Characterization and antioxidant potential of a carotenoid from a newly isolated yeast

Carotenoid pigments of Kocuria flava PUTS1_3 isolated from sediments of Puttalam lagoon mangrove ecosystem, Sri Lanka exhibit bioactive properties

Microorganisms, inhabiting various ecological niches, exhibit a capacity to produce a diverse array of pigments with different shades. These colorful microbial pigments may also potentially possess beneficial bioactivities. This dual functionality together with the ease of mass production and downstream processing has shifted the global attention towards the use of microbially-derived pigments as bioactive colorants in different industries. Therefore, the present study was conducted with the aim of characterizing the pigments from Kocuria flava and identifying their potential biotechnological applications. The bacterium, PUTS1_3, was isolated using the surface sediment samples from the Puttalam mangrove ecosystem, Sri Lanka and it was identified as Kocuria flava using 16S rRNA gene sequencing. The yellow, intracellular pigment of PUTS1_3 was obtained by treating the cell pellet with methanol. Characterization of the pigment extract using UV-visible spectroscopy, TLC, and HPLC confirmed the presence of three carotenoid compounds, including β-carotene. The pigment extract also demonstrated antibacterial activity, against Gram positive bacteria tested. Antioxidant properties were observed with an IC50 value of 181.95 ± 4.57 µg/ml in the DPPH free radical scavenging assay. Although its sun protection factor was comparatively low (SPF 7.69 ± 0.01), the pigment showed promising results as a textile dye demonstrating good color performance and stability in washing and pH stability tests. Moreover, fabrics dyed with the pigment extract displayed antibacterial activity against Staphylococcus aureus (ATCC 25923). These findings suggest the potential use of the yellow pigments of K. flava PUTS1_3 for various biotechnological applications.

Natural Pigments-Based Two-Component White Light Emitting Systems

In this paper, a new class of two component white light emitting systems viz, JaB (java plum + beetroot) {I}, and CaB (carrot + beetroot) {II} were developed through resonance energy transfer (RET) phenomenon by using a fruit (java plum) and two vegetable (carrot and beetroot) extracts. In these white light emitting systems, java plum and carrot are the donors while beetroot is the acceptor. The primary fluorescent pigments present in the natural extracts (i.e., anthocyanin in java plum, β-carotene in carrot, and betanin in beetroot) were responsible for the white light emission. The CIE (Commission Internationale d'Eclairage) coordinates for I and II were {0.32, 0.34} and {0.33, 0.33}, respectively, in solution phase. Interestingly, the white light emission (WLE) was also achieved in agar-agar gel medium. In gel medium, the CIE values were {0.31, 0.34} and {0.33, 0.32} for I and II, respectively. The donor-acceptor distance (r) for I and II were found to be 0.5 and 0.4 nm, respectively. Furthermore, the rate of energy transfer was also quantified with the values of 2.78 × 109 s-1 for JaB (I) and 1.02 × 108 s-1 for CaB (II) systems. The mechanistic investigation of the two white light systems was further supported by DFT studies.

Extraction and characterization of carotenoid pigments with antioxidant and antibacterial potential from marine yeast Rhodotorula sp. KSB1

Pigments are coloring agents used widely in different industrial sectors. There is a demand for using natural pigments rather than synthetic dyes because of the health hazards caused by synthetic dyes. Many natural pigments have different medicinal activities which can contribute to the nutritional value of the product. This study was carried forward with marine yeasts which can produce pigments. A total of 4 marine yeast isolates were recovered from the mangrove area of Sundarbans, West Bengal, India. Among them, the isolate KSB1 produced 856 µg/g total concentration of carotenoid pigment and the dry mass weight was 3.56 g/L. The stability of the extracted pigments was checked using temperature, pH, UV light exposure time, and different saline conditions. The pigments were characterized using HPLC and FTIR analysis. All of the extracted pigments showed good antioxidant activity in DPPH, metal chelating, and reducing power assay. The pigments were also found to have good antibacterial activity against the bacterial pathogens Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli. Carotenoid pigment from KSB1 was found to have maximum activity in all the pathogens. The cytogenotoxicity using onion roots and phytotoxicity analysis indicated that the pigments were non-toxic and safe for cells. Finally, the potential marine yeast was identified using 18 s rRNA sequencing and identified as Rhodotorula sp. KSB1 (Accession no. MH782232).

Direct Extraction of Lipids, β-Carotene, and Polyphenolic Compounds from Wet Microalga Dunaliella salina by Liquefied Dimethyl Ether

Extraction of lipids and high-value products from highly wet microalgae requires significant energy for the drying pretreatment. In this study, we examined the direct extraction of lipids, β-carotene, and polyphenolic compounds from wet Dunaliella salina using liquefied dimethyl ether (DME), which is effective in lipid extraction for biofuel production. The amount of DME-extracted β-carotene was 7.0 mg/g, which was higher than that obtained from the chloroform-methanol extraction. Moreover, the total phenolic content extracted with DME and its antioxidant capacity were slightly higher than those extracted with chloroform-methanol. DME removed almost all the water and extracted 29.2 wt% of total lipids and 9.7 wt% of fatty acids. More lipids were extracted from wet samples by liquefied DME than by chloroform-methanol extraction. The C/N ratio of lipids extracted with DME was 112.0, higher than that of chloroform-methanol. The high C/N ratio suggests that nitrogen-containing phosphatidylcholines may be less easily extracted by liquefied DME and may be highly selective. However, the ratio of saturated fatty acids was 34.8%, lower than that of chloroform-methanol. Na+ and Mg2+ in the culture medium were not extracted using DME. Thus, using the extract with DME has both advantages and disadvantages compared to using the extract with chloroform-methanol; however, it has satisfactory extraction properties. DME is expected to be an environment-friendly alternative solvent because it does not require drying, which is necessary for conventional extraction solvents.

Enhancement of skin localization of β-carotene from red fruit (Pandanus conoideus Lam.) using solid dispersion-thermoresponsive gel delivered via polymeric solid microneedles

Red fruit (Pandanus conoideus Lam.) boasts high β-carotene (BC) content, often consumed orally. However, absorption issues and low bioavailability due to food matrix interaction have led to transdermal delivery exploration. Nevertheless, BC has a short skin retention time. To address these limitations, this study formulates a β-carotene solid dispersion (SD-BC) loaded thermoresponsive gel combined with polymeric solid microneedles (PSM) to enhance in vivo skin bioavailability. Characterization of SD-BC includes saturation solubility, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and in vitro release. Characterization of SD-BC thermoresponsive gel includes gelation temperature, viscosity, rheological behaviour, pH, bio-adhesiveness, spreadability, and extrudability. PSM's mechanical properties and insertion capability were assessed. Ex vivo and in vivo dermato-pharmacokinetic studies, drug content, hemolysis, and skin irritation assessments were conducted to evaluate overall performance. Results confirm amorphous SD-BC formation, enhancing solubility. Both SD-BC thermoresponsive gel and PSM exhibit favourable characteristics, including rheological properties and mechanical strength. In vitro release studies showed a seven-fold increase in BC release compared to plain hydrogel. SD-BC thermoresponsive gel combined with PSM achieves superior ex vivo permeation (Cmax = 305.43 ± 32.07 µg.mL-1) and enhances in vivo dermato-pharmacokinetic parameters by 200-400 %. Drug content, hemolysis, and skin irritation studies confirmed its safety and non-toxicity.

Romanian Wild-Growing Chelidonium majus-An Emerging Approach to a Potential Antimicrobial Engineering Carrier System Based on AuNPs: In Vitro Investigation and Evaluation

Novel nanotechnology based on herbal products aspires to be a high-performing therapeutic platform. This study reports the development of an original engineering carrier system that jointly combines the pharmacological action of Chelidonium majus and AuNPs, with unique properties that ensure that the limitations imposed by low stability, toxicity, absorption, and targeted and prolonged release can be overcome. The metabolite profile of Romanian wild-grown Chelidonium majus contains a total of seventy-four phytochemicals belonging to eight secondary metabolite categories, including alkaloids, amino acids, phenolic acids, flavonoids, carotenoids, fatty acids, sterols, and miscellaneous others. In this study, various techniques (XRD, FTIR, SEM, DLS, and TG/DTG) were employed to investigate his new carrier system's morpho-structural and thermal properties. In vitro assays were conducted to evaluate the antioxidant potential and release profile. The results indicate 99.9% and 94.4% dissolution at different pH values for the CG-AuNPs carrier system and 93.5% and 85.26% for greater celandine at pH 4 and pH 7, respectively. Additionally, three in vitro antioxidant assays indicated an increase in antioxidant potential (flavonoid content 3.8%; FRAP assay 24.6%; and DPPH 24.4%) of the CG-AuNPs carrier system compared to the herb sample. The collective results reflect the system's promising perspective as a new efficient antimicrobial and anti-inflammatory candidate with versatile applications, ranging from target delivery systems, oral inflammation (periodontitis), and anti-age cosmetics to extending the shelf lives of products in the food industry.

Impact of hypromellose acetate succinate and Soluplus® on the performance of β-carotene solid dispersions with the aid of sorbitan monolaurate: In vitro-in vivo comparative assessment

Solid dispersions (SDs) possess the potential to enhance the bioavailability of insoluble active pharmaceutical ingredients (APIs) by effectively converting them into amorphous state. However, SDs have a tendency to recrystallize unless appropriate excipients are employed. The objective of this study was to evaluate the ability of hypromellose acetate succinate HF (HPMCAS-HF) and Soluplus® to inhibit the recrystallization of β-carotene and improve its in vivo bioavailability through the fabrication of ternary β-carotene solid dispersions (SDs) with the aid of specific surfactant. Due to rapid micellization, the dissolution profiles of β-carotene SDs based on HPMCAS-HF/Span 20 (5:5, w/w) or Soluplus®/Span 20 (6:4, w/w) combinations exhibited significant improvement, which were almost 7-10 times higher than β-carotene bulk powder. DSC and PXRD analysis indicated a notable reduction in the crystallinity degree of β-carotene within the SDs. The stability study demonstrated a half-life of β-carotene in the SDs exceeding 30 days. Additionally, the in vivo pharmacokinetics analysis confirmed that the cellulose derivatives/surfactant combinations significantly enhanced the bioavailability of β-carotene by 1.37-fold and 2.3-fold, respectively. Notably, the HPMCAS-HF/Span 20 combination exhibited superior performance. Consequently, the HPMCAS-HF/Span 20 combination held potential for the advancement of an effective drug delivery system for β-carotene.

Untargeted Metabolomic Approach of Curcuma longa to Neurodegenerative Phytocarrier System Based on Silver Nanoparticles

Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits have been appreciated and exploited in traditional Asian medicine since ancient times. Various studies have investigated its complex chemical composition and demonstrated the remarkable therapeutic properties of curcuma's phytoconstituents. Oxidative stress is a decisive driving factor triggering numerous pathologies (neurodegenerative, psychiatric and cardiovascular diseases; diabetes; tumors, etc.). Numerous recent studies have focused on the use of natural compounds and nanomaterials as innovative molecular targeting agents as effective therapeutic strategies. In this study, we report, for the first time, the development of a simple target phytocarrier system that capitalizes on the bioactive properties of curcuma and AgNPs. The complete metabolic profile of curcuma was determined based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS). A total of 80 metabolites were identified under mass spectra (MS)-positive mode from 10 secondary metabolite categories: terpenoids, amino acids, diarylheptanoids, flavonoids, phenolic acids, steroids, fatty acids, coumarins, alkaloids and miscellaneous. In addition, the biological activity of each class of metabolites was discussed. A comprehensive characterization (FT-IR, UV-Vis, DLS, SEM, TEM, EDS, zeta potential and XRD) was performed to study the morphostructural properties of this new phytocarrier system. Antioxidant activity of the new phytocarrier system was evaluated using a combination of in vitro methods (total phenolic assay, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and cyclic voltammetric method (Trolox equivalent antioxidant capacity (TEAC) electrochemical assay)). Antioxidants assays showed that the phytocarrier system exhibits superior antioxidant properties to those of its components, i.e., curcuma or citrate-coated-AgNPs. These data confirm the potential to enhance relevant theoretical knowledge in the area of innovative antioxidant agents, with potential application in neurodegenerative therapeutic strategies.

Enhanced antibacterial activity of Rosehip extract-functionalized Mg(OH)2 nanoparticles: An in vitro and in vivo study

The development of nanoparticles as antimicrobial agents against pathogenic bacteria has emerged as one of the leading global healthcare challenges. In this study, Mg(OH)₂ NPs with controlled morphology and nanometric size, using two distinct counterions, chloride or nitrate, have been synthesized using Rosehip (RH) extract that has privileges beyond conventional chemical and physical methods. Various physicochemical techniques were used to characterize the RH-functionalized Mg-based NPs. They exhibited a spherical shape with a diameter of ~10 nm, low crystallinity compared to non-functionalized NPs, high polyphenol content, and negative zeta potential in three different media (H₂O, TSB, and cell medium). The resulting RH-functionalized Mg-based NPs also exhibited an increased antibacterial activity against Gram-positive (S. Epidermis and S. aureus) and Gram-negative (E. Coli) bacteria compared to those prepared in pure water (0 % RH), an effect that was well evident with low NPs contents (250 μg/mL). A preliminary attempt to elucidate their mechanism of action revealed that RH-functionalized Mg-based NPs could disrupt cellular structures (bacterial cell wall and cytoplasmic membrane) and damage the bacterial cell, as confirmed by TEM imaging. Noteworthy is that Mg-based NPs exhibited higher toxicity to bacteria than to eukaryotic cells. More significantly, was their enhanced in vivo efficacy in a Galleria mellonella invertebrate animal model, when infected with S. aureus bacteria. Overall, our findings indicate that well-engineered Rosehip magnesium-based nanoparticles can be used as a green non-cytotoxic polyphenolic source in different antibacterial applications for the biomedical industry.

Improving solubility and stability of β-carotene by microencapsulation in soluble complexes formed with whey protein and OSA-modified starch

In this study, a soluble complex formed between 0.5% (w/v) heated whey protein isolate (HWPI) and 5% (w/v) octenyl succinic anhydride (OSA)-modified starch at pH 4.5 was used to encapsulate β-carotene for improving its solubility and stability. The apparent aqueous solubility of β-carotene was increased markedly (264.05 ± 72.53 μg/mL) after encapsulation in the soluble complex. Transmission electron microscopy and scanning electron microscopy were used to evaluate the effect of the encapsulation of β-carotene on the structure of the soluble complex. Fourier transform infrared spectroscopy showed that the characteristic peaks of β-carotene disappeared in the soluble complex, suggesting that β-carotene may have been encapsulated into the soluble complex via hydrophobic interactions. X-ray diffraction indicated that the β-carotene was in an amorphous form within the soluble complex. An accelerated stability test showed that the soluble complex could effectively improve the chemical stability of β-carotene during long-term storage under low pH conditions.

Self-Assembled Micelles Based on OSA-Modified Starches for Enhancing Solubility of β-Carotene: Effect of Starch Macromolecular Architecture

Self-assembled micelles based on octenyl succinic anhydride (OSA)-modified starch were prepared to enhance the solubility of β-carotene. The critical micelle concentration (CMC) was lower for OSA-modified starch with a lower molecular weight (Mw) or higher degree of substitution (DS). Above the CMC, OSA-modified starch assembled into spherical micelles with an average hydrodynamic diameter of <20 nm, as determined by dynamic light scattering (DLS). All the radii of gyration ( R_g), obtained from Guinier fitting of small-angle X-ray scattering (SAXS) data, were between 3 and 9 nm, and they were positively correlated with the Mw but negatively correlated with both the DS and the starch concentration. β-Carotene was encapsulated effectively into the starch micelles, and the concentration of β-carotene in the micelles was positively correlated with the concentration, Mw, and DS of the starch, with a maximum value of 53.14 μg/mL. The incorporation of β-carotene enlarged the hydrophobic core and induced a significant increase in the R_g of the micelles determined by SAXS, and it may have also promoted the aggregation of the micelles resulting in a marked increase in the D_h determined by DLS.