Caractérisation des constituants chimiques de Cordia millenii Baker (Boraginaceae) et évaluation de leurs propriétés antibactériennes et antivirales

Abstract

This work deals with characterization, chemical transformations and HIV integrase inhibition, antibacterial and cytotoxicity activities of the crude extracts, fractions and compounds isolated from Cordia millenii Baker; a plant from the Boraginaceae family. Its various parts are used in traditional medicine to treat infectious diseases. The chemical investigation of the plant material (leaves, stem barks and roots) of Cordia millenii Baker, led to the isolation of fifteen (15) compounds which were entirely characterized. The structures of these compounds were elucidated from detailled analysis using spectroscopic data (NMR 1H and 13C, DEPT, COSY, HMBC and NOESY) associated with mass spectroscopic (Electrospray Ionization, Electronic Impact, FAB), cristallography and literature data. The ethyl acetate crude extract of the stem bark led to the isolation of seven compounds which were characterized as cordidepsine (72), a new depsidone metabolite reported here for the first time in Boraginaceae family; allantoin (74), lupenone (75), β-amyrone (76), lupeol (77), β-amyrin (78) and 1’-(26’-hydroxyhexacosanoyl)glycerol (79), a monoglycerol metabolite reported for the first time from Cordia genus.The ethyl acetate fraction of roots led to the isolation of three compounds which were identified as cyclooctasulfur (80), a sulfur allotrop isolated for the first time from plant source; glyceryl-1-hexacosanoate (81) and betulinic acid (82). The ethyl acetate fraction of roots led to the isolation of five compounds which were identified as lup-20(29)-en-3-triacontanoate (83), stigmasterol glycoside (84), tetratriacontanylhexacosanoate (85), ethyle 2’-(4-hydroxyphenyl) propanoate (87) and nonacosyle (E)-3-(4’hydroxyl)cinnamate (88). New hemi-synthetic derivatives, cordicerol A (89) and cordicerol B (90) were obtained respectively through acetylation reactions of 1’-(26’- hydroxyhexacosanoyl)glycerol (79) and glyceryl-1-hexacosanoate (81). Biological assays such as HIV integrase inhibition, antibacterial and cytotoxicity activities were evaluated. Cordidepsine (72) exhibited significant HIV integrase inhibition with IC50 = 4.65 μM. The stem barks EtOAc extract and roots EtOAc fraction inhibited respectively Staphylococcus aureus (65.2 %) and Bacillus subtilis (49.45 %). In addition, the viability cell percentage of ethyl acetate crude extract of the stem barks (99 %), ethyl acetate fraction of roots (96 %) and ethyl acetate of leaves (95 %) reveal that these crude extract and fractions were not toxic on 3T3 heathy cells of human.This work brought our modest contribution for infectious diseases treatment through medicinal plants.