RESUMO
A preliminary ethnopharmacological survey, achieved in French Polynesia, led to the collection of the most cited plants among 63 species used to treat "infectious" diseases, with a description of their medicinal uses. Bibliographical investigations and antimicrobial screening permitted the selection of the botanical species Syzygium malaccense (Myrtaceae) for phytochemical analysis. Leaves of Syzygium malaccense were usually used in mixture with rhizomes of Curcuma longa to treat infectious diseases such as cystitis. The methanolic plant extracts were tested in vitro with an agar microdilution method on 33 bacteria strains and 1 yeast to obtain their Minimal Inhibitory Concentration (MIC), and cytotoxicity against HepG2 cells were evaluated. Antimicrobial synergistic effects of methanolic plant extracts from leaves of Syzygium malaccense and rhizomes from Curcuma longa were also evaluated. The bio-guided isolation of leaf extract from Syzygium malaccense led to the identification of seven alkyl-salicylic acids (anacardic acids or ginkgolic acids C15:0, C15:1, C17:0, C17:1, C17:2, C17:3 and C19:1) described for the first time in this species. All compounds were tested against Staphylococcus aureus (18.75 < MIC < 75.0 µg/mL), Streptococcus pyogenes (2.34 < MIC < 18.75 µg/mL) and Pseudomonas aeruginosa (MIC = 150 µg/mL), and their structure−activity relationships were discussed. The methanolic extract and salicylic derivatives from S. malaccense showed an interesting antimicrobial activity against Gram+ bacteria, without toxicity on hepG2 cells at 400 µg/mL. Moreover, these antibacterial compounds have already been studied for their anti-inflammatory activity, which supports the therapeutic interest of S. malaccense against infectious diseases.
RESUMO
The glucosinolate (GL) profiles in leaf and stem of Rorippa sarmentosa (G.Forst. ex DC.) J.F.Macbr., Lepidium bidentatum Montin var. bidentatum, and Capparis spinosa subsp. cordifolia (Lam.) Fici indigenous to French Polynesia were investigated for the first time using LC-MS analysis. In the present study, we have established the presence of 8 known GLs in R. sarmentosa: 4-(methylsulfinyl)butyl- (1), but-3-enyl- (2), 5-(methylsulfinyl)pentyl- (3), 6-(methylsulfinyl)hexyl- (4), indol-3-ylmethyl- (6), 2-phenylethyl- (7), 8-(methylsulfinyl)octyl- (8), and 9-(methylsulfinyl)nonyl- (9) GLs. We have also tentatively identified for the first time the presence in R. sarmentosa of 7-(methylsulfinyl)heptyl GL (5). In addition, we have identified two known GLs in L. bidentatum var. bidentatum: benzyl- (10) and 4-methoxybenzyl- (11) GLs. Finally, the known methyl GL (12) was shown to be largely predominant in C. spinosa subsp. cordifolia.
