Antioxidant and Antimicrobial Activities of Thai Edible Plant Extracts Prepared Using Different Extraction Techniques.

This study investigated the antioxidant and antimicrobial activities of six Thai edible plant leaf extracts, including Cashew (CN), Chamuang (CM), Monpu (MP), Thurianthet (TT), Kradon (KD) and Pakliang (PL), extracted using ethanol extraction (EE), microwave-assisted extraction (MAE), and ultrasonic-assisted extraction (UAE). The leaf extracts were characterized for percentage yield, total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and-ferric reducing antioxidant power (FRAP) activity, and antimicrobial activity against spoilage. MAE produced the highest percentage yields, among which MAE-extracted MP exhibited the highest yield. Furthermore, the highest TPC and TFC were obtained for MAE, with MAE-extracted KD and CN showing the highest TPC and TFC, respectively, among the samples. The highest DPPH and FRAP values were seen in MAE-processed CN, KD, and MP extracts. The inhibition zone of pathogenic bacteria, minimum inhibitory concentration, and minimum bacterial concentration were determined in all samples except TT. These findings indicate that, compared to EE and UAE, MAE improved the antioxidant and antimicrobial efficacy of the leaf extracts. The aforementioned extracts could be employed as natural food additives to prevent chemical and microbial spoilage of foods.

Buckwheat Flour and Its Starch Prevent Age-Related Cognitive Decline by Increasing Hippocampal BDNF Production in Senescence-Accelerated Mouse Prone 8 Mice.

Buckwheat is an important pseudo-cereal crop worldwide. This study investigated whether long-term administration of buckwheat can suppress age-related cognitive decline in senescence-accelerated mouse prone 8 (SAMP8) mice. For 26 weeks, 18-week-old male SAMP8 mice were fed a standard diet containing 5% (w/w) buckwheat, Tartary buckwheat, wheat, or rice flour. In the Barnes maze and passive avoidance tests, mice fed buckwheat whole flour (BWF) showed improved cognitive performance compared to those fed a control diet, while no improvement was noticed in case of the other diets. Analysis of the gut microbiota showed that BWF and buckwheat outer flour administration increased the abundance of Lactococcus and Ruminiclostridium, respectively, at the genus level. The expression levels of brain-derived neurotrophic factor (BDNF), postsynaptic Arc and PSD95, and the mature neuronal marker NeuN in the hippocampus were increased after BWF administration, which was induced by the activation of the ERK/CREB signaling pathway and histone H3 acetylation. A similar increase in cognitive performance-related hippocampal BDNF expression in SAMP8 mice was observed after the oral administration of starch prepared from BWF. Therefore, the long-term administration of BWF suppresses cognitive decline by increasing hippocampal BDNF production in SAMP8 mice.

Glochidion littorale Leaf Extract Exhibits Neuroprotective Effects in Caenorhabditis elegans via DAF-16 Activation.

A number of plants used in folk medicine in Thailand and Eastern Asia are attracting interest due to the high bioactivities of their extracts. The aim of this study was to screen the edible leaf extracts of 20 plants found in Thailand and investigate the potential neuroprotective effects of the most bioactive sample. The total phenol and flavonoid content and 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity were determined for all 20 leaf extracts. Based on these assays, Glochidion littorale leaf extract (GLE), which showed a high value in all tested parameters, was used in further experiments to evaluate its effects on neurodegeneration in Caenorhabditis elegans. GLE treatment ameliorated H2O2-induced oxidative stress by attenuating the accumulation of reactive oxygen species and protected the worms against 1-methyl-4-phenylpyridinium-induced neurodegeneration. The neuroprotective effects observed may be associated with the activation of the transcription factor DAF-16. The characterization of this extract by LC-MS identified several phenolic compounds, including myricetin, coumestrin, chlorogenic acid, and hesperidin, which may play a key role in neuroprotection. This study reports the novel neuroprotective activity of GLE, which may be used to develop treatments for neurodegenerative diseases such as Parkinson's syndrome.

Long-Term Intake of Glucoraphanin-Enriched Kale Suppresses Skin Aging via Activating Nrf2 and the TßRII/Smad Pathway in SAMP1 Mice.

Sulforaphane, a potent antioxidant compound, is unstable at ambient temperature, whereas its precursor glucoraphanin is stable and metabolized to sulforaphane. Thus, we hypothesized that glucoraphanin-rich diet could effectively induce antioxidant enzyme activities and investigated the protective effects of long-term intake of a glucoraphanin-enriched kale (GEK) diet on skin aging in senescence-accelerated mouse prone 1 (SAMP1) mice. The senescence grading score was significantly lower after treatment with GEK for 39 weeks than that of the control mice. GEK also suppressed the thinning of the dorsal skin layer. Moreover, the GEK treatment enhanced the collagen production and increased the nuclear translocation of Nrf2 and HO-1 expression level in the skin tissue. TßRII and Smad3 expressions were clearly higher in the GEK-treated group than in the control group. Thus, GEK suppressed senescence in SAMP1 mice by enhancing the antioxidant activity and collagen production via the TßRII/Smad3 pathway, suggesting its practical applications for protection against skin aging.

Oral Immunotherapy with a Phosphorylated Hypoallergenic Allergen Ameliorates Allergic Responses More Effectively Than Intact Allergen in a Murine Model of Buckwheat Allergy.

SCOPE: Buckwheat is a common food allergen frequently consumed in Asian countries, with Fag e 1 and Fag e 2 being the major buckwheat allergens. The purpose of this study is to prepare an oral immunotherapy agent by attenuating these allergens via phosphorylation. The immunomodulatory effects of phosphorylated Fag e 2 (P-Fag e 2) in a mouse model of buckwheat allergy are evaluated. METHODS AND RESULTS: Phosphorylated Fag e 1 (P-Fag e 1) and P-Fag e 2 are prepared by dry-heating in the presence of pyrophosphate. Subsequent dot-blot analysis using serum from food-allergic patient indicates that both proteins exhibit reduced allergenicity upon phosphorylation. Mice subjected to oral administration of P-Fag e 2 for 6 weeks exhibit decreased specific serum IgE and increased specific IgA after Fag e 2 sensitization compared to the sham-treated mice. Moreover, the Peyer's patches (PP) of phosphorylated antigen-fed mice show decreased IL-4 production and induction of T follicular helper (Tfh) cells. Increased production of IL-6 is observed in the CD11c+ cells isolated from the PPs of P-Fag e 2-fed mice. CONCLUSION: These results indicate that attenuated allergens can suppress Th2-induced allergic responses via induction of Tfh cells, which are regulated by IL-6 secreted from dendritic cells.

Soybean-Derived Glycine-Arginine Dipeptide Administration Promotes Neurotrophic Factor Expression in the Mouse Brain.

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, plays an important role in cognitive abilities, including memory and learning. We demonstrated that soybean protein hydrolysate (SPH) diet suppresses age-related cognitive decline via the upregulation of BDNF in a mouse model of senescence. Our purpose was to identify novel bioactive peptides in SPH, which enhance BDNF expression. We treated mouse primary astrocytes with SPH as well as with its positively charged chromatographic fraction. Significant increases in the expression of BDNF were observed in the treatment with positively charged fraction of SPH. Among the synthesized peptides, the dipeptide glycine-arginine (GR) increased BDNF expression in vitro, and LC-TOF-MS analysis showed the presence of GR in the SPH. Furthermore, its administration in vivo increased the expression of BDNF in the cerebral cortex and the number of neurons in hippocampus and cerebral cortex. These data indicate that GR might promote neurogenesis by upregulating BDNF levels.

Cyperenoic acid suppresses osteoclast differentiation and delays bone loss in a senile osteoporosis mouse model by inhibiting non-canonical NF-κB pathway.

Cyperenoic acid is a terpenoid isolated from the root of a medicinal plant Croton crassifolius with a wide range of biological activities. In this study, the effects of cyperenoic acid on osteoclast differentiation were investigated both in vitro and in vivo using receptor activator of nuclear factor-κB ligand (RANKL)-induced bone marrow-derived osteoclasts and senescence-accelerated mouse prone 6 (SAMP6). Cyperenoic acid significantly suppressed RANKL-induced osteoclast differentiation at the concentrations with no apparent cytotoxicity. The half maximum inhibitory concentration (IC50) for osteoclast differentiation was 36.69 µM ± 1.02. Cyperenoic acid treatment evidently reduced the expression of two key transcription factors in osteoclast differentiation, NFATc1 and c-Fos. Detailed signaling analysis revealed that cyperenoic acid did not affect MAPK pathways and canonical NF-κB pathway but impaired activation of p100/p52 in the non-canonical NF-κB pathway upon RANKL stimulation. Moreover, the expression of osteoclast-related genes, nfatc1, ctsk, irf8, acp5 and cfos were disrupted by cyperenoic acid treatment. The bone resorption activity by cyperenoic acid-treated osteoclasts were impaired. In a senile osteoporosis mouse model SAMP6, mice fed on diet supplemented with cyperenoic acid showed delay in bone loss, compared to the control. Taken together, plant-derived cyperenoic acid shows great potential as therapeutic agent for osteoporosis.

Solventless extraction methods for immature fruits: Evaluation of their antioxidant and cytoprotective activities.

In this study, extraction of immature fruits using an environmentally friendly pressurized hot water extraction (PHWE) method was compared with the traditional reflux method. Extracts were tested for their polyphenol content using the Folin-Ciocalteu assay and for their antioxidant activity using the oxygen radical absorbance capacity (ORAC) assay. The highest amount of polyphenol was extracted from grape (stem) using PHWE at 100°C, or reflux extraction. This was followed by reflux extraction of grape (fruit). The results were similar for the ORAC assay. All samples extracted using PHWE at 100°C showed cytoprotective activity against H2O2-induced oxidative stress in Crandell-Reese feline kidney (CRFK) cells. This study demonstrated that beneficial compounds can be extracted from immature fruits without the use of organic solvents. The utilization of beneficial compounds present in immature fruits can also contribute to the reduction in agriculture waste generated.

Effects of Sesaminol Feeding on Brain Aß Accumulation in a Senescence-Accelerated Mouse-Prone 8.

Alzheimer's disease (AD) is characterized by the progressive accumulation of extracellular ß-amyloid (Aß) aggregates. Recently, the senescence-accelerated mouse-prone 8 (SAMP8) model was highlighted as a useful model of age-related AD. Therefore, we used the SAMP8 mouse to investigate the preventive effects of sesame lignans on the onset of AD-like pathology. In preliminary in vitro studies, sesaminol showed the greatest inhibitory effect on Aß oligomerization and fibril formation relative to sesamin, sesamolin, and sesaminol triglucoside. Hence, sesaminol was selected for further evaluation in vivo. In SAMP8 mice, feed-through sesaminol (0.05%, w/w, in standard chow) administered over a 16 week period reduced brain Aß accumulation and decreased serum 8-hydroxydeoxyguanosine, an indicator of oxidative stress. Furthermore, sesaminol administration increased the gene and protein expression of ADAM10, which is a protease centrally involved in the non-amyloidogenic processing of amyloid precursor protein. Taken together, these data suggest that long-term consumption of sesaminol may inhibit the accumulation of pathogenic Aß in the brain.

Oral administration of soy peptides suppresses cognitive decline by induction of neurotrophic factors in SAMP8 mice.

SAMP8 mice have a shorter lifespan and show the dysfunction of the central nervous system. We here investigated whether soy peptides (SP) composed mainly of di- and tripeptides has the potential to prevent age-dependent cognitive impairment. SAMP8 and normal aging mice, SAMR1, were fed a diet supplemented with SP or a control diet for 26 weeks to investigate the preventive effects on the progression of cognitive decline using the Morris water maze. The SP-fed groups in SAMP8 and SAMR1 prevented the decline of cognitive ability compared to their controls. Increased expression of neurotrophic factors such as BDNF and NT-3 at mRNA and protein levels were observed in the brain of SP-fed mice, especially SAMP8. Further, the phosphorylated CREB protein level of SAMP8 was markedly up-regulated by SP feeding. These suggest that SPs have the potential for prevention of cognitive impairment via neurotrophic effects.

Enzymatic synthesis of novel phenol acid rutinosides using rutinase and their antiviral activity in vitro.

Novel rutinosides of vanillic acid, sinapic acid, ferulic acid, and caffeic acid were prepared via a rutinase-catalyzed transglycosylation reaction. Reaction mixtures containing rutin, phenolic acid, and rutinase derived from tartary buckwheat ( Fagopyrum tataricum ) seeds were incubated in 20 mM acetate buffer (pH 5.0) at 40 °C. The resulting rutinoside of each phenolic acid was purified by HPLC, and the structure was determined by NMR and FAB-MS analysis. Antiviral activity was determined using feline calicivirus (FCV) strain F9, which is a typical norovirus surrogate. It was found that rutinosylation of the phenolic acids increased their antiviral activity against FCV, with the sinapic acid rutinoside being the most effective. These results will contribute to the development of antiviral agents against noroviruses.

Apple polyphenols suppress antigen presentation of ovalbumin by THP-1-derived dendritic cells.

Apple polyphenol extract (AP) and procyanidin contained in AP were investigated for their immunomodulatory effects using THP-1-derived human dendritic cells (TDDCs). The expression levels of HLA-DR (MHC class II) and CD86 (costimulatory molecule) were measured as an indicator of antigen presentation in TDDCs. A significant decrease in HLA-DR expression was observed in the AP and fractionated procyanidin-treated cells in the presence of ovalbumin (OVA), but no effect on CD86 expression was observed. The uptake of OVA was not inhibited by AP treatment, and the gene expression of membrane-associated RING-CH ubiquitin E3 ligase, MARCH1, was up-regulated by AP treatment. It can therefore be presumed that AP suppresses HLA-DR expression via the ubiquitin-proteasome pathway. Furthermore, the up-regulation of IL-12 and TNF-α was found in the procyanidin trimers-treated cells in the presence of OVA. These results suggest that apple polyphenols would be an effective factor for the development of immunomodulatory agents with suppressive effects of antigen presentation.

Modulation of immunoresponse in BALB/c mice by oral administration of Fag e 1-glucomannan conjugate.

Maillard-type glycosylation was applied to preparation of hypoallergenic agents from a major buckwheat allergen, Fag e 1. Conjugation with arabinogalactan (AG), xyloglucan (XG), or yeast glucomannan (YGM) successfully decreased in vitro allergenicity of Fag e 1. Determination of IgE titer in the tested allergic mice revealed that YGM was the most effective for in vivo allergenicity of Fag e 1 among these water-soluble polysaccharides. Real-time PCR analysis using a set of primer for IL-4 (a typical Th2 cytokine) or IFN-gamma (a typical Th1 cytokine) showed that expressed mRNA for IL-4 in splenocytes drastically decreased with increasing with Fag e 1-YGM conjugate feeding. In addition, based on a flow-cytometric analysis of T cell subsets in the splenocytes, it was confirmed that the feeding led to an improvement of Th1/Th2 balance in the allergic mice where population of Th1 increased from 2.91% to 4.02%, while that of Th2 decreased from 3.75% to 2.72%. Furthermore, it was revealed that differentiation ratio of regulatory T cell (Treg) in the splenocytes increased from 14.5% to 18.7% by the oral administration. These results indicated that Fag e 1-YGM conjugate can be available for an immunomodulating agent for buckwheat allergy.

Quillaja saponin can modulate ovalbumin-induced IgE allergic responses through regulation of Th1/Th2 balance in a murine model.

Quillaja saponin is the extract from the balk of a South American tree, and it is considered to modulate immunological responses. We hypothesized that Quillaja saponin may change allergy-associated cytokine profile and antigen-specific immune responses. The purpose of this study is to investigate whether Quillaja saponin can suppress ovalbumin (OVA)-induced IgE-mediated allergic responses through promoting a dominant Th1 immune response. The spleen cells from BALB/c mice, which were primed by OVA, were used for an in vitro challenge test. The level of total and OVA-specific IgE, IL-4, IFN-gamma, and IL-12 was determined by enzyme-linked immunosorbent assay (ELISA). BALB/c mice were orally administered with saponin for 35 days. The mice were immunized intraperitoneally with OVA on days 14 and 21. After intraperitoneal challenge with OVA on day 35, anaphylactic symptoms were monitored. Total and specific IgE and IgG, specific IgG1 and IgG2a, and histamine levels in serum were analyzed by ELISA. The increase of IL-12 and IFN-gamma levels was observed in the presence of Quillaja saponin, while the IL-4 level was decreased. Furthermore, Quillaja saponin suppressed total and OVA-specific IgE secretion in spleen cells. Balb/c mice that were orally administered Quillaja saponin exhibited lower total and OVA-specific IgE and OVA-specific IgG secretions, whereas total IgG levels remained unchanged. Suppression of OVA-specific IgG1 and an increase of OVA-IgG2a were observed in mice fed saponin. Quillaja saponin also decreased serum histamine levels and diminished anaphylactic symptoms. The present study indicates that Quillajasaponin can suppress allergen-specific IgE-mediated reactivity in a murine model of food allergy, which results from shifting from a Th2-dominated to a Th1-dominated immune response.