Laurence Marcourt

Microphynolides A and B, new spiro-γ-lactone glycosides from Thymelaea microphylla

Two new spiro-γ-lactone glycosides named microphynolide A (1) and microphynolide B (2), together with twelve known compounds including five biflavonoids namely neochamaejasmin A, neochamaejasmin B, daphnodorin B, genkwanol A and stelleranol, one bis-coumarin daphnoretin, two lignans called pinoresinol and matairesinol, one flavonoid glucoside, tiliroside, a sinapyl alcohol glucoside, syringin, and two phytosterols, β-sitosterol and β-sitosterol-3-O-glucoside, were isolated from ethyl acetate extracts of the aerial parts and roots of the plant Thymelaea microphylla Coss. and Dur. All the isolated compounds were characterised by using spectroscopic methods and comparison with the literature data.

Antioxidant and antibacterial activities and polyphenolic constituents of Helianthemum sessiliflorum Pers.

Abstract In this study, the various extracts of aerial parts of Helianthemum sessiliflorum Pers. were examined in vitro for possible source of antioxidants and for antibacterial activity. The antioxidant activity was performed by DPPH radical scavenging method which showed that ethyl acetate extract possessed the best antioxidant potential (IC50 = 32.75 ± 2.07 μg/mL). The significant linear correlation was realised between the values of the total phenolic/flavonoid content and antioxidant activity of plant extracts. The ethyl acetate and n-butanol extracts showed moderate antibacterial activity. In addition, the phytochemical study of n-butanol extract afforded nine known phenolic compounds (1–9). This is the first report of six of them (1, 3, 5–8) in Cistaceae family. The structural identification of the isolated compounds was achieved using several spectroscopic methods.

SYNTHESIS AND ANTIFUNGAL ACTIVITY OF DIARYL HYDRAZONES FROM 2,4-DINITROPHENYLHYDRAZINE

A new series of diarylhydrazones derived from 2,4-dinitrophenylhydrazine were synthesized via condensation with aromatic aldehydes whose structures have been determined by mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectra. Yields were 50–99%. All compounds were screened in vitro for their antifungal activity. Preliminary results indicated that compounds 3g and 3h exhibited promising antifungal potency. Understanding of the structure of these compounds establishes a preliminary structure-activity relationship to form the basis of further investigation.

Identification of Triterpenoids from Schefflera systyla, Odontadenia puncticulosa and Conostegia speciosa and In Depth Investigation of Their in vitro and in vivo Antifungal Activities

As a part of a broad screening of antifungal agents from plant origin, crude extracts from Panamanian plants having related types of constituents displayed significant activities in an agar overlay thin layer chromatography assay against a susceptible strain of Candida albicans. These were the methanolic extract of the leaves of Schefflera systyla and Odontadenia puncticulosa and of the stems of Conostegia speciosa, that are species not previously investigated from a phytochemical viewpoint. For all plants, high-performance liquid chromatography (HPLC) antifungal activity based profiling allowed the rapid localization of antifungal agents that were further obtained by targeted isolation procedure by semi-preparative HPLC or medium pressure liquid chromatography (MPLC) after LC gradient transfer. Different hederagenin saponins and one aglycone were found to be responsible for the antifungal activities of the extracts. Alpha-hederin was the antifungal of S. systyla, pulsatilla saponin D and 3β-O-[β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosylhederagenin of O. puncticulosa and arjunolic acid of C. speciosa. Their minimal inhibitory concentration (MIC) against planktonic and biofilm cells of C. albicans were determined. Alpha-hederin was the most potent compound with a MIC of 4 µg mL-1. Structurally related compounds (hederagenin, medicagenic acid 3-O-β-D-glucopyranoside and medicagenic acid) were used as standards and tested for comparison purposes. In order to better estimate the potential of these triterpenoids as antifungal agents, their cytological effects on C. albicans were determined by transmission electron microscopy (TEM) and the in vivo activity of alpha-hederin, medicagenic acid 3-O-β-D-glucopyranoside and medicagenic acid was evaluated for the first time in the Galleria mellonella larvae model.

¹H AND 13C NMR SPECTRAL ASSIGNMENTS AND X-RAY CRYSTALLOGRAPHY OF N-(3-(1H-IMIDAZOL-1-YL)PROPYL)-2-PHENYLQUINAZOLIN-4-AMINE

ABSTRACT N-(3-(1H-Imidazol-1-yl)propyl)-2-phenylquinazolin-4-amine ( 2) was obtained by nucleophilic substitution of 1-(3-aminopropyl)-imidazole over 4-chloro-2-phenylquinazoline ( 1) with DMF/TEA at room temperature. The precursor and product were characterized by NMR spectroscopy. The structure of the title compound was confirmed by X-ray diffraction methods. The quinazoline fragment ( 2) is essentially planar and makes a dihedral angle of 66.35 ° with the imidazole plane. In the crystal packing the molecules are associated by two strong intermolecular NH∙∙∙∙N hydrogen bonds with graph-set motif R 22 (16). These pairs are linked by two π-π interactions. INTRODUCTION Quinazoline derivatives are known to possess remarkable anti-inflammatory activity as NOS-II 1,2 and PDE-4 3 inhibitors, among others. They are also found to show broncho-dilatory 4 and anti-allergic 5 properties. In addition, these compounds also have a therapeutic benefit as an anti-invasive agent with potential for activity in early and advanced solid tumors, metastatic bone disease and leukemias