Screening and evaluation of cytotoxicity and antiviral effects of secondary metabolites from water extracts of Bersama abyssinica against SARS-CoV-2 Delta.

BACKGROUND: Bersama abyssinica is a common herb in Africa, with diverse medical uses in different areas. The plant is well-known in Tanzania for treating respiratory disorders such as TB, tonsillitis, bronchitis, and asthma, and it has lately been utilized to treat COVID-19 symptoms. Water extract of leaf and stem bark has been registered as an herbal medication known as 'Coviba Dawa' in Tanzania for the relief of bacterial respiratory infections. The extracts, however, have not been scientifically tested for their anti-viral activities. The aim of this work was to test for the cytotoxicity and antiviral effects of bioactive ingredients from B. abyssinica extracts against the Delta variant of the SARS-CoV-2 coronavirus. METHODS: B. abyssinica leaves and stem bark were dried under shade in room temperature and then pulverized to obtain small pieces before soaking into different solvents. One hundred grams of each, leaves and stem bark, were extracted in petroleum ether, dichloromethane, ethyl acetate and methanol. Water extract was obtained by decoction of stem bark and leaves into water. Phenols, flavonoids, tannins, and antioxidants were confirmed as components of the extracts. Analysis of polar extracts of bark stem bark and leaves was done. Antiviral screening and cytotoxicity experiments were conducted in a Biosafety Level 3 (BSL-3) Laboratory facility according to International Standard Operating Procedures (SOPs). RESULTS: By the use of LC-MS/MS analysis, this study confirmed the existence of four phenolic compounds in B. abyssinica water extract; 2,4-di-tert-butylphenol, 4-formyl-2-methoxyphenyl propionate, 7,8-Dihydroxy-4-methylcoumarin, and 2,3, 6-trimethoxyflavone with antioxidant activity. This study showed that, while the water extracts of B. abyssinica had significant antiviral activity against SARS Cov2 virus, it showed no cytotoxicity effect on Vero E6 cells. In particular, the water extract (Coviba dawa) showed 75% while ethylacetate fraction of B. abyssinica leaves showed a 50% in vitro viral inhibition, indicating that these substances may be useful for the development of future anti-viral agents. CONCLUSION: We therefore recommend isolation of compounds for further profiling and development with a broader concentration range. We further recommend studies that determine the antiviral activity of extracts of B.abyssinica on other viral pathogens of clinical concern.

Biological Efficacy of Compounds from Stingless Honey and Sting Honey against Two Pathogenic Bacteria: An In Vitro and In Silico Study.

Honey inhibits bacterial growth due to the high sugar concentration, hydrogen peroxide generation, and proteinaceous compounds present in it. In this study, the antibacterial activity of stingless and sting honey against foodborne pathogenic bacteria isolated from spoiled milk samples was examined. The isolated bacterial strains were confirmed as Bacillus cereus and Listeriamonocytogenes through morphological, biochemical, and 16 s RNA analysis. Physiochemical characterizations of the honey samples revealed that both of the honey samples had an acidic pH, low water content, moderate reducing sugar content, and higher proline content. Through the disc diffusion method, the antibacterial activities of the samples were assayed and better results were observed for the 50 mg/disc honey. Both stingless and sting honey showed the most positive efficacy against Bacillus cereus. Therefore, an in silico study was conducted against this bacterium with some common compounds of honey. From several retrieved constituents of stingless and sting honey, 2,4-dihydroxy-2,5-dimethyl 3(2H)-furan-3-one (furan) and 4H-pyran-4-one,2,3-dihydro of both samples and beta.-D-glucopyranose from the stingless revealed high ligand-protein binding efficiencies for the target protein (6d5z, hemolysin II). The root-mean-square deviation, solvent-accessible surface area, the radius of gyration, root-mean-square fluctuations, and hydrogen bonds were used to ensure the binding stability of the docked complexes in the atomistic simulation and confirmed their stability. The combined effort of wet and dry lab-based work support, to some extent, that the antimicrobial properties of honey have great potential for application in medicine as well as in the food industries.

Evaluation of air quality in indoor and outdoor environments: Impact of anti-COVID-19 measures.

This study monitors the presence of 88 volatile organic compounds (VOCs) and semi-volatile organic compounds (semi-VOCs) at the gas phase of seven indoor settings in a school in the city of Tarragona, Spain, and five outdoor locations around the city. The VOCs and semi-VOCs monitored were solvents (∑Solvents), aldehydes (∑Aldehydes), emerging organic compounds (∑EOCs), and other VOCs and semi-VOCs (∑Others). Passive sampling campaigns were performed using Carbopack X tubes followed by thermal desorption coupled to gas chromatography with mass spectrometry (TD-GC-MS). Overall, 70 of the target compounds included in the method were determined in the indoor air samples analysed, and 42 VOCs and semi-VOCs in the outdoor air samples. Our results showed that solvents were ubiquitous throughout the school at concentrations ranging from 272 µg m-3 to 423 µg m-3 and representing 68%-83% of total target compounds (∑Total). The values of ∑Total in 2021 were three times as high as those observed at the same indoor settings in 2019, with solvents experiencing the greatest increase. A plausible explanation for these observations is the implementation of anti-COVID-19 measures in the indoor settings, such as the intensification of cleaning activities and the use of hydroalcoholic gels as personal hygiene. The ∑Total values observed in the indoor settings evaluated were twenty times higher than those found outdoors. ∑Solvents were the most representative compounds found indoors (74% of the ∑Total). The concentrations of VOCs and semi-VOCs observed in the outdoors were strictly related to combustion processes from automobile traffic and industrial activities, with ∑Others contributing 58%, ∑Solvents 31%, and ∑Aldehydes 11% of the ∑Total. EOCs, on the other hand, were not detected in any outdoor sample.

[Variety of the Composition and Sources of VOCs During the Spring Festival and Epidemic Prevention in the Pearl River Delta].

Volatile organic compounds (VOCs) are the key precursors of the ozone (O3) formation processes in the troposphere and are important control objects for the coordinated governance of O3 and PM2.5. The Spring Festival of 2020 was affected by the novel coronavirus (COVID-19) pneumonia epidemic:companies stopped work and production, and traffic was restricted, providing scientific experimentation opportunities for pollutant emission reduction research. This study analyzed the variety of the composition, chemical reaction activity, and sources of VOCs in the Pearl River Delta during the Spring Festival and the epidemic control period, using real-time online monitoring data of VOCs obtained at four sites(Guangzhou, Dongguan, Zhongshan, and Duanfen)in the Pearl River Delta from January 1, 2020 to February 29, 2020. The results showed that during the Spring Festival and the epidemic control period, the average of φ (VOCs) in the Pearl River Delta was 15.89×10-9, and the maximum hourly average concentration was 45.43×10-9, values that were 44% and 60% lower, respectively, than those before the Spring Festival holiday. Among the VOCs component concentration decreases, the aromatic hydrocarbon component decreased the most, and the decrease in the urban area of the Pearl River Delta (74%) was significantly greater than that in the suburban area (56%). As a result, the contribution rate of aromatic hydrocarbons to the total VOCs was reduced to less than 10%. The analysis of the·OH reaction activity of VOCs(L·OH)and ozone formation potential(OFP)showed that the L·OH and OFP of VOCs decreased significantly in the Pearl River Delta during the Spring Festival and the epidemic control period. Compared with those before the Spring Festival holiday, the total L·OH and total OFP decreased by an average of 60% and 63% in the urban area of the Pearl River Delta, respectively. Additionally, the atmospheric oxidation had also been significantly reduced, which showed a 28% decrease in ρ(Ox). The ratio of toluene/benzene showed that the influence of industrial sources had almost disappeared during the Spring Festival and the epidemic control period, and the total points of the representative components of industrial-related solvent-use sources such as toluene, ethylbenzene, and m/p-xylene dropped by 72% to 91%. The results of this study suggest that solvent-use sources and vehicle exhaust emission sources are the current sources of VOCs that need to be paid attention to in the prevention and control of O3 pollution in the Pearl River Delta region, and the impact of petrochemical sources cannot be ignored in the work of further reducing the background concentration of O3.

Putatively lethal ingestion of isopropyl alcohol-related case: interpretation of post mortem isopropyl alcohol and acetone concentrations remains challenging.

Isopropyl alcohol, or propan-2-ol (IPA), is found in numerous chemicals including alcohol-based hand rubs whose use has been recently widely extended to the general population since the onset of the COVID-19 pandemic. This widespread of IPA use could potentially, but not necessarily, be responsible for an increase in IPA poisoning cases (e.g., in alcoholics and/or for suicide attempt, even more in a lockdown situation). Forensic identification of IPA-related fatalities remains challenging as IPA post mortem detection can also result from antemortem or post mortem production, or post mortem contamination. In order to illustrate this issue, we report the case of a 33-year-old man found dead with a bottle of pure IPA liquid close to him. Toxicological positive results only consisted in IPA (464, 260, 465 and 991 mg/L) and acetone (1560, 2340, 3040 and 1360 mg/L) in blood, vitreous humour, urine and bile, respectively (determinations using headspace gas chromatography with flame ionization detection). These IPA absolute concentrations and IPA-to-acetone ratios appear inferior to those usually reported in the literature (higher than 1000 mg/L and 1.1, respectively) in IPA poisoning cases. In conclusion, this death can be cautiously regarded as an IPA ingestion-related fatality in the hypothesis of a survival time which have promoted IPA metabolism to acetone: this hypothesis is supported by the putative limited IPA-ingested dose. This report emphasizes the fact that post mortem IPA and acetone concentration interpretation involves to take account of (i) results in multiple biological specimens, (ii) complete case history, and (iii) a search of possible IPA presence at the scene of death.