARS-CoV-2 proteins, i.e., 6vxx Spike glycoprotein and 6m0j spike receptor compared to non-structural proteins such as 3CLpro, Mpro, and RdRp proteases. © 2022, Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma. All rights reserved.
ABSTRACT
The emergence of the global pandemic COVID-19 lead to a huge demand for the therapeutic agent to combat the disease. Since the FDA approval of some of HIV-1 main protease inhibitors such as ritonavir lopinavir to treat COVID-19, the investigation of anti-HIV inhibitor to inhibit SARS-CoV-2 main protease (Mpro) is getting considerably much attention. This study evaluates the potency of sixteen selected natural flavonoids which were previously reported active to block HIV-1 protease as potential inhibitors of SARS-CoV-2 Mpro. The molecular docking and dynamic study were completed to know the binding affinity and stability of the protein-ligand complex via docking study along with molecular dynamic simulations. Moreover, drug-likeness was also evaluated through via ADMET evaluation. This study revealed robinin (6), a flavonol molecule with linked to galactose-rhamnose at C3 and rhamnose molecule at C7, exhibited the highest binding affinity (-9 kcal/mol) among others. The amino acids that interacted with robinin were Asn142;Gly143;Arg188;Thr190. The binding affinity of robinin surpassed the binding affinity of ritonavir (-7.7 kcal/mol) and lopinavir (-8.2 kcal/mol). The replacement of the hydroxyl group from the flavonoid skeleton at C-7, C-4' was proposed to affect the binding affinity. The free hydroxyl group particularly in A ring and the position of the hydroxyl group were important to improve the binding affinity. The molecular dynamic simulation showed the stability of Mpro-robinin during the simulation period. The ADME evaluation referring to Lipinski's rule of 5 revealed that the flavonoids (2,5,6,9,10,13,14,15) show low oral bioavailability and absorption. Robinin exhibited a good drug-likeness score (value:1) with an unconcerned level of acute toxicity. From this study, it was concluded that robinin showed the most potent natural flavonoids studied to inhibit SASR-CoV-2 Mpro by both docking study and ADME/tox properties evaluation.
ABSTRACT
This article was aimed at describing the integrative leadership styles concerning library performance. This study used a descriptive-qualitative method with a constructivist and critical interpretive paradigm on the phenomena of library leadership in the current Covid-19 pandemic era. Data were collected through observation and interview techniques with 9 informants, including the head of the library and librarians at Muhammadiyah University library of North Sumatera. Both observation and interview were conducted online because of health crisis conditions making it not possible to do them offline. The results showed that the role of the integrative leadership style, which employed democratic and transformative patterns, has provided a solution for the head of the library and librarians in dealing with service turbulence due to the covid-19. The integration of the two types of leadership styles helps the library encountering difficult times because the policies implemented can be accepted by all parties, without resistance. Improvements in the performance of librarians and library staff during the pandemic so far this study found that pandemic conditions did not stop the goals of achieving satisfaction, effective and affective works, and loyalty to institutions. This achievement showed the success of the lead engaging all elements of the library to work together in providing services to users. To maintain and improve the professionalism of the librarians' performance, professional patterns, accountability, commitment, motivation, innovation, creativity, and communication are carried out within the framework of leadership integration, which ultimately results in more effective and affective job satisfaction. © 2021. All Rights Reserved.