In vitro schistosomicidal activity of the lignan (-)-6,6'-dinitrohinokinin (DNHK) loaded into poly(lactic-co-glycolic acid) nanoparticles against Schistosoma mansoni.

CONTEXT: (-)-6,6'-Dinitrohinokinin (DNHK) display remarkable antiparasitic activity and was, therefore, incorporated into a nanoparticle formulation. OBJECTIVE: Incorporation of DNHK in poly lactic-co-glycolic acid (PLGA) nanoparticles aiming to improve its biological activities. MATERIALS AND METHODS: Synthesis, characterization and incorporation of DNHK into glycolic acid (PLGA) nanoparticles by nanoprecipitation method. The nanoparticles were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, field emission electron microscopic scanning mansoni (FESEM), and dynamic light scattering (DLS). For the in vitro test with Schistosoma mansoni, the DNHK-loaded PLGA was diluted into the medium, and added at concentrations 10-200 µM to the culture medium containing one adult worm pair. The parasites were kept for 120 h and monitored every 24 h to evaluate their general condition, including: pairing, alterations in motor activity and mortality. RESULTS: The loaded PLGA nanoparticles gave an encapsulation efficiency of 42.2% and showed spherical characteristics in monodisperse polymeric matrix. The adult worm pairs were separated after 120 h of incubation for concentrations higher than 50 µM of DNHK-loaded PLGA. The groups incubated with 150 and 200 µM of DNHK-loaded PLGA for 24 and 120 h killed 100% of adult worms, afforded LC50 values of 137.0 ± 2.12 µM and 79.01 ± 1.90 µM, respectively, which was similar to the effect displayed by 10 µM of praziquantel. DISCUSSION AND CONCLUSIONS: The incorporation of DNHK-loaded showed schistosomicidal activity and allowed its sustained release. The loaded PLGA system can be administered intravenously, as well as it may be internalized by endocytosis by the target organisms.

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.

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria

This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of b-amyrin, a-amyrin, and b-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis.

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria.

This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of ß-amyrin, α-amyrin, and ß-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis.

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.