In vitro leishmanicidal activity of some Cameroonian medicinal plants.

Eleven plants used in the Cameroonian traditional medicine for the treatment of some parasitic infections were tested for their activity on the promastigote form of Leishmania donovani. After incubation with different plant extracts at doses of 1600, 800, 400 and 200 microgram/mL, the evaluation of the cell viability was done by the trypan blue exclusion technique and by flow cytometry. This study shows that 48 h after incubation of promastigotes with plant extract, Solanocia mannii and Solanum torvum significantly inhibited the proliferation of promastigotes in culture with IC50 of 60.78±5.05 and 96.08±4.39 using the trypan blue exclusion technique. In addition, IC50 of 43.91±6.49 and 86.13±4.30 were obtained using the flow cytometry technique. Furthermore, 24 h after incubation of promastigotes with the Solanocia mannii and Solanum torvum, there was significant disruption of their long spindle shaped bodies. The results of this study support the popular uses of these plants for the treatment of some parasitic infections in Cameroonian folk medicine.

Chemical constituents of Stereospermum acuminatissimum and their urease and α-chymotrypsin inhibitions.

Phytochemical investigation of the stem bark of Stereospermum acuminatissimum K. Schum. resulted in the isolation of 21 compounds, including two new guanine derivatives, 1,3,7-trimethylguanin-1/3-ium (1) and 3,7-dimethylguanin-1/3-ium (2), and one new phenolic long chain ester, 2-(4-hydroxyphenyl)ethyl hentriacontanoate (3). The known compounds were identified as sterequinones A, F, and H (4, 5, and 6), zenkequinones A-B (7-8), p-coumaric acid (9), methyl caffeate (10), caffeic acid (11), psilalic acid (12), syringaldehyde (13), norviburtinal (14), specioside (15), verminoside (16), tyrosol (17), eutigoside A (18), ellagic acid (19), atranorin (20), and ursolic acid (21). The metabolites were screened for their potential against urease and α-chymotrypsin enzymes, as urease is targeted in peptic ulcer while α-chymotrypsin is used to remove protein debris in ulcer. Compound 20 was found to be excellent urease inhibitor with IC(50) value of 18.2 ± 0.03 µM. Compounds 13 and 18-20 are reported for the first time from the genus Stereospermum. The chemotaxonomic significance of the isolated compounds was also described.

In vitro hepatoprotective and antioxidant activities of crude extract and isolated compounds from Ficus gnaphalocarpa.

The in vitro hepatoprotective effect of the methanolic extract from Ficus gnaphalocarpa (Miq.) Steud. ex A. Rich (Moraceae) on the CCl4-induced liver cell damage as well as the possible antioxidant mechanisms involved in this protective effect, were investigated. The phytochemical investigation of this methanolic extract led to the isolation of six compounds identified as: betulinic acid (1); 3-methoxyquercetin (2); catechin (3); epicatechin (4); quercetin (5); and quercitrin (6). The hepatoprotective activity of these compounds was tested in vitro against CCl4-induced damage in rat hepatoma cells. In addition, radical-scavenging activity, ß-carotene-linoleic acid model system, ferric-reducing antioxidant parameter and microsomal lipid peroxidation assays were used to measure antioxidant activity of crude extract and isolated compounds. Silymarin and trolox were used as standard references and, respectively, exhibited significant hepatoprotective and antioxidant activities. (5), (6) and (2) showed significant antioxidant and hepatoprotective activities as indicated by their ability to prevent liver cell death and lactate dehydrogenase leakage during CCl4 intoxication. These results suggest that the protective effects of crude extract of F. gnaphalocarpa against the CCl4-induced hepatotoxicity possibly involve the antioxidant effect of these compounds.