Anti-infective Activities of Secondary Metabolites from Vitex pinnata.

The phytochemical investigation of Vitex pinnata led to the isolation of a mixture of steroids β-sitosterol and stigmasterol (1a and 1b) and three known flavonoid identified as 5-hydroxy-3, 7, 4’-trimethoxyflavone (2), 5-hydroxy-7,4’-dimethoxy-flavone (3) and 5-hydroxy-3,3’,4’,7-tetramethoxyflavone (4). The structures of all isolated compounds were carried out by NMR and mass spectrometry. The isolated compounds were evaluated for their anti-infective activities against Trypanosoma brucei brucei and Mycobacterium marinum. Compound 1-4 showed moderate antitrypanosomal activity with MIC values of 6.25μg/ml, 19.0, 21.0 and 17.0μM, respectively while no activity observed on anti-mycobacterial. This study is the first to report the presence of three flavones and their antitrypanosomal activity from V. pinnata.

In vitro and in vivo Antitrypanosomal Effects of Methanol and Aqueous Extracts of Picralima nitida.

The methanol and aqueous extracts of the leaves, fruits, seeds, stem bark and roots of Picralima nitida were studied in vitro and in vivo for activity against Trypanosoma brucei brucei in Swiss albino mice. Phytochemicals studies were also conducted for all the plant extracts. The methanol extracts showed appreciably high in vitro and in vivo antitrypanosomal activities compared to the aqueous extracts of the plant. The methanol extract of the root exhibited the highest in vitro antitrypanosomal activity followed by the methanol extract of seed of Picralima nitida. Motility of Trypanosoma brucei brucei was stopped by the methanol extract of the root after 10 min, while the methanol extract of the seed of Picralima nitida stopped the motility of Trypanosoma brucei brucei at 15 min. The methanol extract of the root of Picralima nitida showed the highest in vivo antitrypanosomal activity at 100 mg/kg body weight. The extract cleared the parasite completely from the T. brucei brucei infected Swiss albino mice after day 3 of treatment. There was a statistically significant difference (p<0.05) when the level of parasitemia of the animals treated with the methanol extract of the root of Picralima nitida were compared with the other treatment groups and the untreated control. The phytochemicals detected in these extracts are tannins, flavonoids, alkaloids, steroids, terpenoids, saponins and cyanide glycosides. The in vitro and in vivo antitrypanosomal activity exhibited by these extracts might be attributed to these phytochemicals.

In vitro activity of thienyl-2-nitropropene compounds against Trypanosoma cruzi

The in vitro activity of four 2-nitropropene derivatives, 1-(3-benzothienyl)-2-nitropropene (N1), 1-(3-thienyl)-2-nitropropene (N2), 1-(5-bromo-2-thienyl)-2-nitropropene (N3) and 1-(4-bromo-2-thienyl)-2-nitropropene (N4), were tested against cultures of the parasite Trypanosoma cruzi. Cytotoxicity studies were performed using Vero cells. The blood trypomastigotes, amastigotes and epimastigotes showed differential degrees of sensitivity towards the four tested compounds; the highest activity against the epimastigotes and blood tripomastigotes was exhibited by N1, followed by N3, N4 and finally N2. In contrast, whereas the compounds N1, N3 and N4 exerted similar magnitudes of activity against amastigotes, N2 was found to be a much less potent compound. According to our results, the compound N1 had the highest level of activity (IC50: 0.6 ìM) against epimastigotes.