Phytol/Phytanic acid and insulin resistance: potential role of phytanic acid proven by docking simulation and modulation of biochemical alterations

Hydrodistillation Optimization for Borago officinalis L. Essential Oil and Its Chemical Composition Analysis

The essential oil extracted from Borago officinalis L. aerial parts using hydrodistillation contains several compounds, although it yields low amounts. For the first time, this study investigated the effects of hydrodistillation parameters and optimized conditions to maximize the yield of B. officinalis essential oil while characterizing its chemical composition using gas chromatography-mass spectrometry. A single-factor evaluation of three extraction parameters-extraction time, liquid-to-solid ratio, and soaking time-revealed optimal conditions of 4 h, 10:1 mL/g, and 2 h, respectively. Subsequently, the Box-Behnken response surface method produced a significant polynomial model, determining optimal conditions of an extraction time of 5 h, a liquid-to-solid ratio of 11.06:1 mL/g, and a soaking time of 2 h, 17 min, and 34 s, resulting in an essential oil yield of 0.42%. A total of 21 compounds were identified in B. officinalis essential oil, predominantly nonacosane (29.15%) and phytol (27.92%).

Flavonoid-Rich Trianthema decandra Ameliorates Cognitive Dysfunction in the Hyperglycemic Rats

The present study was aimed at the evaluation of neuroprotective ability of methanolic extract of Trianthema decandra (METD) against hyperglycemia-related cognitive impairment in rats. The extract of T. decandra was standardized by TLC and HPTLC methods. To verify the identity and purity of isolated compounds, they were segregated and characterized using various techniques, including UV-visible spectrophotometry, FT-IR, H-NMR, and Mass spectroscopy. α-Amylase and α-glucosidase inhibition property of the extracts were assessed in-vitro. The screening of the neuroprotective effects of METD in hyperglycemic rats was done utilizing Morri's water (MWM) and elevated plus maze (EPM) model, as well as acetylcholinesterase (AChE) activity. The extracts of Trianthema decandra and its chemical constituents, namely quercetin and phytol, demonstrated a significant protective effect on enzymes like α-amylase and α-glucosidase. Methanol and hydroalcoholic extracts have shown the strongest inhibitory activity followed by chloroform extract. Quercetin and phytol were associated with the methanolic and chloroform extracts which were identified using TLC and HPTLC techniques. During the thirty days of the study, the induction of diabetes in the rats exhibited persistent hyperglycemia, hyperlipidemia, higher escape latency during training trials and reduced time spent in target quadrant in probe trial in Morris water maze test, and increased escape latency in EPM task. Regimen of METD (200 and 400 mg/kg) in the diabetic rats reduced the glucose levels in blood, lipid, and liver profile and showed positive results on Morri's water and elevated plus maze tasks. During the investigation, it was determined that Trianthema decandra extracts and the chemical constituent's quercetin and phytol in it had anti-diabetic and neuroprotective activities.

Unrivalled Insight into Possible Biopharmaceutical Application of Justicia vahlii Roth. (Acanthaceae): Chemodiversity, In Vitro Bioactivities, and Computational Analysis

Justicia vahliiRoth. is an important wild medicinal food plant traditionally used for treating inflammation and various common ailments. This study investigated the chemical composition, antioxidant, enzyme inhibition and toxicity profiles of n-hexane (nHEJv) and chloroform (CEJv) extracts of J. vahlii. Moreover, the effect of the extracts was evaluated on CCl4 induced liver injury. The total phenolic and flavonoid contents were present in both extracts in significant amount. The UPLC-Q-TOF-MS and GC-MS profiling of CEJv tentatively identified several important phytocompounds. The CEJv extract was comparatively more active for antioxidant activity and α-amylase inhibition, whereas the nHEJv extract presented higher inhibition potential against urease, tyrosinase, and α-glucosidase enzymes. Similarly, the in-silicostudy of four major compounds, i. e., 1-acetoxypinoresinol, 3-hydroxysebacic acid, nortrachelogenin, and viscidulin-III have shown a good docking score against the clinically significant enzymes. The acute oral toxicity and brine shrimp lethality assaysrevealed the extracts as non-toxic. The CCl4 treated animals showed a geared depletion of various antioxidant enzymes which were significantly reversed with the treatment of the extracts. Overall, the study's findings revealed J. vahliiwith antioxidant mediated hepatoprotective and enzyme inhibition potential and warrant further research on isolation of the bioactive compounds.

Amelioration of Phytanic Acid-Induced Neurotoxicity by Nutraceuticals: Mechanistic Insights

Phytanic acid (PA) (3,7,11,15-tetramethylhexadecanoic acid) is a methyl-branched fatty acid that enters the body through food consumption, primarily through red meat, dairy products, and fatty marine foods. The metabolic byproduct of phytol is PA, which is then oxidized by the ruminal microbiota and some marine species. The first methyl group at the 3-position prevents the β-oxidation of branched-chain fatty acid (BCFA). Instead, α-oxidation of PA results in the production of pristanic acid (2,10,14-tetramethylpentadecanoic acid) with CO2. This fatty acid (FA) builds up in individuals with certain peroxisomal disorders and is historically linked to neurological impairment. It also causes oxidative stress in synaptosomes, as demonstrated by an increase in the production of reactive oxygen species (ROS), which is a sign of oxidative stress. This review concludes that the nutraceuticals (melatonin, piperine, quercetin, curcumin, resveratrol, epigallocatechin-3-gallate (EGCG), coenzyme Q10, ω-3 FA) can reduce oxidative stress and enhanced the activity of mitochondria. Furthermore, the use of nutraceuticals completely reversed the neurotoxic effects of PA on NO level and membrane potential. Additionally, the review further emphasizes the urgent need for more research into dairy-derived BCFAs and their impact on human health.

Phytochemical Analysis and Evaluation of Antioxidant, Antidiabetic, and Anti-inflammatory Properties of Aegle marmelos and Its Validation in an In-Vitro Cell Model

INTRODUCTION

Persistent hyperglycemia significantly increases oxidative stress and inflammation resulting in multiple cellular and molecular alterations which further exacerbate the diabetes associated complications. Aegle marmelos (L.) Corrêa is a medicinal plant used in the Indian system of medicine for treating various disorders including diabetes. However, studies on phytoconstituents and their pharmacological activity of this plant are limited. Therefore, we aimed to determine the phytochemical components, evaluate the antidiabetic activity, anti-inflammatory activity, and antioxidant activity of A. marmelos leaf extract, and validate its mechanistic effects in an in vitro cell model.

METHODS

The qualitative and quantitative analysis of the different phytoconstituents in the extract was determined using standardized protocols. The antioxidant activity of the extract was evaluated by 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay and ferric reducing antioxidant power (FRAP) assay. The antidiabetic activity of the extract was evaluated by α-amylase inhibition and α-glucosidase inhibition assay. The anti-inflammatory activity was studied using an albumin denaturation assay. In addition, the pharmacological effect(s) of leaf extract was checked in the normal rat kidney fibroblast cells (NRK-49F) under high glucose conditions. Intracellular reactive oxygen species (ROS) generation was measured by fluorometry using fluorescence probe 2',7'-dichlorodihydrofluorescin diacetate (DCF-DA). mRNA expression of inflammatory markers including inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) was studied using real-time quantitative polymerase chain reaction (RT-qPCR). Cell migration was studied using cell scratch assay. Statistical analysis was performed using GraphPad Prism version 8.0.

RESULTS

The phytochemical analysis of A. marmelos leaf extract revealed the presence of alkaloids, phenols, flavonoids, and saponins. The extract showed higher antioxidant activity in the DPPH (IC50=258.21 µg/mL) and FRAP assay (IC50=293.83 µg/mL). The extract exhibited prominent antidiabetic activity by inhibiting enzymes α-Amylase (IC50=73.2 µg/mL) and α-glucosidase (IC50=43.9 µg/mL). In addition, the extract showed effective anti-inflammatory activity by significantly inhibiting the denaturation of egg albumin (IC50=102.8 µg/mL). Further, the leaf extract significantly decreased the high glucose-induced ROS generation as well as inflammatory markers in rat fibroblast cell lines in a dose-dependent manner. Additionally, high glucose-induced cell migration as the measure of cell injury was effectively reduced by the extract treatment.

CONCLUSION

 A. marmelos leaf extract was quantified to possess a substantial amount of important phytoconstituents that have promising pharmacological properties. Besides showing antidiabetic activity, the extract significantly combats the high glucose-induced ROS generation, inflammatory markers expressions, and cell migration. Further, in-depth studies and clinical trials are warranted so as to position these traditional remedies for the treatment of metabolic disorders.

Exploring Folklore Ecuadorian Medicinal Plants and Their Bioactive Components Focusing on Antidiabetic Potential: An Overview

Diabetes mellitus (DM) is a global health concern characterized by a deficiency in insulin production. Considering the systemic toxicity and limited efficacy associated with current antidiabetic medications, there is the utmost need for natural, plant-based alternatives. Herbal medicines have experienced exponential growth in popularity globally in recent years for their natural origins and minimal side effects. Ecuador has a rich cultural history in ethnobotany that plays a crucial role in its people's lives. This study identifies 27 Ecuadorian medicinal plants that are traditionally used for diabetes treatment and are prepared through infusion, decoction, or juice, or are ingested in their raw forms. Among them, 22 plants have demonstrated hypoglycemic or anti-hyperglycemic properties that are rich with bioactive phytochemicals, which was confirmed in several in vitro and in vivo studies. However, Bryophyllum gastonis-bonnieri, Costus villosissimus, Juglans neotropica, Pithecellobium excelsum, and Myroxylon peruiferum, which were extensively used in traditional medicine preparation in Ecuador for many decades to treat diabetes, are lacking in pharmacological elucidation. The Ecuadorian medicinal plants used to treat diabetes have been found to have several bioactive compounds such as flavonoids, phenolics, fatty acids, aldehydes, and terpenoids that are mainly responsible for reducing blood sugar levels and oxidative stress, regulating intestinal function, improving insulin resistance, inhibiting α-amylase and α-glucosidase, lowering gluconeogenic enzymes, stimulating glucose uptake mechanisms, and playing an important role in glucose and lipid metabolism. However, there is a substantial lack of integrated approaches between the existing ethnomedicinal practices and pharmacological research. Therefore, this review aims to discuss and explore the traditional medicinal plants used in Ecuador for treating DM and their bioactive phytochemicals, which are mainly responsible for their antidiabetic properties. We believe that the use of Ecuadorian herbal medicine in a scientifically sound way can substantially benefit the local economy and industries seeking natural products.

Green honey of Banggi Island: A preliminary anti-diabetic study on zebrafish model

Zebrafish is a developing vertebrate model with several advantages, including its small size, and high experimental efficiency. Malaysia exhibit one of the highest diabetes rates in the Western Pacific and incurring an annual cost of 600 million US dollars. The objective of the study is to determine the antidiabetic properties of green honey (GH) using a zebrafish model. Adult zebrafish, aged 3-4 months, were subjected to overfeeding and treated with streptozotocin (STZ) through intraperitoneal injection (IP) on days 7 and 9. The study assessed the oral sucrose tolerance test (OSTT) and the anti-diabetic effects of green honey. The evaluation was conducted at three time points: 30, 60, and 120 min after treatment and sucrose administration. The study utilised a model with a sample size of 5. The study was performed in six groups. These groups are (1) Normal control (non-diabetic, no intervention), (2) Normal control + GH (non-diabetic, supplemented with GH 3 μl), (3) DM control (diabetic, no intervention), (4) DM Gp1 (diabetic, 3 μL GH), (5) DM Gp2 (diabetic, 6 μ L GH), (6) DM Acarbose (diabetic, treated with acarbose). Fasting blood glucose levels for non-diabetic (non-DM) and diabetic (DM) groups were evaluated before and after the 10 days of diabetic induction. DM groups (excess of food and two injections of STZ) have caused a significant increment in the fasting blood glucose to 11.55 mmol/l (p < 0.0001). Both GH treatments effectively decreased postprandial blood glucose levels and the area under the curve in the oral glucose tolerance test (OSTT). Based on these results, it is concluded that green honey could play a role in hyperglycemia management and show potential as a natural alternative to conventional diabetes therapy. The underlying mechanisms need to be clarified, and their potential use in human diabetes therapy needs to be investigated.

Phytanic acid, an inconclusive phytol metabolite: A review

Phytanic acid (PA: 3,7,11,15-tetramethylhexadecanoic acid) is an important biometabolite of the chlorophyll-derived diterpenoid phytol. Its biological sources (occurrence) and ADME (absorption, distribution, metabolism, and elimination) profile are well-discussed in the literature. Cumulative literature suggests that PA has beneficial as well as harmful biological roles in humans and other animals. This study aimed to sketch a brief summary of PA's beneficial and harmful pharmacological effects in test systems on the basis of existing literature reports. Literature findings propose that PA has anti-inflammatory and immunomodulatory, antidiabetic, anti-obesity, anticancer, and oocyte maturation effects. Although a high plasma PA-level mediated SLS remains controversial, it is evident to link it with Refsum's disease and other peroxisomal enzyme deficiency diseases in humans, including RCDP and LD; ZHDA and Alzheimer's disease; progressive ataxia and dysarthria; and an increased risk of some lymphomas such as LBL, FL, and NHL. PA exerts toxic effects on different kinds of cells, including neuronal, cardiac, and renal cells, through diverse pathways such as oxidative stress, mitochondrial disturbance, apoptosis, disruption of Na+/K+-ATPase activity, Ca2+ homeostasis, alteration of AChE and MAO activities, etc. PA is considered a cardiac biomarker in humans. In conclusion, PA may be one of the most important biometabolites in humans.

Anti-Diabetic Activity of Glycyrrhetinic Acid Derivatives FC-114 and FC-122: Scale-Up, In Silico, In Vitro, and In Vivo Studies

Type 2 diabetes (T2D) is one of the most common diseases and the 8th leading cause of death worldwide. Individuals with T2D are at risk for several health complications that reduce their life expectancy and quality of life. Although several drugs for treating T2D are currently available, many of them have reported side effects ranging from mild to severe. In this work, we present the synthesis in a gram-scale as well as the in silico and in vitro activity of two semisynthetic glycyrrhetinic acid (GA) derivatives (namely FC-114 and FC-122) against Protein Tyrosine Phosphatase 1B (PTP1B) and α-glucosidase enzymes. Furthermore, the in vitro cytotoxicity assay on Human Foreskin fibroblast and the in vivo acute oral toxicity was also conducted. The anti-diabetic activity was determined in streptozotocin-induced diabetic rats after oral administration with FC-114 or FC-122. Results showed that both GA derivatives have potent PTP1B inhibitory activity being FC-122, a dual PTP1B/α-glucosidase inhibitor that could increase insulin sensitivity and reduce intestinal glucose absorption. Molecular docking, molecular dynamics, and enzymatic kinetics studies revealed the inhibition mechanism of FC-122 against α-glucosidase. Both GA derivatives were safe and showed better anti-diabetic activity in vivo than the reference drug acarbose. Moreover, FC-114 improves insulin levels while decreasing LDL and total cholesterol levels without decreasing HDL cholesterol.

Anticancer effects of phytol against Sarcoma (S-180) and Human Leukemic (HL-60) cancer cells

Phytol (Pyt), a diterpenoid, possesses many important bioactivities. This study evaluates the anticancer effects of Pyt on sarcoma 180 (S-180) and human leukemia (HL-60) cell lines. For this purpose, cells were treated with Pyt (4.72, 7.08, or 14.16 μM) and a cell viability assay was performed. Additionally, the alkaline comet assay and micronucleus test with cytokinesis were also performed using doxorubicin (6 μM) and hydrogen peroxide (10 mM) as positive controls and stressors, respectively. Results revealed that Pyt significantly reduced the viability and rate of division in S-180 and HL-60 cells with IC50 values of 18.98 ± 3.79 and 1.17 ± 0.34 μM, respectively. Pyt at 14.16 μM exerted aneugenic and/or clastogenic effects in S-180 and HL-60 cells, where the number of micronuclei and other nuclear abnormalities (e.g., nucleoplasmic bridges and nuclear buds) were frequently observed. Moreover, Pyt at all concentrations induced apoptosis and showed necrosis at 14.16 μM, suggesting its anticancer effects on the tested cancer cell lines. Taken together, Pyt showed promising anticancer effects, possibly through inducing apoptosis and necrosis mechanisms, and it exerted aneugenic and/or clastogenic effects on the S-180 and HL-60 cell lines.

Phytosome Supplements for Delivering Gymnema inodorum Phytonutrients to Prevent Inflammation in Macrophages and Insulin Resistance in Adipocytes

Gymnema inodorum (GI) is a leafy green vegetable found in the northern region of Thailand. A GI leaf extract has been developed as a dietary supplement for metabolic diabetic control. However, the active compounds in the GI leaf extract are relatively nonpolar. This study aimed to develop phytosome formulations of the GI extract to improve the efficiencies of their phytonutrients in terms of anti-inflammatory and anti-insulin-resistant activities in macrophages and adipocytes, respectively. Our results showed that the phytosomes assisted the GI extract's dispersion in an aqueous solution. The GI phytocompounds were assembled into a phospholipid bilayer membrane as spherical nanoparticles about 160-180 nm in diameter. The structure of the phytosomes allowed phenolic acids, flavonoids and triterpene derivatives to be embedded in the phospholipid membrane. The existence of GI phytochemicals in phytosomes significantly changed the particle's surface charge from neutral to negative within the range of -35 mV to -45 mV. The phytosome delivery system significantly exhibited the anti-inflammatory activity of the GI extract, indicated by the lower production of nitric oxide from inflamed macrophages compared to the non-encapsulated extract. However, the phospholipid component of phytosomes slightly interfered with the anti-insulin-resistant effects of the GI extract by decreasing the glucose uptake activity and increasing the lipid degradation of adipocytes. Altogether, the nano-phytosome is a potent carrier for transporting GI phytochemicals to prevent an early stage of T2DM.

Elaeagnus umbellata: A miraculous shrub with potent health-promoting benefits from Northwest Himalaya

Medicinal plants encompassing a series of bioactive compounds have gained significant importance for use in the treatment of different diseases. Of them, Elaeagnus umbellata Thunb. (Deciduous shrub found in dappled shade, and sunny hedge) exhibits high medicinal value, with a widespread distribution across the Pir Panjal region of the Himalayas. Fruits serve as an excellent source of vitamins, minerals, and other essential compounds that exhibits hypolipidemic, hepatoprotective, and nephroprotective effects. The phytochemical fingerprint of berries revealed them to have a high content of polyphenols (with major proportion of anthocyanins), followed by monoterpenes and vitamin C. Extract of fruits help in regulating the digestion and absorption of glucose and reduces inflammation and oxidative stress. The phytosterols upholding anticoagulant activity serve the purpose of causing decrease in angina and the blood cholesterol levels. Phytochemicals such as eugenol, palmitic acid, and methyl palmitate exhibit potent antibacterial activity against broad range of disease-causing agents. Additionally, a high percentage of essential oils attribute it with the property of being effective against heart ailments. The present study highlights the importance of E. umbellata in traditional medicinal practices, and summarizes the knowledge of its bioactive constituents and a snapshot vision of remarkable biological activities like antimicrobial, antidiabetic, antioxidant, etc towards understanding its role in the development of efficient drug regimens for use in the treatment of different diseases. It also underlines the need to explore the plant on nutritional aspects to strengthen the existing knowledge pertaining to health promoting potential of E. umbellata.

Convolvulus pluricaulis Choisy’s Extraction, Chemical Characterization and Evaluation of the Potential Effects on Glycaemic Balance in a 3T3-L1 Adipocyte Cell Model

Convolvulus pluricaulis (CP) is a common Indian herb, largely employed in Ayurvedic medicine and known for its neuroprotective and neuroinflammatory action. Its effectiveness against several pathologic/sub-pathologic conditions is widely accepted, but it is not yet completely chemically characterized. In recent years, several researchers have pointed out the involvement of CP and other Convolvulaceae in lipidic and glucidic metabolism, particularly in the control of hyperlipidaemia and diabetic conditions. In this scenario, the aim of the study was to chemically characterize the medium polarity part of the CP whole plant and its fractions and to shed light on their biological activity in adipocyte differentiation using the 3T3-L1 cell model. Our results demonstrated that the CP extract and fractions could upregulate the adipocyte differentiation through the modulation of the nuclear receptor PPARγ (Peroxisome Proliferator-Activated Receptor γ), broadly recognized as a key regulator of adipocyte differentiation, and the glucose transporter GLUT-4, which is fundamental for cellular glucose uptake and for metabolism control. CP also showed the ability to exert an anti-inflammatory effect, downregulating cytokines such as Rantes, MCP-1, KC, eotaxin, and GM-CSF, which are deeply involved in insulin resistance and glucose intolerance. Taken together, these data suggest that CP could exert a potential beneficial effect on glycemia and could be employed as an anti-diabetic adjuvant or, in any case, a means to better control glucose homeostasis.

In Vitro α-Amylase and α-Glucosidase Inhibitory Activity of Green Seaweed Halimeda tuna Extract from the Coast of Lhok Bubon, Aceh

Seaweed belongs to marine biota and contains nutrients and secondary metabolites beneficial for health. This study aimed to determine the antidiabetic activity of extracts and fractions of green seaweed Halimeda tuna. The H. tuna sample was extracted with the maceration method using methanol and then partitioned using ethyl acetate and water to obtain ethyl acetate and water fractions. The methanol extract, ethyl acetate fraction, and water fraction of H. tuna were tested for their inhibitory activity against α-amilase and α-glucosidase. The methanol extract and the fractions with the highest inhibitory activity were phytochemically tested and analyzed using gas chromatography-mass spectrometry (GC-MS). The results showed that the ethyl acetate fraction (IC50 = 0.88 ± 0.20 mg/mL) inhibited α-amylase relatively similar to acarbose (IC50 = 0.76 ± 0.04 mg/mL). The methanol extract (IC50 = 0.05 ± 0.01 mg/mL) and the ethyl acetate fraction (IC50 = 0.01 ± 0.00 mg/mL) demonstrated stronger inhibitory activity against α-glucosidase than acarbose (IC50 = 0.27 ± 0.13 mg/mL). Phytochemical testing showed that the methanol extract and the ethyl acetate fraction contained secondary metabolites: alkaloids, flavonoids, steroids, and phenol hydroquinone. The compounds in methanol extract predicted to have inhibitory activity against α-amylase and α-glucosidase were Docosanol, Neophytadiene, Stigmasta-7,22-dien-3-ol,acetate,(3.beta.,5.alpha.,22E), Octadecanoic acid,2-oxo-,methyl ester, and phytol, while those in the ethyl acetate fraction were n-Nonadecane, Phytol, Butyl ester, 14-.Beta.-H-pregna, Octadecenoic acid, and Oleic acid.

Secondary Terpenes in Cannabis sativa L.: Synthesis and Synergy

Cannabis is a complex biosynthetic plant, with a long history of medicinal use. While cannabinoids have received the majority of the attention for their psychoactive and pharmacological activities, cannabis produces a diverse array of phytochemicals, such as terpenes. These compounds are known to play a role in the aroma and flavor of cannabis but are potent biologically active molecules that exert effects on infectious as well as chronic diseases. Furthermore, terpenes have the potential to play important roles, such as synergistic and/or entourage compounds that modulate the activity of the cannabinoids. This review highlights the diversity and bioactivities of terpenes in cannabis, especially minor or secondary terpenes that are less concentrated in cannabis on a by-mass basis. We also explore the question of the entourage effect in cannabis, which studies to date have supported or refuted the concept of synergy in cannabis, and where synergy experimentation is headed, to better understand the interplay between phytochemicals within Cannabis sativa L.

Potential of Diterpenes as Antidiabetic Agents: Evidence from Clinical and Pre-Clinical Studies

Diterpenes are a diverse group of structurally complex natural products with a wide spectrum of biological activities, including antidiabetic potential. In the last 25 years, numerous diterpenes have been investigated for antidiabetic activity, with some of them reaching the stage of clinical trials. However, these studies have not been comprehensively reviewed in any previous publication. Herein, we critically discussed the literature on the potential of diterpenes as antidiabetic agents, published from 1995 to September, 2021. In the period under review, 427 diterpenes were reported to have varying degrees of antidiabetic activity. Steviol glycosides, stevioside (1) and rebaudioside A (2), were the most investigated diterpenes with promising antidiabetic property using in vitro and in vivo models, as well as human subjects. All the tested pimaranes consistently showed good activity in preclinical evaluations against diabetes. Inhibitions of α-glucosidase and protein tyrosine phosphatase 1B (PTP 1B) activities and peroxisome proliferator-activated receptors gamma (PPAR-γ) agonistic property, were the most frequently used assays for studying the antidiabetic activity of diterpenes. The molecular mechanisms of action of the diterpenes include increased GLUT4 translocation, and activation of phosphoinositide 3-kinase (PI3K) and AMP-activated protein kinase (AMPK)-dependent signaling pathways. Our data revealed that diterpenes hold promising antidiabetic potential. Stevioside (1) and rebaudioside A (2) are the only diterpenes that were advanced to the clinical trial stage of the drug discovery pipeline. Diterpenes belonging to the abietane, labdane, pimarane and kaurane class have shown promising activity in in vitro and in vivo models of diabetes and should be further investigated.

V. In vitro antidiabetic, antioxidant activities and chemical composition of Ajuga parviflora Benth. shoot

Introduction: Ajuga parviflora Benth. (Lamiaceae) is an herbaceous plant that possesses ethnomedicinal values and is well known for its folkloric management of diabetes. This study was aimed to provide an experimental justification for its traditional antidiabetic use. Methods: Hydroalcoholic extract of A. parviflora shoot was quantified for its total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC). Gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectrophotometer (FTIR) spectroscopy were also used for their chemical nature. Additionally, the extract was evaluated for its inhibitory potential against key enzymes linked with hyperglycemia by in vitro means. Subsequently, for estimation of the antioxidant capacities 2,2-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS), and hydrogen peroxide (H2O2) scavenging activities were determined.Results: GC-MS analysis revealed numerous biologically active phytoconstituents including brassicasterol, phytol, and palmitic acid. The presence of different active functional groups such as alcohol, nitrile, amine, alkyl halide, alkene, and alkane was confirmed by FTIR analysis. The extract showed a significant (P≤ 0.05) dose-dependent inhibition for α-amylase enzyme (132.38±1.18 μg/mL), α-glucosidase enzyme (22.66±0.11 μg/mL), DPPH radical (103.03±1.59 μg/mL), ABTS radical (140.10±3.40 μg/mL) and H2O2 radical (298.26±4.37 μg/mL). TPC, TFC, and TTC were found 64.06±0.35 mg/g of the gallic acid equivalent (GAE), 45.27±0.58 mg/g of the rutin equivalent (RE), and 127.42±1.82 mg/g of the tannic acid equivalent (TAE), respectively. Conclusion: A. parviflora extract showed significant antioxidant and antidiabetic potentials. Thus, this plant might be served as a novel approach for discovering new and effective drug molecules against hyperglycemia.

Evaluation of Bioactive Metabolites and Antioxidant-Rich Extracts of Amaranths with Possible Role in Pancreatic Lipase Interaction: In Silico and In Vitro Studies

Fat/carbohydrate-rich diet consumption or elevated secretion of pancreatic lipase (PL) in pancreatic injury results in increased fat digestion and storage. Several metabolites in plant-based diets can help achieve the requirements of nutrition and fitness together. Presently, nutritional metabolites from Amaranthus tricolor, A. viridis, and Achyranthes aspera were assessed and predicted for daily intake. The volatile-metabolite profiling of their extracts using GC-MS revealed various antioxidant and bioactive components. The implication of these specialized components and antioxidant-rich extracts (EC₅₀ free radical scavenging: 34.1 ± 1.5 to 166.3 ± 14.2 µg/mL; FRAP values: 12.1 ± 1.0 to 34.0 ± 2.0 µg Trolox Equivalent/mg) in lipolysis regulation by means of interaction with PL was checked by in silico docking (Betahistine and vitamins: ΔGbind -2.3 to -4.4 kcal/mol) and in vitro fluorescence quenching. Out of the various compounds and extracts tested, Betahistine, ATRA and AVLA showed better quenching the PL fluorescence. The identification of potential extracts as source of functional components contributing to nutrition and fat regulation can be improved through such study.

Medicinal Plants Galega officinalis L. and Yacon Leaves as Potential Sources of Antidiabetic Drugs

Hypoglycemic and antioxidant properties of extracts of medicinal plants Galega officinalis L. (aboveground part) and yacon (Smallanthus sonchifolius Poepp. & Endl.) (leaves) as potential sources of biologically active substances with antidiabetic action have been studied. The pronounced hypoglycemic effect of Galega officinalis extract, devoid of alkaloids, at a dose of 600 mg/kg in experimental diabetes mellitus (DM) has been proven. The established effect is evidenced by a decrease in the concentration of glucose and glycosylated hemoglobin in the blood, increase glucose tolerance of cells, increase C-peptide and insulin content in the plasma of rats' blood. The effective hypoglycemic effect of the extract in the studied pathology was confirmed by histological examination of the pancreas. The cytoprotective effect of the studied extract on pancreatic cells at a dose of 1200 mg/kg was experimentally confirmed. In the standard cut area, an increase was found in the number of Langerhans islets, their average area, diameter, volume, and a number of β-cells relative to these indicators in animals with diabetes. Comparative screening of the antioxidant properties of 30, 50, 70, and 96% water-ethanol extracts of yacon indicates the highest potential of 50% water-ethanol extract to block free radicals in in vitro model experiments. The non-alkaloid fraction of Galega officinalis extract showed moderate antioxidant activity and was inferior to yacon extract in its ability to neutralize reactive oxygen species (ROS) and bind metal ions of variable valence. The level of antioxidant potential of the studied extracts is due to differences in the quantitative content of compounds of phenolic nature in their compositions. The obtained data on the biological effects of Galega officinalis extract on the structural and functional state of β-cells of the pancreas and antioxidant properties of Galega officinalis and yacon extracts substantiate the prospects of using these plants to create antidiabetic medicines and functional foods based on them.

Characterization of the chemical profile and the effects of ethanolic extracts of Maytenus ilicifolia Mart. ex Reissek on glucose metabolism in normal hyperglycemic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Maytenus ilicifolia Mart. ex Reissek, Celastraceae, is popularly known as "espinheira-santa" and used to treat pathologies related to the stomach. However, in popular culture, this species has also been used to treat other disorders such as diabetes, but without scientific evidence, requiring more phytochemical and pharmacological studies on the plant.

AIM OF THE STUDY

This work aims to investigate the anti-hyperglycemic potential of ethanolic extracts obtained from leaves from two different accessions of Maytenus ilicifolia (MIA and MIB) in normal hyperglycemic rats.

MATERIALS AND METHODS

The animals were divided into different experimental groups: normal hyperglycemic (negative control); MIA (treatment of Maytenus ilicifolia extract from access 116); MIB (treatment with Maytenus ilicifolia extract from access 122; and glipizide (positive control). At 30 min after treatment, all animals received glucose overload orally. Blood collection occurred at different periods for the assessment of blood glucose (0, 60, 90 and 210 min after treatment) and at the end of the experiment blood was collected through cardiac puncture and the liver, muscle, pancreas and intestine were dissected for further analysis.

RESULTS

Chromatographic analysis identified oleic and palmitic acid as the most common constituents, and both extracts of Maytenus ilicifolia caused a reduction in blood glucose levels within 60 min after administration of glucose overload when compared to the normal hyperglycemic group. No significant changes were observed in hepatic and muscular glycogen levels, plasma insulin concentration and disaccharidases activity with none of the extracts in the model employed. However, hyperglycemic rats treated with the extracts showed a marked increase in triglyceride and HDL cholesterol levels.

CONCLUSIONS

Our data suggest that Maytenus ilicifolia extracts from different locations showed differences in chemical composition which did not reflect significant differences in the results of biological tests. In addition, it was possible to conclude that the treatment with Maytenus ilicifolia had a discreet anti-hyperglycemic effect; however, it was not possible to identify the responsible mechanism, being necessary, therefore, new studies using different technologies in order to determine the possible mechanisms of action of the extract.

A New Symmetrical Thiazolidinedione Derivative: In Silico Design, Synthesis, and In Vivo Evaluation on a Streptozotocin-Induced Rat Model of Diabetes

By activating PPAR-γ, thiazolidinediones normalize glucose levels in animal models of type 2 diabetes and in patients with this pathology. The aim of the present study was to analyze 219 new derivatives in silico and select the best for synthesis, to be evaluated for acute oral toxicity in female rats and for control of diabetes-related parameters in a rat model of streptozotocin-induced diabetes. The best compound was chosen based on pharmacokinetic, pharmacodynamic, and toxicological parameters obtained in silico and binding orientation observed by docking simulations on PPAR-γ. Compound 1G was synthesized by a quick and easy Knoevenagel condensation. Acute oral toxicity was found at a dose greater than 2000 mg/Kg. Compound 1G apparently produces therapeutic effects similar to those of pioglitazone, decreasing glycaemia and triglyceride levels in diabetic animals, without liver damage. Moreover, it did not cause a significant weight gain and tended to reduce polydipsia and polyphagia, while diminishing systemic inflammation related to TNF-α and IL-6. It lowered the level of endogenous antioxidant molecules such as reduced glutathione and glutathione reductase. In conclusion, 1G may be a candidate for further testing as an euglycemic agent capable of preventing the complications of diabetes.

Natural Bioactive Compounds as Potential Browning Agents in White Adipose Tissue

The epidemic of overweight and obesity underlies many common metabolic diseases. Approaches aimed to reduce energy intake and/or stimulate energy expenditure represent potential strategies to control weight gain. Adipose tissue is a major energy balancing organ. It can be classified as white adipose tissue (WAT) and brown adipose tissue (BAT). While WAT stores excess metabolic energy, BAT dissipates it as heat via adaptive thermogenesis. WAT also participates in thermogenesis by providing thermogenic fuels and by directly generating heat after browning. Browned WAT resembles BAT morphologically and metabolically and is classified as beige fat. Like BAT, beige fat can produce heat. Human adults have BAT-like or beige fat. Recruitment and activation of this fat type have the potential to increase energy expenditure, thereby countering against obesity and its metabolic complications. Given this, agents capable of inducing WAT browning have recently attracted broad attention from biomedical, nutritional and pharmaceutical societies. In this review, we summarize natural bioactive compounds that have been shown to promote beige adipocyte recruitment and activation in animals and cultured cells. We also discuss potential molecular mechanisms for each compound to induce adipose browning and metabolic benefits.

Chemical composition, in vitro antioxidant, anticholinesterase, and antidiabetic potential of essential oil of Elaeagnus umbellata Thunb

Background

Elaeagnus umbellata Thunb. (autumn olive) is a high valued medicinal plant. It belongs to Elaeagnaceae family and is widely distributed in Himalayan regions of Pakistan. In the present study essential oil were extracted from the fruit of this plant and their antioxidant, anticholinesterase and antidiabetic potentials were also evaluated.

Methods

Essential oils were extracted from the fruit of E. umbellata using hydro-distillation method and were characterized by GC-MS. The extracted oil were tested for its antioxidant, anticholinesterase, and antidiabetic potentials using standard protocols.

Results

About 68 compounds were identified by GC-MS. The extracted oil exhibited a fairly high free radical scavenging activities against DPPH and ABTS radicals with IC₅₀ values of 70 and 105 μg/mL respectively (for ascorbic acid, used as standard, the IC₅₀ values were 32 and 29 μg/mL, respectively against the mentioned radicals). The essential oil also exhibited anticholinesterase activities with IC₅₀ values of 48 and 90 μg/mL respectively against AChE and BChE (for galantamine used as standard, the IC₅₀ values were 25 and 30 μg/mL respectively). The essential oil also exhibited antidiabetic potential with IC₅₀ values of 120 and 110 μg/mL respectively against α-glucosidase and α-amylase (IC₅₀ values for standard acarbose = 28 and 30 μg/mL respectively).

Conclusion

Essential oil extracted from the fruits of E. umbellata exhibited reasonable antioxidant, anticholinesterase, and antidiabetic potentials that could be used as alternative medicine in treating diabetes and neurodegenerative disorders. However, further studies are needed to isolate responsible compounds and evaluate the observed potential in animal models.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03228-y.

Escitalopram Ameliorates Cardiomyopathy in Type 2 Diabetic Rats via Modulation of Receptor for Advanced Glycation End Products and Its Downstream Signaling Cascades

Type 2 diabetes mellitus (T2DM) has been recognized as a known risk factor for cardiovascular diseases. Additionally, studies have shown the prevalence of depression among people with diabetes. Thus, the current study aimed to investigate the possible beneficial effects of escitalopram, a selective serotonin reuptake inhibitor, on metabolic changes and cardiac complications in type 2 diabetic rats. Diabetes was induced by feeding the rats high fat-high fructose diet (HFFD) for 8 weeks followed by a subdiabetogenic dose of streptozotocin (STZ) (35 mg/kg, i. p.). Treatment with escitalopram (10 mg/kg/day; p. o.) was then initiated for 4 weeks. At the end of the experiment, electrocardiography was performed and blood samples were collected for determination of glycemic and lipid profiles. Animals were then euthanized and heart samples were collected for biochemical and histopathological examinations. Escitalopram alleviated the HFFD/STZ-induced metabolic and cardiac derangements as evident by improvement of oxidative stress, inflammatory, fibrogenic and apoptotic markers in addition to hypertrophy and impaired conduction. These results could be secondary to its beneficial effects on the glycemic control and hence the reduction of receptor for advanced glycation end products content as revealed in the present study. In conclusion, escitalopram could be considered a favorable antidepressant medication in diabetic patients as it seems to positively impact the glycemic control in diabetes in addition to prevention of its associated cardiovascular complications.

In vitro, in vivo and in silico Antihyperglycemic Activity of Some Semi-synthetic Phytol Derivatives

BACKGROUND

Due to the prevalence of type-2 diabetes across the globe, there is unmet need to explore new molecular targets for the development of cost-effective and safer antihyperglycemic agents.

OBJECTIVE

Structural modification of phytol and evaluation of in vitro, in vivo and in silico antihyperglycemic activity of derivatives establishing the preliminary structure activity relationship (SAR).

METHODS

The semi-synthetic derivatives of phytol were prepared following previously described methods. The antihyperglycemic potential was measured in vitro in terms of increase in 2-deoxyglucose (2-DG) uptake by L-6 rat skeletal muscle cells as well as in vivo in sucrose-loaded (SLM) and streptozotocin (STZ)-induced diabetic rat models. The blood glucose profile was measured at 30, 60, 90, 120, 180, 240, 300 and 1440 min post administration of sucrose in rats. The in silico docking was performed on peroxisome proliferator-activated receptor gamma (PPARγ) as anti-diabetic target along with absorption, distribution, metabolism, excretion and toxicity (ADMET) studies.

RESULTS

Nine semi-synthetic ester derivatives: acetyl (1), lauroyl (2), palmitoyl (3), pivaloyl (4), trans-crotonyl (5), benzoyl (6), m-anisoyl (7), 3,4,5-trimethoxy benzoyl (8) cinnamoyl (9) along with bromo derivative (10) of phytol were prepared. The derivatives 9, 8 and 2 caused 4.5, 3.2 and 2.7 times more in vitro uptake of 2-DG respectively than rosiglitazone (ROSI). The derivatives showed significant improvement on oral glucose tolerance both in SLM (29.6-21%) as well as STZ-induced diabetic (30.8-19.0%) rats. The in silico ADMET, docking studies showed non-toxicity and high binding affinity with PPARγ.

CONCLUSION

The potent antihyperglycemic activity with favorable pharmacokinetics supports phytol derivatives as suitable antidiabetic lead.

Metabolomic Profile of Personalized Donor Human Milk

Human milk could be considered an active and complex mixture of beneficial bacteria and bioactive compounds. Since pasteurization drastically reduces the microbial content, we recently demonstrated that pasteurized donor human milk (DHM) could be inoculated with different percentages (10% and 30%) of mother's own milk (MOM) to restore the unique live microbiota, resulting in personalized milk (RM10 and RM30, respectively). Pasteurization affects not only the survival of the microbiota but also the concentration of proteins and metabolites, in this study, we performed a comparative metabolomic analysis of the RM10, RM30, MOM and DHM samples to evaluate the impact of microbial restoration on metabolite profiles, where metabolite profiles clustered into four well-defined groups. Comparative analyses of DHM and MOM metabolomes determined that over one thousand features were significantly different. In addition, significant changes in the metabolite concentrations were observed in MOM and RM30 samples after four hours of incubation, while the concentration of metabolites in DHM remained constant, indicating that these changes are related to the microbial expansion. In summary, our analyses indicate that the metabolite profiles of DHM are significantly different from that of MOM, and the profile of MOM may be partially restored in DHM through microbial expansion.

IL-6/STAT3 and adipokine modulation using tocilizumab in rats with fructose-induced metabolic syndrome

Metabolic syndrome (MetS) is a low-grade inflammation state that results from an interplay between genetic and environmental factors. The incidence of MetS among individuals with insulin resistance, dyslipidemia, elevated blood pressure, and obesity, which constitute the syndrome, is 40% in the Middle East. The absence of an approved therapeutic agent for MetS is one reason to investigate tocilizumab (TCZ), which might be effective in the treatment of MetS. Results have implicated interleukin 6 (IL-6) in the development of MetS, identifying inflammation as a critical factor in its etiology and offering hope for new therapeutic approaches development. Here, we evaluate whether tocilizumab can be used for metabolic syndrome treatment. We assigned rats to three groups, 8 rats each: a negative-control group, provided with standard rodent chow and water; a fructose-fed group, provided with standard rodent chow and 10% fructose in drinking water for 22 weeks; and a treatment group, fed as per the metabolic syndrome group but treated with tocilizumab (5 mg/kg/week, intraperitoneal) for the final 5 weeks. Treatment with TCZ successfully ameliorated the damaging effects of fructose by stabilizing body weight gain and through the normalization of serum biochemical parameters and histopathological examination. Significant differences in adipokine levels were perceived, resulting in a significant decline in serum leptin and interleukin 6 (IL-6) levels concurrent with adiponectin normalization. Tocilizumab might be an effective agent for the treatment of metabolic syndrome. However, further investigations on human subjects are needed before the clinical application of tocilizumab for this indication.

The modulatory role of prime identified compounds in the bioactive fraction of Homalium zeylanicum in high-fat diet fed-streptozotocin-induced type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Homalium zeylanicum (Gardner) Benth. is a medicinal plant traditionally used in controlling diabetes which thus far has been assessed by the authors only to a very limited extent.

PURPOSE

To fill the research gap in the literature review, we investigated the antihyperglycemic effects of hydro alcohol fraction of bark of H. zeylanicum (HAHZB) by modulating oxidative stress and inflammation in high-fat diet fed-streptozotocin (HFD/STZ)-induced type-2 diabetic rats.

MATERIALS AND METHODS

To understand the antioxidant capacity of HAHZB, oxygen radical absorbance capacity (ORAC) and cell-based antioxidant protection in erythrocytes (CAP-e) were performed. GC-MS/MS analysis was performed to assess the bioactive components in HAHZB. HFD/STZ-induced diabetic rats were treated orally with HAHZB (300 and 400 mg/kg) for 28 days. After the end of the experiment, marker profiling and histopathological observation of blood and pancreas were examined. The study also highlights interaction between diabetes, oxidative stress and inflammation by examining the increased pro-inflammatory cytokines e.g. TNF-α and C-reactive protein (CRP) promotes DNA damage e.g. oxidation of 8-hydroxy-2-deoxyguanosine (8-OHdG) in chronic hyperglycaemia.

RESULTS

In ex vivo cellular antioxidant capacity of -CAP-e and ORAC assays, HAHZB showed remarkable free radical scavenging ability in a dose dependent manner. GC-MS/MS analysis identified 28 no. of compounds and out of which, oleic acid (1.03%), ethyl tridecanoate (11.77%), phytol (1.29), 9,12-octadecadienoic acid, methyl ester, (E,E)-(5.97%), stigmasterol (1.30%) and β-sitosterol (2.86%) have antioxidant, anti-inflammatory and anti-diabetic activities. HAHZB 400 mg/kg significantly (p < 0.001) improved the lipid profile (TC: 74.66 ± 0.59, HDL-C: 22.08 ± 0.46, LDL-C: 38.06 ± 0.69, and TG: 171.92 ± 1.01 mg/dL) as well as restoring antidiabetic markers (SG: 209.62 ± 1.05 mg/dL, SI: 15.07 ± 0.11 μIU/mL, HOMA-IR: 7.79 ± 0.04 %, and HbA1C: 8.93 ± 0.03 %) and renal functional markers (Tg: 291.26 ± 0.57 pg/mL, BUN: 23.79 ± 0.14 mg/dL, and Cr: 1.34 ± 0.04 mg/dL) in diabetic rats. Oxidative stress markers of pancreas (MDA: 3.65 ± 0.17 nM TBARS /mg protein, SOD: 3.14 ± 0.28 U/mg protein, CAT: 7.88 ± 0.23 U/mg protein, GSH: 12.63 ± 0.28 µM/g of tissue) were restored to normal as evidenced by histological architecture of pancreatic islet cells. The increased level of pro-inflammatory cytokines and oxidative DNA damage were significantly restored (TNF-α: 54.48 ± 3.19 pg/mL, CRP: 440.22 ± 7.86 ng/mL, and 8-OHdG: 63.65 ± 1.84 ng/mL) by HAHZB in diabetic rats.

CONCLUSION

The present findings confirm that the presence of bioactive compounds in HAHZB exert therapeutic protective effect by decreasing oxidative, inflammation and pancreatic β-cell damage in oxidative stress induced diabetic rats.

An osteoinductive effect of phytol on mouse mesenchymal stem cells (C3H10T1/2) towards osteoblasts

In recent years, phytochemicals have been widely researched and utilized for the treatment of various medical conditions such as cancer, cardiovascular diseases, age-related problems and are also said to have bone regenerative effects. In this study, phytol (3,7,11,15-tetramethylhexadec-2-en-1-ol), an acyclic unsaturated diterpene alcohol and a secondary metabolite derived from aromatic plants was investigated for its effect on osteogenesis. Phytol was found to be nontoxic in mouse mesenchymal stem cells (C3H10T1/2). At the cellular level, phytol-treatment promoted osteoblast differentiation, as seen by the increased calcium deposits. At the molecular level, phytol-treatment stimulated the expression of Runx2 (a bone-related transcription factor) and other osteogenic marker genes. MicroRNAs (miRNAs) play an essential role in controlling bone metabolism by targeting genes at the post-transcriptional level. Upon phytol-treatment in C3H10T1/2 cells, mir-21a and Smad7 levels were increased and decreased, respectively. It was previously reported that mir-21a targets Smad7 (an antagonist of TGF-beta1 signaling) and thus, protects Runx2 from its degradation. Thus, based on our results, we suggest that phytol-treatment promoted osteoblast differentiation in C3H10T1/2 cells via Runx2 due to downregulation of Smad7 by mir-21a. Henceforth, phytol was identified to bolster osteoblast differentiation, which in turn may be used for bone regeneration.

Olmesartan attenuates type 2 diabetes-associated liver injury: Cross-talk of AGE/RAGE/JNK, STAT3/SCOS3 and RAS signaling pathways

Olmesartan (OLM), an angiotensin receptor blocker, was tested against diabetes/insulin resistance (IR) models associated with renal/cardiovascular complications. Methods: we tested its potential role against diabetes-induced hepatic hitches using an IR/type2 diabetic (IR/D) model induced by high fat/high fructose diet for 7 weeks ​+ ​a single sub-diabetogenic dose of streptozotocin (35mg/kg; i.p). IR/D rats were orally treated with OLM (10 ​mg/kg), pioglitazone (PIO; 5 or 10 ​mg/kg) or their combinations for 4 consecutive weeks. OLM alone opposed the detrimental effects of IR/D; it significantly improved metabolic parameters, liver function, and abated hepatic oxidative stress, and inflammatory cytokine interleukin-6 (IL-6) and its upstream mediator nuclear factor kappa B. Consequently, OLM turned off the downstream cue p-Jak2/STAT3/SOCS3. Moreover, it suppressed the elevated AGE/RAGE/p-JNK pathway and increased the PPARγ/adiponectin cue to signify its anti-inflammatory and anti-oxidant capacity (GSH, MDA). Nevertheless, co-administration of OLM to PIO showed a synergistic improvement in all the aforementioned parameters in a dose dependent manner. Additionally, OLM with PIO₁₀ provoked a surge in hepatic PPARγ and adiponectin (5 and 6 folds) with a sharp decrease of about 85% in the NF-κB/IL-6/p-STAT3/SCOS3 pathway. These effects were confirmed by the histopathological study. In conclusion, OLM and its combination with PIO enhanced insulin sensitivity and guarded against hepatic complications associated with type 2 diabetes probably via modulating various inter-related pathways; namely, metabolic alteration, renin-angiotensin system, inflammatory trajectories, as well as oxidative stress. This study manifests the potential synergistic effects of OLM as an adjuvant therapy to the conventional antidiabetic therapies.

Antihyperglycemic Effects and Mode of Actions of Musa paradisiaca Leaf and Fruit Peel Hydroethanolic Extracts in Nicotinamide/Streptozotocin-Induced Diabetic Rats

The present study aimed to evaluate the antihyperglycemic effects of Musa paradisiaca (M. paradisiaca) leaf and fruit peel hydroethanolic extracts and to suggest their probable mode of actions in nicotinamide (NA)/streptozotocin (STZ)-induced diabetic rats. The leaf and fruit peel hydroethanolic extracts were analyzed by GC-MS that indicated the presence of phytol, octadecatrienoic acid, hexadecanoic acid, and octadecadienoic acid as major components in the leaf extract and vitamin E, octadecenamide, β-sitosterol, and stigmasterol as major phytochemicals in the fruit peel extract. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (60 mg/kg body weight) dissolved in citrate buffer (pH 4.5), 15 minutes after intraperitoneal injection of NA (120 mg/kg body weight). The NA/STZ-induced diabetic rats were, respectively, treated with M. paradisiaca leaf and fruit peel hydroethanolic extracts at a dose of 100 mg/kg body weight/day by oral administration for 28 days. The treatment of NA/STZ-induced diabetic rats with leaf and fruit peel extracts significantly improved the impaired oral glucose tolerance and significantly increased the lowered serum insulin and C-peptide levels. The HOMA-IR (as the index of insulin resistance) and QUICKI (as a marker for insulin sensitivity), as well as HOMA-β cell function were significantly alleviated as a result of treatment of diabetic rats with leaf and fruit peel extracts. In association, the elevated serum-free fatty acids, TNF-α, and IL-6 levels were significantly decreased. In addition, the suppressed adipose tissue PPARγ, GLUT4, adiponectin, and insulin receptor β-subunit mRNA expressions were upregulated while the elevated adipose tissue resistin expression was downregulated in diabetic rats as a result of treatment with the leaf and peel extract. Based on these results, it can be concluded that M. paradisiaca leaf and fruit peel hydroethanolic extracts have antihyperglycemic effects which may be mediated via their insulinotropic and insulin-sensitizing effects.

Antidiabetic Properties of Hydroalcoholic Leaf and Stem Extract of Levisticum officinale: An implication for α-amylase Inhibitory Activity of Extract Ingredients through Molecular Docking

Levisticum officinale (Apiaceae) is a favorite food spice. Iranian folk medicine claims that it has a prominent antidyslipidemic property but this is not documented scientifically so far. This study evaluated antidyslipidemic and the other antidiabetic aspects of the stem and leaf hydroalcoholic extract of it (LOE). Regarding oral glucose tolerance test results, LOE (500 mg/kg) administration 30 min before glucose loading significantly decreased the blood glucose level (13%) at 90 min in male rats. Additionally, LOE treatment (500 mg/kg, orally, once a day) for 14 days significantly reduced the serum glucose level (24.97%) and markedly improved the lipid profile and the insulin, creatinine, alanine aminotransferase and aspartate aminotransferase serum levels in diabetic rats. Moreover, LOE effectively amended the impaired antioxidant status and ameliorated lipid peroxidation in the plasma and pancreas and liver tissues of diabetics. Also, 14 days LOE treatment, significantly decreased the renal sodium-glucose cotransporter 2 and facilitated glucose transporter 2 (GLUT₂) mRNA levels and GLUT₂ gene expression in the enterocytes of jejunum tissue in comparison with diabetic untreated rats. HPLC method revealed the presence of chlorogenic acid, rosmarinic acid, caffeic acid, quercetin and luteolin and GC-MS analysis detected bioactive compounds like phthalides, thymol, phytol, hexanoic acid, carene and menthofuran. LOE showed α-amylase (αΑ) inhibitory activity and in silico studies predicted that among extract ingredients luteolin, quercetin, rosmarinic, caffeic, and hexanoic acids have the greatest αΑ inhibition potecy. Thus, current results justify antidyslipidemic value of L. officinale and shed light on more antidiabetic health benefits of it.

Protective Effects of Phenylpropanoids and Phenylpropanoid-rich Essential Oils on the Cardiovascular System

BACKGROUND

Cardiovascular diseases are the leading cause of global mortality with a tendency to increase due to population ageing as well as an increase in associated risk factors. Although current therapies improve survival rates, they are associated with several side effects, thus justifying the development of novel preventive and/or therapeutic approaches. In this way, plant metabolites such as essential oils have emerged as promising agents due to their biological effects.

OBJECTIVE

Bearing in mind that several essential oils are characterized by high amounts of phenylpropanoids, which may play a crucial role in the activity of these volatile extracts, a comprehensive and systematic review focusing on the cardiovascular effects of phenylpropanoid-rich essential oils is presented.

METHODS

Popular search engines including PubMed, Science Direct, Scopus and Google Scholar were consulted and papers from 2000 onwards were selected. Non-volatile phenylpropanoids were not considered in this review.

RESULTS

A compilation of the current knowledge on this thematic pointed out beneficial effects for volatile phenylpropanoids namely hypotensive, vasorelaxant, antiplatelet aggregation, antidyslipidaemic and antidiabetic, as well as protective properties against ischemia/reperfusion injury and heart hypertrophy.

CONCLUSION

A better understanding of the protective effects of phenylpropanoids on the cardiovascular system is presented, thus paving the way towards future research on plant-based therapies for cardiovascular diseases.

Drought stress modulates secondary metabolites in Brassica oleracea L. convar. acephala (DC) Alef, var. sabellica L

BACKGROUND

Consumer preference today is for the consumption of functional food and the reduction of chemical preservatives. Moreover, the antimicrobial properties and health-promoting qualities of plant secondary metabolites are well known. Due to forecasted climate changes and increasing human population, agricultural practices for saving water have become a concern. In the present study, the physiological responses of curly kale Brassica oleracea L. convar. Acephala (DC) var. sabellica to drought stress and the impact of water limitation on the concentration of selected secondary metabolites were investigated under laboratory-controlled conditions.

RESULTS

Results indicated that drought stress increased the content of trans-2-hexenal, phytol and δ-tocopherol, and decreased chlorophyll content. Moreover, drought stress increased antioxidant capacity and the expression of AOP2, a gene associated with the biosynthesis of aliphatic alkenyl glucosinolates, and of three genes - TGG1, TGGE and PEN2 - encoding for myrosinases, the enzymes involved in glucosinolate breakdown.

CONCLUSION

The present study shows that water limitation during the growing phase might be exploited as a sustainable practice for producing curly kale with a high concentration of nutritionally important health-promoting bioactive metabolites. © 2019 Society of Chemical Industry.

Phytol and its metabolites phytanic and pristanic acids for risk of cancer: current evidence and future directions

This review summarizes the current evidence on the potential role of phytol, a microbial metabolite of chlorophyl A, and its metabolites, phytanic and pristanic acids, in carcinogenesis. Primary food sources in Western diets are the nut skin for phytol and lipids in dairy, beef and fish for its metabolites. Phytol and its metabolites gained interest as dietary compounds for cancer prevention because, as natural ligands of peroxisome proliferator-activated receptor-α and -γ and retinoid X receptor, phytol and its metabolites have provided some evidence in cell culture studies and limited evidence in animal models of anti-carcinogenic, anti-inflammatory and anti-metabolic-syndrome properties at physiological concentrations. However, there may be a narrow range of efficacy, because phytol and its metabolites at supra-physiological concentrations can cause in vitro cytotoxicity in non-cancer cells and can cause morbidity and mortality in animal models. In human studies, evidence for a role of phytol and its metabolites in cancer prevention is currently limited and inconclusive. In short, phytol and its metabolites are potential dietary compounds for cancer prevention, assuming the challenges in preventing cytotoxicity in non-cancer cells and animal models and understanding phytol metabolism can be mitigated.

Comparison of the effects of sulforaphane and pioglitazone on insulin resistance and associated dyslipidemia, hepatosteatosis, and endothelial dysfunction in fructose-fed rats

The purpose of this work was to compare the influences of sulforaphane (SFN) to those of the standard insulin sensitizer pioglitazone (PIO) on high fructose diet (HFrD)-induced insulin resistance, dyslipidemia, hepatosteatosis, and vascular dysfunction in rats. Male Sprague Dawley rats (150-200 g) were fed on a standard diet (control) or a high fructose diet (HFrD, 60% w/w fructose) for 60 days. From day 16, two subgroups of HFrD-fed rats received either SFN (0.5 mg/kg/day, orally) or PIO (5 mg/kg/day, orally) along with HFrD until the end of the experiment. Fructose-fed rats showed significant decreases in food intake, body weight and feeding efficiency; effects that were not altered by either treatment. Data from insulin tolerance test (ITT), oral glucose tolerance test (OGTT), and HOMA-IR and HOMA-β indices demonstrated impaired insulin sensitivity and glucose utilization in HFrD-fed rats. SFN and PIO treatments significantly reduced OGTT_AUC (Glass's Delta values = 1.12 and 0.84, respectively), decreased ITT_AUC (Glass's Delta values = 1.05 and 0.71, respectively), significantly diminished HOMA-IR index (by 55.6% and 77.6%, respectively), and increased HOMA-β value (by 1.8 and 1.3 fold, respectively) compared to the HFrD rats. Moreover, SFN and PIO ameliorated hepatic oxidative stress and reduced serum levels of C-reactive protein and lactate dehydrogenase in HFrD-fed rats. Furthermore, SFN and PIO administrations improved insulin resistance-associated heaptosteatosis and enhanced vascular responsiveness to acetylcholine-induced relaxations. However, only SFN was able to enhance serum HDL-C levels in HFrD group. These finding suggests that SFN elicited insulin-sensitizing, hepatoprotective, and vasculoprotective effects in HFrD insulin-resistant rats that were comparable to those exerted by PIO.

Amelioration of experimental metabolic syndrome induced in rats by orlistat and Corchorus olitorius leaf extract; role of adipo/cytokines

OBJECTIVES

To determine the efficacy of Corchorus olitorius (C. olitorius) leaf extract in the prevention of metabolic syndrome induced in rats by high-fat diet (HFD) and compare it with that of orlistat.

METHODS

Phytochemical analysis was performed. Effect of orlistat and C. olitorius extract on lipase activity and acute food intake were investigated. Body weight, biochemical parameters and histopathological examination were demonstrated.

KEY FINDINGS

Corchorus olitorius extract inhibited the pancreatic lipase activity, but orlistat was more potent. Cumulative food intake has not changed by the tested agents. In obese rats, C. olitorius or orlistat significantly decreased weight gain and visceral white adipose tissue. They exhibited a significant reduction in serum glucose, total cholesterol, triglycerides, low density lipoprotein cholesterol, free fatty acids, IL-1β, tumour necrosis factor-α (TNF-α), insulin and leptin levels of obese rat groups while high density lipoprotein cholesterol and adiponectin levels were significantly increased by them. Histopathological examination of the liver revealed that C. olitorius was more effective than orlistat in the alleviating of steatosis and adipocyte hypertrophy shown in obese control rats.

CONCLUSIONS

Corchorus olitorius is effective as orlistat in preventing obesity, hyperlipidaemia, steatosis and insulin resistance. These actions may be mediated by inhibiting of lipase activity, TNF-α, IL-1β and leptin resistance along with increasing of adiponectin.

Lavatera critica controls systemic insulin resistance by ameliorating adipose tissue inflammation and oxidative stress using bioactive compounds identified by GC-MS

BACKGROUND

Lavatera critica, a leafy green herb, is reported to have many pharmacological activities; but, the improvement of insulin sensitivity against the high gram-fat diet (HGFD)-caused insulin resistance (IR) has not yet been studied.

OBJECTIVE

This study evaluated the role of Lavatera critica leaf extract (LCE) in systemic insulin resistance through the alleviation of adipose tissue inflammation and oxidative damage in HGFD fed mice.

METHODS

The mice were fed with HGFD for 10 weeks and the diet was supplemented with LCE each day for the next five weeks. Body weight, food intake, leptin, blood glucose, insulin, insulin resistance, and pro- and anti-inflammatory genes expression were assessed on day 106.

RESULTS

The HGFD control mice displayed markedly elevated adipose tissue inflammation, oxidative stress, insulin inactivity, and hyperglycemia. Administration of LCE in the HGFD mice, especially a dose of 100 mg/kg, lowered the body weight, food intake, plasma leptin, plasma glucose, plasma insulin, insulin resistance, and increased the food efficacy ratio when compared with the HGFD control mice. The oral glucose tolerance test (OGTT) revealed that LCE prevented further increase in the circulating levels after the glucose load. LCE-treated mice demonstrated a marked suppression of pro-inflammatory cytokines mRNA expression. On the other hand, the mice showed a higher anti-inflammatory genes mRNA expression in the adipose tissue. In addition, LCE treatment improved the oxidative damage as evidenced by the reduced levels of lipid hydroperoxides and thiobarbituric acid reactive substances coupled with the increased antioxidants (superoxide dismutase, total glutathione, glutathione/glutathione disulfide ratio and glutathione peroxidase) in the adipose tissue, plasma and erythrocytes. Gas chromatography-mass spectrometry analysis of the bioactive compounds revealed the presence of 9, 12, 15-octadecatrienoic acid, vitamin E, phytol, hexadecanoic acid, benzenepropanoic acid, and stigmasterol.

CONCLUSIONS

These findings prove that LCE improves the insulin-sensitizing activity in the mouse model of HGFD-caused IR, probably due to the amelioration of adipose tissue inflammation and oxidative damage. Hence, the LCE could serve as a useful anti-diabetic agent.

Phytol stimulates the browning of white adipocytes through the activation of AMP-activated protein kinase (AMPK) α in mice fed high-fat diet

In vivo and in vitro studies show that phytol stimulates the browning of mice iWAT and formation of brown-like adipocytes in the differentiated 3T3-L1 through the activation of the AMPKα signaling pathway.