Antibacterial iridoid glucosides from Eremostachys laciniata.

Eremostachys laciniata (L) Bunge (family: Lamiaceae alt. Labiatae; subfamily: Lamioideae) is one of the 15 endemic Iranian herbs of the genus Eremostachys. A decoction of the roots and flowers of E. laciniata has traditionally been taken orally for the treatment of allergies, headache and liver diseases. Three antibacterial iridoid glucosides, phloyoside I (1), phlomiol (2) and pulchelloside I (3) have been isolated from the rhizomes of this plant. The structures of these compounds were elucidated unequivocally by a series of 1D and 2D NMR analyses. The antibacterial activity and brine shrimp toxicity of these compounds were assessed using the resazurin microtitre assay and the brine shrimp lethality assay, respectively. All three iridoid glycosides 1-3 exhibited from low to moderate levels (MIC = 0.05-0.50 mg/mL) of antibacterial activity. Of these compounds, compound 3 was the most active, and displayed antibacterial activity against 9 of 12 different strains tested. The most noteworthy activity of 3 was against Bacillus cereus, penicillin-resistant Escherichia coli, Proteus mirabilis and Staphylococcus aureus with an MIC value of 0.05 mg/mL.

The evaluation of antibacterial, antifungal and antioxidant activity of methanolic extract of mindium laevigatum (vent.) rech. F., from central part of iran.

BACKGROUND: Mindium laevigatum (Vent.) Rech. F. plant grows in central part of Iran. And used by local people as medical plant. OBJECTIVES: The purpose of this study was to investigate the in vitro antibacterial, antifungal and antioxidant activities of the methanolic extracts of aerial and flower parts of plant. MATERIALS AND METHODS: The leaves and stem and flower of bark from M. laevigatum were separately collected, air-dried and powdered. Then the plant species extracts were prepared with methanol, water 80:20 and two polar and non-polar subfractions were realized. The antioxidant activity was evaluated by scavenging the radicals 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), ß-Carotene linoleic acid assay and reducing power methods. The antifungal and antibacterial evaluation was performed by disc diffusion and minimum inhibitory concentration methods. RESULTS: The total phenolic analysis of subfractions found 182 ± 4.2 µg.gr(-1) for polar and 158 ± 3.9 µg.gr(-1) for non-polar extracts. The antifungal activity of the extracts against the various fungal varied from 14.0 to 34 mm. MIC values from 50 to 400 µg.mL(-1) were satisfactory when compared with other plant products. The antibacterial results revealed that the subfraction extracts are mostly effective against Staphylococcus aureus. The antioxidant results showed polar subfraction has more activity against non-polar subfraction. CONCLUSION: These findings demonstrated that the extract of Mindium laevigatum has remarkable in vitro antifungal and antioxidant activity.