Anti-plasmodial polyvalent interactions in Artemisia annua L. aqueous extract – possible synergistic and resistance mechanisms

Artemisia annua hot water infusion (tea) has been used in in vitro experiments against P. falciparum malaria parasites to test potency relative to equivalent pure artemisinin. High performance liquid chromatography (HPLC) and mass spectrometric analyses were employed to determine the metabolite profile of tea including the concentrations of artemisinin (47.5±0.8 mg L-1), dihydroartemisinic acid (70.0±0.3 mg L-1), arteannuin B (1.3±0.0 mg L-1), isovitexin (105.0±7.2 mg L-1) and a range of polyphenolic acids. The tea extract, purified compounds from the extract, and the combination of artemisinin with the purified compounds were tested against chloroquine sensitive and chloroquine resistant strains of P. falciparum using the DNA-intercalative SYBR Green I assay. The results of these in vitro tests and of isobologram analyses of combination effects showed mild to strong antagonistic interactions between artemisinin and the compounds (9-epi-artemisinin and artemisitene) extracted from A. annua with significant (IC50 <1 μM) anti-plasmodial activities for the combination range evaluated. Mono-caffeoylquinic acids, tri-caffeoylquinic acid, artemisinic acid and arteannuin B showed additive interaction while rosmarinic acid showed synergistic interaction with artemisinin in the chloroquine sensitive strain at a combination ratio of 1:3 (artemisinin to purified compound). In the chloroquine resistant parasite, using the same ratio, these compounds strongly antagonised artemisinin anti-plasmodial activity with the exception of arteannuin B, which was synergistic. This result would suggest a mechanism targeting parasite resistance defenses for arteannuin B’s potentiation of artemisinin

Renewable, ethical? Assessing the energy justice potential of renewable electricity

Energy justice is increasingly being used as a framework to conceptualize the impacts of energy decision making in more holistic ways and to consider the social implications in terms of existing ethical values. Similarly, renewable energy technologies are increasingly being promoted for their environmental and social benefits. However, little work has been done to systematically examine the extent to which, in what ways and in what contexts, renewable energy technologies can contribute to achieving energy justice. This paper assesses the potential of renewable electricity technologies to address energy justice in various global contexts via a systematic review of existing studies analyzed in terms of the principles and dimensions of energy justice. Based on publications including peer reviewed academic literature, books, and in some cases reports by government or international organizations, we assess renewable electricity technologies in both grid integrated and off-grid use contexts. We conduct our investigation through the rubric of the affirmative and prohibitive principles of energy justice and in terms of its temporal, geographic, socio-political, economic, and technological dimensions. Renewable electricity technology development has and continue to have different impacts in different social contexts, and by considering the different impacts explicitly across global contexts, including differences between rural and urban contexts, this paper contributes to identifying and understanding how, in what ways, and in what particular conditions and circumstances renewable electricity technologies may correspond with or work to promote energy justice

Integrating medicinal plants extraction into a high-value biorefinery : an example of Artemisia annua L.

A principle of biorefining is extended to medicinal plants with the view of developing a more sustainable business model for biomass producers and extractors. This is demonstrated for Artemisia annua L. currently cultivated or harvested in the wild for extraction of a single compound, artemisinin, comprising on average 1 wt% dry weight of the plant biomass. We scaled extraction of artemisinin by a non-toxic to bacterial fermentation solvent tetrafluoroethane to a 5 L pilot scale. We identified a number of co-metabolites that could be extracted from the plant along with artemisinin and describe the multi-step extraction-fractionation sequence that potentially could be transferred to a large-scale multi-step extraction process. We also show possible routes to higher-value compounds on the basis of A. annua secondary metabolites, exemplified by the conversion of flavonoids to monomers

The land of black gold, corruption, poverty and sabotage:Overcoming the Niger Delta’s problems through the establishment of a Nigerian Non-Renewable Revenue Special Fund (NNRSF)

Through statistics published by the Shell Petroleum Development Company (SPDC), the paper explores why oilfield sabotage from 2009 to 2015 remains a problem in the Niger Delta, despite the 2009 amnesty programme. It explains why some of these incidents are a direct result of the failure to implement socio-economic development in successive state agencies due to corruption, a consequence of the natural resource curse. The article then explores why and how a Nigerian Non-Renewable Revenue Special Fund overseen by the United Nations Development Programme should be established which would not only manage a portion of oil revenue funds from the Niger Delta but also initiate valid social and economic projects in order to help reduce the prevalence of sabotage and instability in the region