Stabilization of Black Locust Flower Extract via Encapsulation Using Alginate and Alginate–Chitosan Microparticles

Black locust flower extract contains various polyphenols and their glucosides contribute to the potential health benefits. After intake of these bioactive compounds and passage through the gastrointestinal tract, their degradation can occur and lead to a loss of biological activity. To overcome this problem, the bioactive compounds should be protected from environmental conditions. This study aimed to encapsulate the black flower extract in the microparticles based on biodegradable polysaccharides, alginate, and chitosan. In the extract, the total antioxidant content was found to be 3.18 ± 0.01 g gallic acid equivalent per 100 g of dry weight. Also, the presence of lipids (16), phenolics (27), organic acids (4), L-aspartic acid derivative, questinol, gibberellic acid, sterol, and saponins (2) was confirmed using the UHPLC–ESI–MS analysis. In vitro assays showed that the extract has weak anti-α-glucosidase activity and moderate antioxidant and cytotoxic activity against the HeLa cell line. The extrusion method with secondary air flow enabled the preparation of microparticles (about 270 μm) encapsulated with extract. An encapsulation efficiency of over 92% was achieved in the alginate and alginate–chitosan microparticles. The swelling study confirmed a lower permeability of alginate–chitosan microparticles compared with alginate microparticles. For both types of microparticles, the release profile of antioxidants in the simulated gastrointestinal fluids at 37 °C followed the Korsmeyer–Peppas model. A lower diffusion coefficient than 0.5 indicated the simple Fick diffusion of antioxidants. The alginate–chitosan microparticles enabled a more sustained release of antioxidants from extract compared to the alginate microparticles. The obtained results indicated an improvement in the antioxidant activity of bioactive compounds from the extract and their protection from degradation in the simulated gastric conditions via encapsulation in the polymer matrixes. Alginate–chitosan showed slightly slower cumulative antioxidant release from microparticles and better antioxidant activity of the extract compared to the alginate system. According to these results, alginate–chitosan microparticles are more suitable for further application in the encapsulation of black locust flower extract. Also, the proposed polymer matrix as a drug delivery system is safe for human use due to its biodegradability and non-toxicity

Procedure for extraction of ellagic acid from lady`s mantles (Alchemilla vulgaris L.) RS-P-2017/0289.

Pronalazak se odnosi na nov postupak ekstrakcije elaginske kiseline iz herbe biljne vrste gospin plašt (Alchemilla vulgaris L.). Postupak ekstrakcije pokazuje neočekivanu selektivnost za elaginsku kiselinu, dok je sadržaj drugih jedinjenja ispod granica detekcije. Ispitivanja ekstrakta A. vulgaris pokazuju zadovoljavajuću antioksidativnu aktivnost, a određen je i sadržaj ukupnih flavonoida. Dobijeni ekstrakt herbe A. vulgaris može biti primenjen kao prirodni aditiv u prehrambenoj, kozmetičkoj i farmaceutskoj industriji, jer ima jak antioksidativni i zaštitni efekat.Решење о признању патента 990 број 2019/8183-П-2017/0289 од 14.05.2019. објава патента: Гласник интелектуалне својине 5/2019, Завод за интелектуалну својину, Република Србија. (RS 58657 B1

Hemijski sastav i biološka aktivnost ekstrakta semena šljive

The aim of this paper was to estimate the biological activity of the plum seed extract and to define the chemical composition by using the ESI-MS method. During the investigation of the antioxidant activity, the extract showed a better ability to inhibit DPPH radicals compared with amygdalin standard. The results of the antimicrobial study indicate that the extract has a greater effect on Gram-negative bacteria compared with amygdalin. Gram-positive bacteria and fungi remained resistant in both cases. Unlike amygdalin, the extract showed a greater antimicrobial activity against the same microbiological strains. Amygdalin was isolated from the extract before the investigation of antiproliferative activity against MDA-MB-361, MDA-MB-453, HeLa and LS174 cell lines using MTT assay. Unlike the MDA-MB-453 cell line, the activity of standard and isolated amygdalin was not observed at the concentrations lower than 400 μg cm-3 on MDA-MB-361 cell line. The isolated amygdalin has not shown the activity in other cell lines. The antiproliferative activity of amygdalin standard was also noticed on HeLa and LS-174 cell lines at the concentrations of 333.27 and 333.17 μg cm-3, respectively.Cilj ovog rada bila je procena biološke aktivnosti ekstrakta semena šljive i definisanje hemijskog sastava primenom ESI-MS metode. Tokom ispitivanja antioksidativne aktivnosti, ekstrakt je pokazao bolju sposobnost inhibiranja DPPH radikala u poređenju sa standardom amigdalina. Rezultati antimikrobne studije pokazali su da ekstrakt ima veći uticaj na rast Gram-negativnih bakterija u odnosnu na amigdalin. Gram-pozitivne bakterije i gljivice ostale su rezistentne u oba slučaja. Za razliku od amigdalina, ekstrakt je pokazao veću antimikrobnu aktivnost na iste sojeve mikroorganizama. Amigdalin je izolovan iz ekstrakta pre ispitivanja antiproliferativne aktivnosti na MDA-MB-361, MDA-MB-453, HeLa i LS174 ćelijskim linijama upotrebom MTT testa. Za razliku od MDA-MB-453 ćelijskih linija, aktivnost standarda i izolovanog amigdalina nije uočena na MDA-MB-361 ćelijskim linijama pri koncentracijama nižim od 400 μg cm-3. Izolovani amigdalin nije pokazao aktivnost na ostalim ćelijskim linijama. Antiproliferativna aktivnost standarda amigdalina uočena je i na HeLa i LS-174 ćelijskim linijama pri koncentracijama 333.27 i 333.17 μg cm-3, respektivno

Postupak primene termoosetljivih hidrogelova za modifikovano oslobađanje elaginske kiseline

Pronalazak se odnosi na novu primenu hidrogelova poli(N-izopropilakrilamid-ko-2-hidroksipropilmetakrilata), p(NIPAM-HPMet)-a i poli(N-izopropilakrilamida), p(NIPAM)-a, kao nosača za modifikovano oslobađanje elaginske kiseline i ekstrakta Alchemilla vulgaris L. sa visokim sadržajem elaginske kiseline. Analiza FTIR spektara homopolimera p(NIPAM)-a i kopolimera p(NIPAM-HPMet)-a sa uklopljenim standardom elaginske kiseline i ekstraktom Alchemilla vulgaris L., ukazuju na formiranje intermolekulskih vodoničnih veza između lanaca homopolimera, tj. kopolimera, s jedne strane i elaginske kiseline, s druge strane. Hidrogelovi p(NIPAM) i p(NIPAM-HPMet) su se pokazali kao pogodni nosači elaginske kiseline, jer omogućavaju njeno modifikovano oslobađanje

Risks in the Role of Co-Creating the Future of Tourism in “Stigmatized” Destinations

The primary goal of this paper was to investigate the strength of the influence of different types of risk on the travelers’ intention to visit destinations in future, that are, prejudiced due to COVID-19, marked as “stigmatized”, “isolated”, or “risky destinations”. Field interview research was conducted at the “Belgrade Nikola Tesla Airport” (Serbia). The results obtained by multiple regression analysis showed that all types of risks influenced the intention of travelers, with financial risk showing a more significant impact. Canonical discriminant analysis indicated that men were most afraid of human induced risk, service quality risk, natural disaster and COVID-19 risk, and they chose safer destinations. Among the women, the biggest fear was financial risk, socio-psychological risk, and food safety risk. Older respondents and those under the influence of external factors decided on safer destinations, while financial status did not play a significant role in predicting the choice of destination. The selection of the destination according to the degree of security was determined by the ordinal regression methodology. The entire research presents a certain novelty, because so far in the numerous studies on the topic of the negative consequences of COVID-19 on tourism, there has been no discussion of stigmatized or risky destinations that received that epithet, and were therefore negatively and unfairly marked in the minds of tourists for future visits

Optimization of the Microwave-Assisted Extraction of Caffeine from Roasted Coffee Beans

This study aimed to develop a fast procedure for caffeine extraction from roasted coffee beans. The microwave-assisted extraction was carried out in the microwave oven with an operating frequency of 2450 MHz. The response surface methodology based on a Box–Behnken design was used to model and optimize the extraction process. Among the analyzed extraction parameters (factors), the influence of extraction time (2–6 min), liquid-to-solid ratio (5–15 mL/g), and microwave power (336–595 W) were considered, while the yield of extracted caffeine was observed as the response of the system. Water was used as the solvent of choice for the extraction of caffeine. The optimum conditions were as follows: extraction time, 2 min; liquid-to-solid ratio, 15 mL/g; and microwave power, 500 W. In this optimized condition, the expected extraction yield of caffeine was 1.01 g/100 g dry weight (value confirmed by experimental assays). The total energy consumed of 1.7 kWh/100 g of purified caffeine indicated a more energy-efficient procedure by about 1200–15,000 times than the reported procedures. This study showed that caffeine can be quantitatively extracted from roasted coffee beans through a green approach and that the isolated caffeine has a high purity degree, which was confirmed by the UHPLC-ESI-MS/MS method. With this quality, isolated caffeine could be further used as an active ingredient in the food industry, while for pharmaceutical purposes, it must be further purified

Modeling and optimization of bioactive compounds from chickpea seeds (Cicer arietinum L)

The aim of study was to model and optimize the extraction of polyphenols and flavonoids with expressed antioxidant activity from chickpea seeds using a central composite design. The optimal extraction conditions were the extraction time of 145.5 min, ethanol concentration of 83.7% and liquid-to-solid ratio of 24.9 (expressed as cm(3) per g). The content of total polyphenol and flavonoid was 2.75 g gallic acid equivalent per kilogram of the dried extract and 0.147 g rutin equivalent per kilogram of the dried extract, respectively. Using 2,2-diphenyl-1-picrylhydrazyl assay, it was found that the optimal extract had the IC50 of 1.55 mg cm(-3)

Preparation and Characterization of Alginate Hydrogels with High Water-Retaining Capacity

Hydrogels are very attractive materials due to their multifunctional properties. Many natural polymers, such as polysaccharides, are used for the preparation of hydrogels. The most important and commonly used polysaccharide is alginate because of its biodegradability, biocompatibility, and non-toxicity. Since the properties of alginate hydrogel and its application depend on numerous factors, this study aimed to optimize the gel composition to enable the growth of inoculated cyanobacterial crusts for suppressing the desertification process. The influence of alginate concentration (0.1–2.9%, m/v) and CaCl2 concentration (0.4–4.6%, m/v) on the water-retaining capacity was analyzed using the response surface methodology. According to the design matrix, 13 formulations of different compositions were prepared. The water-retaining capacity was defined as the system response maximized in optimization studies. The optimal composition of hydrogel with a water-retaining capacity of about 76% was obtained using 2.7% (m/v) alginate solution and 0.9% (m/v) CaCl2 solution. Fourier transform infrared spectroscopy was used for the structural characterization of the prepared hydrogels, while the water content and swelling ratio of hydrogels were determined using gravimetric methods. It was concluded that alginate and CaCl2 concentrations play the most important role regarding the gelation time, homogeneity, water content, and swelling ratio of the hydrogel

ESTIMATION OF THE POSSIBILITY FOR FURTHER APPLICATION OF ETHANOLIC FRACTION OBTAINED DURING ALGINATE PRODUCTION FROM BROWN SEAWEED BIOMASS

The first stage in alginate production is the depigmentation and defatting of brown seaweed biomass using 70% (v/v) ethanol. The obtained ethanolic fraction is discarded from the further production process as a side product. Having in mind these facts, this study aimed to valorize the ethanolic extract generated during the alginate extraction from brown seaweed (Laminaria digitata). The possibility of valorization of the extract was estimated based on the determination of the total phenolic and flavonoid content, and the antioxidant activity. For the extract, the total phenolic and flavonoid content was 29.3 g gallic acid equivalent per 100 g dry weight and 1.49 g rutin equivalent per 100 g dry weight, respectively. The results of the DPPH assay showed that the extract exhibited antioxidant activity with the IC50 value of 42.9 μg/mL. The antioxidant activity of the extract was almost the same as for synthetic antioxidant butylated hydroxytoluene (IC50 = 36.6 μg/mL). The obtained results indicated that the brown seaweed extract represents the source of phenolic compounds that have an expressed antioxidant activity. This approach is important because it utilizes the extract as the secondary raw material for the recovery of valuable compounds that can be significant as a starting raw material in various branches of industry

Improvement of Alginate Extraction from Brown Seaweed (<i>Laminaria digitata</i> L.) and Valorization of Its Remaining Ethanolic Fraction

This study aimed to improve the conventional procedure of alginate isolation from the brown seaweed (Laminaria digitata L.) biomass and investigate the possibility of further valorization of the ethanolic fraction representing the byproduct after the degreasing and depigmentation of biomass. The acid treatment of biomass supported by ultrasound was modeled and optimized regarding the alginate yield using a response surface methodology based on the Box–Behnken design. A treatment time of 30 min, a liquid-to-solid ratio of 30 mL/g, and a treatment temperature of 47 °C were proposed as optimal conditions under which the alginate yield related to the mass of dry biomass was 30.9%. The use of ultrasonic radiation significantly reduced the time required for the acid treatment of biomass by about 4 to 24 times compared to other available conventional procedures. The isolated alginate had an M/G ratio of 1.08, which indicates a greater presence of M-blocks in its structure and the possibility of forming a soft and elastic hydrogel with its use. The chemical composition of the ethanolic fraction including total antioxidant content (293 mg gallic acid equivalent/g dry weight), total flavonoid content (14.9 mg rutin equivalent/g dry weight), contents of macroelements (the highest content of sodium, 106.59 mg/g dry weight), and microelement content (the highest content of boron, 198.84 mg/g dry weight) was determined, and the identification of bioactive compounds was carried out. The results of ultra high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry analysis confirmed the presence of 48 compounds, of which 41 compounds were identified as sugar alcohol, phenolic compounds, and lipids. According to the 2,2-diphenyl-1-picrylhydrazyl assay, the radical scavenging activity of the ethanolic fraction (the half-maximal inhibitory concentration of 42.84 ± 0.81 μg/mL) indicated its strong activity, which was almost the same as in the case of the positive control, synthetic antioxidant butylhydroxytoluene (the half-maximal inhibitory concentration of 36.61 ± 0.79 μg/mL). Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus) were more sensitive to the ethanolic fraction compared to Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei). The obtained results indicated the possibility of the further use of the ethanolic fraction as a fertilizer for plant growth in different species and antifouling agents, applicable in aquaculture