Krill Phospholipids Research Articles

Kinetic stability and bioavailability of curcumin nanoemulsions stabilized with krill oil phospholipids

Curcumin is a phenolic compound with widely reported bioactive properties. However, its low water solubility leads to low stability and bioavailability. Krill oil (KO) is a rich source of phospholipids naturally structured with omega-3 fatty acids (FA) that emerges as a suggested vehicle for curcumin. This study was aimed to prepare curcumin nanoemulsions (NE) using KO phospholipids as a surfactant to improve the absorption of curcumin after oral ingestion. NE were formulated with i) purified krill phospholipids (PCK), and ii) NE with crude KO without the addition of co-surfactants. As a reference, a NE was formulated using soy phosphatidylcholine (PC). Using 8 % of PCK and 4 cycles of ultrasound, NE with unimodal particle size dispersion were formed. The physicochemical analysis of the NE was monitored for 70 days at 4 and 30 °C; the nanoemulsified curcumin followed first-order degradation kinetics with a half-life (t1/2) for PC, KO, and PCK of 396, 328, and 162 days, respectively. TBARS values reached a maximum of 30 μM for KO and PCK NE, but according to the ABTS method, they had better antioxidant activities (>4.9 μM Trolox). Concerning pharmacokinetics, KO NE displayed the best bioavailability data with an AUC of 684.54 ± 72.62 ng h/mL, increasing five times more its absorption with respect to non-nanoemulsified curcumin. According to our data, NEs can guarantee the stability of curcumin during storage at 4 °C and improve its absorption after oral intake. Indeed, self-emulsified KO NEs enhance the bioavailability of curcumin to the same or better extent than soy PC conventional, but with the advantage of providing functional ingredients (omega-3 FA and astaxanthin).

A comprehensive study of the colloidal properties, biocompatibility, and synergistic antioxidant actions of Antarctic krill phospholipids

Excipient selection is crucial to address the oxidation and solubility challenges of bioactive substances, impacting their safety and efficacy. AKPL, a novel ω-3 polyunsaturated fatty acids (PUFAs) esterified phospholipid derived from Antarctic krill, demonstrates unique antioxidant capabilities and synergistic effects. It exhibits pronounced surface activity and electronegativity at physiological pH, as evidenced by a critical micelle concentration (CMC) of 0.15 g/L and ζ-potential of −49.9 mV. In aqueous environments, AKPL self-assembles into liposomal structures, offering high biocompatibility and promoting cell proliferation. Its polyunsaturated bond-rich structure provides additional oxidation sites, imparting antioxidant properties superior to other phospholipids like DSPC and DOPC. Additionally, AKPL augments the efficacy of lipophilic antioxidants, such as alpha-tocopherol and curcumin, in aqueous media through both intermolecular and intramolecular interactions. In sum, AKPL emerges as an innovative unsaturated phospholipid, offering new strategies for encapsulating and delivering oxygen-sensitive agents.

Protective effect and mechanism insight of purified Antarctic krill phospholipids against mice ulcerative colitis combined with bioinformatics

Antarctic krill oil is functional oil and has a complex phospholipids composition that poses difficulties in elucidating its effect mechanism on ulcerative colitis (UC). The mechanism of UC action was studied by bioinformatics, and the therapeutic effect of Antarctic krill phospholipids (APL) on dextran sulfate sodium (DSS)-induced colitis mice was verified. GO functional enrichment analysis uncovered an enrichment of these genes in the regulation of cell–cell adhesion, membrane region, signaling receptor activator activity, and cytokine activity. Meanwhile, the KEGG results revealed the genes were enriched in the TNF signaling pathway, pathogenic Escherichia coli infection, inflammatory bowel disease and tight junction. Animal experiments showed that APL treatment alleviated the UC symptoms and reduced inflammatory damage. Meanwhile, the expressions of the tight junction (TJ) proteins, ZO-1 and occludin, were restored, and the levels of IL-6 and TNF-α were reduced. Moreover, Firmicutes/Bacteroidetes ratio in the intestinal microbiota was regulated, and the contents of short-chain fatty acids metabolites were raised. These findings would provide an insight for the beneficial effects of APL and dietary therapy strategies for UC.

Selective antibacterial activities and storage stability of curcumin-loaded nanoliposomes prepared from bovine milk phospholipid and cholesterol

Present study prepared curcumin-loaded nanoliposomes using bovine milk, krill phospholipids and cholesterol; and investigated the effects of cholesterol on membrane characteristics, storage stability and antibacterial properties of the curcumin nanoliposomes. Bovine milk phospholipids which have higher saturation than krill phospholipids resulted in formation of curcumin-loaded nanoliposomes with higher encapsulation efficiency (84.78%), larger absolute value of zeta potential and vesicle size (size: 159.15 ± 5.27 nm, zeta potential: −28.3 ± 0.62 mV). Cholesterol helps to formation of a more hydrophobic, compact and tighter bilayer membrane structure which improved the storage stability of nanoliposomes under alkaline (66.25 ± 0.46%), heat (43.25 ± 0.69%) and sunlight (49.44 ± 1.78%) conditions. In addition, curcumin-loaded nanoliposomes can effectively target infectious bacteria which secrete pore-forming toxins such as Staphylococcus aureus by causing the bacterial cell wall to lysis. Findings from present work can guide future development of novel antibacterial agents for use in food preservation.

Monodisperse microsphere-based immobilized metal affinity chromatography approach for preparing Antarctic krill phospholipids followed by HILIC-MS analysis

Phospholipids enriched krill is a functional food beneficial in cardiovascular diseases. Herein, monodisperse microsphere-based immobilized metal affinity chromatographic material (MM-IMAC) was synthesized with Ti4+ incorporated to enrich phospholipids from krill by coordination with phosphate group. The extract was profiled by hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) with 154 phospholipid molecular species detected. The parameters were loading solvent n-hexane/isopropanol (2:8, v/v), flow rate 0.8 mL·min−1, and eluting volume 1 mL. Besides, eicosapentaenoic and docosahexaenoic acids structured phospholipids were located, such as phosphatidylcholine (PC) 20:5/22:6, phosphatidylinositol (PI) 18:0/20:5, etc. Finally, this method was validated in linearity (R2 ≥ 0.9953), sensitivity (LOD ≤ 0.53 μg·mL−1 and LOQ ≤ 1.66 μg·mL−1), precision (RSDintraday ≤ 4.86% and RSDinterday ≤ 6.25%), and recovery (58–83%). It indicated that the MM-Ti4+-IMAC-HILIC-MS was reliable and efficient in specific study of phospholipids in food matrix.

Real-time detection of authenticity and adulteration of krill phospholipids with soybean phospholipids using rapid evaporative ionization mass spectrometry: Application on commercial samples

The functional food ingredient of krill phospholipids are easily adulterated with soybean phospholipids due to their similar appearance and physical behavior. In this study, a novel in-situ method was developed for real-time detection of authenticity and adulteration of krill phospholipids with soybean phospholipids using an electric heating probe based rapid evaporative ionization mass spectrometry (REIMS). The commercial samples could be directly analyzed without preparation. The REIMS conditions were optimized such that the cauterizing duration was 3 s, the temperature of the heating probe was 450 °C and the flow rate of auxiliary solvent was 100 μL min−1. The compositions of krill and soybean phospholipids were analyzed by mass spectrometry, and the obtained data was used to establish the multivariate statistical models. The results indicated that the krill phospholipids could be successfully distinguished from soybean phospholipids with accuracy ≥96.58% on the basis of the characteristic ions of m/z 279.23, 301.22, 629.45, 807.43, 831.43 and 833.44. The effectiveness of these marker ions was proved by blind sample tests. This method provides a reference for evaluating the adulteration of krill phospholipids in the market and expands the application field of REIMS technology.

Curcumin-loaded liposomes prepared from bovine milk and krill phospholipids: Effects of chemical composition on storage stability, in-vitro digestibility and anti-hyperglycemic properties

Present study prepared curcumin liposomes with high encapsulation efficiency (>70%) using bovine milk and krill phospholipids; and investigated the effects of phospholipids composition on storage stability, in-vitro bioavailability, antioxidative and anti-hyperglycemic properties of the curcumin liposomes. Curcumin liposomes prepared from bovine milk phospholipids have smaller particle sizes (163.1 ± 6.42 nm) and greater negative zeta potentials (−26.7 mv) as compared to that prepared from krill phospholipids (particle size: 212.2 ± 4.1 nm, zeta potential: −15.23 mv). In addition, curcumin liposomes from bovine milk phospholipids demonstrated better stability under harsh storage conditions (alkaline conditions, oxygen, high temperature and relative humidity). Nevertheless, curcumin-loaded liposomes prepared from bovine milk phospholipids have inferior bioavailability compared to that prepared from krill phospholipids. No significant differences can be observed in terms of anti-oxidative and anti-hyperglycemic properties of liposomes prepared from both bovine milk and krill phospholipids. Findings from present study will open up new opportunities for development of stable curcumin liposomes with good functional properties (high digestibility, bioavailability and pharmacological effects).

PP.30.17] KRILL OIL PHOSPHOLIPIDS IMPROVE LIPID PROFILE IN HYPERTENSIVE PERSONS

Objective: The aim of this study was to assess the effectiveness of three-month treatment with krill oil phospholipids on lipid profile of persons with arterial hypertension. Design and method: The study comprised 159 persons with arterial hypertension (69 men and 90 women), aged 55.63 ± 10.84 years. All participants were given Krill Oil (500 mg capsules containing 225 mg krill phospholipids) for three months. Lipid status (total cholesterol, LDL-cholesterol, HDL-cholesterol and total triglycerides) was assessed with standard biochemical analysis at the beginning of the study and after three months of krill oil phospholipids therapy. Blood pressure was measured with standard oscillometric device. Regular antihypertensive therapy was not changed during the treatment. Results: Mean systolic blood pressure (SPB) at the beginning of the study was 134.12 ± 16.62 mmHg; mean diastolic blood pressure (DBP) was 81.49 ± 9.58 mmHg. After three months of therapy, mean SBP was similar 135.38 ± 16.86 mmHg, and DBP was similar 82.23 ± 9.56 mmHg. After krill oil phospholipids therapy, total cholesterol decreased from 6.43 to 6.02 mmol/L; the average LDL-cholesterol decreased from 4.09 to 3.76 mmol/L; the average triglycerides decreased from 2.56 to 2.15 mmol/L, whereas the average HDL-cholesterol significantly increased from 1.21 to 1.29 mmol/L. All changes were highly statistically significant. Conclusions: Three-month therapy with krill oil phospholipids significantly improves lipid profile in hypertensive persons.

Biomarkers of bone development and oxidative stress in gilthead sea bream larvae fed microdiets with several levels of polar lipids and α-tocopherol

Although dietary marine phospholipids are able to improve culture performance of marine fish larvae in a further extend than soybean lecithin, both types of phospholipids (PL) markedly increase oxidative risk. The inclusion of a fat-soluble antioxidant such as the vitamin E α-tocopherol could allow a better control of oxidative stress. The objective of this study was to determine the combined effect of graded levels of α-tocopherol with different levels and sources of krill phospholipids (KPL) and soybean lecithin (SBL) on growth, survival, resistance to stress, oxidative status, bone metabolism-related genes expression and biochemical composition of sea bream larvae. Sea bream larvae were completely weaned at 16 dph and fed for 30 days seven microdiets with three different levels of PL (0, 40 and 80 g kg−1 diet) and two of α-tocopherol 1500 and 3000 mg kg−1 diet. Sea bream larvae fed diets without PL supplementation showed the lowest survival, growth and stress resistance, whereas increase in PL, particularly KPL, markedly promoted larval survival and growth. However, feeding SBL markedly increased TBARs and GPX gene expression increasing the peroxidation risk in the larvae. Besides, KPL inclusion improved incorporation of n-3 HUFA and, particularly, EPA into larval tissues, these fatty acids being positively correlated with the expression of BMP-4, RUNX 2, ALP, OC and OP genes and to bone mineralization for a given larval size class. The increase in dietary α-tocopherol tends to improve growth in relation to the n-3 HUFA levels in the diet, denoting the protective role of this vitamin against oxidation. Indeed, dietary α-tocopherol decreased the oxidative stress in the larvae as denoted by the reduction in larval TBARs contents and gene expression of SOD and CAT, but not GPX. Thus, increase in dietary α-tocopherol effectively prevented the formation of free radicals from HUFA, particularly EPA, but did not affect the incidence of bone anomalies or the expression of genes related to osteogenetic processes.

Effect of krill phospholipids versus soybean lecithin in microdiets for gilthead seabream (Sparus aurata) larvae on molecular markers of antioxidative metabolism and bone development

The objective of the present study was to compare the effectiveness of dietary marine phospholipids (MPL) obtained from krill and soybean lecithin (SBL) on the rearing performance and development of seabream (Sparus aurata) larvae. Larvae were fed from 16 to 44 day posthatching (dph) five formulated microdiets with three different levels (50, 70 and 90 g kg–1) of phospholipids (PL) obtained either from an MPL or from a SBL source. Larvae-fed MPL show a higher survival, stress resistance and growth than those-fed SBL, regardless the dietary PL level. Overall, the increase in MPL up to 70 g kg–1 total PL in diet was enough to improve larval gilthead seabream performance, whereas even the highest SBL inclusion level (90 g kg–1 PL) was not able to provide a similar success in larval growth or survival. Inclusion of SBL markedly increased the peroxidation risk as denoted by the higher TBARs in larvae, as well as a higher expression of CAT, GPX and SOD genes. Moreover, SBL tends to produce larvae with a lower number of mineralized vertebrae and a lower expression of osteocalcin, osteopontin and BMP4 genes. Finally, increasing dietary MPL or SBL lead to a better assimilation of polyunsaturated fatty acids in the larvae, n-3HUFA (especially 20:5n-3) or n-6 fatty acids (especially 18:2n-6), respectively. In conclusion, MPL had a higher effectiveness in promoting survival, growth and skeletal mineralization of gilthead seabream larvae in comparison with SBL.

Selenium levels in early weaning diets for gilthead seabream larvae

Abstract The inclusion of complementary antioxidative factors, such as selenium (Se), could counteract the high oxidation risk in early weaning diets high in polyunsaturated fatty acids (PUFA). The present study investigated the effects of graded levels of Se derived yeast with krill phospholipids (KPL) on skeletal development, survival, stress resistance, oxidative status and biochemical composition of seabream larvae. Seabream larvae were completely weaned at 16 dph and fed five microdiets for 30 days with different levels of Se: 2SE, 4SE, 6SE, 8SE and 12SE (1.73, 3.91, 6.41, 8.47, 11.65 mg kg− 1 dietary dry weight, respectively). Increases in Se up to 11.65 mg kg− 1 dietary dry weight significantly improved survival rate (54%) and stress resistance, but did not affect larval growth. Seabream larvae fed diets supplemented with 12SE (11.65 mg kg− 1) showed a gradual increase in this mineral according to dietary Se levels, denoting the progressive absorption of this nutrient. The degree of larval lipid oxidation, as indicated by malondialdehyde (MDA) content and antioxidant enzyme (AOE) gene expression, was significantly lower in larvae fed 8SE and 12SE diets compared to those fed 2SE and 4SE diets. Furthermore, a reactive response as a result of Se inclusion was observed by the increase in osteocalcin, osteonectin, osteopontin, alkaline phosphatase and matrix gla protein gene expression in larval tissues, suggesting a well skeletal development. These results denoted the high efficiency of Se as an antioxidant factor and the importance of the inclusion of adequate levels (11.65 mg Se kg− 1 diet) in early weaning diets.

Optimum krill phospholipids content in microdiets for gilthead seabream (Sparus aurata) larvae

The aim of the present study was to determine the optimum dietary levels of krill phospholipids (KPL) for sea bream (Sparus aurata) larvae, and its influence on larval development and digestive enzymes activity. Larvae were fed five formulated microdiets with five different levels of KPL. Complete replacement of live preys with the experimental microdiets for seabream larvae produced high survival and growth rates, particularly in fish fed the highest levels of KPL. In the present study, increase in dietary KPL up to 120 g kg−1 (100 g kg−1 total PL) significantly improved larval survival and growth, whereas further increase did not improve those parameters. An increase in alkaline phosphatase, trypsin and lipase activity with the elevation of KPL up to 120 g kg−1 was also found denoting a better functioning of digestive system. Besides, there was a linear substrate stimulatory effect of dietary KPL on phospholipase A2 activity. Finally, increasing dietary KPL lead to better assimilation of n-3 HUFA especially eicosapentaenoic acid, reflected in the higher content of these fatty acids in both neutral and polar lipids of the larvae. In summary, KPL were found to be an excellent source of lipids for seabream larvae. Optimum inclusion levels of this ingredient in microdiets to completely substitute live preys at this larval age were found to be 120 g kg−1 KPL.

Potential of three new krill products for seabream larval production

The objective of this study was to evaluate three products derived from krill as sources of essential fatty acids, protein and, particularly, phospholipids in microdiets for larval gilthead seabream (Sparus aurata). Their effect on larval performance, biochemical composition and histological development was investigated. The addition of krill phospholipids, rich in highly unsaturated fatty acids, improved larval sea bream growth in terms of weight and length, enhanced hepatic utilization of dietary lipids and reduced the incidence of enterocyte injuries. These results confirm the higher nutritional value of marine phospholipids for the early development of marine fish larvae in comparison with soybean phospholipids.

Importance of oxidative degradation on peroxide-decomposing activities of antarctic krill phospholipids.

The peroxide-decomposing activity of Antarctic krill Euphausia superba lipid was studied. Chromatographic analysis by silicic acid showed that krill phospholipids are mainly composed of phosphatidyl choline (PC) with phosphatidyl ethanolamine, lysoPC and oxygenated polar materials. All chromatographic fractions showed varying activity in the decomposition of methyl linoleate hydroperoxides. In order to elucidate the mechanism of peroxide degradation, the tion, partial hydrolysis and oxidation for different periods of time. With hydrogenation, peroxidedecomposing activity was lost and the browning of PC was inhibited as well, With the progress of oxidation, both the peroxide-decomposing activity and the browning of PC were enhandced. Hydrolysis of any part of PC decreased the peroxide-decomposing activity. These results suggest that oxidative degradation is necessary for phospholipids to show peroxide-decomposing activity.