ABSTRACT
ABSTRACT The phytochemical study of Galium tunetanum Lam., Rubiaceae, leaves led to the isolation of 13 compounds from the chloroform-methanol and the methanol extracts, including six iridoid glycosides, one non-glycoside iridoid, two p-coumaroyl iridoid glycosides, two phenolic acids, and two flavonoid glycosides. The structural determination of the isolated compounds was performed by mono- and bidimensional NMR spectroscopic data, as well as ESI-MS experiments. All compounds were isolated from this species for the first time. The anti-angiogenic effects of the isolated iridoids were also reported on new blood vessels formation using the chick embryo chorioallantoic membrane as in vivo model. Results showed that among the isolated iridoids tested at the dose of 2 µg/egg, asperuloside (1), geniposidic acid (2), and iridoid V1 (3) reduced microvessel formation of the chorioallantoic membrane on morphological observations using a stereomicroscope. The anti-angiogenic effects of the active compounds, expressed as percentages of inhibition versus control, were 67% (1), 59% (2), and 54% (3), respectively. In addition, the active compounds were able to inhibit angiogenesis in the chorioallantoic membrane assay, in a dose-dependent manner (0.5-2 µg/egg) as compared to the standard retinoic acid.
ABSTRACT
Aims: Myrtus communis L. (Myrtle) is a plant widely used in traditional medicine in the Mediterranean Sea. The aim of this study was to determine the phenolic content of Myrtus communis L. leaves and to investigate the antioxydant activity of the methanol extract and its fractions. Methodology: Myrtus communis L. leaves were extracted using organic solvents with different polarities to get the following fractions: Methanol extract (ME), chloroform extract (CE), ethyl acetate extract (EE) and aqueous extract (AqE). Total polyphenol, flavonoid and tannins contents were evaluated for all extracts. The antioxidant capacity of different extracts was assessed using nine in vitro tests. Results: The results show that ME had the highest total phenolic content (149.25±3.11 mg GAE/g of dry extract), the aqueous extract had the highest tannins content (83.35±0.36 mg TAE/ g of dry extract), whereas, EE had the highest total flavonoid content (38.4±0.9 mg QE/ g of dry extract).The EE exhibited an interesting antioxidant activity using ABTS radical scavenging assay (IC50=0.0015 mg/ml) and the DPPH test (IC50=0.004 mg/ml), while EA showed an important activity in the hydroxyl radical scavenging test (IC50=0.08 mg/ml), H2O2, (IC50=0.015 mg/ml), iron chelating (IC50=0.5 mg/ml) and reducing power (EC50=0.03 mg/ml). The greatest activity in inhibiting the oxidation of β-carotene/ linoleic acid was induced by CE and EE extracts (93.95%, and 90.29%, respectively). All extracts showed a very strong antiperoxidant effect against FTC and MDA tests. Conclusion: Myrtus communis L. leaves extracts have an important antioxidant activity which is most likely due to their polyphenolic content.