Poly-Unsaturated Fatty Acids (PUFAs) from Cunninghamella elegans Grown on Glycerol Induce Cell Death and Increase Intracellular Reactive Oxygen Species

Cunninghamella elegans NRRL-1393 is an oleaginous fungus able to synthesize and accumulate unsaturated fatty acids, amongst which the bioactive gamma-linolenic acid (GLA) has potential anti-cancer activities. C. elegans was cultured in shake-flask nitrogen-limited media with either glycerol or glucose (both at ≈60 g/L) employed as the sole substrate. The assimilation rate of both substrates was similar, as the total biomass production reached 13.0-13.5 g/L, c. 350 h after inoculation (for both instances, c. 27-29 g/L of substrate were consumed). Lipid production was slightly higher on glycerol-based media, compared to the growth on glucose (≈8.4 g/L vs. ≈7.0 g/L). Lipids from C. elegans grown on glycerol, containing c. 9.5% w/w of GLA, were transformed into fatty acid lithium salts (FALS), and their effects were assessed on both human normal and cancerous cell lines. The FALS exhibited cytotoxic effects within a 48 h interval with an IC50 of about 60 μg/mL. Additionally, a suppression of migration was shown, as a significant elevation of oxidative stress levels, and the induction of cell death. Elementary differences between normal and cancer cells were not shown, indicating a generic mode of action; however, oxidative stress level augmentation may increase susceptibility to anticancer drugs, improving chemotherapy effectiveness.

Chemical Composition of Essential Oils of Aromatic and Medicinal Herbs Cultivated in Greece-Benefits and Drawbacks

The current study investigated and determined the major compounds of six essential oils derived from different plant species cultivated in Greece (Lavandula angustifolia, Origanum vulgare, Pistacia lentiscus var. chia, Citrus reticulata, Citrus limon and Crithmum maritimum). The results proved that all these essential oils have a high potential for use as food preservatives, since among the compounds determined were sabinene, b-myrcene, a-pinene, carvacrol and limonene, all of which were responsible for the strong antimicrobial activity against Staphylococcus aureus. However, the amounts of some compounds, such as linalool and citral, were at high levels, and this can be a danger for some sensitive population groups due to allergic reactions. The essential oil compounds which were identified using GC-MS and quantified through GC-FID represented more than 95% of the total essential oils of the investigated plant species. Finally, all essential oils provided high phenolic content.

Impact of olive mill wastewaters on the physiological behavior of a wild-type new Ganoderma resinaceum isolate

A new wild-type Ganoderma resinaceum isolate was cultivated on glucose-enriched liquid cultures with olive mill wastewaters (OMWs) in initial phenolic compounds concentrations 0.0 (control), 0.5, 0.8, and 1.5 g/l. The effect of the fungus on the reduction of phenolics and color was assessed, whereas biomass production, glucose consumption, intra-cellular (IPS) and extra-cellular (EPS) polysaccharides biosynthesis, antioxidant activity of the biomass, and laccase synthesis were monitored. Results showed that significant phenolic reduction (94.5%) and decolorization (76.5%) occurred, 14.6 g/l of biomass was produced, glucose was almost totally consumed, EPS were produced in sufficient amounts (0.79 g/l), whereas the presence of OMWs enhanced the synthesis of IPS (maximum absolute values 4.0-5.2 g/l corresponding to 35-42% w/w). Kinetic analysis demonstrated that EPS and IPS values fluctuated with time, regardless of the available amount of glucose in the media, showing a maximum in the 17th day of culture. Laccase was highly synthesized in the middle of the fermentation, reaching the maximum value of 14 U/ml. Little growth was however observed at 1.5 g/l phenolics. Strong correlation between total phenolic content and free radical scavenging activity has been noticed in the methanolic extracts of the mycelium. Results strongly suggest the potentiality of G. resinaceum utilization in the OMW waste treatment.

Affinity Crystallography Reveals Binding of Pomegranate Juice Anthocyanins at the Inhibitor Site of Glycogen Phosphorylase: The Contribution of a Sugar Moiety to Potency and Its Implications to the Binding Mode

Anthocyanins (ACNs) are dietary phytochemicals with an acknowledged therapeutic significance. Pomegranate juice (PJ) is a rich source of ACNs with potential applications in nutraceutical development. Glycogen phosphorylase (GP) catalyzes the first step of glycogenolysis and is a molecular target for the development of antihyperglycemics. The inhibitory potential of the ACN fraction of PJ is assessed through a combination of in vitro assays, ex vivo investigation in hepatic cells, and X-ray crystallography studies. The ACN extract potently inhibits muscle and liver isoforms of GP. Affinity crystallography reveals the structural basis of inhibition through the binding of pelargonidin-3-O-glucoside at the GP inhibitor site. The glucopyranose moiety is revealed as a major determinant of potency as it promotes a structural binding mode different from that observed for other flavonoids. This inhibitory effect of the ACN scaffold and its binding mode at the GP inhibitor binding site may have significant implications for future structure-based drug design endeavors.

Varietal and Geographical Discrimination of Greek Monovarietal Extra Virgin Olive Oils Based on Squalene, Tocopherol, and Fatty Acid Composition

Extra virgin olive oil (EVOO) is an important component of the Mediterranean diet and a highly priced product. Despite the strict legislation to protect it from fraudulent practices, there is an increasing demand to characterize EVOOs and evaluate their authenticity. For this purpose, 68 monovarietal EVOOs, originating from three regions of Greece (Peloponnese, Crete, and Lesvos) and two local cultivars (Koroneiki and Kolovi), were obtained during the harvesting period of 2018-2019. Fatty acids, squalene, and tocopherols were determined chromatographically according to official methods in order to study the effect of cultivar and geographical origin. Squalene and γ-tocopherol differed significantly amongst the cultivars tested. Koroneiki samples exhibited higher squalene content than Kolovi samples, whereas the opposite was observed for γ-tocopherol. The tocopherol level was highly geographical dependent, with EVOOs from Peloponnese displaying the highest concentration of α-tocopherol, whereas the content of γ-tocopherol was significantly higher in samples from Lesvos. Unsupervised and supervised multivariate analysis resulted in a satisfactory grouping of EVOOs according to cultivar. γ-Tocopherol, squalene, and the majority of fatty acids were the most discriminant variables, with γ-tocopherol, linoleic, linolenic, and gadoleic acid being present at higher levels in samples from the Kolovi cultivar. Koroneiki samples were characterized with higher levels of squalene, palmitic, palmitoleic, and arachidic acid.

Gas Chromatography-Mass Spectrometry-Based Metabolite Profiling for the Assessment of Freshness in Gilthead Sea Bream (Sparus aurata)

Gilthead sea bream (Sparus aurata) is one of the most important farmed Mediterranean fish species, and there is considerable interest for the development of suitable methods to assess its freshness. In the present work, gas chromatography–mass spectrometry-based metabolomics was employed to monitor the hydrophilic metabolites of sea bream during storage on ice for 19 days. Additionally, the quality changes were evaluated using two conventional methods: sensory evaluation according to European Union’s grading scheme and K-value, the most widely used chemical index of fish spoilage. With the application of chemometrics, the fish samples were successfully classified in the freshness categories, and a partial least squares regression model was built to predict K-value. A list of differential metabolites were found, which were distinguished according to their evolution profile as potential biomarkers of freshness and spoilage. Therefore, the results support the suitability of the proposed methodology to gain information on seafood quality.

Investigation of Anthocyanins Stability from Pomegranate Juice (Punica Granatum L. Cv Ermioni) under a Simulated Digestion Process

Background: Pomegranate gained a widespread popularity as a functional food due to the high content of bioactive components of the whole fruit, as well as its juice and extracts. There is a large amount of research that assigns them very important functions for the human organism. Methods: The anthocyanins (ACNs) of pomegranate juice (PJ) from the Ermioni variety are quantitatively identified and their stability under a simulated digestion process (SDP) is investigated. ACNs, as well as phenolic compounds, were isolated through solid phase extraction and determined using high-performance liquid chromatography in every stage of the SDP. Total phenolics, total monomeric ACNs, polymeric color and antioxidant activity were also determined in pomegranate juice and during the digestion process. Results: The predominant anthocyanin was Cy-3-glucoside followed by the corresponding 3,5-diglucoside, which accounted for 40.8% and 27.4% of the total ACN content, respectively. About 65% of the total monomeric ACN content remained intact by the end of the simulated digestion process. Conclusions: The PJ of the Ermioni variety seems to retain a large amount of the bioactive compounds after the SDP. The antioxidant activity and total phenolic content (TPC) remain almost stable during the SDP, suggesting that the products formed during ACN degradation maintain the antioxidant activity of the parent molecule.

Lipid production and characterization by Mortierella (Umbelopsis) isabellina cultivated on lignocellulosic sugars

AIMS

To study and characterize the lipids produced by Mortierella (Umbelopsis) isabellina, during its growth on mixtures of glucose and xylose.

METHODS AND RESULTS

Glucose and xylose were utilized as carbon sources, solely or in blends, under nitrogen-limited conditions, in batch-flask trials (initial sugars at 80 g l^-1 ). Significant lipid production (maximum lipid 17·8 g l^-1 ; lipid in DCW 61·0% w/w; lipid on glucose consumed 0·23 g g^-1 ) occurred on glucose employed solely, while xylose concentration in the growth medium was conversely correlated with lipid accumulation. With increasing xylose concentrations into the blend, lipid storage decreased while xylitol in significant concentrations (up to 24 g l^-1 ) was produced. Irrespective of the sugar blend employed, significant quantities of endopolysaccharides were detected in the first growth steps (in the presence of nitrogen into the medium or barely after its disappearance) while lipids were stored thereafter. Neutral lipids, mainly composed of triacylglycerols, were the main microbial lipid fraction. Phospholipids were quantified both through fractionation and subsequent gravimetric determination and also through determination of phosphorus, and it seemed that the second method was more accurate. Phospholipids were mainly composed of phosphatidylcholine and another nonidentified compound presumably being phosphatidyldimethylethanolamine.

CONCLUSIONS

Mortierella isabellina is suitable to convert lignocellulosic sugars into lipids.

SIGNIFICANCE AND IMPACT OF THE STUDY

Differentiations between metabolism on xylose and glucose were reported. Moreover, this is one of the first reports indicating extensive analysis of microbial lipids produced by M. isabellina.