Activity of the Lichen Usnea steineri and its Major Metabolites against Gram-positive, Multidrug-resistant Bacteria.

The antimicrobial activity and possible synergistic effects of extracts and compounds isolated from Usnea steineri were evaluated against four resistant bacterial species. A phytochemical study of the acetone extract of U. steineri resulted in the isolation and characterization of difractaic acid and (+)-usnic acid as the main compounds. The acetone extract showed strong activity (less than 10 µg/mL) against resistant strains of Staphylococcus epidermidis and Enterococcus faecalis, and (+)-usnic acid exhibited strong activity against S. epidermidis (MIC 3.12 µg/mL), S. aureus and S. haemnolyticus (MIC 12.5 µg/mL). Combinations of penicillin and tetracycline with (+)-usnic acid did not show any synergistic antimicrobial effects. Difractaic acid was inactive. Our results showed that the acetone extract of U. steineri possesses significant in vitro antimicrobial activity, which is likely related to the presence of (+)-usnic acid.

In vivo analgesic and anti-inflammatory activities of Rosmarinus officinalis aqueous extracts, rosmarinic acid and its acetyl ester derivative.

CONTEXT: Despite several pharmacological applications of Rosmarinus officinalis L. (Lamiaceae), studies on its analgesic and anti-inflammatory properties have been scarce. OBJECTIVE: The aim of this work was to use in vivo models to evaluate the analgesic and anti-inflammatory activities of the aqueous extracts obtained from leaves (AEL) and stems (AES) of Rosmarinus officinalis, as well as its isolated compound--rosmarinic acid (RA). We also prepared and assessed the acetyl ester derivative of RA. MATERIALS AND METHODS: The analgesic activity was evaluated using abdominal constriction and formalin tests. For the evaluation of the anti-inflammatory effects, carrageenin-induced paw edema in rats were used. The extracts were used at doses of 100, 200 and 400 mg kg⁻¹ compounds were tested at 10, 20 and 40 mg kg⁻¹. RESULTS: Orally administered AEL, AES and RA were not significantly active at any of the doses tested during the abdominal constriction test; the acetyl ester derivative of RA displayed significant analgesic activity. In the carrageenin-induced paw edema assay, the acetyl derivative of RA at all the tested doses produced significant anti-inflammatory effects and reduced the number of paw licks in the second phase of the formalin test. DISCUSSION AND CONCLUSION: The results suggest that the analgesic effects of the acetyl derivative of RA operate via a peripheral-mediated mechanism. The acetyl ester derivative of RA is potentially applicable as a new lead compound for the management of pain and inflammation.

Antibacterial activity of the essential oil from Rosmarinus officinalis and its major components against oral pathogens.

The essential oil of Rosmarinus officinalis L. (rosemary) was obtained by hydro-distillation and analysed by gas chromatography-mass spectrometry. Sixty-two constituents were identified, representing 98.06% of the total oil content. Oxygenated monoterpenes were the predominant components. The rosemary oil was characterized as having prominent (> 5%) contents of camphor (18.9%), verbenone (11.3%), a-pinene (9.6%), beta-myrcene (8.6%), 1,8-cineole (8.0%), and beta-caryophyllene (5.1%). The antimicrobial activity of the oil as well as of its major constituents was tested against the following microorganisms: Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, Streptococcus salivarius, Streptococcus sobrinus, and Enterococcus faecalis, which are potentially responsible for the formation of dental caries in humans. The microdilution method was used for determination of the minimum inhibitory concentration (MIC) during evaluation of the antibacterial activity. The essential oil displayed low activity against the selected microorganisms. In the present study, the pure major compounds were more active than the essential oil. Among all the microorganisms tested, the pathogen S. mitis was the most susceptible and E. faecalis was the most resistant to the evaluated samples. This is the first report on antimicrobial activity of the major components of rosemary oil against oral pathogens.

Antimicrobial activity of Rosmarinus officinalis against oral pathogens: relevance of carnosic acid and carnosol.

The in vitro inhibitory activity of crude EtOH/H2O extracts from the leaves and stems of Rosmarinus officinalis L. was evaluated against the following microorganisms responsible for initiating dental caries: Streptococcus mutans, S. salivarius, S. sobrinus, S. mitis, S. sanguinis, and Enterococcus faecalis. Minimum inhibitory concentrations (MIC) were determined with the broth microdilution method. The bioassay-guided fractionation of the leaf extract, which displayed the higher antibacterial activity than the stem extract, led to the identification of carnosic acid (2) and carnosol (3) as the major compounds in the fraction displaying the highest activity, as identified by HPLC analysis. Rosmarinic acid (1), detected in another fraction, did not display any activity against the selected microorganisms. HPLC Analysis revealed the presence of low amounts of ursolic acid (4) and oleanolic acid (5) in the obtained fractions. The results suggest that the antimicrobial activity of the extract from the leaves of R. officinalis may be ascribed mainly to the action of 2 and 3.

Evaluation of the antibacterial activity of the methylene chloride extract of Miconia ligustroides, isolated triterpene acids, and ursolic acid derivatives.

The methylene chloride extract of Miconia ligustroides (DC.) Naudin (Melastomataceae), the isolated compounds ursolic and oleanolic acids and a mixture of these acids, and ursolic acid derivatives were evaluated against the following microorganisms: Bacillus cereus (ATCC 14579), Vibrio cholerae (ATCC 9458), Salmonella choleraesuis (ATCC 10708), Klebsiella pneumoniae (ATCC 10031), and Streptococcus pneumoniae (ATCC 6305). The microdilution method was used for determination of the minimum inhibitory concentration (MIC) during evaluation of the antibacterial activity. The methylene chloride extract showed no activity against the selected microorganisms. Ursolic acid was active against B. cereus, showing a MIC value of 20 microg/mL. Oleanolic acid was effective against B. cereus and S. pneumoniae with a MIC of 80 microg/mL in both cases. The mixture of triterpenes, ursolic and oleanolic acids, did not enhance the antimicrobial activity. However, the acetyl and methyl ester derivatives, prepared from ursolic acid, increased the inhibitory activity for S. pneumoniae.