Isolation, characterization, and immunological effects of alpha-galacto-oligosaccharides from a new source, the herb Lycopus lucidus Turcz

Application of an α-galactosidase from Bacteroides fragilis on structural analysis of raffinose family oligosaccharides

Raffinose family oligosaccharides (RFOs) have diverse structures and exhibit various biological activities. When using RFOs as prebiotics, their structures need to be identified. If we first knew whether an RFO was classical or non-classical, structural identification would become much easier. Here, we cloned and expressed an α-galactosidase (BF0224) from Bacteroides fragilis which showed strict specificity for hydrolyzing α-Gal-(1 → 6)-Gal linkages in RFOs. BF0224 efficiently distinguished classical from non-classical RFOs by identifying the resulting hydrolyzed oligo- and mono-saccharides with HPAEC-PAD-MS. Using this strategy, we identified a non-classical RFO from Pseudostellaria heterophylla (Miquel) Pax with DP6 (termed PHO-6), as well as a classical RFO from Lycopus lucidus Turcz. with DP7 (termed LTO-7). To characterize these RFO structures, we employed four other commercial or reported α-galactosidases in combination with NMR and methylation analysis. Using this approach, we elucidated the accurate chemical structure of PHO-6 and LTO-7. Our study provides an efficient analytical approach to structurally analyze RFOs. This enzyme-based strategy also can be applied to structural analysis of other glycans.

Prebiotics for depression: how does the gut microbiota play a role?

Depression, a mood disorder characterized by persistent feelings of sadness and aversion to activity that can interfere with daily life, is a condition of great concern. Prebiotics, which are non-digestible substances selectively utilized by host microorganisms for health benefits, have gained attention for their potential to improve overall wellness and alleviate various disorders including depression. This study aims to review clinical trials utilizing carbohydrate-type prebiotics such as inulin-type fructans, galactooligosaccharides (GOS), human milk oligosaccharides, resistant starch, prebiotic phytochemicals including epigallocatechin gallate (EGCG), chlorogenic acids, resveratrol, and prebiotic lipids (n-3 polysaturated fatty acids) to determine their effects on depression. Our findings suggest that GOS at a daily dosage of 5 g and eicosapentaenoic acid at or less than 1 g can effectively mitigate depressive symptoms. While EGCG exhibits potential antidepressant properties, a higher dosage of 3 g/d may be necessary to elicit significant effects. The plausible mechanisms underlying the impact of prebiotics on depression include the synthesis of neurotransmitters, production of short-chain fatty acids, and regulation of inflammation.

Purification and identification of oligosaccharides from Cimicifuga heracleifolia Kom. rhizomes

Even though Cimicifuga sp. is widely used in functional foods around the world, the content and structure of its oligosaccharides remain unclear. Here, we isolated a mixture of oligosaccharides from Cimicifuga heracleifolia Kom. rhizomes with a yield of 9.5% w/w. Twenty-six oligosaccharide monomers from the mixture were purified using optimized SEC and HILIC techniques. The oligosaccharides were identified as belonging to two groups by using HPAEC-PAD, MALDI-TOF-MS, NMR and GC-MS methylation analyses. One group belongs to sucrose and inulin type fructo-oligosaccharides (FOS) {β-d-Fruf-(2 → 1)-[β-d-Fruf-(2 ↔ 1)]_n=1-12-α-d-Glcp} with a 3-14 degree of polymerization (DP). Oligosaccharides in the other group belong to the inulo-n-ose type FOS {β-d-Fruf-(2 → 1)-[β-d-Fruf-(2 → 1)]_m=0-12-β-d-Frup} with a DP of 2-14. This appears to be the first time that these oligosaccharides have been purified from Cimicifuga heracleifolia Kom., thus providing useful information concerning the utilization of Cimicifuga heracleifolia Kom. in functional foods.

Lycopus lucidus Turcz Water Extract Ameliorates the Metabolic Disorder by Up-Regulated Major Urinary Protein Expression in High-Fat Diet-Induced Obesity

Despite a century of research on obesity, metabolic disorders and their complications, including dyslipidemia, insulin resistance, and fatty liver disease remain a serious global health problem. Lycopus lucidus Turcz (LT) is a traditional medicine used for its anti-inflammatory properties that has not been evaluated for its efficacy in improving obesity. In this study, mice were fed a normal diet (n = 10) or obesity was induced with a high-fat diet (HFD, n = 20, 60% kcal from fat) for 4 weeks. The HFD mice were then divided into two groups, one of which received LT supplementation with water extract for 13 weeks [HFD (n = 10) or HFD with LT water extract (n = 10, 1.5%)]. LT reduced body and adipose tissue weight by elevating energy expenditure by increasing fatty oxidation in epididymal white adipose tissue (eWAT) and muscle. LT ameliorated dyslipidemia and hepatic steatosis by restricting lipogenesis. Additionally, LT normalized the impaired glucose homeostasis by diet-induced obesity to improve pancreatic islet dysfunction with increasing hepatic major urinary protein expression. Moreover, LT attenuated the inflammation and collagen accumulation in the liver and eWAT. In conclusion, these results suggest that LT can treat obesity-related metabolic disorders such as adiposity, dyslipidemia, hepatic steatosis, insulin resistance, and inflammation.

Pimarane Diterpenoids from Aerial Parts of Lycopus lucidus and Their Antimicrobial Activity

The ethyl acetate fraction obtained from aerial parts of L. lucidus was subjected for isolation of new bioactive compounds, which enabled isolation of five new pimarane-type diterpenoids, namely, 3β, 8β, 12β, 18-tetrahydroxy pimar-15-ene (10), 7α, 8β, 12β, 18-tetrahydroxy pimar-15-ene (11), 3β, 8β, 11β, 12α, 18-pentahydroxy pimar-15-ene (12), 12β acetoxy, 8β, 3β, 18-trihydroxy pimar-15-ene (13), and 3β acetoxy, 8β, 12β, 18-trihydroxy pimar-15-ene (14), along with nine known compounds. The structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated new pimarane diterpenoids were examined for antimicrobial activity against Gram-negative and Gram-positive bacteria strains. Among them, the compound 3β, 8β, 12β, 18-tetrahydroxy pimar-15-ene (10) was most effective, exhibiting minimum inhibitory concentration (MIC) values of 15.62 µg/mL against Staphylococcus epidermidis, 31.25 µg/mL against Staphylococcus aureus, 62.5 µg/mL against Pseudomonas aeruginosa, and 125 µg/mL against Escherichia coli.

Probiotics, Prebiotics and Postbiotics on Mitigation of Depression Symptoms: Modulation of the Brain-Gut-Microbiome Axis

The brain–gut–microbiome axis is a bidirectional communication pathway between the gut microbiota and the central nervous system. The growing interest in the gut microbiota and mechanisms of its interaction with the brain has contributed to the considerable attention given to the potential use of probiotics, prebiotics and postbiotics in the prevention and treatment of depressive disorders. This review discusses the up-to-date findings in preclinical and clinical trials regarding the use of pro-, pre- and postbiotics in depressive disorders. Studies in rodent models of depression show that some of them inhibit inflammation, decrease corticosterone level and change the level of neurometabolites, which consequently lead to mitigation of the symptoms of depression. Moreover, certain clinical studies have indicated improvement in mood as well as changes in biochemical parameters in patients suffering from depressive disorders.

Structural Characterization and Immunomodulatory Activity of a Novel Polysaccharide From Lycopi Herba

Lycopi Herba has been broadly used as a traditional medicinal herb in Asia due to its ability to strengthen immunity. However, it is still obscure for its material basis and underlying mechanisms. Polysaccharide, as one of the most important components of most natural herbs, usually contributes to the immunomodulatory ability of herbs. Here, we aimed to detect polysaccharides from Lycopi Herba and examine their potential immunomodulatory activity. A novel polysaccharide (LHPW) was extracted from Lycopi Herba and purified by DEAE-52 cellulose chromatography and G-100 sephadex. According to physicochemical methods and monosaccharide composition analysis, LHPW was mainly composed of galactose, glucose, fructose, and arabinose. NMR and methylation analyses indicated that LHPW was a neutral polysaccharide with a backbone containing →3,6)-β-D-Galp-(1→, →4)-β-D-Galp-(1→ and →4)-α-D-Glcp-(1→, with the branches of →1)-β-D-Fruf-(2→ and →6)-α-D-Galp-(1→. Immunological tests indicated that LHPW could activate macrophage RAW264.7 and promote splenocyte proliferation. This study discovered a novel polysaccharide from Lycopi Herba and showed it was a potential immunomodulator.

In Vitro and In Silico Studies of Soluble Epoxide Hydrolase Inhibitors from the Roots of Lycopus lucidus

Soluble epoxide hydrolase (sEH) is an enzyme that is considered a potential therapeutic target in human cardiovascular disease. Triterpenes (1–4) and phenylpropanoids (5–10) were isolated from Lycopus lucidus to obtain sEH inhibitors through various chromatographic purificationtechniques. The isolated compounds were evaluated for their inhibitory activity against sEH, and methyl rosmarinate (7), martynoside (8), dimethyl lithospermate (9) and 9″ methyl lithospermate (10) showed remarkable inhibitory activity, with the IC₅₀ values ranging from 10.6 ± 3.2 to 35.7 ± 2.1 µM. Kinetic analysis of these compounds revealed that 7, 9 and 10 were competitive inhibitors bound to the active site, and 8 was the preferred mixed type inhibitor for allosteric sites. Additionally, molecular modeling has identified interacting catalytic residues and bindings between sEH and inhibitors. The results suggest that these compounds are potential candidates that can be used for further development in the prevention and treatment for cardiovascular risk.

Protective effects of α-galacto-oligosaccharides against a high-fat/western-style diet-induced metabolic abnormalities in mice

In this study, we investigated the effects of a newly synthesized α-galacto-oligosaccharide mixture (α-GOSg), 0.5% in drinking water, on high-fat/western-style diet (HFWD)-induced metabolic abnormality in mice in a study of 13 weeks. Raffinose family oligosaccharides (RFOs) were included as a comparison. Mice treated with α-GOSg had significantly lower body weight and body fat (p < 0.05), while RFOs were less effective. Both α-GOSg and RFOs significantly reduced serum levels of total cholesterol and low-density lipoprotein cholesterol, alanine aminotransferase and liver lipids. However, only α-GOSg significantly decreased the histopathological score for liver steatosis and downregulated hepatic fatty acid synthesis gene acetyl CoA carboxylase-α. α-GOSg also significantly reduced the content of bile acids in the small intestine and significantly increased the abundance of gut Bifidobacterium and decreased the abundance of Clostridium leptum. These actions are proposed to be key mechanisms contributing to the beneficial health effects of α-GOSg.

Immunomodulatory Effects of Enzymatic-Synthesized α-Galactooligosaccharides and Evaluation of the Structure-Activity Relationship

In this study, α-galactooligosaccharides (α-GOSs) were synthesized using galactose as the substrate and α-galactosidase from Aspergillus niger as the catalyst. In the reaction, synthesized products of U1, U2, U3, and U4 were detected by high-performance liquid chromatography. By mass spectrometry, nuclear magnetic resonance, and 1-phenyl-3-methyl-5-pyrazolone derivatization, U1 was the mixture of disaccharides of α-d-Gal p-(1→1)-α-d-Gal, α-d-Gal p-(1→2)-α-d-Gal, α-d-Gal p-(1→3)-α-d-Gal, α-d-Gal p-(1→4)-α-d-Gal, U2 was identified to be α-d-Gal p-(1→6)-α-d-Gal, U3 was the mixture of galactotrisaccharides linked by one α-(1→6)-glycosidic linkage and one other α-glycosidic linkage, and U4 was identified as α-d-Gal p-(1→6)-α-d-Gal p-(1→6)-α-d-Gal. Afterward, the synthesized α-GOSs (U1, U2, U3, U4, and their mixture) as well as α-GOSs (manninotriose, stachyose, ciceritol, and verbascose) obtained from natural materials were used as subjects to evaluate their immunomodulatory effects in vitro by culturing mouse macrophage RAW264.7 cells. The results showed that α-GOS with a higher degree of polymerization had better immunomodulatory activity, while to a certain extent, α-GOS linked with α-(1→6)-galactosidic linkage showed a better immunomodulatory effect.

Protective effect of free phenolics from Lycopus lucidus Turcz. root on carbon tetrachloride-induced liver injury in vivo and in vitro

Protective effect of free phenolics from Lycopus lucidus Turcz. root (FPLR) on CCl₄-induced hepatotoxicity in vivo and in vitro was first evaluated. Oral administration of FPLR (100 mg/kg bw) to mice significantly reduced the CCl₄-induced elevation of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, triacylglycerols, total cholesterol, and total bilirubin. FPLR also increased the hepatic GSH contents and antioxidant enzyme activities of SOD and CAT and decreased the hepatic MDA level. Histopathological examinations further confirmed that the FPLR could protect the liver from CCl₄-induced damage. Further research indicated that FPLR prevented the DNA fragmentation caused by CCl₄ based on TUNEL assay. Moreover, immunohistochemistry staining demonstrated that pretreatment with FPLR significantly inhibited the elevation of hepatic TNF-α, IL-6, IL-8, iNOS, COX-2, and Caspase-3 in CCl₄-treated mice. In vitro experiments showed that FPLR remarkably reduced BRL hepatocyte apoptosis and damage caused by CCl₄ treatment. These findings indicate that FPLR could be developed as a functional food or medication for therapeutic purpose and prevention of hepatic injury.

Synthesis of Stachyobifiose Using Bifidobacterial α-Galactosidase Purified from Recombinant Escherichia coli

The prebiotic effects of GOS (galactooligosaccharides) are known to depend on the glycosidic linkages, degree of polymerization (DP), and the monosaccharide composition. In this study, a novel form of α-GOS with a potentially improved prebiotic effect was synthesized using bifidobacterial α-galactosidase (α-Gal) purified from recombinant Escherichia coli. The carbohydrate produced was identified as α-d-galactopyranosyl-(1→6)-O-α-d-glucopyranosyl-(1→2)-[α-d-galactopyranosyl-(1→6)-O-β-d-fructofuranoside] and was termed stachyobifiose. Among 17 nonprobiotics, 16 nonprobiotics showed lower growth on stachyobifiose than β-GOS. In contrast, among the 16 probiotics, 6 probiotics showed higher growth on stachyobifiose than β-GOS. When compared with raffinose, stachyobifiose was used less by nonprobiotics than raffinose. Moreover, compared with stachyose, stachyobifiose was used less by Escherichia coli, Enterobacter cloacae, and Clostridium butyricum. The average amounts of total short-chain fatty acids (SCFA) produced were in the order of stachyobifiose > stachyose > raffinose > β-GOS. Taken together, stachyobifiose is expected to contribute to beneficial changes of gut microbiota.

An update on oligosaccharides and their esters from traditional chinese medicines: chemical structures and biological activities

A great number of naturally occurring oligosaccharides and oligosaccharide esters have been isolated from traditional Chinese medicinal plants, which are used widely in Asia and show prominent curative effects in the prevention and treatment of kinds of diseases. Numerous in vitro and in vivo experiments have revealed that oligosaccharides and their esters exhibited various activities, including antioxidant, antidepressant, cytotoxic, antineoplastic, anti-inflammatory, neuroprotective, cerebral protective, antidiabetic, plant growth-regulatory, and immunopotentiating activities. This review summarizes the investigations on the distribution, chemical structures, and bioactivities of natural oligosaccharides and their esters from traditional Chinese medicines between 2003 and 2013.

Immunomodulatory activity in vitro and in vivo of verbascose from mung beans (Phaseolus aureus)

In the present study, the immunostimulatory activity of verbascose from mung beans (Phaseolus aureus) was evaluated by using in vitro cell models and in vivo animal models. The results of in vitro experiments showed that verbascose could enhance the ability of devouring neutral red of peritoneal macrophages and promote the release of nitric oxide and immune reactive molecules such as interleukin (IL)-6, IL-1β, interferon (IFN)-α, and IFN-γ. Treatment with verbascose at a dose of 200 μg/mL exhibited the best effects. For assay in vivo, administration of verbascose at a medium dose of 90 mg/kg body weight could significantly increase the index of spleen, activity of lysozyme in spleen and serum, hemolysin level in serum, and swelling rate of earlap in the delayed type of hypersensitivity (DTH) of immunosuppressed mice. All of the results suggested that verbascose had potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent in functional foods.

Stachyose-enriched α-galacto-oligosaccharides regulate gut microbiota and relieve constipation in mice

This study probed the effects of Deshipu stachyose granules (DSG), a novel oligosaccharide preparation (55.3% stachyose, 25.8% raffinose, and 9.7% verbascose), on gut microbiota and constipation in mice. Mice were administered intragastrically without or with DSG (0.42, 0.83, and 2.49 g/kg bw), and feces were collected after 14 days of treatment and subjected to classical microbiological assays. Selective index (SI) and prebiotic index (PI) were incorporated to evaluate the prebiotic effect. DSG at 0.83 g/kg bw scored the highest SI and PI scores, thus supporting a strong prebiotic role. In addition, the impact of DSG (0.42, 0.83, and 1.68 g/kg bw) on defecation function of constipated mice was determined. Ink propulsion rate in the small intestine was significantly improved by DSG treatment. DSG supplementation also distinctly increased the weight and number of black feces within 5 h and evidently shortened the defecating time of first black feces, as compared with the constipation control mice. All of these findings indicate that DSG may promote the growth of beneficial intestinal bacteria and inhibit pathogenic bacteria and also facilitate intestinal peristalsis and fecal excretion, thereby enhancing intestinal health and relieving constipation.

Isolation, characterization, and hepatoprotective effects of the raffinose family oligosaccharides from Rehmannia glutinosa Libosch

This study was aimed to isolate and characterize the raffinose family oligosaccharides (RGOs) from a novel plant source of Rehmannia glutinosa Libosch, and further evaluate whether RGOs can attenuate CCl4-induced oxidative stress and hepatopathy in mice. HPLC analysis showed that RGOs were mainly composed of stachyose (61.7%, w/w), followed by 23.7% raffinose and 7.1% sucrose. Administration of RGOs orally daily in mice for 21 days significantly reduced the impact of CCl4 toxicity on the serum markers of liver damage, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total-cholesterol (TC), and triglycerides (TG). RGOs also increased antioxidant levels of hepatic glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC), and ameliorated the elevated hepatic formation of malonaldehyde (MDA) induced by CCl4 in mice, which coincided with the histological alteration. These findings exhibited the potential prospect of RGOs as functional ingredients to prevent ROS-related liver damage.

Manninotriose is a major carbohydrate in red deadnettle (Lamium purpureum, Lamiaceae)

BACKGROUND AND AIMS

There is a great need to search for natural compounds with superior prebiotic, antioxidant and immunostimulatory properties for use in (food) applications. Raffinose family oligosaccharides (RFOs) show such properties. Moreover, they contribute to stress tolerance in plants, acting as putative membrane stabilizers, antioxidants and signalling agents.

METHODS

A large-scale soluble carbohydrate screening was performed within the plant kingdom. An unknown compound accumulated to a high extent in early-spring red deadnettle (Lamium purpureum) but not in other RFO plants. The compound was purified and its structure was unravelled with NMR. Organs and organ parts of red deadnettle were carefully dissected and analysed for soluble sugars. Phloem sap content was analysed by a common EDTA-based method.

KEY RESULTS

Early-spring red deadnettle stems and roots accumulate high concentrations of the reducing trisaccharide manninotriose (Galα1,6Galα1,6Glc), a derivative of the non-reducing RFO stachyose (Galα1,6Galα1,6Glcα1,2βFru). Detailed soluble carbohydrate analyses on dissected stem and leaf sections, together with phloem sap analyses, strongly suggest that stachyose is the main transport compound, but extensive hydrolysis of stachyose to manninotriose seems to occur along the transport path. Based on the specificities of the observed carbohydrate dynamics, the putative physiological roles of manninotriose in red deadnettle are discussed.

CONCLUSIONS

It is demonstrated for the first time that manninotriose is a novel and important player in the RFO metabolism of red dead deadnettle. It is proposed that manninotriose represents a temporary storage carbohydrate in early-spring deadnettle, at the same time perhaps functioning as a membrane protector and/or as an antioxidant in the vicinity of membranes, as recently suggested for other RFOs and fructans. This novel finding urges further research on this peculiar carbohydrate on a broader array of RFO accumulators.

Antioxidant, antiproliferative, and pro-apoptotic activities of a saponin extract derived from the roots of Panax notoginseng (Burk.) F.H. Chen

Dietary and medicinal uses of Panax notoginseng have been associated with reduced risk of cancer. This study was designed to investigate the profiles of P. notoginseng saponin extract (PNSE), the major bioactive ingredients in P. notoginseng (Burk.) F.H. Chen, by high-performance liquid chromatography, and, for the first time, the anticancer effect of PNSE in the human colon cancer cell line LoVo was further evaluated. The major saponins present in PNSE were ginsenosides Rg1 (31.1%) and Rb1 (34.4%), and the total content of the eight saponins identified (notoginsenoside R1, ginsenosides Rg1, Re, Rb1, Rc, and Rd, and isomeric ginsenosides Rb2 and Rb3) was 81.7%, indicating that it was a highly purified standardized saponin extract. Furthermore, PNSE was found to have a markedly cytotoxic effect and antiproliferative activity against the LoVo cell line in a dose- and time-dependent manner. Flow cytometry analysis demonstrated that PNSE caused cell cycle arrest at S phase. Moreover, PNSE was found to possess antioxidative capacities in the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay and hydroxyl radical scavenging assay in vitro. Taken together, the present results suggest that naturally occurring PNSE may provide significant natural defense against human colon cancer.