From Aloe vera Leaf Waste to the Extracts with Biological Potential: Optimization of the Extractions, Physicochemical Characterization, and Biological Activities

In the study, the optimization of the extraction from Aloe vera leaf waste was performed via varying solid-to-solvent ratio, solvent type, extraction time, and technique (maceration, heat-, ultrasound-, and microwave-assisted extractions—HAE, UAE, and MAE, respectively). The optimal extraction conditions for achieving the highest polyphenol content are a 1:30 ratio, 70% ethanol, and 30 min of HAE. Total flavonoid and protein contents were significantly higher in the extract from MAE, while total condensed tannin content was the highest in HAE. LC-MS analysis quantified 13 anthraquinone and chromone compounds. The variations in the FT-IR spectra of the extracts obtained by different extraction procedures are minor. The influence of extraction conditions on the antioxidant ability of the extracts depended on applied antioxidant assays. The extracts possessed medium inhibition properties against Staphylococcus aureus and weak inhibitory activity against Enterococcus feacalis. The extracts had stimulative effect on HaCaT cell viability. Regarding the extraction yield, there was a significant difference between the used extraction techniques (MAE > HAE > maceration and UAE). The presented study is an initial step in the production of polyphenol-rich extracts from A. vera leaf waste aimed to be used for the potential preparation of pharmaceutical and cosmetic formulations for the skin

Vaccinium myrtillus leaf waste extracts with natural deep eutectic solvent

Vaccinium myrtillus leaf waste extracts were prepared using lactic acid+amonium acetate and maceration, heat- and ultrasound-assisted extractions (HAE and UAE, respectively). The obtained extracts were characterized via analysis of total polyphenol content (TPC), pH, zeta potential, conductivity, density, surface tension, viscosity, and antioxidant potential. The TPC was the highest in the extract prepared in HAE (53.0±0.9 mg GAE/g), whereas the extracts from maceration and UAE possessed significantly lower TPC (50.4±0.7 and 49.5±0.4 mg GAE/g). The ABTS radical scavenging potential was the highest in the extract prepared in HAE (38.4±1.1 µmol TE/g), followed by the extract obtained using UAE (33.7±1.5 µmol TE/g) and maceration (30.2±1.7 µmol TE/g). The DPPH antioxidant capacity followed the same trend: HAE>UAE>maceration. The zeta potential was low in all extracts (2.66±0.48 mV for macerate, 2.57±0.20 mV for HAE, and 3.17±0.13 mV for UAE), while the conductivity was in the range of 1.87±0.13 and 1.84±0.11 mS/cm (maceration and HAE) to 2.10±0.11 mS/cm (UAE). The density varied from 1.105±0.009 g/mL for macerate to 1.122±0.006 and 1.117±0.001 g/mL for HAE and UAE extracts. There were no statistically significant differences in the surface tension and viscosity (~23.5 mN/m and ~5.5 mPa∙s). The highest TPC and antioxidant potential were measured in the extract obtained using HAE, whereas the extract prepared by ultrasound waves possessed the highest zeta potential and conductivity. Therefore, the extraction technique should be chosen depending on the future application of V. myrtillus extract

Vaccinium myrtillus L. Leaf Waste as a Source of Biologically Potent Compounds: Optimization of Polyphenol Extractions, Chemical Profile, and Biological Properties of the Extracts

The aims of the present research include (1) optimization of extraction from Vaccinium myrtillus leaf waste via investigation of plant material:medium ratio, extraction medium, and extraction period, employing extractions at room and high temperatures, or using ultrasound and microwaves (M, HAE, UAE, and MAE, respectively), (2) physicochemical characterization, and (3) investigation of extract biological potential. The statistical analysis revealed that optimal levels of parameters for the greatest polyphenolic yield were a proportion of 1:30 g/mL, ethyl alcohol 50% (v/v) during 2 min of microwave irradiation. By LC-MS analysis, 29 phenolic components were detected; HAE showed the highest richness of almost all determined polyphenols, while chlorogenic acid and quercetin 3-O-glucuronide were dominant. All extracts showed a high inhibition of Staphylococcus aureus growth. The effect of different parameters on extracts’ antioxidant capacity depended on the used tests. The extracts also showed a stimulative influence on keratinocyte viability and anti-inflammatory activity (proven in cell-based ELISA and erythrocyte stabilization assays). The extraction procedure significantly affected the extraction yield (MAE ≥ maceration ≥ UAE ≥ HAE), whereas conductivity, density, surface tension, and viscosity varied in a narrow range. The presented research provides evidence on the optimal extraction conditions and technique, chemical composition, and antioxidant, antimicrobial, anti-inflammatory, and keratinocyte viability properties of bilberry extracts for potential applications in pharmacy and cosmetics

Comparison of maceration and ultrasound-assisted extraction of antioxidant compounds from Vaccinium myrtillus L.

Vaccinium myrtillus L.(Ericaceae), a perennial, wild, and small deciduous shrub that grows in the mountains and forests of Europe, contains anthocyanins, phenolic acids, flavonoids, fatty acids, stilbenes, iridoid glycosides, dietary fibers, vitamins, and minerals. The leaves' extracts are widely used in traditional medicine due to their astringent, antiseptic, antioxidant, anti-inflammatory, skin-rejuvenating, lipid-lowering, hypolipidemic, and hypoglycemic activities. The novel extraction techniques, including ultrasound-assisted extraction, provide various benefits, such as reducing solvent consumption and extraction time and increasing extraction yield, and quality. Hence, in the present study, V. myrtillus extracts were prepared using dried leaves (0.66 g), 50% ethanol as the extraction solvent (20 mL), and maceration (60 min) or ultrasound-assisted extraction (ultrasound probe, amplitude of 60% for 5 min). The obtained extracts were examined in terms of total polyphenol content (TPC) and antioxidant activity (ABTS, DPPH, FRAP, and CUPRAC assays). The TPC of the extract prepared using maceration was 55.2±0.7 mg gallic acid equivalents (GAE)/g of plant material, while the TPC of the extract prepared using an ultrasound probe was 55.6±1.0 mg GAE/g. The DPPH radical scavenging activities of the extracts correlated with the TPC and amounted to 1.81±0.05 mg/mL for macerate and 1.79±0.02 mg/mL for the extract obtained using an ultrasound probe, whereas ABTS antioxidant capacity did not correlate with the polyphenol concentration, 31.4±0.9 µmol Trolox equivalents (TE)/g for the macerate and 43.4±1.1 µmol TE/g for the extract from the ultrasound-assisted extraction. According to the results of FRAP and CUPRAC assays, the antioxidant potential was similar for both extracts (15.3±0.2 and 15.5±0.2 µmol Fe2+/g and 45.7±0.5 and 46.0±0.7 µmol TE/g, respectively). Due to higher ABTS radical scavenging potential and significantly shorter extraction time, V. myrtillus extract prepared using an ultrasound probe was favored. The present research was an initial step in the preparation of V. myrtillus extracts which can be potentially implemented in food, pharmaceutical, and cosmetic formulations

Stabilnost lipozomalnih čestica sa inkapsuliranim ekstraktom majčine dušice

Wild thyme contains biologically active compounds, particularly polyphenols (flavonoids and phenolic acids) that exert antitumor, antimicrobial, anti-inflammatory, antioxidant, immunomodulatory, analgesic, and spasmolytic activities. Nevertheless, the mentioned bioactive compounds have low stability, solubility, and bioavailability, thus their application is limited. Liposomal particles have been widely used for the encapsulation of bioactive components, due to their high structural integrity, stability during storage, and controlled release capability. In the present study, phospholipid-cholesterol liposomal particles, as the carrier for wild thyme extract, were developed. The stability of extract-loaded liposomes was monitored for 21 days by measuring vesicle size, polydispersity index (PDI), and zeta potential. The particle size and PDI of extract-loaded liposomes did not change drastically during 21 days of storage and amounted to ~450 nm and ~0.155, respectively. The zeta potential varied in the liposomes and started to decrease after 7 days of storage (from -21.0 mV to 20.3 mV, without a statistically significant difference), while the zeta potential value after 21 days was statistically significantly lower in comparison to the 1st day (19.3 mV). The beneficial effects of polyphenols on human health, as well as showed storage stability of the prepared liposomes highlight the use of the wild thyme extract-loaded phospholipid-cholesterol liposomal particles for potential application in food, pharmaceutical, and cosmetic industries

Characterization of Vaccinium myrtillus leaf extract-loaded liposomes

Vaccinium myrtillus L. leaves contain bioactive components, such as polyphenols, stilbenes, iridoid glycosides, fatty acids, and fibers. However, polyphenols possess low solubility, stability, and bioavailability, thus the encapsulation of the mentioned active principles in different carriers is necessary. Liposomes are widely used as a carrier for the encapsulation, preservation, and controlled release of polyphenols in various products. Therefore, the aims of the presented research are the development and characterization of V. myrillus leaf extract-loaded liposomes via the determination of encapsulation efficiency, particle size, polydispersity index (PDI), zeta potential, and mobility.ExcellMater Conference 2024: Innovative Biomaterials for Novel Medical Devices, Belgrade, Serbia, April 10-12, 2024

Characterization of Vaccinium myrtillus leaf extract-loaded liposomes

Vaccinium myrtillus L. leaves contain bioactive components, such as polyphenols, stilbenes, iridoid glycosides, fatty acids, and fibers. However, polyphenols possess low solubility, stability, and bioavailability, thus the encapsulation of the mentioned active principles in different carriers is necessary. Liposomes are widely used as a carrier for the encapsulation, preservation, and controlled release of polyphenols in various products. Therefore, the aims of the presented research are the development and characterization of V. myrillus leaf extract-loaded liposomes via the determination of encapsulation efficiency, particle size, polydispersity index (PDI), zeta potential, and mobility.ExcellMater Conference 2024: Innovative Biomaterials for Novel Medical Devices, Belgrade, Serbia, April 10-12, 2024