Carotenoids, polyphenols and micronutrient profiles of Brassica oleraceae and plum varieties and their contribution to measures of total antioxidant capacity.

The consumption of phytochemicals such as carotenoids and polyphenols within whole fruits and vegetables has been associated with decreased incidence of various inflammation and oxidative stress related chronic diseases, which may be due to direct antioxidant effects, or indirect mechanisms such as affecting signal transduction/gene expression. Within the present study, we investigated the antioxidant composition of two major groups of vegetables and fruits, Brassica oleraceae and prunus spp., and estimated their contribution to antioxidant capacity. For this purpose, 17 plum and 27 Brassica varieties were collected in Luxembourg, and analysed for their individual polyphenol and carotenoid profile, vitamin C, dietary fibre, and minerals/trace elements, and their correlation with markers of antioxidant capacity (FRAP, ABTS, Folin-Ciocalteu). Total carotenoid and polyphenol content varied considerably between the different Brassica and plum varieties, with highest concentrations in the variety Kale (13.3 ± 0.58 mg/100g wet weight) and Cherry plum (1.96 ± 0.28 mg/100g) for carotenoids; and Kale (27.0 ± 0.91 mg/100g) and Kirks plum (185 ± 14 mg/100g) for polyphenols. In developed multiple linear-regression-models for Brassica, flavonoids, anthocyanins, lutein and vitamin C were found to be the best predictors of antioxidant capacity as assessed by FRAP (R(2)=0.832) and flavonoids, neochlorogenic acid and vitamin C as assessed by ABTS (R(2)=0.831); while for plums these were selenium, total sugars, chlorogenic acid and vitamin C (R(2)=0.853), and selenium, chlorogenic acid and flavonoids for FRAP (R(2)=0.711). When considering Brassica and plum consumption in Luxembourg, it is estimated that both contribute to an antioxidant intake equivalent to 26 and 6 mg per day of ascorbic acid equivalents, respectively.

Dimeric bisindole alkaloids from the stem bark of Strychnos nux-vomica L.

Strychnos nux-vomica L. (Loganiaceae) is famous for its monomeric alkaloid content, such as strychnine, a convulsant poison. The stem bark of the tree is traditionally used to treat intermittent fever in South East Asia. In various studies, it appeared that dimeric indolo-monoterpenic alkaloids possess a promising activity on Plasmodium falciparum. Three bisindolomonoterpenic alkaloids together with strychnochrysine, previously identified in the root bark of S. nux-vomica, were isolated from the stem bark. The structures of these compounds were established using NMR spectroscopy and mass spectrometry. Stereochemistry of the compounds was confirmed by molecular modelling. This then allowed the structural determination of strychnoflavine, a coloured bisindole alkaloid previously isolated from the root bark of the tree. Moreover, the conformational inversion in alkaloids possessing an ether bond in the strychnane moiety could be easily predicted by specific δ (13)C NMR values. These longicaudatine-type alkaloids were found to display in vitro antiplasmodial activity against a chloroquine resistant strain and a chloroquine sensitive strain. The most interesting was strychnochrysine showing an IC(50) value at around 10 µM.

Antiplasmodial alkaloids from the stem bark of Strychnos malacoclados.

From the stem bark of Strychnos malacoclados, one new bisindole alkaloid, 3-hydroxylongicaudatine Y (1), was isolated along with the known alkaloids vomicine (2), bisnordihydrotoxiferine (3), divarine (4), longicaudatine (5), longicaudatine Y (6), and longicaudatine F (7). All the compounds were tested for their antimalarial activity against the chloroquine-sensitive 3D7 and -resistant W2 strains of Plasmodium falciparum. Longicaudatine was the most active compound with IC50 values of 0.682 and 0.573 µM, respectively. The activity of compounds 1, 3, 4, 6, and 7 against the two strains ranged from 1.191 to 6.220 µM and 0.573 to 21.848 µM, respectively. Vomicine (2), the only monomer isolated, was inactive. The alkaloids of the longicaudatine-type ( 1, 5-7) were more active than those of the caracurine-type (3- 4). The presence of the ether bridge in the molecule seems to increase the antiplasmodial activity. Compounds 1, 5, and 7 were tested against the WI-38 human fibroblast cell line. Longicaudatine was the most cytotoxic compound with an IC50 of 2.721 µM. Longicaudatine F was 40-46 times more active against the two strains of P. falciparum than against the human fibroblasts and was thus considered as the more selective alkaloid. The structures of the compounds were determined based on the analysis of their spectral data.

In vitro antiplasmodial activity of plants used in Benin in traditional medicine to treat malaria.

AIM OF THE STUDY: The aim of the study was to evaluate the in vitro antiplasmodial activity of crude extracts of 12 plant species traditionally used in Benin for the treatment of malaria in order to validate their use. MATERIALS AND METHODS: For each species, dichloromethane, methanol and total aqueous extracts were tested. The antiplasmodial activity of extracts was evaluated using the measurement of the plasmodial lactate dehydrogenase activity on chloroquine-sensitive (3D7) and resistant (W2) strains of Plasmodium falciparum. The selectivity of the different extracts was evaluated using the MTT test on J774 macrophage-like murine cells and WI38 human normal fibroblasts. RESULTS: The best growth inhibition of both strains of Plasmodium falciparum was observed with the dichloromethane extracts of Acanthospermum hispidum DC. (Asteraceae) (IC(50)=7.5 microg/ml on 3D7 and 4.8 microg/ml on W2), Keetia leucantha (K. Krause) Bridson (syn. Plectronia leucantha Krause) (Rubiaceae) leaves and twigs (IC(50)=13.8 and 11.3 microg/ml on 3D7 and IC(50)=26.5 and 15.8 microg/ml on W2, respectively), Carpolobia lutea G.Don. (Polygalaceae) (IC(50)=19.4 microg/ml on 3D7 and 8.1 microg/ml on W2) and Strychnos spinosa Lam. (Loganiaceae) leaves (IC(50)=15.6 microg/ml on 3D7 and 8.9 microg/ml on W2). All these extracts had a low cytotoxicity. CONCLUSION: Our study gives some justifications for the traditional uses of some investigated plants.

Fagraldehyde, a secoiridoid isolated from Fagraea fragrans.

A secoiridoid aglycone with an atypical skeleton, named fagraldehyde (1), together with several known secoiridoids (gentiopicroside (2), sweroside (3), and swertiamarin (4)) were isolated from the bark and leaves of Fagraea fragrans collected in Cambodia. The conformations of 1 were evaluated on the basis of molecular modeling and NOESY correlations. A hypothetical biogenesis of fagraldehyde was proposed to explain the unusual skeleton. Compound 1 was weakly active in vitro against Plasmodium falciparum.

In vitro antimicrobial activity of plants used in Cambodian traditional medicine.

The purpose of the present study was to screen 27 plant species used in the traditional medicine of Cambodia for in vitro antibacterial and antifungal activities. Thirty-three methanolic extracts were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium smegmatis and Candida albicans. Screened by disk diffusion assay, the extracts showed antimicrobial activity especially on Gram-positive bacteria. None of the crude methanolic extracts showed activity against P. aeruginosa. Twenty-five selected extracts were evaluated using a micro-dilution test. Harrisonia perforata (roots) and Hymenodictyon excelsum (bark) exhibited a bactericidal effect against S. aureus at a concentration of 500 microg/ml. Azadirachta indica (bark), Harrisonia perforata (roots and stem) and Shorea obtusa (roots) exhibited a bactericidal effect against M. smegmatis at 250 microg/ml.