Spray drying of Eugenia dysenterica extract: effects of in-process parameters on product quality

A 2³ full factorial design was used to assess the impact of spraying air flow rate (30-50 L/min), drying air inlet temperature (90-150 ºC) and extract feed rate (4-6 g/min) on the quality of Eugenia dysenterica DC., Myrtaceae, spray-dried extracts. Response surface methodology (RSM) was applied to analyze the significance of the effects of process factors on product quality and to obtain fitted equations to predict dry powder properties. Powder yields were satisfactory, ranging from 34.64 to 63.92%. The dried products showed moisture contents and water activities below 5% and 0.5, respectively. The recuperation ratios of total polyphenols, tannins and flavonoids ranged from 88.66 to 99.07%, 70.38 to 81.87% and 74.51 to 98.68%, respectively. Additionally, in some conditions the parameters related to dry product’s flowability and compressibility varied over a range acceptable for pharmaceutical purposes. RSM proved that studied factors significantly affected most of the quality indicators at different levels. The spray drying technology is an attractive and promising alternative for the development of intermediate phytopharmaceutical products of E. dysenterica

Evaluation of Functional Stability and Batch-to-Batch Reproducibility of a Castanea sativa Leaf Extract with Antioxidant Activity

A growing body of evidence suggests that free radicals are generated by UV irradiation being responsible for skin injury. In this regard, the topical use of formulations composed of plant extracts with antioxidant activity could represent a useful strategy for the prevention of photoaging and oxidative-stress-mediated diseases. The aim of this study was to assess the reproducibility of the extraction method and the functional stability of a Castanea sativa leaf extract in view of its application as topical antioxidant. Measurements of 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging activity, total phenols (measured by the Folin Ciocalteu assay) and phenolic composition (high-performance liquid chromatography unit coupled to a UV detector) were carried out on three different batches. The influence of pH and temperature on the extract’s DPPH scavenging activity was assessed in aqueous and glyceric solutions (0.025% w/v) over a 3-month period. Minor differences were found between the three extract batches for all the evaluated parameters, and therefore the reproducibility of the extraction method can be inferred. pH presented a great influence in the extract functional stability. Major antioxidant activity decrease was found at pH 7.1, while lower changes were observed at pH 5. Glyceric solutions were stable throughout the test period. At 40°C and pH 5, a marked decrease of activity was observed. Again, glyceric solutions were the most stable, even at 40°C. Proper selection of pH and solvent is mandatory to ensure the stability of the studied extract after being incorporated in semisolid forms. In view of these results, glycerine is proposed as the best vehicle for topical formulations incorporating C. sativa leaf extract, which should have a pH around 5