Valquiria Linck Bassani

HPLC method to assay total saponins in Ilex paraguariensis aqueous extract

Ilex paraguariensis St. Hilaire is a South American tree from which leaves and twigs are used to prepare a commonly consumed tea in several South American countries. The plant is known as “erva-mate” in Portuguese or “yerba mate” in Spanish. Considering the potential use of the saponins as surfactant as well as its therapeutic potential, the present work was designed to propose extraction and quantitation methods for the saponins present in Ilex paraguariensis. The saponins were extracted by decoction, hydrolyzed and quantified by a HPLC method with UV detection. The saponins concentration was expressed in ursolic acid (total saponins). The method showed linearity for ursolic acid in the range of 13.5 to 135 µg mL -1 . The aqueous extract presented total saponins concentration of 352 µg mL -1 . The results also suggest the possibility of use of similar method for assaying triterpenoid saponins in other plants.

Aromatic Plants from Brazil. II. The Chemical Composition of Some Eugenia Essential Oils

ABSTRACT Essential oils were obtained from the leaves of six Eugenia species collected from different areas of Brazil and were analyzed by GC and GC/MS. Forty-four compounds representing 89.6–95.7% of the oils were identified. Only Eugenia schuechiana and E. plicato-costata showed considerable amounts of monoterpenes: among them, α-pinene was the most abundant (13.2 and 20.9%). In all analyzed samples, bicyclic sesquiterpenes were present, particularly the selinene group (41%) in E. uniflora; another group of hydrocarbon and oxygenated sesquiterpenes, this time with the aromadendrene nucleus, was found in all samples in different amounts. The oils of E. rostrifolia and E. involucrata were found to be especially rich in sesquiterpene hydrocarbons (77.7% and 84.4%), with considerable amounts of viridiflorene (>30%); β-caryophyllene and its oxide are the main components of the essential oil of E. schuechiana and E. plicato-costata (31.9% and 26.9%), while E. uniflora and E. tinguyensis were characterized by ...

Preparation and characterization of spray-dried polymeric nanocapsules

Recently, much interest has been generated by colloidal drug delivery systems such as nanocapsules because of the possibilities for controlled release, increased drug efficacy, and reduced toxicity after parenteral administration. Nanocapsules of poly-ε-caprolactone and Eudragit S90® were prepared. However, these systems present physicochemical instability. To dry these nanocapsule suspensions with the view of obtaining a solid form, the spray-drying process was used. Spray-dried powders of nanocapsules of poly-ε-caprolactone and Eudragit S90® were prepared by atomization in a Büchi 190 Mini-spray dryer using colloidal silicon dioxide as a technological carrier. The morphological analysis of the surface at the powders showed that nanocapsules remain intact, and no change in particle size was detected after the spray-drying process. These results suggest that this method can be an interesting alternative to dry nanocapsule suspensions.

Influence of β-cyclodextrin complexation on carbamazepine release from hydroxypropyl methylcellulose matrix tablets

The in vitro release profiles of carbamazepine and beta-cyclodextrin either complexed or simply mixed and subsequently incorporated in hydrophilic matrix tablets containing 15 or 30% hydroxypropyl methylcellulose were evaluated. Solubility studies revealed a linear relationship between the increase in carbamazepine solubility and the increase in beta-cyclodextrin concentration. Drying methods (spray-drying and freeze-drying) were used to obtain carbamazepine/beta-cyclodextrin solid complexes in order to prepare tablets. The results demonstrated that matrix tablets containing carbamazepine/beta-cyclodextrin solid complexes displayed faster carbamazepine and beta-cyclodextrin release compared to that containing simple physical mixture. Gelling and matrix formation was impaired in formulation containing 15% hydroxypropyl methylcellulose and spray-dried complex. The comparison of spray-drying and freeze-drying revealed no significant influence of both drying methods on carbamazepine and beta-cyclodextrin dissolution rate when carbamazepine/beta-cyclodextrin complexes were incorporated in 30% hydroxypropyl methylcellulose matrix tablets. The results point to the possibility of modulating carbamazepine release using a hydroxypropyl methylcellulose matrix associated to the drug complexed with beta-cyclodextrin.

Studies on coumestrol/β-cyclodextrin association: inclusion complex characterization.

Coumestrol is an estrogenic and antioxidant agent, characterized by its low solubility in aqueous and lipophilic media, once in the aglicone form. In order to improve its solubility in water, coumestrol was associated with beta-cyclodextrin in aqueous media followed by freeze-drying and characterized by SEM, (1)H NMR and molecular modeling. The analysis proved the existence of an inclusion complex, with higher probability of inclusion of the coumestrol B-ring into the wider rim of the beta-cyclodextrin molecule.

Daidzein/cyclodextrin/hydrophilic polymer ternary systems

Objective: To evaluate the effect of different cyclodextrins (β-cyclodextrin [β-CD], methyl-β-cyclodextrin [Mβ-CD], or hydroxypropyl-β-cyclodextrin [HPβ-CD]) and/or hydrophilic polymers (carboxymethylcellulose, hydroxypropylmethylcellulose [HPMC], polyethyleneglycol, or polyvinylpyrrolidone [PVP]) on daidzein solubility in water. Materials and methods: The corresponding associations were characterized in aqueous media using phase-solubility studies. The morphology of daidzein/cyclodextrin freeze-dried complexes was characterized using scanning electron microscopy, and their spatial configuration was proposed by means of nuclear magnetic resonance spectroscopy. Results and discussion: In the presence of 6 mM of cyclodextrins, the solubility of daidzein in water was significantly enhanced: 5.7-fold (β-CD), 7.2-fold (Mβ-CD), and 9.4-fold (HPβ-CD). The analysis of the three solid complexes proved that the formation of inclusion complexes occurred through the insertion of the B and C rings of daidzein molecule into the cyclodextrins cavity. The association of daidzein/cyclodextrin complexes to the hydrophilic polymers HPMC or PVP (1%, w/w) was able to improve the solubility of daidzein even further. Conclusion: The highest solubilizing effect was obtained for daidzein/HPβ-CD/PVP ternary system (12.7-fold).

Preparation and characterization of spray-dried powders from Achyrocline satureioides (Lam.) DC extracts

Two Achyrocline satureioidesspray‐dried extracts were prepared from 80% ethanol using raw material pretreated with petroleum ether (P1) in one case and nontreated crude vegetable drug (P2) in the other case. The atomization was carried out in a Büchi 190 Mini‐spray dryer using colloidal silicon dioxide as technological carrier. The ethanol content was previously reduced to 10% (v/v) in a low pressure distillation system and the extracts were concentrated four‐fold. The nonpolar fraction was maintained in a homogeneous suspension by addition of 2% (w/w) polysorbate 80. The main flavonoids in the feed solutions and in the spray‐dried powders were assayed by HPLC and their concentrations in the final products, P1 and P2, were 99%–101%. Both spray‐dried extracts presented good physical properties (hygroscopicity, particle form and size). The results suggest that the petroleum ether treatment of raw material did not influence the technological properties of the final spray dried products.

Enhanced water-solubility of albendazole by hydroxypropyl-β-cyclodextrin complexation

The inclusion complexation of methyl (5-(propylthio)-1H-benzimidazol-2-yl) carbamate, albendazole (ABZ) with 2-hydroxypropyl-β-cyclodextrin (HPβCD) in water was investigated with a view to improving the low aqueous solubility of the drug. The combination of albendazole and HPβCD in a molar ratio of 1/10 resulted in a significant increase in the aqeous solublity of the drug, up to 3500 times. Albendazole/HPβCD complexes could be recommended as a parenterally administered formulation because of its good solubility properties and the safety of the cyclodextrin used.

Optimization of headspace solid-phase microextraction for analysis of β-caryophyllene in a nanoemulsion dosage form prepared with copaiba (Copaifera multijuga Hayne) oil

Recent studies have shown the anti-inflammatory activity of Copaiba oils may be addressed to the high content of β-caryophyllene, the most common sesquiterpene detected, especially in the Copaifera multijuga Hayne species. In the present study, nanoemulsions were proposed as a delivery system for copaiba oil in view to treat locally inflamed skin. This article describes the optimization and validation of a stability-indicating SPME-GC method, for β-caryophyllene analysis in the nanoemulsions produced by high pressure homogenization. SPME methods are performed with PDMS (polydimethylsiloxane) fiber (100 μm). Three SPME parameters were evaluated by a three-level-three-factor Box-Behnken factorial design as potentially affecting the technique efficiency. According to the results obtained, the best conditions to extract β-caryophyllene were: (i) sampling temperature of 45°C, (ii) sampling time of 20 min and (iii) no NaCl addition. Results coming from the forced degradation tests showed a reduction of β-caryophyllene peak area when both caryophyllene methanolic solution and nanoemulsions were exposed to acid hydrolysis, UV-A irradiation, oxidative (H(2)O(2)) and thermolitic (60°C) conditions. Such reduction occurred in lower extent in the nanoemulsions, suggesting a protective effect of the formulation to β-caryophyllene content. Since no degradation products were detected in the same retention time of β-caryophyllene, the specificity of the method was demonstrated. The method was linear in the range of 0.14-0.68 μg mL(-1) of β-caryophyllene (r(2)>0.999), and was also validated for precision (R.S.D.≤5.0%), accuracy (97.85-101.87%) and robustness. Finally, the method was applied to quantification of β-caryophyllene content in the developed formulations.

Influência do método de extração nos teores de metilxantinas em erva-mate (Ilex paraguariensis a. St.-Hil., aquifoliaceae)

Ilex paraguariensis A. St. -Hil. is a native species of southern South America. The caffeine content in Ilex paraguariensis leaves has been considered an important quality parameter for mate-derived products. In this work different extraction methods for the determination of these methylxantines are compared. The influence of the extraction conditions on the methylxanthine yields was evaluated. Extraction by decoction with acidic aqueous solution (H2SO4 4N) presented the higher efficiency in the theobromine extraction. The extraction in a Soxhlet with acidic aqueous solution and decoction with acidic aqueous solution showed the highest caffeine yield. For the concomitant theobromine and caffeine quantification, the decoction with acidic aqueous solution is suggested.Ilex paraguariensis A. St. -Hil. is a native species of southern South America. The caffeine content in Ilex paraguariensis leaves has been considered an important quality parameter for mate-derived products. In this work different extraction methods for the determination of these methylxantines are compared. The influence of the extraction conditions on the methylxanthine yields was evaluated. Extraction by decoction with acidic aqueous solution (H2SO4 4N) presented the higher efficiency in the theobromine extraction. The extraction in a Soxhlet with acidic aqueous solution and decoction with acidic aqueous solution showed the highest caffeine yield. For the concomitant theobromine and caffeine quantification, the decoction with acidic aqueous solution is suggested.