Antioxidative and Antidiabetic Effects of Natural Polyphenols and Isoflavones

Variation in Phenolic Compounds Content and Antioxidant Activity of Different Plant Organs from Rumex crispus L. and Rumex obtusifolius L. at Different Growth Stages

The study investigated the accumulation of phenolic compounds and the antioxidant activity of extracts of various parts of R. crispus and R. obtusifolius, collected at the flowering stage and the fruiting stage. Half of the collected plants were divided into root, stem, leaves, and reproductive organs (inflorescence). The other half was used to study the vertical distribution of biologically active components and antioxidants throughout the plant. The samples were analyzed for total catechins content, total proanthocyanidins content, total phenolic content, and total antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'azinobis(3)ethylbenzthiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) assays). All analyses were performed in four replicates. In general, a similar trend was observed in the distribution of phenolic compounds in the studied species. The maximum content of these secondary metabolites was noted in the reproductive organs, both in the flowering and fruiting period. Stems were characterized by a minimum content of the studied classes of substances. The antioxidant activity of the sorrels studied parts can be arranged in the following order: the generative part (flowers, seeds) > leaves > root > stem (for flowering and fruiting stages). It was found that parts of the root closer to the stem differed in higher activity.

Antidiabetic Potential of Mangifera indica L. cv. Anwar Ratol Leaves: Medicinal Application of Food Wastes

Background and objectives: Anwar Ratol is one of the most famous cultivar of mango in South Asia, especially Pakistan. Mango leaves are left as food waste. This study evaluated the potential of mango (Anwar Ratol) leaves for their use against diabetes mellitus. Material and Methods: In this study, hydro-alcoholic extract of the plant leaves was prepared and evaluated by electrospray ionization mass spectroscopy (ESI-MS) and high-performance liquid chromatography (HPLC) for the presence of phytochemicals. The plant extract was administered to Alloxan induced diabetic mice followed by evaluation through oral glucose tolerance test; determination of postprandial glucose, body weight, lipid profile and histopathological evaluation of pancreas. Results: Chemical evaluation revealed the presence of mangiferin, rhamnetin, catechin, epicatechin, iriflophenone 3-C-β-D-glucoside, gallic acid and other phenolic and flavonoid compounds. The plant extract exhibited a decrease in postprandial blood glucose following seven days therapy in diabetic mice. The extract also prevented the rise in blood glucose level as determined by glucose tolerance test in diabetic mice. Furthermore, therapy of diabetic mice with the extract prevented a decrease in body weight and decline in beta-cell mass associated with alloxan and improved lipid profile. Conclusion: The findings of the study clearly suggested that the leaf extract of the plant might possess anti-diabetic activity possibly due to the presence of mangiferin and other phytochemicals such as phenolic and flavonoid compounds. This study will serve as a basis for the use of mango leaf extract against diabetes. Furthermore, this study will also provide basis for the bioassay-based fractionation and isolation of active principles responsible for the antidiabetic potential of mango leaves.

Polyphenols in the treatment of autoimmune diseases

In addition to protecting body from infections and diseases, the immune system produces auto-antibodies that can cause complex autoimmune disorders, such as Type I diabetes, primary biliary cirrhosis, rheumatoid arthritis, and multiple sclerosis, to name a few. In such cases, the immune system fails to recognize between foreign agents and its own body cells. Different factors, such as genetic factors (CD25, STAT4), epigenetic factors (DNA methylation, histone modifications) and environmental factors (xenobiotics, drugs, hormones) trigger autoimmunity. Glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), immunosuppressive and biological agents are currently used to manage autoimmune diseases of different origins. However, complete cure remains elusive. Many dietary and natural products including polyphenols have been widely studied as possible alternative treatment strategies for the management of autoimmune disorders. Polyphenols possess a wide-range of pharmacological and therapeutic properties, including antioxidant and anti-inflammatory activities. As immunomodulatory agents, polyphenols are emerging pharmaceutical tools for management of various autoimmune disorders including vitiligo, ulcerative colitis and multiple sclerosis (MS). Polyphenols activate intracellular pathways such as arachidonic acid dependent pathway, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway, mitogen-activated protein kinases (MAPKs) pathway, phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway and epigenetic modulation, which regulate the host's immune response. This timely review discusses putative points of action of polyphenols in autoimmune diseases, characterizing their efficacy and safety as therapeutic agents in managing autoimmune disorders.

Optimization of Ultrasonic-Assisted Extraction of Total Phenolics from Citrus aurantium L. Blossoms and Evaluation of Free Radical Scavenging, Anti-HMG-CoA Reductase Activities

The objective of this study was to develop an ultrasonic-assisted procedure for the extraction of total phenolics from Citrus aurantium L. blossoms (CAB) and evaluate the free radical scavenging activity and anti-HMG-CoA reductase activity of the total phenolics. In this work, a Box- Behnken design based on single-factor experiments was used to explore the optimum extraction process. Under the optimum conditions (extraction solvent 70.31% ethanol, extraction temperature 61.94 °C, extraction time 51.73 min, and liquid-to-solid ratio 35.63 mL/g), the extraction yield of total phenolics was 95.84 mg gallic acid equivalents (GAE)/g dry matter (DM), which was highly consistent with the theoretical value (96.12 mg GAE/g DM). The higher contents of total phenolics and five main phenolic compounds obtained from the optimized ultrasonic-assisted extraction (UAE) proved its efficiency when compared with conventional heat reflux extraction (HRE). The total phenolic extract showed excellent free radical scavenging properties against 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·), 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) radical (ABTS⁺·), hydroxyl radical (·OH) and superoxide anion radical (·O₂^-), with IC₅₀ values of 197.007, 83.878, 218.643, and 158.885 μg/mL, respectively; the extracts also showed good inhibition of β-hydroxy-β-methylglutaryl-CoA reductase (HMG-CoA reductase) activity, with an IC₅₀ value of 117.165 μg/mL. Total phenolics from CAB could be a potential source of natural free radical scavenger and HMG-CoA reductase inhibitor.

Antidiabetic Effects of Hydroxytyrosol: In Vitro and In Vivo Evidence

Insulin resistance, a pathological condition characterized by defects in insulin action leads to the development of Type 2 diabetes mellitus (T2DM), a disease which is currently on the rise that pose an enormous economic burden to healthcare systems worldwide. The current treatment and prevention strategies are considerably lacking in number and efficacy and therefore new targeted therapies and preventative strategies are urgently needed. Plant-derived chemicals such as metformin, derived from the French lilac, have been used to treat/manage insulin resistance and T2DM. Other plant-derived chemicals which are not yet discovered, may have superior properties to prevent and manage T2DM and thus research into this area is highly justifiable. Hydroxytyrosol is a phenolic phytochemical found in olive leaves and olive oil reported to have antioxidant, anti-inflammatory, anticancer and antidiabetic properties. The present review summarizes the current in vitro and in vivo studies examining the antidiabetic properties of hydroxytyrosol and investigating the mechanisms of its action.

Nobiletin ameliorates hepatic ischemia and reperfusion injury through the activation of SIRT-1/FOXO3a-mediated autophagy and mitochondrial biogenesis

Hepatic ischemia and reperfusion injury are characterized by impaired autophagy, mitochondrial dysfunction, and subsequent compromise of cellular homeostasis following hepatic surgery or transplantation. Nobiletin, a natural flavonoid, is a beneficial antioxidant that possesses anti-inflammatory and anti-cancer activities. We investigated the effect of nobiletin on hepatic IR injury and described the underlying mechanisms. C57BL/6 mice were subjected to 60 min of partial hepatic ischemia, treated with nobiletin (5 mg/kg) or vehicle at the start of reperfusion, and killed at 5 h of reperfusion. Hepatic ischemia and reperfusion increased hepatocellular oxidative damage, inflammation, and cell death, but these changes were alleviated upon nobiletin treatment. Nobiletin increased the expression of proteins that control autophagy, mitochondrial dynamics, and biogenesis. Specifically, the SIRT-1/FOXO3a and PGC-1α pathways were activated by nobiletin. IR-induced AKT activation was associated with FOXO3a phosphorylation, which resulted in a significant reduction in the nuclear FOXO3a levels and potentially attenuated autophagy-regulatory gene expression. Nobiletin increased FOXO3a expression and its nuclear translocation via the inhibition of AKT. Specific inhibition of SIRT-1 abolished the protective effect of nobiletin, causing decreased FOXO3a expression, followed by autophagy induction and decreased PGC-1α expression and mitochondrial dynamics. Taken together, our data indicate that SIRT-1 directly mediates the protective effect of nobiletin against hepatic ischemia and reperfusion injury. The activation of autophagy and mitochondrial function through the SIRT-1/FOXO3a and PGC-1α pathways indicate that nobiletin could have therapeutic potential for treating hepatic ischemia and reperfusion injury.

Nobiletin, an antioxidant found in citrus peel, may protect the liver from reperfusion injury, damage following blood flow interruption. When blood flow is restricted and then restored, as in transplant, surgery, or shock, cells are injured, largely due to damage to the cellular powerhouses, the mitochondria. Nobiletin is known to have many benefits, including anti-cancer and anti-inflammatory activities, but its mechanism of action is not well understood. Sang Won Park and Hwajin Kim, at the Gyeongsang National University School of Medicine, in Jinju, South Korea, and co-workers, investigated how nobiletin might protect the liver against interruption of blood flow. They found that nobiletin triggered cells to dismantle damaged mitochondria and produce new, functioning mitochondria, greatly reducing liver damage. These results illuminate how nobiletin works and may lead to better treatments for liver reperfusion injury.

The milk thistle (Silybum marianum) compound Silibinin stimulates leukopoiesis from mouse embryonic stem cells

The milk thistle compound Silibinin (i.e., a 1:1 mixture of Silybin A and Silybin B) stimulates vasculogenesis of mouse embryonic stem (ES) cells. Because vasculogenesis and leukopoiesis are interrelated, the effect of Silibinin on leukopoiesis of ES cells was investigated. Treatment of differentiating ES cells with hydrosoluble Silibinin-C-2',3-dihydrogen succinate dose-dependent increased the number of CD18+ , CD45+ , and CD68+ cells, indicating leukocyte/macrophage differentiation. Silibinin treatment activated phosphoinositide 3-kinase (PI3K), AKT (protein kinase B), signal transducer and activator of transcription 3 (STAT3), stimulated hypoxia-induced factor-1α (HIF-1α), and vascular endothelial growth factor receptor 2 (VEGFR2) expression and raised intracellular nitric oxide (NO). Western blot experiments showed that upon coincubation with either the PI3K inhibitor LY294002, the STAT3 inhibitor Stattic, the AKT antagonist AKT inhibitor VIII, or the NO inhibitor L-NAME, the Silibinin-induced expression of CD18, CD45, and CD68 was abolished. Moreover, the stimulation of HIF-1α and VEGFR2 expression was blunted upon STAT3 and PI3K/AKT inhibition. Treatment of differentiating ES cells with L-NAME abolished the stimulation of VEGFR2 and VE-cadherin expression achieved with Silibinin, indicating that NO is involved in vasculogenesis and leukocyte differentiation pathways. In summary, the data of the present study demonstrate that Silibinin stimulates leukocyte differentiation of ES cells, which is associated to vasculogenesis and regulated by PI3K/AKT-, STAT3-, and NO-mediated signaling.

Reductions in Postprandial Plasma Allantoin Concentrations With Increasing Doses of Polyphenol Rich Curry Intake - A Randomized Crossover Trial

While dietary or supplementary antioxidants are thought to inhibit or delay oxidation of biological molecules, their utility in vivo has been marred by equivocal evidence. Consumption of polyphenol rich foods has been thought to alleviate postprandial oxidative stress and/or improve endothelial function. Although, previous studies suggested the utility of allantoin as a biomarker of oxidative stress, controlled dose response studies with dietary antioxidants to test this in humans have been limited. We therefore investigated the effects of 2 doses of polyphenol rich curry consumption on postprandial plasma concentrations of allantoin, allantoin to uric acid ratio, F2-isoprostanes using liquid chromatography-tandem mass spectrometry (LCMS-MS) and measured endothelial function using peripheral arterial tonometry (endoPAT). In a randomized controlled crossover trial in 17 non-smoking, healthy, Chinese men, aged 23.7 ± 2.4 years and BMI 23.1 ± 2.3 kg/m², the volunteers consumed 3 test meals in a random order, consisting of either non-curry Dose 0 Control (D0C, 0 g spices), or Dose 1 Curry (D1C, 6 g spices) or Dose 2 Curry (D2C, 12 g spices), after overnight fast. There were significant reductions in postprandial allantoin concentrations (p < 0.001) and allantoin to uric acid ratio (p < 0.001) at 2 h and 3 h following test meal consumption, indicating improvements in postprandial redox balance with increasing curry doses, although there were no differences between treatments on F2-isoprostane concentrations or on RHI (measured at 2 h only). Allantoin may have a utility as a biomarker of redox balance, in an acute setting. The study was registered at www.clinicaltrials.gov (Identifier No. NCT02599272).

Linkages between stratospheric ozone, UV radiation and climate change and their implications for terrestrial ecosystems

Linkages between stratospheric ozone, UV radiation and climate change: terrestrial ecosystems.

Hydroxytyrosol Exerts Anti-Inflammatory and Anti-Oxidant Activities in a Mouse Model of Systemic Inflammation

Hydroxytyrosol (3,4-dihydroxyphenil-ethanol, HT), the major phenol derived from olive oil consumption, has shown different anti-inflammatory and anti-oxidant activities in vitro which may explain the chronic-degenerative diseases preventive properties of olive oil. The aim of this study was to examine the ability of HT reduce inflammatory markers, Cyclooxygenase-2 (COX2) and Tumour Necrosis Factor alfa (TNF-α and oxidative stress in vivo on a mouse model of systemic inflammation. Balb/c mice were pre-treated with HT (40 and 80 mg/Kg b.w.) and then stimulated by intraperitoneal injection of lipopolysaccharide (LPS). Blood was collected to measure COX2 gene expression by qPCR and TNF-α level by ELISA kit in plasma. In addition, the total anti-oxidant power of plasma and the DNA damage were measured by FRAP test and COMET assay, respectively. LPS increased the COX2 expression, the TNF-α production and the DNA damage. HT administration prevented all LPS-induced effects and improved the anti-oxidant power of plasma. HT demonstrated in vivo anti-inflammatory and anti-oxidant abilities. The results may explain the health effects of olive oil in Mediterranean diet. HT represents an interesting molecule for the development of new nutraceuticals and functional food useful in chronic diseases prevention.

Biochemical and Physiological Parameters in Rats Fed with High-Fat Diet: The Protective Effect of Chronic Treatment with Purple Grape Juice (Bordo Variety)

High-fat-diet (HFD) has been related to metabolic and cardiovascular diseases. Consumption of grapes and their byproducts containing phenolic compounds has been reported due to the benefits they produce for human health. The purpose of this study was to investigate the antioxidant and protective effect of chronic intake of purple grape juice on certain biochemical and physiological changes promoted by the consumption of HFD. Forty male rats were randomly divided into four groups to receive standard or HFD diet and/or conventional (CGJ) or organic grape juice (OGJ) for three months. Dietary intake, body weight gain, cardiometabolic parameters, and serum lipoperoxidation were investigated. Results showed that consumption of CGJ and OGJ changed the pattern of food and drink intake of the animals. There was a reduction in the body weight of animals that consumed grape juices and an increase in the weight gain in HFD and OGJ rats. HFD increased abdominal fat and the abdominal fat/weight ratio, and both grape juices prevented these modifications. HFD increased hepatic enzymes levels (aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT)) and reduced urea. Purple grape juices prevented some of these changes. HFD enhanced lipid peroxidation (thiobarbituric acid reactive substances (TBARS)) in serum and CGJ and OGJ prevented this increase. The consumption of purple grape juice has the potential to prevent and ameliorate most of the alterations provoked by HFD, therefore regular intake of grape products could promote beneficial effects.

Aqueous extracts of walnut (Juglans regia L.) leaves: quantitative analyses of hydroxycinnamic and chlorogenic acids

Identification of both hydroxycinnamic and chlorogenic acids present in aqueous extracts of walnut leaves (Juglans regia L.) were carried out by using, for the first time, standard compounds not commercially available for qualitative identification. In particular, in addition to caffeic, ferulic, p-coumaric and sinapic acids, cis and trans mono-caffeoylquinic, dicaffeoylquinic, mono-feruloylquinic and cis and trans mono-p-coumaroylquinic acid isomers were detected and quantified by Ultra High Pressure Liquid Chromatography and the seasonal variations of these secondary metabolites were investigated.

Effects of Cultivation Month and Genetic Background on Phenolic Content of Citrus tachibana Peel

Species of the Citrus genus are known as rich sources of phenolic compounds. Peels of Citrus tachibana and Citrus unshiu are used in herbal formulations, sometimes in similar ways. In this study, we examined the effects of plant maturity and genetic background on the total phenolic contents and quantities of specific flavonoids in C. tachibana peel. In addition, we compared these values in C. tachibana and C. unshiu peels. The total phenolic contents and the contents of nobiletin, tangeretin, and hesperidin were higher in the extracts of the immature peel than in those of the mature peels of C. tachibana; moreover, the quantities of these compounds were also influenced by the genetic background of C. tachibana. In the extracts of C. unshiu peel, the contents of total phenolics, nobiletin, and tangeretin were lower than those of C. tachibana peel. However, the hesperidin content was higher in extracts of C. unshiu peel than those of C. tachibana peel. This study evaluated the phenolic and flavonoid contents of C. tachibana and C. unshiu in an effort to provide new insights into herbal medicines for further study and utilization.

Antioxidant, antihyperglycemic, and antidiabetic activity of Apis mellifera bee tea

Diabetes has emerged as one of the largest global epidemics; it is estimated that by 2035, there will be 592 million diabetic people in the world. Brazilian biodiversity and the knowledge of traditional peoples have contributed to the treatment of several diseases, including diabetes. Apis mellifera bee tea is used by indigenous Brazilians to treat diabetes, and this traditional knowledge needs to be recorded and studied.The objective of this study was to record the use and to evaluate the antioxidant, antihyperglycemic, and antidiabetic activity of Apis mellifera bee tea, which is used by the Guarani and Kaiowá indigenous people for the treatment of diabetes. Semi-structured interviews were performed with Guarani and Kaiowá ethnic indigenous people from the State of Mato Grosso do Sul, Brazil, seeking to identify the animal species used for medicinal purposes. For the experimental procedures, tea prepared with macerated Apis mellifera bees was used. In vitro assays were performed to evaluate antioxidant activity; direct free radical scavenging, protection against oxidative hemolysis, lipid peroxidation were evaluated in human erythrocytes and potential in inhibiting the formation of advanced glycation end products (AGEs). In vivo, normoglycemic Swiss male mice treated with Apis mellifera tea (AmT) were subjected to the oral glucose tolerance test and compared with control and metformin-treated groups. Diet-induced diabetic mice were treated for 21 days with AmT and evaluated for glycemia and malondialdehyde levels in the blood, liver, nervous system, and eyes. During interviews, the indigenous people described the use of Apis mellifera bee tea for the treatment of diabetes. In in vitro assays, AmT showed direct antioxidant activity and reduced oxidative hemolysis and malondialdehyde generation in human erythrocytes. The AmT inhibited the formation of AGEs by albumin-fructose pathways and methylglyoxal products. In vivo, after oral glucose overload, normoglycemic mice treated with AmT had reduced hyperglycemia at all times evaluated up to 180 min. AmT also reduced hyperglycemia and malondialdehyde levels in the blood, liver, nervous system, and eyes of diabetic mice to similar levels as those in metformin-treated mice and normoglycemic controls. In summary, Apis mellifera bee tea showed antioxidant, antihyperglycemic, and antidiabetic activity, which provides support for the therapeutic application of Guarani and Kaiowá indigenous knowledge.

Antidiabetic Effect of Cyclocarya paliurus Leaves Depends on the Contents of Antihyperglycemic Flavonoids and Antihyperlipidemic Triterpenoids

Cyclocarya paliurus has been used commonly to treat diabetes in China. However, the effective components and the effect of plant origin remain unclear. In this study, C. paliurus leaves with different chemical compositions were selected from five geographical locations, and their effects on streptozotocin (STZ)-induced diabetic mice were evaluated with both ethanol and aqueous extracts. Glucose levels, lipid levels, and biomarkers of liver and kidney function were measured. The principal components of both C. paliurus ethanol and aqueous extracts from different geographical locations differed quantitatively and qualitatively. Results showed that C. paliurus extracts with better antihyperglycemic effects were characterized by higher contents of total flavonoids, especially quercetin-3-O-glucuronide and kaempferol-3-O-glucuronide. Furthermore, significantly negative correlations were found between triterpenoids contents and lipid levels. These results revealed the potential antihyperglycemic capacity of C. paliurus flavonoids and the antihyperlipidemic effect of C. paliurus triterpenoids. Thus, we suggest that the composition of C. paliurus compounds might help to design therapeutic alternatives for the treatment of diabetes mellitus. However, geographic origins and the extraction solvents can also affect the effectiveness of the treatment as these factors influence the chemical compositions and thereby the biological activities.

Effects of Chlorogenic Acid-Enriched and Hydroxyhydroquinone-Reduced Coffee on Postprandial Fat Oxidation and Antioxidative Capacity in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Chlorogenic acids (CGAs) reduce blood pressure and body fat, and enhance fat metabolism. In roasted coffee, CGAs exist together with the oxidant component hydroxyhydroquinone (HHQ). HHQ counteracts the antihypertensive effects of CGA, but its effects on CGA-induced fat oxidation (FOX) are unknown. Here we assessed the effects of CGA-enriched and HHQ-reduced coffee on FOX. Fifteen healthy male volunteers (age: 38 ± 8 years (mean ± SD); BMI: 22.4 ± 1.5 kg/m²) participated in this crossover study. Subjects consumed the test beverage (coffee) containing the same amount of CGA with HHQ (CGA-HHQ(+)) or without HHQ (CGA-HHQ(−)) for four weeks. Postprandial FOX and the ratio of the biological antioxidant potential (BAP) to the derivatives of reactive oxygen metabolites (d-ROMs) as an indicator of oxidative stress were assessed. After the four-week intervention, postprandial FOX and the postprandial BAP/d-ROMs ratio were significantly higher in the CGA-HHQ(−) group compared with the CGA-HHQ(+) group (4 ± 23 mg/min, group effect: p = 0.040; 0.27 ± 0.74, group effect: p = 0.007, respectively). In conclusion, reducing the amount of HHQ facilitated the postprandial FOX effects of CGA in coffee. Our findings also suggest that the mechanism underlying the inhibition of FOX by HHQ is related to postprandial oxidative stress.

Berry Phenolic Antioxidants - Implications for Human Health?

Antioxidants present in the diet may have a significant effect on the prophylaxis and progression of various diseases associated with oxidative stress. Berries contain a range of chemical compounds with antioxidant properties, including phenolic compounds. The aim of this review article is to provide an overview of the current knowledge of such phenolic antioxidants, and to discuss whether these compounds may always be natural gifts for human health, based on both in vitro and in vivo studies. It describes the antioxidant properties of fresh berries (including aronia berries, grapes, blueberries, sea buckthorn berries, strawberries and other berries) and their various products, especially juices and wines. Some papers report that these phenolic compounds may sometimes behave like prooxidants, and sometimes demonstrate both antioxidant and prooxidant activity, while others note they do not behave the same way in vitro and in vivo. However, no unwanted or toxic effects (i.e., chemical, hematological or urinary effect) have been associated with the consumption of berries or berry juices or other extracts, especially aronia berries and aronia products in vivo, and in vitro, which may suggest that the phenolic antioxidants found in berries are natural gifts for human health. However, the phenolic compound content of berries and berry products is not always well described, and further studies are required to determine the therapeutic doses of different berry products for use in future clinical studies. Moreover, further experiments are needed to understand the beneficial effects reported so far from the mechanistic point of view. Therefore, greater attention should be paid to the development of well-controlled and high-quality clinical studies in this area.

Identification of Antidiabetic Compounds from Polyphenolic-rich Fractions of Bulbine abyssinica A. Rich Leaves

Background:

Bulbine abyssinica has been reported to possess a variety of pharmacological activities traditionally. Previous work suggested its antidiabetic properties, but information on the antidiabetic compounds is still lacking.

Objective:

The present research exertion was aimed to isolate and identify biologically active polyphenols from B. abyssinica leaves and to evaluate their efficacy on carbohydrate digesting enzymes.

Materials and Methods:

Fractionation of the polyphenolic contents from the methanolic extract of B. abyssinica leaves was executed by the silica gel column chromatography to yield different fractions. The antioxidant activities of these fractions were carried out against 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2-diphenyl-1-picrylhydrazyl radicals, and ferric ion-reducing antioxidant power (FRAP). In vitro antidiabetic experimentation was performed by evaluating the α-amylase and α-glucosidase inhibitory capacity. The isolated polyphenols were then identified using liquid chromatography and mass spectroscopy (LC/MS).

Results:

Out of the eight polyphenolic fractions (BAL 1–8), BAL-4 has the highest inhibitory activity against ABTS radicals whereas BAL-6 showed potent ferric ion-reducing capacity. BAL-5 was the most effective fraction with antidiabetic activity with IC₅₀of 140.0 and 68.58 ± 3.2 μg/ml for α-amylase and α-glucosidase inhibitory activities, respectively. All the fractions competitively inhibited α-amylase, BAL-5 and BAL-6 also inhibited α-glucosidase competitively, while BAL-4 and BAL-1 exhibited noncompetitive and near competitive inhibitions against α-glucosidase, respectively. The LC/MS analysis revealed the presence of carvone in all the fractions.

Conclusions:

The present study demonstrates the antioxidant and antidiabetic activities of the isolated polyphenols from B. abyssinica.

SUMMARY

Polyphenols were successfully isolated and identified from Bulbine abyssinica leaves

The isolated polyphenols are biologically active with high antioxidant as well as inhibitor of carbohydrate-digesting enzymes

B. abyssinica can be a good source of amylase and glucosidase inhibitors

B. abyssinica can be used as complementary or alternative therapeutic agents especially for the treatment of diabetes

Carvone, quercetin, and psoralen could be the compounds responsible for the α-amylase and α-glucosidase inhibitory activities.

Abbreviations Used: ABTS: 2,2'-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion-reducing antioxidant power, LC/MS: Liquid chromatography and mass spectroscopy, AGEs: Advanced glycation end products, TLC: Thin-layer chromatography, MeOH: Methanol, PNP-G: ρ-Nitrophenyl-α-D-Glucoside, R²: Coefficient of determination, mgQE: Milligram quercetin equivalent, mgTAE: Milligram tannic acid equivalent, mgCE: Milligram catechin equivalent, g: Gram

Environmental effects of ozone depletion, UV radiation and interactions with climate change: UNEP Environmental Effects Assessment Panel, update 2017

The Environmental Effects Assessment Panel (EEAP) is one of three Panels of experts that inform the Parties to the Montreal Protocol. The EEAP focuses on the effects of UV radiation on human health, terrestrial and aquatic ecosystems, air quality, and materials, as well as on the interactive effects of UV radiation and global climate change. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously held. Because of the Montreal Protocol, there are now indications of the beginnings of a recovery of stratospheric ozone, although the time required to reach levels like those before the 1960s is still uncertain, particularly as the effects of stratospheric ozone on climate change and vice versa, are not yet fully understood. Some regions will likely receive enhanced levels of UV radiation, while other areas will likely experience a reduction in UV radiation as ozone- and climate-driven changes affect the amounts of UV radiation reaching the Earth's surface. Like the other Panels, the EEAP produces detailed Quadrennial Reports every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). In the years in between, the EEAP produces less detailed and shorter Update Reports of recent and relevant scientific findings. The most recent of these was for 2016 (Photochem. Photobiol. Sci., 2017, 16, 107-145). The present 2017 Update Report assesses some of the highlights and new insights about the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. A full 2018 Quadrennial Assessment, will be made available in 2018/2019.

Chain-breaking antioxidant activity of hydroxylated and methoxylated magnolol derivatives: the role of H-bonds

Chemical modification of magnolol, an uncommon dimeric neolignan contained in Magnolia genus trees, provides a unique array of polyphenols having interesting biological activity potentially related to radical scavenging. The chain-breaking antioxidant activity of four new hydroxylated and methoxylated magnolol derivatives was explored by experimental and computational methods. The measurement of the rate constant of the reaction with ROO˙ radicals (k_inh) in an apolar solvent showed that the introduction of hydroxyl groups ortho to the phenolic OH in magnolol increased the k_inh value, being 2.4 × 10⁵ M^-1 s^-1 and 3.3 × 10⁵ M^-1 s^-1 for the mono and the dihydroxy derivatives respectively (k_inh of magnolol is 6.1 × 10⁴ M^-1 s^-1). The di-methoxylated derivative is less reactive than magnolol (k_inh = 1.1 × 10⁴ M^-1 s^-1), while the insertion of both hydroxyl and methoxyl groups showed no effect (6.0 × 10⁴ M^-1 s^-1). Infrared spectroscopy and theoretical calculations allowed a rationalization of these results and pointed out the crucial role of intramolecular H-bonds. We also show that a correct estimation of the rate constant of the reaction with ROO˙ radicals, by using BDE(OH) calculations, requires that the geometry of the radical is as close as possible to that of the parent phenol.

A Comprehensive Database and Analysis Framework To Incorporate Multiscale Data Types and Enable Integrated Analysis of Bioactive Polyphenols

The development of a given botanical preparation for eventual clinical application requires extensive, detailed characterizations of the chemical composition, as well as the biological availability, biological activity, and safety profiles of the botanical. These issues are typically addressed using diverse experimental protocols and model systems. Based on this consideration, in this study we established a comprehensive database and analysis framework for the collection, collation, and integrative analysis of diverse, multiscale data sets. Using this framework, we conducted an integrative analysis of heterogeneous data from in vivo and in vitro investigation of a complex bioactive dietary polyphenol-rich preparation (BDPP) and built an integrated network linking data sets generated from this multitude of diverse experimental paradigms. We established a comprehensive database and analysis framework as well as a systematic and logical means to catalogue and collate the diverse array of information gathered, which is securely stored and added to in a standardized manner to enable fast query. We demonstrated the utility of the database in (1) a statistical ranking scheme to prioritize response to treatments and (2) in depth reconstruction of functionality studies. By examination of these data sets, the system allows analytical querying of heterogeneous data and the access of information related to interactions, mechanism of actions, functions, etc., which ultimately provide a global overview of complex biological responses. Collectively, we present an integrative analysis framework that leads to novel insights on the biological activities of a complex botanical such as BDPP that is based on data-driven characterizations of interactions between BDPP-derived phenolic metabolites and their mechanisms of action, as well as synergism and/or potential cancellation of biological functions. Out integrative analytical approach provides novel means for a systematic integrative analysis of heterogeneous data types in the development of complex botanicals such as polyphenols for eventual clinical and translational applications.

Acacia nilotica leaf improves insulin resistance and hyperglycemia associated acute hepatic injury and nephrotoxicity by improving systemic antioxidant status in diabetic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Acacia nilotica (L.) Delile is used as a traditional anti-diabetic remedy in Bangladesh, Pakistan, Egypt, Nigeria and is mentioned in Ayurveda as well.

AIM

The objective of the study was to evaluate the ethnomedicinal claim of A. nilotica leaf (ANL) extract for its efficiency in ameliorating diabetic complications.

MATERIALS AND METHODS

ANL was orally administrated (50 and 200mg/kg) to alloxanized mice (blood glucose > 200mg/dL) for 20d. Parameters of glucose metabolism, hepatotoxicity, hyperlipidemia and nephrotoxicity were measured with emphasis on elevated oxidative stress. ANL was chemically characterized using GC-MS. Further, docking studies were employed to predict molecular interactions.

RESULTS

ANL lowered (65%, P< 0.001) systemic glucose load in diabetic mice, which was otherwise 398% higher than control. ANL lowered (35%) insulin resistance, without any significant effect on insulin sensitivity (P> 0.05). Anti-hyperglycemic properties of ANL was further supported by lowering of HbA1c (34%; P< 0.001) and improved glucose utilization (OGTT). Overall diabetic complications were mitigated as reflected by lowered hepatic (ALT, AST) and renal (creatinine, BUN) injury markers and normalization of dyslipidemia. Elevated systemic oxidative stress was lowered by increased catalase and peroxidase activities in liver, kidney and skeletal muscle, resulting in 32% decrease of serum MDA levels. Apart from high phenolic and flavonoid content, tocopherol, catechol and β-sitosterol, identified in ANL, demonstrated substantial binding affinity with Nrf2 protein (5FNQ) reflecting possible crosstalk with intracellular antioxidant defense pathways.

CONCLUSION

The present study revealed the potentials of A. nilotica to alleviate diabetes-related systemic complications by limiting oxidative stress which justified the ethnopharmacological antidiabetic claim.

Relation between polyphenols, malondialdehyde, antioxidant capacity, lactate dehydrogenase and toxic elements in human colostrum milk

The present study investigated the interrelationships between the concentration of total polyphenols (TP), malondialdehyde (MDA), total antioxidant capacity (TAC), lactate dehydrogenase activity (LDH) and content of toxic elements (Al, As, Cd, Ni, Pb) in human colostrum milk (n = 75), and further assessed their potential association with maternal lifestyle characteristics. As and Cd were always below detection limits while Al, Ni and Pb were found at the level of 89.7, 6.2 and 1.3 μg L^-1, respectively. Concentrations of TP and MDA, in the studied group were 46.91 ± 21.25 mg GAE L^-1 and 0.66 ± 0.27 nmol mL^-1, respectively, and were inversely correlated (Rs = -0.32; p < 0.01). TP and TAC increased significantly with maternal consumption of vegetables (Rs = 0.25 and Rs = 0.37, respectively; p < 0.05). Concentration of Al was positively correlated with MDA (Rs = 0.21; p < 0.01) and negatively with TP (Rs = -0.28; p < 0.01). Positive correlation was also found between Pb and MDA (Rs = 0.32; p < 0.01). No association with place of living (urban/rural), women's age and former smoking were found for any studied milk parameter. The results add to the general understanding of factors influencing redox balance in milk and potentially affecting its quality.

Early diagnosis of type 2 diabetes based on multiple biomarkers and non-invasive indices

We previously reported that type 2 diabetes risk, early impaired glucose tolerance and insulin resistance can be predicted by measuring the fasting levels of certain biomarkers. Here we validated these findings in randomly recruited healthy volunteers (n = 101) based on biomarker expression as well as various non-invasive indices. Weight, body mass index, waist circumference and visceral fat differed between individuals with impaired fasting glucose and/or impaired glucose tolerance, and normal subjects. Fasting plasma levels of glycated hemoglobin, leptin, pro-insulin and retinol binding protein 4 differed between impaired fasting glucose/impaired glucose tolerance and normal subjects group and between newly detected diabetes and normal subjects group. Insulin resistance was correlated with fasting levels of insulin and leptin/adiponectin (r = 0.913); of insulin, retinol binding protein 4 and leptin/adiponectin (r = 0.903); and of insulin, glycated albumin, and leptin/adiponectin (r = 0.913). Type 2 diabetes risk, early impaired glucose tolerance and insulin resistance were predicted with >98% specificity and sensitivity by comparing fasting glucose levels to the estimated Matsuda Index based on fasting levels of insulin, adiponectin and leptin with or without oxidative lineolate metabolites. Non-invasive indices are slightly correlated with glucose tolerance and insulin resistance but do not increase the accuracy of predicting type 2 diabetes risk.

Comprehensive evaluation of the role of soy and isoflavone supplementation in humans and animals over the past two decades

Soy and soy-based foods are considered healthy, particularly in many Asia-Pacific countries, where soy products have long been consumed. Soy and soy-related products have been found to help prevent the occurrence of cardiovascular diseases and certain types of cancer, such as breast and prostate cancer. These products can also have antioxidative effects that alleviate hot flashes during menopause and bone loss. These biological and therapeutic functions are primarily due to the isoflavones derived from soy, whose structure is similar to the structure of 17-β-oestradiol. Despite the many health benefits for humans and animals, the application of isoflavones remains controversial because of their anti-oestrogenic properties. We focused on general information regarding isoflavones, as well as their structure, function, and application. We summarized evidence showing that dietary or supplemental isoflavones exert protective effects on the health of humans and animals. Based on the literature, we conclude that soy foods and isoflavones may be effective and safe; however, more high-quality trials are needed to fully substantiate their potential use.

Nutritional habits, risk, and progression of Parkinson disease

Parkinson disease (PD) is a multifactorial disease, where a genetic predisposition combines with putative environmental risk factors. Mounting evidence suggests that the initial PD pathological manifestations may be located in the gut to subsequently affect brain areas. Moreover, several lines of research demonstrated that there are bidirectional connections between the central nervous system and the gut, the "gut-brain axis" that influences both brain and gastrointestinal function. This opens a potential therapeutic window suggesting that specific dietary strategies may interact with the disease process and influence the risk of PD or modify its course. Dietary components can also theoretically modulate the chronic activation of the inflammatory response that is associated with aging, the strongest risk factor for PD, that has been suggested to hasten the underlying neurodegenerative process in PD. Here, we reviewed the evidence supporting an association between certain dietary compound and either the risk or progression of PD and have provided an overview of the possible pathomechanisms linking nutrition and neurodegeneration. The results of our review would not support a clear role for any dietary components in reducing the risk or progression of PD. However, the evidence favouring a connection between gut abnormalities, inflammation, and neurodegeneration in PD have become too compelling to be ignored, so that further research, also in the field of nutritional genomics, is highly warranted.

Significance of Microbiota in Obesity and Metabolic Diseases and the Modulatory Potential by Medicinal Plant and Food Ingredients

Metabolic syndrome is a cluster of three or more metabolic disorders including insulin resistance, obesity, and hyperlipidemia. Obesity has become the epidemic of the twenty-first century with more than 1.6 billion overweight adults. Due to the strong connection between obesity and type 2 diabetes, obesity has received wide attention with subsequent coining of the term "diabesity." Recent studies have identified unique contributions of the immensely diverse gut microbiota in the pathogenesis of obesity and diabetes. Several mechanisms have been proposed including altered glucose and fatty acid metabolism, hepatic fatty acid storage, and modulation of glucagon-like peptide (GLP)-1. Importantly, the relationship between unhealthy diet and a modified gut microbiota composition observed in diabetic or obese subjects has been recognized. Similarly, the role of diet rich in polyphenols and plant polysaccharides in modulating gut bacteria and its impact on diabetes and obesity have been the subject of investigation by several research groups. Gut microbiota are also responsible for the extensive metabolism of polyphenols thus modulating their biological activities. The aim of this review is to shed light on the composition of gut microbes, their health importance and how they can contribute to diseases as well as their modulation by polyphenols and polysaccharides to control obesity and diabetes. In addition, the role of microbiota in improving the oral bioavailability of polyphenols and hence in shaping their antidiabetic and antiobesity activities will be discussed.

Evaluation of the Antidiabetic Activity and Chemical Composition of Geranium collinum Root Extracts-Computational and Experimental Investigations

The root of Geranium collinum Steph is known in Tajik traditional medicine for its hepatoprotective, antioxidant, and anti-inflammatory therapeutic effects. The present study was conducted to evaluate of potential antidiabetic, antioxidant activities, total polyphenolic and flavonoid content from the different extracts (aqueous, aqueous-ethanolic) and individual compounds isolated of the root parts of G. collinum. The 50% aqueous-ethanolic extract possesses potent antidiabetic activity, with IC₅₀ values of 0.10 μg/mL and 0.09 μg/mL for the enzymes protein-tyrosine phosphatase (1B PTP-1B) and α-glucosidase, respectively. Phytochemical investigations of the 50% aqueous-ethanolic extract of G. collinum, led to the isolation of ten pure compounds identified as 3,3',4,4'-tetra-O-methylellagic acid (1), 3,3'-di-O-methylellagic acid (2), quercetin (3), caffeic acid (4), (+)-catechin (5), (-)-epicatechin (6), (-)-epigallocatechin (7), gallic acid (8), β-sitosterol-3-O-β-d-glucopyranoside (9), and corilagin (10). Their structures were determined based on 1D and 2D NMR and mass spectrometric analyses. Three isolated compounds exhibited strong inhibitory activity against PTP-1B, with IC₅₀ values below 0.9 μg/mL, more effective than the positive control (1.46 μg/mL). Molecular docking analysis suggests polyphenolic compounds such as corilagin, catechin and caffeic acid inhibit PTP-1B and β-sitosterol-3-O-β-d-gluco-pyranoside inhibits α-glucosidase. The experimental results suggest that the biological activity of G. collinum is related to its polyphenol contents. The results are also in agreement with computational investigations. Furthermore, the potent antidiabetic activity of the 50% aqueous-ethanolic extract from G. collinum shows promise for its future application in medicine. To the best of our knowledge, we hereby report, for the first time, the antidiabetic activity of G. collinum.

Potential of Lichen Compounds as Antidiabetic Agents with Antioxidative Properties: A Review

The advancement in the knowledge of potent antioxidants has uncovered the way for greater insight in the treatment of diabetic complications. Lichens are a rich resource of novel bioactive compounds and their antioxidant potential is well documented. Herein we review the antidiabetic potential of lichens which have received considerable attention, in the recent past. We have correlated the antidiabetic and the antioxidant potential of lichen compounds. The study shows a good accordance between antioxidant and antidiabetic activity of lichens and points out the need to look into gathering the scarce and scattered data on biological activities for effective utilization. The review establishes that the lichen extracts, especially of Parmotrema sp. and Ramalina sp. have shown promising potential in both antidiabetic and antioxidant assays. Ubiquitous compounds, namely, zeorin, methylorsellinate, methyl-β-orcinol carboxylate, methyl haematommate, lecanoric acid, salazinic acid, sekikaic acid, usnic acid, gyrophoric acid, and lobaric acid have shown promising potential in both antidiabetic as well as antioxidant assays highlighting their potential for effective treatment of diabetic mellitus and its associated complications. The available compilation of this data provides the future perspectives and highlight the need for further studies of this potent herbal source to harvest more beneficial therapeutic antidiabetic drugs.

Nobiletin ameliorates ischemia-reperfusion injury by suppressing the function of Kupffer cells after liver transplantation in rats

This study aims to explore the protective effects of nobiletin against hepatic ischemia-reperfusion (IR) injury after liver transplantation. Kupffer cells (KCs) were activated and co-cultured with different concentration of nobiletin for 24h in vitro, inflammatory products and activity of TLR4/NF-κB signaling pathway were detected. Sprague-Dawley rats were selected and underwent orthotopic liver transplantation. Donors were injected intravenously with nobiletin (50mg/kg) or saline solution, once a day for 1 week before the surgery. Recipients were randomly paired and sacrificed at the indicated time points (3, 6, and 24h after the surgery), the graft liver tissues and blood samples were collected for analysis. Hepatic function, inflammatory mediators, apoptosis of hepatocytes, histological changes, KCs and CD4+ T-lymphocyte infiltration were assessed. Results showed nobiletin dose-dependently suppressed the expression of inflammatory mediators and the activity of TLR4/NF-κB signaling pathway in activated KCs. Furthermore, nobiletin alleviated liver damage induced by IR in vivo, significantly decreased the serum levels of alanine aminotransferase, aspartate transaminase, inflammatory cytokines and alleviated the histopathology changes. Moreover, liver in the nobiletin treated group exhibited less KCs and CD4+ lymphocyte infiltration and lower hepatocyte apoptosis after operation. In addition, activity of TLR4/NF-κB signaling pathway in KCs was also suppressed, consistent with the results in vitro. Collectively, Nobiletin can ameliorate IR injury after liver transplantation and may be a promising new strategy to protect against liver IR injury.

Grape Polyphenols' Effects in Human Cardiovascular Diseases and Diabetes

The consumption of fruits and vegetables, as well as foods enriched in bioactive compounds and nutraceuticals, has increased due to consumers' interest in the relevance of food composition for human health. Considerable recent interest has focused on bioactive phenolic compounds in grape, as they possess many biological activities, such as antioxidant, cardioprotective, anticancer, anti-inflammation, anti-ageing and antimicrobial properties. Observational studies indicate that the intake of polyphenol-rich foods improves vascular health, thereby significantly reducing the risk of hypertension, and cardiovascular disease (CVD). Other researchers have described the benefits of a grape polyphenol-rich diet for other types of maladies such as diabetes mellitus. This is a comprehensive review on the consumption of polyphenolic grape compounds, concerning their potential benefits for human health in the treatment of cardiovascular diseases and diabetes.

8-Hydroxyirilone 5-methyl ether and 8-hydroxyirilone, new antioxidant and α-amylase inhibitors isoflavonoids from Iris germanica rhizomes

Iris species are well recognized as wealthy sources of isoflavonoids. In the present study, phytochemical investigation of the rhizomes of Iris germanica (Iridaceae) procure the isolation of two new isoflavonoids namely, 8-hydroxyirilone 5-methyl ether (2) and 8-hydroxyirilone (3), along with eight known isoflavonoids: irilone 4'-methyl ether (1), irilone (4), irisolidone (5), irigenin S (6), irigenin (7), irilone 4'-O-β-d-glucopyranoside (8), iridin S (9), and iridin (10). The isolated flavonoids were structurally characterized with the assist of comprehensive spectroscopic analyses (UV, IR, 1D and 2D NMR, and HRMS) and comparing with the published data. They were estimated for their antioxidant and antidaibetic capacities using DPPH and α-amylase inhibition assays, respectively. Compounds 2, 3, and 4 exhibited prominent antioxidant activities with IC₅₀ values of 12.92, 9.23, and 10.46μM, respectively compared to propyl gallate (IC₅₀ 7.11μM). Moreover, 2-5 possessed highest α-amylase inhibitory activity with % inhibition 66.1, 78.3, 67.3, and 70.1, respectively in comparison to acarbose (reference α-amylase inhibitor). Additionally, their structure-activity relationship has been discussed.

Rutin inhibits proliferation, attenuates superoxide production and decreases adhesion and migration of human cancerous cells

Lung and colorectal cancer are the principal causes of death in the world. Rutin, an active flavonoid compound, is known for possessing a wide range of biological activities. In this study, we examined the effect of rutin on the viability, superoxide anion production, adhesion and migration of human lung (A549) and colon (HT29 and Caco-2) cancer cell lines. In order to control the harmlessness of the tested concentrations of rutin, the viability of cancer cell lines was assessed using a 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. ROS generation was measured by lucigenin chemiluminescence detecting superoxide ions. To investigate the effect of rutin on the behavior of human lung and colon cancer cell lines, we performed adhesion assays, using various purified extracellular matrix (ECM) proteins. Finally, in vitro cell migration assays were explored using modified Boyden chambers. The viability of cancerous cells was inhibited by rutin. It also significantly attenuated the superoxide production in HT29 cells. In addition, rutin affected adhesion and migration of A549 and HT29 cell. These findings indicate that rutin, a natural molecule, might have potential as anticancer agent against lung and colorectal carcinogenesis.

Evaluation of Hypoglycemic and Genotoxic Effect of Polyphenolic Bark Extract from Quercus sideroxyla

Quercus sideroxyla is a wood species whose bark has phenolic compound and should be considered to be bioactive; the hypoglycemic and genotoxic properties of Q. sideroxyla bark were evaluated in this study. Total phenolic compound was determined in crude extract (CE) and organic extract (OE). The OE has the highest amount of phenols (724.1 ± 12.0 GAE/g). Besides, both CE and OE demonstrated effect over the inhibition of α-amylase in vitro. Hypoglycemic activity was assessed by glucose tolerance curve and the area under curve (UAC); OE showed the highest hypoglycemic activity. In addition, diabetes was induced by streptozotocin (65 mg/kg) and the extracts (50 mg/kg) were administered for 10 days; OE showed hypoglycemic effect compared with diabetic control and decreased hepatic lipid peroxidation. Acute toxicity and genotoxicity were evaluated in CE; results of acute toxicity did not show any mortality. Besides, the comet assay showed that CE at a dose of 100 mg/kg did not show any genotoxic effect when evaluated at 24 h, whereas it induced slight damage at 200 mg/kg, with the formation of type 1 comets.

Plant Cell Cancer: May Natural Phenolic Compounds Prevent Onset and Development of Plant Cell Malignancy? A Literature Review

Phenolic compounds (PCs) are known as a chemically diverse category of secondary and reactive metabolites which are produced in plants via the shikimate-phenylpropanoid pathways. These compounds-ubiquitous in plants-are an essential part of the human diet, and are of considerable interest due to their antioxidant properties. Phenolic compounds are essential for plant functions, because they are involved in oxidative stress reactions, defensive systems, growth, and development. A large body of cellular and animal evidence carried out in recent decades has confirmed the anticancer role of PCs. Phytohormones-especially auxins and cytokinins-are key contributors to uncontrolled growth and tumor formation. Phenolic compounds can prevent plant growth by the endogenous regulation of auxin transport and enzymatic performance, resulting in the prevention of tumorigenesis. To conclude, polyphenols can reduce plant over-growth rate and the development of tumors in plant cells by regulating phytohormones. Future mechanistic studies are necessary to reveal intracellular transcription and transduction agents associated with the preventive role of phenolics versus plant pathological malignancy cascades.

Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model

Parkinson’s disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE’s ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model.