Résumé:
In this work, we focused on phytochemical and biological study of two plant species:
Retama monosperma (L.) (fabaceae) and Blackstonia grandiflora (Viv.) Maire
(Gentianaceae).
A phytochemical study of Blackstonia grandiflora aerial parts extracts lead to isolation
of new oxygenated xanthone named 1,8-dihydroxy-2,3,4- trimethoxyxanthone, as well as to
four known compounds namely methylswertianin; decussatin; halenaquinone and
gentiopicroside.
A detailed chemical investigation of the secondary metabolites from the extracts of
fruits of Retama monosperma lead to isolation of four known compounds namely
isorhamnetin; kaempferol; quercetin and genistein-8-C-glucoside. All compound structures
were determined by CPG-MS, 1 D and 2-D NMR techniques.
The compounds isolated from EtOAc extract of R. monosperma exhibited a great ability
to inhibit the formation of fluorescent AGEs in BSA/Ribose system, whereas the aerial parts
extracts from B. grandiflora showed a weak inhibitory ability against pentosidine-like AGE
formation. Those extracts displayed a moderate inhibitory potency against vesperlysine-like
AGE formation compared with the standard antiglycation agent aminoguanidine.
The study of anti bacterial activity of aerial parts extracts of B. grandiflora carried out
against two gram-negative bacteria (Escherichia coli ATCC 25922; Pseudomonas aeruginosa
ATCC 27853) and two gram-positive bacteria (Staphylococcus aureus ATCC 29213;
Bacillus sp.) using diffusion method. The results indicated a good inhibition of EtOAc extract of bacterial growth especially gram-negative bacteria. Furthermore, CH2Cl2 extract showed a significant inhibitory effect against gram-positive bacteria.
