Comparative study of the ethanol extracts of six Acinos Miller species: chemical composition, antimicrobial and antioxidative activities

The ethanol extracts of selected Acinos Miller species were investigated in terms of chemical composition, antimicrobial and antioxidative activities. Qualitative and quantitative analyses of the extracts were performed using GC and GC-MS. Eighty-six constituents, accounting for 93.70-99.99% of the total composition of the extracts, were identified. The ethanol extracts of A. majoranifolius, A. suaveolens and A. alpinus were characterized by domination of monoterpenes, representing 85.03%, 57.39% and 28.02% of the total extracts, respectively. Fatty acids and their esters in the A. arvensis and A. graveolens extracts reached 28.97% and 30.75%. Also, n-alkanes were the major compounds found in A. hungaricus ethanol extract (30.98%). The extracts were characterized by determination of total polyphenols, flavonoids and tannins. Besides, the antioxidant activity of the investigated extracts was estimated by two assays: DPPH and FRAP test. The highest antioxidant activity was observed in the extract of A. alpinus which had high levels of all examined polyphenol classes. A disk diffusion method was employed for the determination of the antimicrobial activities of the ethanol extracts. Gram-positive: Bacillus subtilis, Sarcina lutea, Staphylococcus aureus, Clostridium pyogenes, Enterococcus sp., Micrococcus flavus; Gram-negative: Klebsiella pneumoniae, Pseudomonas aerugionsa, Salmonella enteritidis, Proteus vulgaris, Escherichia coli and fungal organisms: Aspergillus niger, Candida albicans and Saccharomyces cerevisiae were used as test microorganisms. The results of preliminary bioassay demonstrated that the A. alpinus ethanol extract could be a possible source of compounds with antioxidant and antimicrobial activity

Revisiting Synthesis Model of Sparse Audio Declipper

The state of the art in audio declipping has currently been achieved by SPADE (SParse Audio DEclipper) algorithm by Kiti\'c et al. Until now, the synthesis/sparse variant, S-SPADE, has been considered significantly slower than its analysis/cosparse counterpart, A-SPADE. It turns out that the opposite is true: by exploiting a recent projection lemma, individual iterations of both algorithms can be made equally computationally expensive, while S-SPADE tends to require considerably fewer iterations to converge. In this paper, the two algorithms are compared across a range of parameters such as the window length, window overlap and redundancy of the transform. The experiments show that although S-SPADE typically converges faster, the average performance in terms of restoration quality is not superior to A-SPADE

Spasmolytic, Antimicrobial, and Antioxidant Activities of Spray-Dried Extracts of <i>Gentiana asclepiadea</i> L. with In Silico Pharmacokinetic Analysis

This study aimed to evaluate the spasmolytic activity of an underground parts extract of Gentiana asclepiadea L. (Gentianaceae), assess its antioxidant and antimicrobial activities, and explore the impact of extract encapsulation on the aforementioned bioactivities. An extract encapsulated by spray drying with whey protein, pure extract, and pure whey protein were comparatively tested. The main compounds identified via HPLC-DAD analysis underwent in silico ADME assessment. The spasmolytic effect was tested on a model of spontaneous rat ileum contractions, and the mechanism of action was further evaluated on acetylcholine-, KCl-, CaCl2-, BaCl2-, histamine-, N(ω)-nitro-L-arginine methyl ester-, and glibenclamide-modified contractions. The most abundant compounds were secoiridoids (dominantly gentiopicroside), followed by C-glycosylated flavonoids and xanthones. Both pure and encapsulated extracts achieved significant spasmolytic effects, despite the spasmogenic activity of pure whey protein. The extract may exert its spasmolytic effect through multiple pathways, predominantly by antagonizing the Ca2+ channel and opening the K+ channel, while the nitric oxide pathway appears not to be involved. The antimicrobial and antioxidant activities of the pure extract were moderate. The extract stabilized by encapsulation retained all of the tested bioactivities of the unencapsulated extract. The obtained results suggest that G. asclepiadea has potential for use in the treatment of some gastrointestinal complaints and that the encapsulated extract could be a valuable functional ingredient in pharmaceutical and food products

Consistent dictionary learning for signal declipping

Clipping, or saturation, is a common nonlinear distortion in signal processing. Recently, declipping techniques have been proposed based on sparse decomposition of the clipped signals on a fixed dictionary, with additional constraints on the amplitude of the clipped samples. Here we propose a dictionary learning approach, where the dictionary is directly learned from the clipped measurements. We propose a soft-consistency metric that minimizes the distance to a convex feasibility set, and takes into account our knowledge about the clipping process. We then propose a gradient descent-based dictionary learning algorithm that minimizes the proposed metric, and is thus consistent with the clipping measurement. Experiments show that the proposed algorithm outperforms other dictionary learning algorithms applied to clipped signals. We also show that learning the dictionary directly from the clipped signals outperforms consistent sparse coding with a fixed dictionary