Neha Pandey

Updates on artemisinin: an insight to mode of actions and strategies for enhanced global production

Application of traditional Chinese drug, artemisinin, originally derived from Artemisia annua L., in malaria therapy has now been globally accepted. Artemisinin and its derivatives, with their established safety records, form the first line of malaria treatment via artemisinin combination therapies (ACTs). In addition to its antimalarial effects, artemisinin has recently been evaluated in terms of its antitumour, antibacterial, antiviral, antileishmanial, antischistosomiatic, herbicidal and other properties. However, low levels of artemisinin in plants have emerged various conventional, transgenic and nontransgenic approaches for enhanced production of the drug. According to WHO (2014), approximately 3.2 billion people are at risk of this disease. However, unfortunately, artemisinin availability is still facing its short supply. To fulfil artemisinin’s global demand, no single method alone is reliable, and there is a need to collectively use conventional and advanced approaches for its higher production. Further, it is the unique structure of artemisinin that makes it a potential drug not only against malaria but to other diseases as well. Execution of its action through multiple mechanisms is probably the reason behind its wide spectrum of action. Unfortunately, due to clues for developing artemisinin resistance in malaria parasites, it has become desirable to explore all possible modes of action of artemisinin so that new generation antimalarial drugs can be developed in future. The present review provides a comprehensive updates on artemisinin modes of action and strategies for enhanced artemisinin production at global level.

Protection of Artemisia annua roots and leaves against oxidative stress induced by arsenic

The present study was conducted to examine differential responses of roots and leaves of Artemisia annua to different arsenic concentrations (50, 100, and 150 μΜ) and treatment durations (1, 3, 5, or 7 d). The values of bioconcentration factor and translocation factor calculated on the basis of total As-accumulation in roots and shoots suggested that A. annua is a good As-accumulator. Above and below ground plant biomass was enhanced at 100 μΜ As but at 150 μΜ As was significantly reduced. As-treatment caused membrane damage more in the roots than in the leaves as reflected by higher degree of lipid peroxidation in the roots than in the leaves. In response to As stress, plants activated antioxidative defense for detoxification of induced reactive oxygen species (ROS), As sequestration via phytochelatins (PCS) as well as production of a wide range of secondary metabolites. All of them were activated differently in roots and leaves. Among enzymatic antioxidants, leaves significantly elevated superoxide dismutase (SOD), ascorbate peroxidase, and glutathione reductase, whereas in roots SOD, catalase, and peroxidase played significant role in ROS detoxification. Plants activated As-sequestration pathway through thiols, glutathione, and PCS and their respective genes were more induced in leaves than in roots. Further gas chromatography in tandem with mass spectroscopy analysis revealed differential modulation of secondary metabolites in leaves and roots to sustain As-stress. For example, roots synthesized linoleic acid (4.85 %) under As-treatment that probably stimulated stress-signalling pathways and in turn activated differential defense mechanisms in roots to cope up with the adverse effects of As.