Design and semisynthesis of new herbicide as 1,2,3-triazole derivatives of the natural maslinic acid.

Interesting biological activities (anti-inflammatory, anticancer, antiviral, antioxidant, antidiabetic…) have been reported for maslinic acid (MA) and MA-based compounds. In continuation of our previous work on MA, herbicide potential of Tunisian plant extracts and 1,4-triazolyl derivatives of MA, we now wish to report semisynthesis of new MA-based triazole hybrid compounds with herbicide potential. These compounds were synthesized through Cu-catalyzed azide-alkyne cycloaddition (CuAAC) under microwave irradiation conditions between propargylated MA and a series of phthalimide azides. Here, the first partner of CuAAC reaction (propargylated MA) resulted from propargylation of C-28 carboxylic acid group of isolated MA from the well-known Mediterranean plant Olea europaea L. (Oleaceae). So far, phthalimide azide derivatives were achieved by trapping of N-acyliminium ion, in-situ generated under catalytic condition of Bi(OTf)3, by aromatic nucleophiles. The cycloaddition reaction afforded regiospecifically 1,4-disubstituted triazoles in good yields. The latter hybrid compounds were shown to exhibit a high inhibition potential of seed germination. This constitutes the first step in development of potent herbicides since one of the final semisynthesized structures can serve as a promising lead candidate for further studies.

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.

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.

An alkaloid, two conjugate sesquiterpenes and a phenylpropanoid from Pachypodanthium confine Engl. and Diels.

Two sesquiterpene-trimethoxystyrene conjugates (E)-1-[3'-(4'',8''-dimethylnona-3'',7''-dienyl)cyclohex-3'-enyl]-2,4,5-trimethoxybenzene (1) and (Z)-1-[3'-(4'',8''-dimethylnona-3'',7''-dienyl)cyclohex-3'-enyl]-2,4,5-trimethoxybenzene (2), a phenylpropanoid 1,2,4-trimethoxy-5-(1-methoxy-ethyl)-benzene (3), and an aporphine alkaloid N-acetylpachypodanthine (4), were isolated in addition to several known compounds from cyclohexane, dichloromethane and alkaloid extracts from bark of Pachypodanthium confine. The structures of these compounds were established based on the interpretation of their high resolution NMR (HSQC, HMBC, COSY and NOESY) spectral data.