Turbo-extraction of glycosides from Stevia rebaudiana using a fractional factorial design

ABSTRACT Stevia rebaudiana (Bertoni) Bertoni, Asteraceae, leaf extract has recently called the attention of food industry as a proposal for natural sweetener. The sweet flavor is attributed to the glycosides, in especial stevioside and rebaudioside A, which are the plant main chemical markers. The aim of the work reported here was to optimize the turbo-extraction of stevia leaves using water, ethanol 70% and 90% (w/w) as green solvents. A 25-2 factorial design was applied to study the linear effects of the drug size, solvent to drug ratio, temperature, time and also the turbolysis speed on the extraction of glycosides. The glycosides exhaustive extraction showed that ethanol 70% gave better results and was used for turbo-extraction. The stevioside and rebaudioside A contents were quantified by a validated method by high performance liquid chromatographic with photodiode array detector. The contents of stevioside and rebaudioside A in fluid extract increased with the drug size, but decreased at high shearing speeds and solvent to drug ratio, while their yields decreased at higher temperature and were not affected by turbo speed. An increase in solvent to drug ratio reduced significantly the glycosides percent in dried extract. Optimal solution for S. rebaudiana leaves turbo-extraction was determined by desirability functions. The optimal extraction condition corresponded to drug size of 780 µm, solvent to drug ratio of 10, extraction time of 18 min; temperature of 23 ºC and turbo speed of 20,000 rpm, resulting in yields of 4.98% and 2.70%, for stevioside and rebaudioside A, respectively. These yields are comparable to the ones recently published for dynamic maceration, but with the advantage of shorter extraction times. This work demonstrates that turbolysis is promising for S. rebaudiana glycosides extraction and stimulate new research on the purification of these extracts, which may become an interesting source of income for developing countries such as India and Brazil.

Nanoparticles containing curcuminoids (Curcuma longa): development of topical delivery formulation

Solid lipid nanoparticles incorporating Curcuma longa L., Zingiberaceae, curcuminoids were produced by the hot melt emulsion method. A Box–Behnken factorial design was adopted to study the nanoparticles production at different levels of factors such as the percentage of curcuminoids, time of homogenization and surfactant ratio. The optimized nanoparticles were incorporated into hydrogels for stability, drug release and skin permeation tests. The average nanoparticle sizes were 210.4 nm; the zeta potential of −30.40 ± 4.16; the polydispersivity was 0.222 ± 0.125. The average encapsulation efficiency of curcumin and curcuminoids was 52.92 ± 5.41% and 48.39 ± 6.62%, respectively. Solid lipid nanocapsules were obtained with curcumin load varying from 14.2 to 33.6% and total curcuminoids load as high as 47.7%. The topical formulation containing SLN-Curcuminoids showed good spreadability and stability when subjected to mechanical stress test remained with characteristic color, showed no phase separation and no significant change in pH. As a result of slow release, the nanoparticles were able to avoid permeation or penetration in the pig ear epidermis/dermis during 18 h. The topical formulation is stable and can be used in further in vivo studies for the treatment of inflammatory reactions, in special for radiodermitis.

Dynamic maceration of Copaifera langsdorffii leaves: a technological study using fractional factorial design

The Copaifera langsdorffii Desf., Fabaceae, is a Brazilian native tree, known as copaiba, which oil is commonly used in folk medicine as muscle relaxant, wound healing, antiseptic and anti-inflammatory to respiratory and urinary tracts. Despite of the wide use of the oil of Copaifera species, scientific works related to the study of its leaves are rarely found. In fact, processes for flavonoid extraction from C. langsdorffii leaves have not been studied yet leaving a wide field to be investigated. In this work, the 2(5-2) fractional factorial design was selected in order to study how the factors of a dynamic maceration process influence the responses of total flavonoids, total phenols, quercetrin and afzelin contents, and antioxidant activity in extracts from C. langsdorffii leaves. The results demonstrated that the significant factors studied were the drug load in extractor, the ethanol/water ratio and the stirring speed whereas the temperature and the extraction time were not significant. In conclusion, this study allowed visualizing which factors were considered the most important in copaiba leaves dynamic maceration and their effect in extract antioxidant activity. Furthermore, this technological study gives directions to optimize future extraction experiments from C. langsdorffii.

Box-Behnken design to study the bergenin content and antioxidant activity of Endopleura uchi bark extracts obtained by dynamic maceration

Brazil has one of the world's largest biodiversity in flora and a plant that has attracted attention is the Endopleura uchi (Huber) Cuatrec., Humiriaceae, which is native of the Brazilian Amazon. Among the many popular uses, this species is utilized in the treatment of woman's genito urinary tract affections and also as anti-inflammatory. It is believed that their actions derive from the major constituent, bergenin. The objective of this work was to study the Endopleura uchi barks extraction using the dynamic maceration method and the effects of the extraction time, drug to solvent ratio and temperature. A Box-Behnken design was applied to study the influence of these factors and the respective response surfaces. The extract characterization was made by determination of its antioxidant activity by DPPH; total polyphenol content and bergenin content. In general, the extracts showed good antioxidant activity, with the IC50 ranging from 4.02 to 5.87 µg/mL. The polyphenol content ranged from 31.89 to 47.82%. High levels of chemical markers are observed in all extracts, with average bergenin content of 35.58%. The result showed that the multivariate study of extraction is key step in the development and standardization of extracts Endopleura uchi.

Spray-dried extracts from Syzygium cumini seeds: physicochemical and biological evaluation

Aqueous extract from seeds of Syzygium cumini (L.) Skeels, Myrtaceae, obtained by dynamic maceration was spray-dried and characterized by its physico-chemical and antihyperglycaemic action. The extract showed to possess high amount of polyphenols, significant in vitro free radical scavenger activity using the DPPH method and an antihyperglycaemic effect in alloxan-induced experimental diabetes. S. cumini spray-dried extracts were obtained using silicon dioxide and cassava starch as adjuvants. The powders showed acceptable flowability, compactability, and low hygroscopicity at 43% relative humidity. Besides, the spray-dried extracts showed in vivo antihyperglycaemic and in vitro scavenger activity comparable to the lyophilized extract. Thus, experimental data indicates that the extract from S. cumini has a relevant activity and that spray-drying could be adequately used to perform the technological processing of S. cumini fluid extracts.