Chemical composition, antioxidant activity and cytotoxicity of the essential oils of the leaves and stem of Tarchonanthus camphoratus

The aim of this study was to investigate the chemical composition, antioxidant potential and cytotoxicity of the essential oil of the fresh leaf, dry leaf and dry stem of Tarchonanathus campharatus. The antioxidant activity of the oils were examined by the 1,1-Diphenyl-2-picryl-hydrazil (DPPH), 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS.+), nitric oxide radical scavenging and reducing power methods. The brine shrimp lethality test and the MTT cytotoxicity test were used to investigate the cytotoxicity of the oils. Sesquiterpene hydrocarbons are the major components in the essential oil of the fresh leaves (36.46%) and of the dry leaves (59.18) whereas an aldehyde, butanal (35.77%) is the major component in the essential oil of the dry stem. The oils did not show significant antioxidant activity as evidenced by their high LC50 values in all the antioxidant assays. The cytotoxicity results indicated that the oils had low toxicity with LC50 values ranging from 400 to 900 μg/ml and 400 to 1100 μg/ml for the brine shrimp lethality test and MTT cytotoxicity assay respectively

Antioxidant activity and cytotoxicity of the leaf and bark extracts of Tarchnanthus camphorates

Purpose: To investigate the antioxidant potential and cytotoxicity of the leaf and bark extracts of Tarchonanathus campharatus. Methods: The antioxidant activity of the aqueous leaf extract (Aq LF), methanol leaf extract (MET LF), dichloromethane leaf extract (DCM LF), methanol bark extract (MET BK), dichloromethane bark extract (DCM BK), and ethyl acetate bark extract (Et Ac BK) were examined by 1,1-Diphenyl-2-picryl-hydrazil (DPPH), 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS.+), nitric oxide radical scavenging, reducing power and iron chelating activity methods. Brine shrimp lethality and MTT cytotoxicity tests were used to investigate the cytotoxicity of the extracts. Results: The Aq LF, DCM LF, MET LF and MET BK showed good DPPH, ABTS radical scavenging and total reducing power activities. Total reducing power was high and in the rank order of DCM LF > Aq LF > MET LF > MET BK. All the extracts, however, showed weak nitric oxide scavenging activity as well as weak iron chelating ability. Flavonoids, phenols, tannins and saponins were present in some of the extracts, but alkaloids, terpenoids, cardenolides and cardiac glycosides were absent in all the extracts. All the extracts did not show significant cytotoxic properties (p ≥ 0.05) with 50% inhibitory concentration IC50 values > 30 μg/ml in both cytotoxicity assays. Conclusion: The antioxidant activity and low cytotoxicity of Tarchonanthus camphoratus probably justify its use in folk medicin

Markers for predicting mortality in untreated HIV-infected children in resource-limited settings: a meta-analysis.

OBJECTIVES: To evaluate the prognostic value of selected laboratory and growth markers on the short-term risk of mortality in untreated HIV-infected children in resource-limited settings. DESIGN: A meta-analysis of individual longitudinal data on children aged 12 months onwards from 10 studies (nine African, one Brazilian in the 3Cs4kids collaboration). METHODS: The risk of death within 12 months based on age and the most recent measurements of laboratory and growth markers was estimated using Poisson regression models, adjusted for cotrimoxazole prophylaxis use and study effects. RESULTS: A total of 2510 children contributed 357 deaths during 3769 child-years-at-risk, with 81% follow-up occurring after start of cotrimoxazole. At first measurement, median age was 4.0 years (interquartile range, 2.2-7.0 years), median CD4% was 15% and weight-for-age z-score -1.9. CD4% and CD4 cell count were the strongest predictors of mortality, followed by weight-for-age and haemoglobin. After adjusting for these markers, the effects of total lymphocyte count and BMI-for-age were relatively small. Young children who were both severely malnourished and anaemic had high mortality regardless of CD4 values, particularly those aged 1-2 years. By contrast, high CD4% or CD4 cell count values predicted low mortality level amongst either children older than 5 years or those younger with neither severe malnutrition nor anaemia. CONCLUSIONS: CD4 measurements are the most important indicator of mortality and wider access to affordable tests is needed in resource-limited settings. Evaluation of antiretroviral initiation in children also needs to consider weight-for-age and haemoglobin. Prevention and treatment of malnutrition and anaemia is integral to HIV paediatric care and could improve survival

From "learning from the field" to jointly driving change

The theme of the 8th edition of the Geneva Health Forum (GHF) was Improving access to health: learning from the field. While ‘the field' often denotes people,patients, communities, and healthcare workers, we challenge the notion and its usage. A group of like-minded conference participants set up a working group to examine the term ‘the field' and look at questions related to language, power, participation, and rights. By highlighting deficiencies of existing terms and jargon, we explain why language is a form of power that matters in public health. We describe global, regional, and national case studies that facilitate full participation to achieve more equitable health outcomes. By concluding with concrete recommendations,we hope to contribute to these shared goals: to correct power imbalances between health authorities and the people that they intend, and are expected, to serve. The authors are all members of the working group

Beulverhalten von Kugelschalen unter stetig veraenderlichen Flaechenlasten Schlussbericht

TIB: RN 5905(2124) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Determinants of Zika virus host tropism uncovered by deep mutational scanning

Arboviruses cycle between, and replicate in, both invertebrate and vertebrate hosts, which for Zika virus (ZIKV) involves Aedes mosquitoes and primates. The viral determinants required for replication in such obligate hosts are under strong purifying selection during natural virus evolution, making it challenging to resolve which determinants are optimal for viral fitness in each host. Herein we describe a deep mutational scanning (DMS) strategy whereby a viral cDNA library was constructed containing all codon substitutions in the C-terminal 204 amino acids of ZIKV envelope protein (E). The cDNA library was transfected into C6/36 (Aedes) and Vero (primate) cells, with subsequent deep sequencing and computational analyses of recovered viruses showing that substitutions K316Q and S461G, or Q350L and T397S, conferred substantial replicative advantages in mosquito and primate cells, respectively. A 316Q/461G virus was constructed and shown to be replication-defective in mammalian cells due to severely compromised virus particle formation and secretion. The 316Q/461G virus was also highly attenuated in human brain organoids, and illustrated utility as a vaccine in mice. This approach can thus imitate evolutionary selection in a matter of days and identify amino acids key to the regulation of virus replication in specific host environments