In vitro assessment of genotoxic and cytotoxic effects of Artemisia annua L. tincture

The genus Artemisia (fam. Asteraceae) is one of the largest and widely distributed with around 500 species, majority used as aromatic and medicinal plants. Artemisia annua L. is widely used as a dietary spice, herbal tea, as a supplement, and in a non-pharmaceutical form for treatment of malaria and fever. It is orally consumed as capsules, extracts and tinctures and topically applied as an essential oil diluted in lotions and ointments. Artemisinin is the main constituent of Artemisia annua L. extracts. Since the discovery that the artemisinin is efficient in malaria treatment, there is also a growth in consumption of A. annua extracts for antitumour and even recently for antiviral treatments against SARS-CoV-2 infections. This study aimed to investigate genotoxic effect in peripheral blood culture and cytotoxic effects in cancer and normal cell lines, of commercially available A. annua L. tincture in series of dilutions. Both comet and neutral red uptake assays revealed dose-dependent genotoxicity and cytotoxicity of A. annua tincture dilutions. Comet assay revealed significantly increased DNA damage in peripheral blood cells while neutral-red assays showed increase in cytotoxicity (p<0.001) in both normal and cancer cell cultures treated with the lowest extract dilution compared to the highest one applied. Obtained results indicate caution needed in A. annua L. tincture use, especially when poorly diluted.

In Vitro Adventitious Regeneration of Artemisia annua L. Influencing Artemisinin Metabolism

Artemisia annua L. is a herbaceous plant belonging to the Asteraceae family, known for producing, although at low levels, the sesquiterpene lactone artemisinin (AN), which is highly effective against malaria. In this study, an in vitro regeneration process of A. annua L. using ‘Artemis’ progeny was established and the potential of tissue culture for inducing new variability in terms of AN metabolism of in vitro regenerated plants was investigated. Among the plant growth regulators tested, the cytokinin 6-benzyladenine (BA) at 4.4 μM in combination with the auxin indole-butyric acid (IBA) at 0.35 μM yielded the greatest frequency of shoot induction. The optimal multiplication medium contained BA at 0.9 μM and naphthaleneacetic acid (NAA) at 0.05 μM. Regenerated plants (RPs), after transferring to the greenhouse and subsequently to the field, were analyzed during the growth cycle at different sampling times, showing a peak of AN content 20 days before blossom. Variability among different RPs and sampling times, in terms of AN and its precursors dihydroartemisinic acid (DHAA) and artemisinic acid (AA) was observed. This suggests that adventitious shoot induction could provide a useful strategy to induce variability influencing artemisinin metabolism as a consequence of in vitro manipulation.

Ovicidal and Physiological Effects of Essential Oils Extracted from Six Medicinal Plants on the Elm Leaf Beetle, Xanthogaleru-Ca Luteola (Mull.)

Plant essential oils may serve as safe alternatives to detrimental synthetic pesticides due to relatively lower side effects on the environment and non-targeted organisms. The current study was conducted to investigate the ovicidal toxicity and physiological disruptions of six medicinal plant essential oils, including Artemisia annua L., Lavandula angustifolia Mill., Origanum vulgare L., Rosmarinus officinalis Spenn., Satureja hortensis L., and Thymus vulgaris L., on elm leaf beetle Xanthogaleruca luteola (Mull.). The LC50 (Lethal Concentration to kill 50% of tested insects) values of 122.8, 287.5, 152.8, 180.6, 315.9, and 1366.2 ppm were recorded for T. vulgaris, L. angustifolia, A. annua, S. hortensis, R. officinalis, and O. vulgare, respectively, 72 h after treatment of 3-day-old eggs of the pest. Significant decreases in the amounts of glucose, protein, and triglyceride macromolecules were also observed after treatment. The application of essential oils derived from T. vulgaris, A. annua, and S. hortensis at 400 ppm revealed 100% ovicidal activity. Accordingly, tested essential oils, particularly the essential oil of T. vulgaris, have been promising potential as biorational insecticides in the management of X. luteola.