<i>In vitro</i> antiplasmodial and cytotoxic activities of sesquiterpene lactones from <i>Vernonia fimbrillifera</i> Less. (Asteraceae)

<p>Due to the <i>in vitro</i> antiplasmodial activity of leaf extracts from <i>Vernonia fimbrillifera</i> Less. (Asteraceae), a bioactivity-guided fractionation was carried out. Three sesquiterpene lactones were isolated, namely 8-(4’-hydroxymethacrylate)-dehydromelitensin (<b>1</b>), onopordopicrin (<b>2</b>) and 8α-[4’-hydroxymethacryloyloxy]-4-epi-sonchucarpolide (<b>3</b>). Their structures were elucidated by spectroscopic methods (1D and 2D NMR and MS analyses) and by comparison with published data. The isolated compounds exhibited antiplasmodial activity with IC₅₀ values ≤ 5 μg/mL. Cytotoxicity of the compounds against a human cancer cell line (HeLa) and a mouse lung epithelial cell line (MLE12) was assessed to determine selectivity. Compound <b>3</b> displayed promising selective antiplasmodial activity (SI > 10).</p

Anti-inflammatory and antioxidant activities of <i>Rungia congoensis</i>, a traditional vegetable consumed by <i>Yombe</i> people from Kongo Central area (DR. Congo)

<p><i>Rungia congoensis</i>, a traditional vegetable from Kongo Central area (DR. Congo) was studied for establishing microscopic characters and characterised by chromatographic techniques and their <i>in vitro</i> biochemical activities against ROS production were evaluated in cellular models and on an enzyme, myeloperoxidase (MPO), involved in inflammation. Microscopically leaf can be characterised by non-glandular and glandular trichomes, sinuous anticlinal epidermal cells, diacytic stomata and helical vessels. Methanolic extract displayed high cellular antioxidant activity at the concentrations range of 0.1–10 μg mL⁻¹ and 1–20 μg mL⁻¹ using lucigenin on neutrophils and DCFH-DA on HL 60, respectively. This extract also showed, more efficient effects on extracellular and intracellular ROS production and MPO activity. Antioxidant and anti-inflammatory activities of <i>R. congoensis</i> were significantly higher, positively correlated with their phytochemical constituents such as flavonoids, iridoids and phenolic acids; and could justify their use as traditional vegetable and potent local nutraceutical resource.</p

Image3_Unveiling antiplasmodial alkaloids from a cumulative collection of Strychnos extracts by multi-informative molecular networks.TIF

Malaria, a disease known for thousands of years and caused by parasites of the Plasmodium genus, continues to cause many deaths throughout the world today, particularly due to the emergence of parasite resistance to the current therapeutic arsenal. Plants of the Strychnos genus, remarkable due to their multiple traditional uses as well as their alkaloid content, are promising candidates to develop new antimalarial treatments. Indeed, previous research on this plant group has shown promising (≤ 5 µg/ml) or good (between 5 and 15 µg/ml) antiplasmodial activities. Using the chloroquine-sensitive strain of Plasmodium falciparum (3D7), and artemisinin as positive control, a screening of antiplasmodial activities from 43 crude methanolic extracts from 28 species of the Strychnos genus was carried out in three independent assays. A total of 12 extracts had good (6 extracts) or promising (6 extracts) antiplasmodial activities. These results allowed both to confirm known activities but also to detect new ones. These extracts were then analyzed by HPLC-ESI(+)-Q/TOF, and the processed MS/MS data allowed to generate a molecular network in which the antiplasmodial activities were implemented as metadata. The exploration of the molecular network revealed the presence of alkaloids still unknown, and potentially active against malaria, in particular alkaloids close to usambarensine and its derivatives. This study shows that the emergence of molecular networking offers new leads for identifications of alkaloids from the Strychnos genus. The presence of unknown alkaloids potentially active against malaria confirms all the interest to continue in studying the Strychnos genus. Bioassay- and mass-guided fractionations as well as various dereplication tools would allow to identify and characterize these interesting alkaloids further.</p

Image2_Unveiling antiplasmodial alkaloids from a cumulative collection of Strychnos extracts by multi-informative molecular networks.TIF

Malaria, a disease known for thousands of years and caused by parasites of the Plasmodium genus, continues to cause many deaths throughout the world today, particularly due to the emergence of parasite resistance to the current therapeutic arsenal. Plants of the Strychnos genus, remarkable due to their multiple traditional uses as well as their alkaloid content, are promising candidates to develop new antimalarial treatments. Indeed, previous research on this plant group has shown promising (≤ 5 µg/ml) or good (between 5 and 15 µg/ml) antiplasmodial activities. Using the chloroquine-sensitive strain of Plasmodium falciparum (3D7), and artemisinin as positive control, a screening of antiplasmodial activities from 43 crude methanolic extracts from 28 species of the Strychnos genus was carried out in three independent assays. A total of 12 extracts had good (6 extracts) or promising (6 extracts) antiplasmodial activities. These results allowed both to confirm known activities but also to detect new ones. These extracts were then analyzed by HPLC-ESI(+)-Q/TOF, and the processed MS/MS data allowed to generate a molecular network in which the antiplasmodial activities were implemented as metadata. The exploration of the molecular network revealed the presence of alkaloids still unknown, and potentially active against malaria, in particular alkaloids close to usambarensine and its derivatives. This study shows that the emergence of molecular networking offers new leads for identifications of alkaloids from the Strychnos genus. The presence of unknown alkaloids potentially active against malaria confirms all the interest to continue in studying the Strychnos genus. Bioassay- and mass-guided fractionations as well as various dereplication tools would allow to identify and characterize these interesting alkaloids further.</p

Image5_Unveiling antiplasmodial alkaloids from a cumulative collection of Strychnos extracts by multi-informative molecular networks.TIF

Malaria, a disease known for thousands of years and caused by parasites of the Plasmodium genus, continues to cause many deaths throughout the world today, particularly due to the emergence of parasite resistance to the current therapeutic arsenal. Plants of the Strychnos genus, remarkable due to their multiple traditional uses as well as their alkaloid content, are promising candidates to develop new antimalarial treatments. Indeed, previous research on this plant group has shown promising (≤ 5 µg/ml) or good (between 5 and 15 µg/ml) antiplasmodial activities. Using the chloroquine-sensitive strain of Plasmodium falciparum (3D7), and artemisinin as positive control, a screening of antiplasmodial activities from 43 crude methanolic extracts from 28 species of the Strychnos genus was carried out in three independent assays. A total of 12 extracts had good (6 extracts) or promising (6 extracts) antiplasmodial activities. These results allowed both to confirm known activities but also to detect new ones. These extracts were then analyzed by HPLC-ESI(+)-Q/TOF, and the processed MS/MS data allowed to generate a molecular network in which the antiplasmodial activities were implemented as metadata. The exploration of the molecular network revealed the presence of alkaloids still unknown, and potentially active against malaria, in particular alkaloids close to usambarensine and its derivatives. This study shows that the emergence of molecular networking offers new leads for identifications of alkaloids from the Strychnos genus. The presence of unknown alkaloids potentially active against malaria confirms all the interest to continue in studying the Strychnos genus. Bioassay- and mass-guided fractionations as well as various dereplication tools would allow to identify and characterize these interesting alkaloids further.</p

Image4_Unveiling antiplasmodial alkaloids from a cumulative collection of Strychnos extracts by multi-informative molecular networks.tif

Malaria, a disease known for thousands of years and caused by parasites of the Plasmodium genus, continues to cause many deaths throughout the world today, particularly due to the emergence of parasite resistance to the current therapeutic arsenal. Plants of the Strychnos genus, remarkable due to their multiple traditional uses as well as their alkaloid content, are promising candidates to develop new antimalarial treatments. Indeed, previous research on this plant group has shown promising (≤ 5 µg/ml) or good (between 5 and 15 µg/ml) antiplasmodial activities. Using the chloroquine-sensitive strain of Plasmodium falciparum (3D7), and artemisinin as positive control, a screening of antiplasmodial activities from 43 crude methanolic extracts from 28 species of the Strychnos genus was carried out in three independent assays. A total of 12 extracts had good (6 extracts) or promising (6 extracts) antiplasmodial activities. These results allowed both to confirm known activities but also to detect new ones. These extracts were then analyzed by HPLC-ESI(+)-Q/TOF, and the processed MS/MS data allowed to generate a molecular network in which the antiplasmodial activities were implemented as metadata. The exploration of the molecular network revealed the presence of alkaloids still unknown, and potentially active against malaria, in particular alkaloids close to usambarensine and its derivatives. This study shows that the emergence of molecular networking offers new leads for identifications of alkaloids from the Strychnos genus. The presence of unknown alkaloids potentially active against malaria confirms all the interest to continue in studying the Strychnos genus. Bioassay- and mass-guided fractionations as well as various dereplication tools would allow to identify and characterize these interesting alkaloids further.</p

Antioxidant potentiality of three herbal teas consumed in Bandundu rural areas of Congo

<p>The aim of this study was to evaluate and compare the cellular antioxidant activities of <i>Lantana montevidensis</i>, <i>Lippia multiflora,</i> and <i>Ocimum gratissimum</i> leaves often consumed as herbal teas in a rural area of Bandundu severely affected by konzo, which is related to oxidative damage. Consequently, dietary supplements with proven antioxidant potentialities could be of real interest to promote in this area. Phytochemical screening by TLC and HPLC-DAD of extracts revealed the presence of verbascoside as a major phenolic compound. Verbascoside in <i>L. montevidensis</i> and <i>O. gratissimum</i> is reported here for the first time<i>.</i> All extracts displayed high ABTS and DPPH radical-scavenging activities at the concentration range of 1–40 μg mL⁻¹ according to order: <i>L. multiflora</i> > <i>O. gratissimum</i> > <i>L. montevidensis</i>. <i>L. multiflora</i> showed the best cellular antioxidant activity using DCFH-DA on HL-60 monocytes assay at 1–20 μg mL⁻¹. These herbal teas may be used as nutraceuticals for their potent antioxidant activity.</p