Cytotoxic effect of nanoparticles synthesized from Salvia officinalis L. and Ricinus communis aqueous extracts against vero cell line and evaluation of their antioxidant activities

The development of safe carriers for the use of plant extracts in industrial and health fields constitute a matter of serious concern. The development of plant derived nanoparticles may help to overcome such barriers. However, the major concern is still the safety of these carriers. The present study describes the synthesis of nanoparticles derived from Salvia officinalis L. and Ricinus communis and the evaluation of their cytotoxic and antioxidant effects. It is shown in this study that the aqueous extracts of S. officinalis L. and R. communis have the potentials to reduce silver nitrate ions to silver nanoparticles. The biosynthesized nanoparticles were analyzed by spectrophotometer and granulometric tests. The biological activities of these extracts and nanoparticles were carried out. S. officinalis L. leaf extract had the strongest antioxidant activity, followed by R. communis leaf and fruit extracts. Altogether, the synthesized nanoparticles were safe and may serve as antioxidant products in many fields.Key words: Plant material, biosynthesis of nanoparticle, cytotoxicity, cell culture, free radicals

Chemical composition of 8 <it>eucalyptus</it> species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities

<p>Abstract</p> <p>Background</p> <p>In 1957, Tunisia introduced 117 species of <it>Eucalyptus</it>; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, <it>Eucalyptus</it> essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of <it>Eucalyptus</it> oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi.</p> <p>Methods</p> <p>The essential oils of eight <it>Eucalyptus</it> species harvested from the Jbel Abderrahman, Korbous (North East Tunisia) and Souinet arboreta (North of Tunisia) were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: <it>Haemophilus influenzae</it>, <it>Klebsiella pneumoniae</it>, <it>Pseudomonas aeruginosa</it>, <it>Staphylococcus aureus</it>, <it>Streptococcus agalactiae</it>, <it>Streptococcus pneumoniae</it> and <it>Streptococcus pyogenes</it>. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out.</p> <p>Results</p> <p>Twenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively), four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to <it>Eucalyptus</it> oils. The cytotoxic effect and the antiviral activity varied significantly within <it>Eucalyptus</it> species oils.</p> <p>Conclusions</p> <p><it>E. odorata</it> showed the strongest activity against <it>S. aureus</it>, <it>H. influenzae</it>, <it>S. agalactiae</it>, <it>S. pyogenes</it>, <it>S. pneumoniae</it> and against all the tested fungal strains. In addition, <it>E. odorata</it> oil showed the most cytotoxic effect. However, the best antiviral activity appeared with <it>E. bicostata</it>. Virus pretreatment with <it>E. bicostata</it> essential oil showed better antiviral activity (IC₅₀ = 0.7 mg/ml, SI = 22.8) than cell-pretreatment (IC₅₀ = 4.8 mg/ml, SI = 3.33). The essential oil of <it>E. astringens</it> showed antiviral activity only when incubated with virus prior to cell infection. This activity was dose-dependent and the antiviral activity diminished with the decreasing essential oil concentration.</p

Characteristics and outcomes of COVID-19 patients admitted to hospital with and without respiratory symptoms

Background: COVID-19 is primarily known as a respiratory illness; however, many patients present to hospital without respiratory symptoms. The association between non-respiratory presentations of COVID-19 and outcomes remains unclear. We investigated risk factors and clinical outcomes in patients with no respiratory symptoms (NRS) and respiratory symptoms (RS) at hospital admission. Methods: This study describes clinical features, physiological parameters, and outcomes of hospitalised COVID-19 patients, stratified by the presence or absence of respiratory symptoms at hospital admission. RS patients had one or more of: cough, shortness of breath, sore throat, runny nose or wheezing; while NRS patients did not. Results: Of 178,640 patients in the study, 86.4&nbsp;% presented with RS, while 13.6&nbsp;% had NRS. NRS patients were older (median age: NRS: 74 vs RS: 65) and less likely to be admitted to the ICU (NRS: 36.7&nbsp;% vs RS: 37.5&nbsp;%). NRS patients had a higher crude in-hospital case-fatality ratio (NRS 41.1&nbsp;% vs. RS 32.0&nbsp;%), but a lower risk of death after adjusting for confounders (HR 0.88 [0.83-0.93]). Conclusion: Approximately one in seven COVID-19 patients presented at hospital admission without respiratory symptoms. These patients were older, had lower ICU admission rates, and had a lower risk of in-hospital mortality after adjusting for confounders