Concentration of Gamma-Linolenic and Stearidonic Acids as Free Fatty Acids and Ethyl Esters from Viper's Bugloss Seed Oil by Urea Complexation

Solid-state fermentation produces greater stearidonic acid levels in genetically engineered Mucor circinelloides

Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) are important dietary components due to their health benefits and preventative role in cardiovascular disease. Fish-based and plant seed oils are rich in stearidonic acid (SDA; 18:4 n-3) which are readily metabolized into ω-3 PUFAs such as eicosapentaenoic acid. However, these natural sources of SDA are generally low yielding and are unlikely to meet global demands, so new sustainable microbial fermentative sources of SDA need to be identified. Expression of delta15-desaturase in the oleaginous filamentous fungus Mucor circinelloides (McD15D) has been used to construct a recombinant SDA-producing McD15D strain that produces 5.0% SDA levels using submerged fermentation conditions. Switching to solid-state fermentation conditions in the same medium with submerged fermentation resulted in this engineered strain producing significantly higher amounts of SDA. A Box-Behnken design (BBD) of response surface methodology (RSM) approach has been used to identify optimal glucose and ammonium tartrate concentrations and temperature levels to maximize SDA production. The use of these optimal solid-state fermentation conditions resulted in the spores and mycelium of the recombinant McD15D producing 19.5% (0.64 mg g^-1 ) and 12.2% (1.52 mg g^-1 ) SDA content respectively, which represents an overall increase in SDA yield of 188.0% when compared to SDA yields produced using submerged fermentation conditions.

A new urea adducts method for PUFA concentration using green food grade solvents and avoiding ethyl carbamate formation

This study aimed to selectively enrich stearidonic acid (SDA) together with γ-linolenic acid (GLA) in Echium plantagineum oil by urea complexation. The complexation process at room temperature was carried out replacing common organic solvents, such as hexane and ethanol, by alternative compounds, included in Green Solvent and Food Grade categories, adapting this process towards the principles of Green Chemistry. This substitution was also intended to avoid the generation of the toxic compound ethyl carbamate. Among all the solvents studied, the mixture propionic acid and α-pinene provided the best results, leading to a final product comprised of ∼99% of PUFA, with ∼45% SDA (∼14% in the original oil), and without apparition of ethyl carbamate. The procedure was tested on other raw materials (salmon and microalgae oils). The solvent was efficiently recuperated from the liquid phase (∼87% recovery) and reutilized once with almost identical results.

α-Linolenic and γ-linolenic acids exercise differential antitumor effects on HT-29 human colorectal cancer cells

α-Linolenic acid (ALA, 18:3n-3) and γ-gamma linolenic acid (GLA, 18:3n-6) are polyunsaturated fatty acids (PUFA) that improve the human health. The present study focused on testing the in vitro antitumor actions of pure ALA and GLA on the HT-29 human colorectal cancer cell line. Cell viability was checked by MTT ((3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, cell membrane damage by the lactate dehydrogenase assay, apoptosis was tested by both caspase-3 activity trial and transmission electron microscopy images, and protein composition was analyzed by quantitative proteomics analysis. MTT test revealed IC₅₀ values of 230 and 255 μM for ALA and GLA, respectively, at 72 h. After 24 h of incubation, both ALA and GLA induced apoptosis on HT-29 colorectal cancer cells according to the caspase-3 assay and microscopy images. SWATH/MS analysis evidenced that ALA significantly affected the mitochondrial protein import pathway and the citric acid cycle pathway, while GLA did not significantly affect any particular pathway. In summary, both ALA and GLA showed concentration-dependent inhibitory effects on HT-29 cells viability and induced cell death by apoptosis. ALA significantly affected cellular pathways, while GLA does not have specific actions on either pathway. Both n-3 and n-6 C18 PUFA are bioactive food components useful in the colorectal cancer prevention.

The dietary c9,t11-conjugated linoleic acid enriched from butter reduces breast cancer progression in vivo

The c9,t11-conjugated linoleic acid (CLA), which is the minor polyunsaturated fatty acid (PUFA) naturally present in butter, has gained attention due to its important preventive effect against breast cancer in vitro. In this paper, the enrichment of c9,t11-CLA from butter was optimized and the preventive effect of dietary c9,t11-CLA against breast cancer in vivo was investigated. Results showed that the concentration of c9,t11-CLA increased more than 10 times via a one-step urea complexation. Furthermore, the dietary c9,t11-CLA showed obvious preventive effect against breast cancer in decreasing the tumor weight and volume, and reducing the tumor incidence up to 50%. In addition, the expression of progesterone receptor and Ki-67 decreased significantly with the treatment of c9,t11-CLA. In conclusion, the dietary c9,t11-CLA enriched from butter showed a preventive effect against breast cancer in vivo via the inhibition of the hormonal receptor and cell proliferation. PRACTICAL APPLICATIONS: This paper provided new insight into the preparation of specific c9,t11-CLA isomer. It can be enriched from butter in large-scale with low-cost by urea complexation. Meanwhile, the enriched dietary c9,t11-CLA can be further processed into cancer prevention functional foods.