Phytochemical and antiplasmodial evaluation of five Colombian plants with ethnopharmacological background of antimalarial use

Background: The study of medicinal plants has made it possible to develop products and drugs for the treatment of different diseases. Several plants in Colombia have a history of popular use for the treatment of malaria. The objective of this work was to provide information on the antiplasmodic and phytochemical activity of five neotropical native plants with a folk use for the treatment of malarial.Methods: The ethanolic extract of each species was obtained by percolation method and characterized by TLC, HPLC, and 1H-NMR. The in vitro antiplasmodial activity was evaluated against Plasmodium falciparum (strain FCR-3, chloroquine-resistant).Results: Ethanolic extracts of Ambelania duckey, Cecropia metensis, Cecropia membranacea, and Verbena littoralis showed no activity. However, Curarea toxicofera extract exhibited an IC50 of 7.6 ± 3.9 μg/mL and was classified as moderately active. Furthermore, hemolytic activity was assayed, none of the extracts were tested positive. A preliminary phytochemical study was carried out using tube analysis, thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and hydrogen nuclear magnetic resonance (1H-NMR). Steroids or triterpenes, and phenolic compounds were detected by TLC in all extracts. These findings were confirmed by characteristic aliphatic and aromatic signals in 1H-NMR spectra, corresponding to triterpenes and phenolics, respectively. Additionally, alkaloids were extracted from C. toxicofera and detected by aromatic signals in 1H-NMR spectra.Conclusion: ethanolic extract of C. toxicofera showed antiplasmodial activity (IC50 of 7.6 ± 3.9 μg/mL); this activity may be due to the bisbenzylisoquinoline alkaloids. The ethanol extracts of A. duckey, C. membranacea, C. metensis, and V. littoralis did not present antiplasmodial activity.

Comparison of the antimalarial activity of a Colombian traditional Uitoto remedy with laboratory preparations

BACKGROUND & OBJECTIVES

In Colombian Amazonia, Uitoto indigenous people use a preparation of Curarea toxicofera (Menispermaceae) to prevent and treat malaria. To open the way for the production of a standardized herbal remedy, we compared the activity of the traditional preparation with laboratory preparations.

METHODS

People were interviewed on their mode of use and preparation of what is considered the best remedy against fevers in this area. The herbal remedy was prepared according to the healer's recommendations. The plant was also submitted to continuous distillation and percolation extraction. The preparations were then tested against Plasmodium falciparum, in vitro. Traditional preparation and extract obtained by percolation were tested on Plasmodium berghei infected mice. Chemical profiles were also explored by thin-layer chromatography.

RESULTS

Yields of extraction were around 7% in the preparations (percolation was the most efficient). The phytochemical profile showed a mix of steroids, flavonoids and alkaloids qualitatively similar in all preparations. In vitro, the extracts showed inhibitory concentration 50 <10μg/mL: the traditional preparation was almost three times less active than laboratory preparations. In vivo, percolation was also more active than traditional preparation, inhibiting 78% of the parasite growth at 400mg/kg/day by oral route.

INTERPRETATION & CONCLUSION

Pharmacological activities suggest that both the original remedy (prepared according to traditional pharmacopeia) and the extracts obtained by percolation extraction exhibit relevant antiparasitic activity. C. toxicofera should therefore be considered for the elaboration of an improved traditional medicine by implementing toxicological studies and carefully following quality control guidelines for its preparation.

Pharmacological activity of Curarea toxicofera in combination with classical antimalarial treatments

ETHNOPHARMACOLOGICAL RELEVANCE

In the Leticia-Amazonas area, Uitoto indigenous people use a preparation of Curarea toxicofera (Wedd) Barneby & Krukoff (Menispermaceae) alone or combined with prescribed medications to prevent and treat malaria.

AIM OF STUDY

To determine the in vitro and in vivo antiplasmodial activity of traditional preparations of Curarea toxicofera alone and in combination with classical antimalarials.

MATERIAL AND METHODS

The traditional preparation was evaluated in vitro against P. falciparum FCR3 CQ resistant strain, alone and combined. The preparation was further administered orally alone or combined with chloroquine and artesunate in mice infected with Plasmodium berghei ANKA strain on the four-day antimalarial test model.

RESULTS

The herbal remedy used alone was able to significantly decrease the parasitemia both in vitro (IC₅₀ 7.3 µg/ml) and in vivo (ED₅₀ 328 mg/Kg) but it was less active than chloroquine (IC₅₀ 0.29 µg/ml in vitro and ED₅₀ 2.3 mg/Kg/day in vivo), and than artesunate (IC₅₀ 0.002 µg/ml and ED₅₀ 3.7 mg/Kg/day). Interestingly it presented synergism with chloroquine in vitro (Combination Index: 0.39) and in vivo; and was additive with artesunate in vitro (Combination Index: 0.94) and in vivo.

CONCLUSION

The traditional preparation showed potential as an antimalarial and, when used in combination, does not negatively affect the efficacy of the drugs evaluated. Pre-clinical studies should be conducted with a standardized preparation to confirm its efficacy and safety alone and in combination with chloroquine and artesunate.

Caveolins in glial cell model systems: from detection to significance

Glial cells prevail in number and in diversity of cellular phenotypes in the nervous system. They have also gained prominence due to their multiple physiological and pathophysiological roles. Our current knowledge of the asymmetry and heterogeneity of the plasma membrane demands an in depth analysis of the diverse array of membrane microdomains postulated to exist in the context of glial cells. This review focuses and analyzes the studies reported to date on the detection of caveolae membrane rafts and the caveolin family members in glial cell model systems, the conditions leading to changes in their level of expression, and their functional and clinical significance. Outstanding in this work emerge the ubiquitous expression of caveolins, including the typically regarded 'muscle-specific' cav3, in diverse glial cell model systems, their participation in reactive astrogliosis, cancer, and their key relevance to calcium signaling. The knowledge obtained to date demands incorporation of the caveolins and caveolae membrane rafts in our current models on the role of glial cells in heath and neurological disease.