The present work is devoted to the exploration antioxidant and antiradical activity of twenty anthraquinones isolated from the Cameroonian flora at B3LYP/6-311++G(d,p) level of theory using the B3LYP/6-31 + G(d,p) geometrical data as geometry optimization starting points. The single electron transfer mechanism has been adopted to examine both biological activities. The classification of the antiradical profile to integrate the electrodonating power (ω−), electroaccepting power (ω+), donor index (Rd) and acceptor index (Ra) has been performed using the donor-acceptor map (DAM). The antioxidant and radical powers of compounds analyzed have been compared to that of two classical vitamins (vitamin C and gallic acid). The stability of each anthraquinone derivative of the molecular library has been developed according to thermodynamic and kinetic concepts. The global reactivity descriptors (GRDs; electrophilicity index (ω), electronegativity (χ), global softness (S), and global hardness (η)) have been used to analyze the reactivity. The topological analysis of optimized structures indicates that the strength of the hydrogen bonds formed is situated between 44.205 and 52.001 kJ/mol. Our B3LYP results reveal that 3-methoxy-1-vismiaquinone (in a configuration without hydrogen bond) exhibits the best antioxidant capacity in gas phase. A comparison between antioxidant performance of molecules examined and that of classical vitamins (gallic acid, caffeic acid, ferulic acid, and ascorbic acid (vitamin C)) displayed the fact that the single electron transfer (SET) mechanism is more prominent for compounds of the molecular library analyzed. In the same vein, the antiradical behaviors of anthraquinone derivatives have shown to be higher than that of gallic acid and vitamin C in gas phase and water. The 5,8-dihydroxy-2-methylantraquinone structure in a configuration bearing one hydrogen bond has been found to be the best antiradical of the series in aqueous solution.

Fractionation of the methanol extract of the leaves of Oricia renieri and Oricia suaveolens (Rutaceae) led to the isolation of 13 compounds including the hitherto unknown furoquinoline alkaloid named 6,7-methylenedioxy-5-hydroxy-8-methoxy-dictamnine (1) and a flavanone glycoside named 5-hydroxy-4'-methoxy-7-O-[α-L-rhamnopyranosyl(1‴→5″)-β-D-apiofuranosyl]-flavanoside (2), together with 11 known compounds (3-13). The structures of the compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral data and comparison. All compounds isolated were examined for their activity against human carcinoma cell lines. The alkaloids 1, 5, 12, 13 and the phenolic 2, 8, 11 tested compounds exhibited non-selective moderate cytotoxic activity with IC50 8.7-15.9 μM whereas compounds 3, 4, 6, 7, 9 and 10 showed low activity.

A phytochemical investigation of the roots of Citrus x paradisi Macfad. (Rutaceae) led to the isolation of two new compounds, namely 1-formyl-5-hydroxy-N-methylindolin-1-ium (1) and decyloxycleomiscosin D (2), along with ten known compounds: 1,1-dimethylpyrrolidin-1-ium-2-carboxylate (3), furan-2,3-diol (4), 5-methoxyseselin (5), umbelliferone (6), scopoletin (7), citracridone I (8), citracridone II (9), citracridone III (10), limonin (11) and lupeol (12). The structures were determined through the comprehensive spectroscopic analysis of 1D and 2D NMR and EI- and ESI-MS, as well as a comparison with the published data. Notably, compounds 3 and 4 from the genus Citrus are reported here for the first time. In addition, the MeOH extract of the roots and compounds 1–7 were screened against the human adenocarcinoma alveolar basal epithelial cell line A549 and the Caucasian prostate adenocarcinoma cell line PC3 using the MTT assay. While the extract showed significant activity, with IC50 values of 35.2 and 38.1 µg/mL, respectively, compounds 1–7 showed weak activity, with IC50 values of 99.2 to 250.2 µM and 99.5 to 192.7 µM, respectively.

No abstract

A chemical investigation of the leaves of Tabernaemontana inconspicua Stapf. led to the isolation of a new phenylpropanol derivative, namely irisdichototin G (1), together with nine known compounds, including one polyol derivative, dambonitol (2); three alkaloids, 10-hydroxycoronaridine (3), voacristine (4) and vobasine (5); two triterpenes lupeol (6), betulinic acid (7) and three sterols, sitosterol (8), sitosterol-3-O-β-D-glucopyranoside (9) and stigmasterol (10). The structure of the new compound, as well as those of the known ones, was established by means of spectroscopic methods: NMR analysis (1H and 13C NMR, 1H-1H-COSY, HSQC, HMBC and NOESY), high-resolution mass spectrometry (HR-ESI-MS) and comparisons with previously reported data. Among the known compounds, compound 2 was firstly reported from the family Apocynaceae. Compounds 1–5 were tested for their antimicrobial effects against three Gram-negative organisms associated with human wound and systemic infections, namely Haemophilus influenzae 9435337A, Klebsiella pneumoniae 17102005 and Pseudomonas aeruginosa 2137659B. Compounds 1, 3, and 5 showed significant antimicrobial effects with minimum inhibitory concentrations (MIC) of 62.5 μg/mL, 62.5 μg/mL and 7.81 μg/mL, respectively, against Haemophilus influenzae, whereas compounds 1 and 5 showed significant antimicrobial effects, with a MIC value of 31.25 μg/mL against Pseudomonas aeruginosa. In addition, compound 3 showed significant antimicrobial activity, with a MIC value of 31.25 μg/mL against Klebsiella pneumoniae.