A bioactive chalcone from the aerial parts of Indigofera conferta Gillet.

Ethnobotanical information indicates that Indigofera conferta is used in northern Nigeria for the management of poisonous snakebites and the methanol extract was previously reported to have antivenin activity. In this study, we report the isolation of an oxyprenylated bioactive secondary metabolite; 2',4'- dihydroxy-4-prenyloxychalcone from the chloroform fraction of the aerial parts of the plant's methanol extract and the in vivo evaluation of the compound against Naja nigricollis venom. The compound has demonstrated significant (p < 0.05) and dose-dependent antivenin activity against LD99 Naja nigricollis venom. At a dose of 10 mg/kg, the compound protected 60% of the animals tested from death. The observed activity lends credence to the traditional use of the plant in the management of snake bites in northern Nigeria. The compound, 2',4'- dihydroxy-4-prenyloxychalcone, could also serve as a lead in the development of novel antisnake venom agents.

Biochemical evaluation and molecular docking assessment of glucosamines from Neocarya macrophylla fruits against Naja nigricollis venom.

Two new glucosamines, Microphyllose A and B were isolated from the chloroform fraction of Neocarya macrophylla fruit using flash column chromatography. The structures of these compounds were elucidated based on chemical tests and the analysis of their spectral data (IR, 1D- & 2D-NMR). The compounds have demonstrated significant (p < 0.05) antivenom activity against Naja nigricollis venom with 60 and 80% protection, respectively. When subjected to molecular docking, the compounds have demonstrated different binding affinities against three toxins (phospholipase A2, neurotoxin and cardiotoxin) from Naja nigricollis venom and they were further screened for ADMET analysis based on Lipinski's and Veber's rule and the compounds have failed absorptivity for oral medications. To the best of our knowledge, this is the first report of isolation and molecular docking analysis of these compounds from medicinal plants.

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C-F···H-C bonds.

4-(2-Fluorophenyl)-7-methoxycoumarin (6) was synthesized by Pechmann reaction under mild conditions via a three-step reaction. The solution-state 1H NMR spectra of 6 showed a strong intramolecular interaction between F and H5 (J FH = 2.6 Hz) and 13C NMR suggested that this C-F···H-C coupling is a through-space interaction. The 2D 19F-{1H} HOESY and 1H-{19F} 1D experiments were done to confirm this F···H interaction. The single crystal X-ray structure and the DFT-optimized structure showed that the fluorinated phenyl ring favors the orientation with the fluorine atom closer to H5 than H3. The X-ray structure also showed the existence of the intermolecular C-F···H-C interaction.