Phytochemical and biological studies of Atriplex inflata f. Muell.: isolation of secondary bioactive metabolites.

OBJECTIVES: This work describes the phytochemical and biological investigation of the Tunisian Atriplex inflata F. Muell (Chenopodiaceae). METHODS: Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including 1D NMR and 2D NMR, ESI-HRMS and comparison with available literature data. The isolates were evaluated for their antioxidant activity by the DPPH• , ABTS+• , Fe3+ and catalase assays and also for their antibacterial and anticholinesterase activity. KEY FINDINGS: The chemical study of Atriplex inflata F. Muell led to the isolation of two fatty acids (9E)-methyl-8,11,12-trihydroxyoctadec-9-enoate 1 and (9E)-8,11,12-trihydroxyoctadecenoic acid 2 together with (Z)-litchiol B 3 and 20-hydroxyecdysone 4. Three of which are reported here for the first time in Atriplex genus. Based on the biosynthesis of hydroxylated arachidonic acid and derivatives, a plausible biogenesis pathway of the two fatty acids (1 and 2) was proposed. (Z)-litchiol B (3) was found to be the most active against Staphylococcus aureus. According to the literature, this is the first time that compounds 1, 2 and 3 were tested for their eventual biological activity. CONCLUSIONS: In the results of the present work, we have proposed the biogenesis pathway of unsaturated fatty acid and described the structure-activity relationship.

Semi-synthesis of new antimicrobial esters from the natural oleanolic and maslinic acids.

In this article, we report an effective procedure for the selective isolation of oleanolic acid 1 and maslinic acid 2 (3.4 and 8.5mg/g DW, respectively) from pomace olive (Olea europaea L.) using an ultrasonic bath, and the synthesis of a series of new triterpenic acid esters. The compounds were characterized by their spectral data and were evaluated for their antimicrobial activity. Among the compounds tested, those having sulfur and chlorine atoms were found to be antibacterial. They showed activity against two Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis and two Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa (MICs within a range of 5-25µg/mL). The fungus Penicillium italicum was found to be the most sensitive to both sulfur derivatives: (3ß)-3-((thiophene-2-carbonyl)oxy)-olean-12-en-28-oic acid (1a) (IZ=22mm) and (2α,3ß-2,3-bis((thiophene-2-carbonyl)oxy)olean-12-en-28-oic acid (2a) (IZ=24mm).

New septanoside and 20-hydroxyecdysone septanoside derivative from Atriplex portulacoides roots with preliminary biological activities.

The phytochemical investigation of a Tunisian plant Atriplex portulacoides (Chenopodiaceae) led to the isolation of two new compounds designated as portulasoid (2) and septanoecdysone (3) along with the known 20-hydroxyecdysone (20HE) (1). Their chemical structures were elucidated on the basis of extensive spectroscopic methods including ES-HRMS, 1D and 2D-NMR. The isolated compounds were finally tested for their antioxidant activity by using DPPH, ABTS(+), Fe(3+) and catalase assays and also for their antibacterial and anticholinesterase activities.