In vitro susceptibility of Plasmodium falciparum Welch field isolates to infusions prepared from Artemisia annua L. cultivated in the Brazilian Amazon

Silva, Luiz Francisco Rocha e; Magalhães, Pedro Melillo de; Costa, Mônica Regina Farias; Alecrim, Maria das Graças Costa; Chaves, F. C. M.; Hidalgo, Ari de Freitas; Pohlit, Adrian Martin; Vieira, Pedro Paulo

doi:10.1590/s0074-02762012000700004

Cited by 18 publications

(19 citation statements)

References 26 publications

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“…The overall extraction efficiency of this study was however quite low (7.27% for 12 h, 4.51% for 2 h compared to 53.8% for the dried leaves infusion) (Wright et al, 2010). Silva et al (2012) on the other hand observed high extraction efficiencies of 78-91% after boiling the dried leaves with no squeezing which are similar to those of Räth et al (2004). Van der Kooy and Verpoorte (2011) studied the extraction efficiency of artemisinin at different temperatures and found as expected that with increasing temperatures the extraction efficiency of artemisinin increased.…”

Section: Extraction Efficiency and Stability Of Artemisinincontrasting

confidence: 53%

“…The results of these experiments were confirmed with in vivo tests performed in mice where it was found that a dose of 18 mg/kg of artemisinin in planta suppressed parasitaemia by 95% while a 30 mg/kg dose of pure artemisinin suppressed the paraesatemia by 88%. Silva et al (2012) tested the effectiveness of the tea infusion against field isolated Plasmodium falciparum which were resistant to chloroquine. The infusions were determined to be an effective low toxicity treatment against chloroquine-resistant Plasmodium falciparum, having an IC 50 of 0.11-0.14 mg/mL, however no synergistic effects were noted and thereby contradicting the results reported by De Donno et al (2012) and Wright et al (2010).…”

Section: Identification Of Other Compounds In the Artemisia Annua Formentioning

confidence: 99%

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The complexity of medicinal plants: The traditional Artemisia annua formulation, current status and future perspectives

Kooy

Sullivan

2013

Journal of Ethnopharmacology

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Section: Extraction Efficiency and Stability Of Artemisinincontrasting

confidence: 53%

Section: Identification Of Other Compounds In the Artemisia Annua Formentioning

confidence: 99%

The complexity of medicinal plants: The traditional Artemisia annua formulation, current status and future perspectives

Kooy

Sullivan

2013

Journal of Ethnopharmacology

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“…Furthermore, the dose of 400 kg ha -1 of silicate induced higher concentrations of artemisinin than those previously reported in plants without the application of silicate (94.0 μg mL -1 ; Mueller et al, 2004 ; Räth et al, 2004 ). Clearly, these results show wide variation in the artemisinin content in A. annua infusion samples, indicating that many factors, such as temperature, contact time, percentage of material, solvent, and plant genetics can influence the solubility of artemisinin and its subsequent therapeutic effects ( van der Kooy and Verpoorte, 2011 ; Rocha e Silva et al, 2012 ). In this context, it is likely that the unexpected very low concentrations of artemisinin in infusion samples, which were obtained from A. annua treated with 1600 kg ha -1 and, especially with 800 kg ha -1 of silicate, may have been affected by some of these factors, which may impact the solubility of artemisinin, resulting in almost undetectable levels.…”

Section: Discussionmentioning

confidence: 93%

Si-Accumulation In Artemisia annua Glandular Trichomes Increases Artemisinin Concentration, but Does Not Interfere In the Impairment of Toxoplasma gondii Growth

et al. 2016

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Artemisia annua is used as a source of artemisinin, a potent therapeutic agent used for the treatment of infectious diseases, chiefly malaria. However, the low concentration (from 0.01 to 1.4% of dried leaf matter) of artemisinin in the plant obtained with the traditional cropping system makes it a relatively expensive drug, especially in developing countries. Considering that artemisinin and silicon (Si) are both stored in A. annua glandular trichomes, and that Si accumulation has never been investigated, this study aimed to look into Si effects on A. annua trichome artemisinin concentration, and whether leaf infusion from Si-treated A. annua plants is able to control Toxoplasma gondii growth. T. gondii is the etiologic agent of toxoplasmosis, a zoonotic parasitic disease whose traditional treatment shows significant side effects. The experimental design consisted of A. annua seedlings randomly planted in soil treated with different doses of calcium/magnesium silicate (0, 200, 400, 800, and 1600 kg ha-1). Analysis of foliar macronutrients showed significant increases of nitrogen content only at the highest dose of silicate. Foliar micronutrients, Si concentrations, and plant height were not affected by any of the silicate doses. However, the dose of 400 kg ha-1 of silicate increased the trichome size, which in turn raised artemisinin concentration in leaves and the infusion. In contrast, the 800 and 1600 kg ha-1 doses dramatically decreased artemisinin concentration. HeLa cell treatment with the infusion of A. annua grown in soil treated with 400 kg ha-1 of silicate decreased parasite proliferation in a dose-dependent manner when the treatment was carried out after or along with T. gondii infection. However, this effect was similar to A. annua grown in soil without silicate treatment. Thus, it can be concluded that, even though Si applied to the soil at 400 kg ha-1 has a positive effect on the A. annua glandular trichome size and the artemisinin concentration, this outcome cannot be directly associated with the efficiency of A. annua infusion on T. gondii growth, suggesting that other components from A. annua leaves could be acting in synergy with artemisinin.

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“…Parasite inhibition was expressed as a percentage of the growth of untreated (negative) controls. All assays were performed in triplicate [ 45 ]. Extracts that inhibited parasite growth by ≥80 % at concentrations of 50 μg/mL were further evaluated using the procedure described below.…”

Section: Methodsmentioning

confidence: 99%

In vitro and in vivo anti-malarial activity of plants from the Brazilian Amazon

Lima

Silva

Melo

et al. 2015

Malar J

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BackgroundThe anti-malarials quinine and artemisinin were isolated from traditionally used plants (Cinchona spp. and Artemisia annua, respectively). The synthetic quinoline anti-malarials (e.g. chloroquine) and semi-synthetic artemisinin derivatives (e.g. artesunate) were developed based on these natural products. Malaria is endemic to the Amazon region where Plasmodium falciparum and Plasmodium vivax drug-resistance is of concern. There is an urgent need for new anti-malarials. Traditionally used Amazonian plants may provide new treatments for drug-resistant P. vivax and P. falciparum. Herein, the in vitro and in vivo antiplasmodial activity and cytotoxicity of medicinal plant extracts were investigated.MethodsSixty-nine extracts from 11 plant species were prepared and screened for in vitro activity against P. falciparum K1 strain and for cytotoxicity against human fibroblasts and two melanoma cell lines. Median inhibitory concentrations (IC50) were established against chloroquine-resistant P. falciparum W2 clone using monoclonal anti-HRPII (histidine-rich protein II) antibodies in an enzyme-linked immunosorbent assay. Extracts were evaluated for toxicity against murine macrophages (IC50) and selectivity indices (SI) were determined. Three extracts were also evaluated orally in Plasmodium berghei-infected mice.ResultsHigh in vitro antiplasmodial activity (IC50 = 6.4–9.9 µg/mL) was observed for Andropogon leucostachyus aerial part methanol extracts, Croton cajucara red variety leaf chloroform extracts, Miconia nervosa leaf methanol extracts, and Xylopia amazonica leaf chloroform and branch ethanol extracts. Paullinia cupana branch chloroform extracts and Croton cajucara red variety leaf ethanol extracts were toxic to fibroblasts and or melanoma cells. Xylopia amazonica branch ethanol extracts and Zanthoxylum djalma-batistae branch chloroform extracts were toxic to macrophages (IC50 = 6.9 and 24.7 µg/mL, respectively). Andropogon leucostachyus extracts were the most selective (SI >28.2) and the most active in vivo (at doses of 250 mg/kg, 71 % suppression of P. berghei parasitaemia versus untreated controls).ConclusionsEthnobotanical or ethnopharmacological reports describe the anti-malarial use of these plants or the antiplasmodial activity of congeneric species. No antiplasmodial activity has been demonstrated previously for the extracts of these plants. Seven plants exhibit in vivo and or in vitro anti-malarial potential. Future work should aim to discover the anti-malarial substances present.

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In vitro susceptibility of Plasmodium falciparum Welch field isolates to infusions prepared from Artemisia annua L. cultivated in the Brazilian Amazon

Abstract: Artemisinin is the active antimalarial compound obtained from the leaves of

Cited by 18 publications

References 26 publications

The complexity of medicinal plants: The traditional Artemisia annua formulation, current status and future perspectives

The complexity of medicinal plants: The traditional Artemisia annua formulation, current status and future perspectives

Si-Accumulation In Artemisia annua Glandular Trichomes Increases Artemisinin Concentration, but Does Not Interfere In the Impairment of Toxoplasma gondii Growth

In vitro and in vivo anti-malarial activity of plants from the Brazilian Amazon

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