Simultaneous production of algal biomass and lipid by heterotrophic cultivation of linoleic acid-rich oleaginous microalga Chlorella sorokiniana using high acetate dosage.

The low-cost carbon source, acetate, was utilized to feed a linoleic acid-rich Chlorella sorokiniana for microalgal biomass and lipid accumulation. Remarkably high tolerance capability to high acetate dosage up to 30 g/L was observed, with heterotrophy being the preferred trophic mode for algal growth and lipogenesis when supplemented 20 g/L acetate. Transcriptome analysis revealed a marked activation of pathways involved in acetate bioconversion and lipogenesis upon exposure to high-level of acetate. However, the enhancement of photorespiration inhibited photosynthesis, which ultimately led to a decrease in biomass and lipid under mixotrophy. Heterotrophic acetate-feeding generated more superior amino acid profiling of algal biomass and a predominant linoleic acid content (50 %). Heterotrophic repeat fed-batch strategy in 5 L fermenter significantly increased the growth performance and lipid titer, with the highest levels achieved being 23.4 g/L and 7.0 g/L, respectively. This work provides a viable approach for bio-products production through acetate-based heterotrophic algal cultivation.

Impact of Lycium barbarum arabinogalactan on the fecal metabolome in a DSS-induced chronic colitis mouse model.

Ulcerative colitis (UC) is often accompanied by the dysbiosis of gut microbiota and metabolism. Our previous study indicated that arabinogalactan from Lycium barbarum (LBP-3) could markedly attenuate the symptoms of chronic UC in mice by modulating the structure of gut microbiota. This study explored the impact of LBP-3 on the fecal metabolomic profiling of the same cohort of mice by HPLC-TripleTOF/MS. Untargeted metabolomic analyses indicated that supplementation with LBP-3 markedly reversed 18 of the 48 differential metabolites (mainly belonging to amino acids and organic acids) disturbed by DSS. Targeted metabolomics revealed that the lower levels of tryptophan, lysine, diiodothyronine, kynurenine, and betaine and higher levels of phenylalanine, leucine, glutamine, isoleucine, homoserine, (S)-2-hydroxyglutarate, 2-isopropylmalic acid, ascorbic acid, gluconic acid, and taurine, which were caused by DSS induction, were reversed by LBP-3 treatment. In addition, pathway analysis showed that the pentose phosphate pathway, phenylalanine metabolism, ascorbate and aldarate metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis were strongly affected by LBP-3. More importantly, the above amino acids, organic acids, and metabolic pathways changed by LBP-3 were correlated with the abundance of gut microbiota such as Turicibacter, Lactobacillus, Parasutterella, Odoribacter, Veillonella, Faecalibacterium, and Ruminococcaceae. This study advances our understanding of the interaction between the microbiome and metabolomics in DSS-induced chronic colitis after LBP-3 treatment.

Arabinogalactan derived from Lycium barbarum fruit inhibits cancer cell growth via cell cycle arrest and apoptosis.

Previous studies have shown that crude polysaccharides from the Lycium barbarum fruit could inhibit cancer cell growth, but the major effective constituents are yet to be identified. In this study, we compared the effects of L. barbarum fruit polysaccharide fractions on the growth of hepatoma cells (SMMC-7721 and HepG2), cervical cancer cells (HeLa), gastric carcinoma cells (SGC-7901), and human breast cancer cells (MCF-7). LBGP-I-3 showed stronger inhibitory effects on MCF-7 cells (cell viability of 48.96%) than SMMC-7721 (cell viability of 78.91%) and HeLa cells (cell viability of 55.94%), and had no effect on HepG2 and SGC-7901 cells. In addition, LBGP-I-3 had no inhibitory effect on normal liver cells (L02, cell viability of 115.58%). Investigation of the underlying mechanism suggested that LBGP-I-3 inhibited the growth of cancer cells by cell cycle arrest and apoptosis. LBGP-I-3 arrested the cell cycle at the G0/G1 phase, altered mitochondrial function, activated oxidative stress, and regulated the MAPK signaling pathway to induce apoptosis. Thus, LBGP-I-3 may be a potential functional food ingredient for the prevention of cancer without toxicity to normal cells in vitro. These results could help further elucidate the structure-activity relationship of L. barbarum fruit polysaccharides and functional food development.

Lycium barbarum polysaccharides extend the mean lifespan of Drosophila melanogaster.

The fruits of Lycium barbarum are considered medicinal foods with high nutritional value and bioactivity. In this study, we aimed to evaluate the effect of a crude L. barbarum polysaccharide (LBP) and two derived fractions, LBP-1 and LBP-2, on the lifespan of Drosophila melanogaster (fruit fly). The average lifespan of fruit flies was extended by supplementing their diet with either of the three LBP preparations. In vivo analysis of antioxidant activities detected increased superoxide dismutase (SOD) and catalase (CAT) activities and decreased malondialdehyde (MDA) levels. Dietary LBP supplements significantly reduced the mortality rate of fruit flies induced by paraquat and hydrogen peroxide. Importantly, the strongest anti-aging activity was exhibited by the LBP-2 fraction, containing arabinogalactan with a molecular weight of 9 × 104 Da. Further studies showed that the anti-aging activity of LBP was, at least in part, mediated by an age-related signaling pathway (MAPK, TOR, S6K) and the expression of longevity genes (Hep, MTH, and Rpn11).

Preparation, structural characterization and bioactivity of 4-O-Methylglucuronoxylan from Artemisia sphaerocephala Krasch.

We obtained four soluble acid xylan fractions AGP-III-A, AGP-III-B, AGP-III-C and AGP-III-D from the insoluble Artemisia sphaerocephala Krasch gum (ASKG) polysaccharide by weak alkali treatment combined with H2O2-Vc oxidative degradation. Activity studies showed that the degradation components could reduce the cell viability of several cancer cell lines in a concentration-dependent manner, especially 4-O-Methylglucuronoxylan AGP-III-C with specific molecular weight and branching degree significantly reduced cancer cells viability and induced HepG2 apoptosis, also caused mitochondrial membrane dysfunction upregulated ROS levels, and induced G0/G1 arrest in HepG2 cells by cell cycle assay. Further, AGP-III-C mediates apoptosis in HepG2 cells by upregulating MAPK phosphorylation. The structure of AGP-III-C was characterized by uronic acid reduction, permethylation with GC-MS, and 2D-NMR analysis. The structure of AGP-III-C had a linear (1→4)-linked ß-Xylf residue backbone with one branched 4-O-Me-α-GlcAp attached to the main chain by a (1→2)-glycosidic bond at every two ß-(1→4)-Xylf units.

Physicochemical properties, antioxidant activity and immunological effects in vitro of polysaccharides from Schisandra sphenanthera and Schisandra chinensis.

Schisandra sphenanthera and Schisandra chinensis are widely consumed either as food or for medicinal purposes. Nevertheless, no detailed comparative assessments of their physicochemical properties and biological activity have been reported. In this paper, using hot-water extraction, alcohol precipitation, and deproteinization, we obtained polysaccharidic extracts from Schisandra sphenanthera and Schisandra chinensis (denoted as SSP and SCP, respectively) and investigated their antioxidant and immunological activities. The extracts were different from each other with regard to sugar, protein, and uronic acid contents. Both extracts were mainly composed of arabinose, glucose, and galactose, but their contents varied greatly; SSP had more galacturonic acid. Compared with SCP, SSP had stronger free radical scavenging ability, protective effects on biomolecules, cellular antioxidant activity, owing to its higher protein (35.35 ±â€¯1.73%) and uronic acid (12.81 ±â€¯1.15%) contents. With respect to cell viability, neutral red phagocytosis, NO production, and acid phosphatase activity, SCP had stronger effects than SSP; this was largely due to its high levels of mannose, galactose, arabinose, and glucose. These results provide evidence to support the use Schisandra-derived polysaccharides for several purposes, including clinical, agricultural, and industrial applications.

Physicochemical properties and biological activities of polysaccharides from Lycium barbarum prepared by fractional precipitation.

Traditional separation and purification process of Lycium barbarum polysaccharides (LBP) includes water extraction, alcohol precipitation, deproteinization and ion-exchange column chromatography, which is complicated and time-consuming. In our study, retentate LBP-I and dialysate LBP-O were obtained from LBP by water extraction, alcohol precipitation and deproteinization. LBP-I was separated by fractional precipitation and three fractions (LBP-I-1, LBP-I-2 and LBP-I-3) were obtained. The three fractions were further purified by gel permeation chromatography to LBGP-I-1, LBGP-I-2 and LBGP-I-3 with yields of 0.05%, 0.03%, and 0.19%, respectively, which are higher than yields by traditional method. The physicochemical properties, biological activities of LBGP-I-1, LBGP-I-2 and LBGP-I-3 were investigated. The results indicated that LBGP-I-1 (3.19 × 104 Da) consists of arabinose (21.95%), glucose (51.22%) and galactose (17.07%); LBGP-I-2 (2.92 × 104 Da) mainly consists of arabinose (19.35%), glucose (32.26%) and galactose (35.48%); LBGP-I-3 (9.12 × 104 Da) mainly consists of arabinose (48.15%) and galactose (44.44%). LBGP-I-1 and LBGP-I-2 were different from the components purified by traditional method. LBGP-I-3 could most significantly enhance macrophages NO, phagocytic capacity, and acid phosphatase. LBP-O exhibits the strongest anti-oxidant activities in vitro. These results provided a reference for applications of Lycium barbarum polysaccharides which would benefit the development of industry and agriculture.

Purification and activity characterization of polysaccharides in the medicinal lichen Umbilicaria tornata from Taibai Mountain, China.

Water-soluble polysaccharides from Umbilicaria tornata (UTP) were purified and preliminarily characterized. The antioxidant and antitumor activities of crude UTP and two purified fractions (UTP-1 and UTP-2) were evaluated using in vitro experiments. The results showed that the molecular weights of UTP-1 and UTP-2 were 84.86 and 28.66 kDa, respectively. Both UTP-1 and UTP-2 were composed of glucose and xylose, with their molar ratios being 1.3:0.9 and 0.9:4.6, respectively. In addition, crude UTP, UTP-1 and UTP-2 showed dose-dependent DPPH and hydroxyl radical scavenging and reducing activities. However, crude UTP exhibited stronger antioxidant activity than UTP-1 and UTP-2, particularly in terms of DPPH radicals. Crude UTP and the two purified fractions inhibited the growth of HeLa, HepG2, A375, MCF-7, SGC7901 and Caco2 cancer cells in vitro. Compared with UTP-1 and UTP-2, crude UTP presented significantly higher antitumor activity in vitro against HeLa and HepG2 cells (p < 0.05). These findings provide a scientific basis for the deeper exploration and resource development of U. tornata.