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We report the chemistry and biological activities of a Cameroonian Citrus clementina Hort. Ex Tanaka, a vegetatively propagated species. The compounds isolated from this plant were determined to be the known 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (1) , tangerine (3), nobilletin (4) and 5,7,8,4'-tetramethoxyflavone (5), citracridone I (6), 5-hydroxynoracronycine (7), citracridone III (8), xanthyletin (10), suberosin (9), E-suberenol (11), E-methoxysuberenol (13), 6-formylumbelliferone (12), aurantiamide acetate (2), limonin (14), stigmasterol, βsitosterol and β-sitosterol-3-O-β-D-glucoside. Their structures of the compounds were established on the basis of NMR spectroscopic data and comparison with published data.Methanol leaf extract and compounds 1, 2, 4, 6, 7 and 10 were evaluated for their antiinflammatory, antioxidant, urease and anti-diabetic effects. Compound 10 showed antioxidant activity, anti-inflammatory effect, urease activity and anti-diabetic activity with IC 50 values of 47.3 µM, 33.5 µM, 25.2 µM and 33.9 µM respectively, values that were comparable to the respective positive standards.

Piliostigma thonningii (Schum.) Milne-Redh. is a plant rich in quercetin-3-O-rhamnoside (quercitrin), a flavonoid involved in the antioxidant and antimicrobial processes. Microwave assisted extraction (MAE) is a method which gives better extraction yield, enhance the quality of extracts while decreasing the extraction time. This effect, a sequential optimization by response surface methodology using a central composite design, help to determine the optimal conditions for obtaining more antioxidant compounds of P. thonningii leaves. The response surface curves showed that there was a positive interaction between the extraction time and the solvent concentration on the DPPH scavenging and iron chelating activities of the extracts. The optimal ethanolic extraction parameters for the highest yield of flavonoids were an extraction time of 69 s, an irradiation power of 380 W and a solid-liquid ratio of 1/10 (w/v). On the residue, the optimal extraction parameters for simultaneously obtaining the highest flavonoids yield and the highest antioxidant activity were an extraction time of 49 s, an irradiation power of 520 W and an ethanol concentration of 67% (v/v). HPLC analysis has shown the second optimization helped to further maximize the extraction of active compound quercetin-3-Orhamnoside. Electron microscopy of the powders before and after extraction has shown that microwave heating causes cellular damage. Compared to the maceration extraction method, the combined extracts of sequential MAE provide higher antioxidant activities.

<p>To contribute to control bacterial infections, we proposed evaluating the antibacterial activities and modes of action of <em>Aeollanthus heliotropioides </em>essential oil and its<em> </em>hydroethanolic extract. Solvent extracts and essential oil were obtained from the aromatic plant's aerial parts by hydroethanolic maceration and hydro-distillation. The analyses of the chemical composition were performed using gas chromatography coupled with mass spectrometry. The <em>microdilution method evaluated the in vitro antibacterial potential of the essential oil and solvent extracts</em>. The Inhibition of biofilms formation was carried out using a colorimetric biofilm microdilution assay with crystal violet as a dye. The effect of extract and essential oil on the release of nucleic acids was performed using a spectrophotometric method. The time-kill kinetic assay was assessed for hydroethanolic extracts and essential oil. The extraction yield was 0.1%, and the major compounds identified in the essential oil were linalool (43.47%) and cis-α-farnesene (42.67%). The phytochemical screening revealed flavonoids, saponins, phenols, triterpenes, catechin tannins, and quinones. Minimum Inhibitory Concentrations (MICs) ranged from 2.08 mg/mL to 10 mg/mL. Concerning the modes of action, the essential oil showed its bactericidal effect at 2 hours. The reduction of <em>Escherichia coli</em> biofilms formation was found at 0.21 mg/mL. The essential oil treatments resulted in a release of nucleic acids at a concentration of 2.1 mg/mL. These results justify using the essential oil and hydroethanolic extracts of <em>Aeollanthus heliotropioides</em> as a potential source of molecules with antibacterial activity.<strong></strong></p>

The stem bark of Ancistrocarpus densispinosus Oliv. exhibited triterpenoids, including the rare fernane-type, fern-9(11)-ene-2α,2β-diol (1) a possible chemotaxonomically distinct biomolecule for the genus. Other triterpenoids that were isolated from this plant include the ursane-type ursolic acid (2) and corosolic acid (3), friedelane-type friedelin (4) and canophyllol (5), lupane-type lupeol (6), betulin (7), betulinic acid (8) and hennadiol (9), oleanoic acid (10), maslinic acid (11) and taraxerol (12), and three sterols stigmasterol, stigmasterol-3-O-β-D-glucopyranoside and sitosterol. This is the first report of the chemistry of a plant of the Ancistrocarpus species. The structures of the compounds were elucidated based on their NMR spectroscopy, IR and MS techniques and by comparisons of their experimental data with those reported in the literature. The twelve triterpenoids 1-12 were found to be inactive against five bacterial strains Escherochia coli, Bacillus subtilis, Pseudomonas agarici, Micrococcus luteus and Staphylococcus warneri; inactive against KB-3-1 cervix carcinoma cancer cell line and inactive as antioxidants in the DPPH assay.