Inhibition of intestinal glucose absorption by anti-diabetic medicinal plants derived from the James Bay Cree traditional pharmacopeia

Phytochemical screening, HPLC fingerprinting and in vitro assessment of therapeutic potentials of different apricot cultivars against diabetes, Alzheimer's disease and cancer

Plant-based natural compounds are widely used to treat various ailments owing to their readily availability and minimal adverse effects. This study aimed to perform qualitative and quantitative biochemical profiling and assess the in vitro anti-diabetic, anti-Alzheimer, and anti-cancer activities of various apricot (Prunus armeniaca) cultivars. High-performance liquid chromatography (HPLC) was utilized to determine the concentrations of bioactive compounds across 10 distinct apricot cultivars. Initial phytochemical screening revealed a significant content of secondary metabolites. Subsequently, methanolic extracts from these cultivars were evaluated for their therapeutic potential against several human cancer cell lines, including prostate cancer (PC-3), lung cancer (A-549), breast cancer (MCF-7), cervical cancer (HELA), and kidney cancer (HEK). Notably, the breast cancer cell line MCF-7 showed a pronounced inhibition rate post-treatment with the apricot extracts. Correlation analysis exhibited phenols are highly correlated with flavonoids (r = 0.92), DPPH (r = 0.95), and alpha-amylase (%) inhibition (r = 0.96), and showed a significant correlation with other parameters. Principal Component Analysis (PCA) revealed that PC1 explained 43.31 % of the variance, while PC2 explained 12.88 %, together explaining 80.033 % of the total variance. PC1 was identified as the dominant axis, indicating the primary pattern of variation among the variables. Hierarchical Cluster Analysis (HCA) divided the cultivars into 2 main clusters, with cluster 2 further subdivided into various sub-clusters and sub-sub-clusters. This analysis highlighted distinct genetic similarities and differences among the apricot cultivars. Among the tested cultivars, 'Irani' and 'Tilton' were found to contain the highest levels of bioactive constituents. This research marks the first comprehensive examination of the impacts of these two apricot cultivars. The findings from this study provide a robust scientific foundation for the future isolation and purification of therapeutic compounds, potentially leading to their application in pharmaceuticals or dietary supplements. This research contributes significantly to the understanding of the pharmacological properties of apricot cultivars and establishes a basis for further investigation into their clinical benefits.

Evaluating the biological (antidiabetic) potential of TEM, FTIR, XRD, and UV-spectra observed berberis lyceum conjugated silver nanoparticles

Diabetes is a life-threatening disease that affects different parts of the body including the liver, kidney, and pancreas. The core root of diabetes is mainly linked to oxidative stress produced by reactive oxygen species (ROS). Berberis lyceum Royle (BLR) is the source of natural products. It comprises numerous bioactive compounds having antioxidant activities. In the current investigation, silver nanoparticles from BLR root extract were synthesized, characterized, and assessed for antidiabetic potential. UV spectrophotometry, Transmission electron microscopy (TEM), Fourier transform infra-red spectroscopy (FTIR), and x-ray diffraction (XRD) were applied for the characterization of NPs. It was evident from the morphological studies that the synthesized NPs were spherical and the average size was 11.02 nm. Results revealed that BLR-AgNPs showed higher radical scavenging activity as compared to BLR extract. Moreover, BLR-AgNPs displayed superior in vivo and in vitro antidiabetic activity in comparison to BLR extract. Glucose level (116.5 ± 5.1 mg/dL), liver function test (ALAT: 54.038 ± 6.2 IU/L; ASAT: 104.42 ± 13.9 IU/L; ALP: 192.6 ± 2.4 IU/L; bilirubin: 1.434 ± 0.14 mg/dL; total protein: 5.14 ± 0.24 mg/dL), renal function test (urea: 39.6 ± 0.63 mg/dL; uric acid: 21.4 ± 0.94 mg/dL; creatinine: 0.798 ± 0.03 mg/dL; albumin: 4.14 ± 0.2 mg/dL), lipid profile level (cholesterol: 101.62 ± 3 mg/dL; triglyceride: 110.42 ± 7 mg/dL; HDL-C: 29.7 ± 3 mg/dL; LDL-C: 47.056 ± 1 mg/dL; VLDL-C: 22.0 ± 1.3 mg/dL) and hematology (WBCs: 3.82 ± 0.24 103 /μL; RBCs: 4.78 ± 0.42 106 /μL; Hb: 12.6 ± 1.0 g/dL; Hematocrit: 39.4 ± 3.7%; MCV: 65.8 ± 3 fL; platelets: 312 ± 22.4; neutrophils: 34.8 ± 1.87; eosinophils: 3.08 ± 0.43; monocytes: 3.08 ± 0.28; lymphocytes: 75.6 ± 3.77) confirmed the significant antidiabetic potential of BLR-AgNPs. Histopathological examination authenticated that BLR-AgNPs caused a significant revival in the morphology of the liver, kidney, and pancreas. Hence, findings of the study suggested the BLR-AgNPs as a potent antidiabetic agent and could be an appropriate nanomedicine to prevent diabetes in future. RESEARCH HIGHLIGHTS: Berberis lyceum extract as a reducing, capping, and stabilization agent for the BLR-AgNPs synthesis Evaluation of α-amylase inhibition, antioxidant, and α-glucosidase inhibition potential Thorough characterization using Fourier transform infrared spectroscopy, Transmission electron microscopy, x-ray diffraction, and UV-VIS spectrophotometer, which is 1st of its kind In-vivo antidiabetic activity evaluation through multiple biomarkers.

Hypoglycemic, anti-inflammatory, and neuroprotective potentials of crude methanolic extract from Acacia nilotica L. - results of an in vitro study

Acacia nilotica L., also known as babul, belonging to the Fabaceae family and the Acacia genus, is typically used for ornamental purposes and also as a medicinal plant found in tropical and subtropical areas. This plant is a rich source of bioactive compounds. The current study aimed to elucidate the hypoglycemic, anti-inflammatory, and neuroprotective potential of A. nilotica's crude methanolic extract. The results of the in vitro antidiabetic assay revealed that methanolic extract of A. nilotica inhibited the enzyme α-glucosidase (IC50: 33 μg mL-1) and α-amylase (IC50: 17 μg mL-1) in a dose-dependent manner. While in the anticholinesterase enzyme inhibitory assay, maximum inhibition was shown by the extract against acetylcholinesterase (AChE) (637.01 μg mL-1) and butyrylcholinesterase (BChE) (491.98 μg mL-1), with the highest percent inhibition of 67.54% and 71.50% at 1000 μg mL-1, respectively. This inhibitory potential was lower as compared to the standard drug Galantamine that exhibited 82.43 and 89.50% inhibition at the same concentration, respectively. Moreover, the methanolic extract of A. nilotica also significantly inhibited the activities of cyclooxygenase 2 (COX-2) and 5-lipoxygenase (5-LOX) in a concentration-dependent manner. The percent inhibitory activity of 5-LOX and COX-2 ranged from 42.47% to 71.53% and 43.48% to 75.22%, respectively. Furthermore, in silico, in vivo, and clinical investigations must be planned to validate the above-stated bioactivities of A. nilotica.

Spectrophotometric and Chromatographic Assessment of Total Polyphenol and Flavonoid Content in Rhododendron tomentosum Extracts and Their Antioxidant and Antimicrobial Activity

In the literature, the chemical composition of Rhododendron tomentosum is mainly represented by the study of isoprenoid compounds of essential oil. In contrast, the study of the content of flavonoids will contribute to the expansion of pharmacological action and the use of the medicinal plant for medical purposes. The paper deals with the technology of extracts from Rh. tomentosum shoots using ethanol of various concentrations and purified water as an extractant. Extracts from Rh. tomentosum were obtained by a modified method that combined the effects of ultrasound and temperature to maximize the extraction of biologically active substances from the raw material. Using the method of high-performance thin-layer chromatography in a system with solvents ethyl acetate/formic acid/water (15:1:1), the following substances have been separated and identified in all the extracts obtained: rutin, hyperoside, quercetin, and chlorogenic acid. The total polyphenol content (TPC) and total flavonoid content (TFC) were estimated using spectrophotometric methods involving the Folin-Ciocalteu (F-C) reagent and the complexation reaction with aluminum chloride, respectively. A correlation analysis was conducted between antioxidant activity and the polyphenolic substance content. Following the DPPH assay, regression analysis shows that phenolic compounds contribute to about 80% (r2 = 0.8028, p < 0.05) of radical scavenging properties in the extract of Rh. tomentosum. The extract of Rh. tomentosum obtained by ethanol 30% inhibits the growth of test cultures of microorganisms in 1:1 and 1:2 dilutions of the clinical strains #211 Staphylococcus aureus and #222 Enterococcus spp. and the reference strain Pseudomonas aeruginosa ATCC 10145.

Development of functional noodles by encapsulating mango peel powder as a source of bioactive compounds

Antioxidant compounds such as phenolics and carotenoids scavenge reactive oxygen species and protect against degenerative diseases such as cancer and cardiovascular disease when used as food additives or supplements. Mango peel is a by-product of mango which is a good source of bioactive substances such as phytochemicals, antioxidants, and dietary fibers. Unfortunately, the study on mango peel as a potential food additive is very limited. Accordingly, the present study aimed to develop functional noodles through extrusion technology with the encapsulation of mango peel powder as a natural source of bioactive compounds. First, mango peel powder (MPP) was prepared and incorporated during the mixing of ingredients before noodles formation at three different levels (2.5, 5 and 7.5 %). Afterward, the noodles were studied to determine how the encapsulated MPP affects the proximate composition, physicochemical characteristics, polyphenols, carotenoids, anthocyanin, antioxidant and antidiabetic activity, and sensory characteristics. The noodles exhibited a dose-dependent relationship in the content of bioactive components and functional activities with the encapsulation of MPP levels. A significantly (p 0.05) higher value was noticed in 7.5 % of MPP-encapsulated noodles than in any level of MPP encapsulation in noodles. The fiber and protein contents in the MPP-encapsulated noodles were increased by about 0-1.22 % and 0-3.16 %, respectively. However, noodles' color index and water absorption index were decreased with the level of MPP encapsulation. The cooking loss of noodles increased from 4.64 to 5.17, 6.49, and 7.32 %, whereas the cooked weight decreased from 35.11 to 34.40, 33.65, and 33.23 % with 2.5, 5.0, and 7.5 % of MPP encapsulation, respectively. However, MPP was stable during storage of noodles exhibiting higher phenolic content and antioxidant activity than control samples. The sensory evaluation showed that MPP-encapsulated noodles at levels 2.5 and 5 % had approximately similar overall acceptability values with the control sample. As a result of the findings, it appears that adding MPP up to 5 % to noodles improves their nutritional quality without changing their cooking, structural, or sensory aspects. Therefore, mango peel powder can be a potential cheap source for the development of functional noodles and food ingredients.

In Vitro Evaluation of Antidiabetic Potential of Cleistocalyx nervosum var. paniala Fruit Extract

Diabetes mellitus is a complex global public health condition. Medicinal plants are significant resources in the research of alternative new drug active compounds. Cleistocalyx nervosum var. paniala (C. nervosum) is an indigenous berry fruit widely grown in Southeast Asia. The fruit of C. nervosum exhibit various medicinal properties and health benefits. This study aimed to investigate antidiabetic properties of C. nervosum fruit extract by in vitro assays and in vitro models. C. nervosum fruit extracted using three different solvents (hexane, ethanol, and distilled water) were tested for α-amylase and α-glucosidase inhibitory activities, followed by glucose uptake in HepG2 and L6 myoblasts. Lipid accumulation in 3T3-L1 cells treated with C. nervosum fruit extracts was then examined. The results revealed that ethanolic extract of C. nervosum fruit showed better inhibition against α-amylase (IC₅₀ of 0.42 μg/mL) and α-glucosidase (IC₅₀ of 0.23 μg/mL) compared with other extracts. Furthermore, ethanolic extract showed higher glucose uptake potential than the standard antidiabetic drug, metformin, in HepG2 cells. The ethanolic extracts resulted in enhanced glucose utilization in L6 myoblasts compared to untreated control. All extractions showed no significantly increased lipid accumulation in 3T3-L1 cells compared to the untreated control cells. The investigation confirmed that the ethanolic extract exhibited the highest antidiabetic activity among all extracts. These results imply that C. nervosum fruit extract has antidiabetic properties and therefore they may be used as useful therapeutic agents for treating diabetes.

LC-DAD-ESI-MS/MS and NMR Analysis of Conifer Wood Specialized Metabolites

Many species from the Pinaceae family have been recognized as a rich source of lignans, flavonoids, and other polyphenolics. The great common occurrence of conifers in Europe, as well as their use in the wood industry, makes both plant material and industrial waste material easily accessible and inexpensive. This is a promising prognosis for both discovery of new active compounds as well as for finding new applications for wood and its industry waste products. This study aimed to analyze and phytochemically profile 13 wood extracts of the Pinaceae family species, endemic or introduced in Polish flora, using the LC-DAD–ESI-MS/MS method and compare their respective metabolite profiles. Branch wood methanolic extracts were phytochemically profiled. Lignans, stilbenes, flavonoids, diterpenes, procyanidins, and other compounds were detected, with a considerable variety of chemical content among distinct species. Norway spruce (Picea abies (L.) H.Karst.) branch wood was the most abundant source of stilbenes, European larch (Larix decidua Mill.) mostly contained flavonoids, while silver fir (Abies alba Mill.) was rich in lignans. Furthermore, 10 lignans were isolated from the studied material. Our findings confirm that wood industry waste materials, such as conifer branches, can be a potent source of different phytochemicals, with the plant matrix being relatively simple, facilitating future isolation of target compounds.

In Vitro Digestibility and Bioaccessibility of Nutrients and Non-Nutrients Composing Extruded Brewers' Spent Grain

This study aimed to evaluate the effect of the extrusion process on the bioaccessibility of brewers’ spent grain (BSG) nutrients (carbohydrates and proteins) and non-nutrients (bioactive compounds). BSG and extruded BSG (EBSG) were digested in vitro simulating human oral-gastro-intestinal digestion and colonic fermentation. The duodenal bioaccessibility of glucose, amino acids and phenolic compounds was analyzed. The fermentability of the dietary fiber was assessed by analysis of short-chain fatty acids. Additionally, assessment of the bioaccessibility of phenolic compounds after colonic fermentation was undertaken. The antioxidant, anti-inflammatory and antidiabetic properties of the bioaccessible compounds were studied. Extrusion caused no change in the digestibility of gluten and glucose bioaccessibility (p > 0.05). Moreover, the bioaccessibility of amino acids and phenolic compounds significantly increased (p < 0.05) due to extrusion. However, higher short-chain fatty acid content was formed in colonic fermentation of BSG (p < 0.05) compared to EBSG. The latter inhibited intracellular ROS formation in IEC-6 cells and showed anti-inflammatory properties in RAW264.7 cells. With respect to antidiabetic properties, glucose absorption was lower, and the inhibition of carbohydrases higher (p < 0.05), in the presence of EBSG compared to BSG. The effects of EBSG and BSG digests on glucose transporters were not significantly different (p > 0.05). In conclusion, extrusion positively affected the nutritional value and health-promoting properties of BSG.

Integrating In Silico and In Vitro Approaches to Screen the Antidiabetic Properties from Tabernaemontana divaricata (Jasmine) Flowers

The purpose of this study was to assess different in vitro biological activities such as phytochemical constituents, enzymatic antioxidant status, cytotoxicity through hemolytic activity, and antidiabetic potential of plant methanolic extract through glucose uptake by yeast cells. Further, using in silico approach by the SwissADME technique the drug-likeness rules for bioactive components were characterized, while potential interactions were identified via molecular docking of a ligand with target proteins by GOLD 5.3.0. The results showed that T. divaricata was rich in TPC and TFC, i.e., 62.32 ± 4.02 and 24.53 ± 0.61, respectively, and the cytotoxic potential was 10% towards human RBCs, while protein estimation revealed the presence of protein in the extract, which was 22.82 ± 4.6. DPPH assay in comparison with ascorbic acid and several enzymatic assays, such as CAT, SOD, and POD, showed maximum antioxidant potential, i.e.,15.9 ± 2.33%, 65.57 ± 13.4%, 3.02 ± 3.4, 15.87 ± 0.5, and 0.74 ± 0.2, respectively. Glucose uptake by yeast cells, i.e., α-amylase and α-glucosidase, showed a maximum antidiabetic potential such as 75.11 ± 1.44%, 41.81 ± 3.75%, and 35.9 ± 1.24%, respectively. Our results indicate that the methanolic extract of T. divaricata has antioxidant potential and inhibits α-amylase and α-glucosidase activity and possesses maximum antidiabetic potential. The results provide scientific proof that the medicinal plant being studied is a powerful source of natural antioxidant, antidiabetic, and medicinally significant substances. In silico study, using a molecular docking, unveiled that two compounds showed good interactions with 5kzw protein with considerable binding affinities and fulfilled docking parameters. It may conclude that T. divaricata is an important vegetable with a potent source of natural antioxidants and antidiabetic activity justifying its traditional use in green therapeutics.

Iridoids and polyphenols from chilean Gaultheria spp. berries decrease the glucose uptake in Caco-2 cells after simulated gastrointestinal digestion

Berries are rich food sources of potentially health-beneficial (poly)phenols. However, they may undergo chemical modifications during gastrointestinal digestion. The effect of simulated gastrointestinal digestion on the content and composition of secondary metabolites from Gaultheria phillyreifolia and G. poeppigii berries was studied. The influence of the digested extracts on the in vitro metabolism and absorption of carbohydrates was evaluated. After simulated digestion, 31 compounds were detected by UHPLC-DAD-MS. The total content of anthocyanins decreased by 98-100%, flavonols by 44-56%, phenylpropanoids by 49-75% and iridoids by 33-45%, the latter showing the highest stability during digestion. Digested extracts inhibited α-glucosidase (IC₅₀ 2.8-24.9 μg/mL) and decreased the glucose uptake in Caco-2 cells by 17-28%. Moreover, a decrease in the mRNA expression of glucose transporters SGLT1 (38-92%), GLUT2 (45-96%), GLUT5 (28-89%) and the enzyme sucrase-isomaltase (82-97%) was observed. These results show the effect of simulated gastrointestinal digestion on the content and composition of Gaultheria berries.

In vitro, acute and subchronic evaluation of the antidiabetic activity of Atractylis flava Desf n-butanol extract in alloxan-diabetic rats

Background

Diabetes mellitus is a serious complex multifactorial disorder that imposes huge health and economic burden on societies. Because the currently available medications have many drawbacks, it's important to look for alternative therapies. Medicinal plants utilized in folk medicine are ideal candidates. Therefore, this work assessed the antidiabetic action of n-butanol extract from the whole plant Atractylis flava Desf (BEAF). These ethnomedicinal properties of BEAF were scientifically validated using in vitro and in vivo assays. In vitro antidiabetic effect of the BEAF was conducted using α-Glucosidase and α-Amylase assays. While the antihyperglycemic activity was assessed using two rat models: Alloxan-induced diabetic rats and oral glucose challenged rats. Experimental diabetes was induced by a single intraperitoneal injection of alloxan at a dose of 150 mg/kg and animals with fasting blood glucose levels (BGL) > 200 mg/dL were considered diabetic. Glibenclamide (5 mg/kg) was used as a typical drug.

Results

The BEAF at all tested dose levels (100, 250, and 500 mg/kg) showed a significant decrease in blood glucose level in all the two animal models. Besides, the plant extract exhibited a potent inhibitory effect on α-Amylase and α-Glucosidase activity at a concentration of 1000 µg/mL with 76.17% and 89.37%, respectively.

Conclusion

BEAF exerts in vitro and in vivo antidiabetic effects, these results suggest that the plant extract can be a therapeutic resource in the treatment of diabetes and hyperlipidemia.

Preclinical Study of the Antidiabetic Effect of Traganum nudatum in Diabetic Rats

AIMS

The aim of the study was to study the antidiabetic effect of Traganum nudatum in an animal model of diabetes.

BACKGROUND

Traganum nudatum (T. nudatum) is a medicinal plant widely used in folk medicine by the Moroccan population to treat various diseases including diabetes.

OBJECTIVE

The objective of the study was to evaluate the antihyperglycemic and hypoglycemic of the aqueous Traganum nudatum extract in normal and streptozotocin-induced diabetic rats.

METHODS

Normal and streptozotocin-induced diabetic rats were treated orally by the extract of Traganum nudatum (T. nudatum) at a dose of 50 mg/kg. The blood glucose levels were determined for 6 hours and 15 days during this treatment. The oral glucose tolerance and phytochemical tests and the analysis of histopathological changes of the liver were performed. The antioxidant activity of aqueous T. nudatum extract was also assessed using the method of trapping of free radical 2,2- diphenyl-1 picrylhydrazyl (DPPH).

RESULTS

T. nudatum Aerial Part Aqueous Extract (TNAPAE) reduced the blood glucose levels in both normal and diabetic rats. The results demonstrated that TNAPAE treatment exhibited a significant hypoglycemic effect without altering the body weight. In addition, a noticeable influence on glucose tolerance was also observed after TNAPAE treatment. Moreover, TNAPAE was able to exhibit a beneficial effect on the histological structure of the liver. Finally, a potential antioxidant effect has been shown in vitro.

CONCLUSION

In conclusion, this study demonstrates the antihyperglycemic and hypoglycemic effects of T. nudatum in rats supporting its traditional use for the management of diabetes.

Swertiamarin and quercetin combination ameliorates hyperglycemia, hyperlipidemia and oxidative stress in streptozotocin-induced type 2 diabetes mellitus in wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Swertiamarin (Sw) and quercetin (Qu) have been isolated from different plants and are reported for their antidiabetic activities. The plants from which swertiamarin and quercetin were isolated are also traditionally used in the treatment of diabetes mellitus.

AIM OF THE STUDY

The present study is aimed to evaluate the synergistic effect of a combination of swertiamarin and quercetin (CSQ) on α-amylase in vitro and on streptozotocin (STZ) induced diabetes mellitus in vivo.

METHODS

Swertiamarin was isolated from the plant Enicostemma axillare and quercetin was procured in its pure form. Sw, Qu and CSQ were evaluated for in vitro α-amylase inhibitory activity. Based on the in vitro study results, CSQ was assessed for in vivo streptozotocin induced diabetes mellitus in Wistar rats. The effect of CSQ on blood glucose levels, body weight, serum biochemical parameters and antioxidant enzymes such as glutathione (GSH), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and lipid peroxide levels were estimated. The histopathological observations of pancreatic tissues were also made.

RESULTS

The purity of swertiamarin was confirmed by HPLC. The results showed that CSQ was found to possess high percentage of inhibition in an in vitro α-amylase inhibitory study. In a STZ-induced type 2 diabetes mellitus (T2DM), body weight of rats in CSQ treated and control groups were unaltered. A marked reduction in the blood glucose levels was observed in the CSQ treated groups on 14th and 28th day. Decrease in the levels of low-density lipoprotein (LDL), triglycerides, total cholesterol and an increase in high-density lipoprotein (HDL) cholesterol level was observed in a dose dependant in CSQ treated groups. However, CSQ treated groups could significantly improve antioxidant protection by increasing the levels of serum GSH, SOD, Catalase and GPx and decreasing the levels of lipid peroxide (p < 0.05). In the histopathological study, the pancreatic islets of Langerhans and vacuolization have shown significant increase in both the treated groups.

CONCLUSIONS

The combination of swertiamarin and quercetin (CSQ) has proven a preventive and therapeutic effect against T2DM and suggests that this is a potential combination of phytoconstituents for excellent hypoglycemic activity in T2DM.

UHPLC-ESI-QTOF-MS/MS characterization, antioxidant and antidiabetic properties of sorghum grains

The phenolic compounds composition, antioxidant and antidiabetic properties of eight brown sorghum genotypes were investigated. DPPH radical scavenging activity was highest in SOR 03, followed by SOR 11, SOR 08 and SOR 33. SOR 33, SOR 03, SOR 08, SOR 11 showed the highest ABTS radical scavenging activity. Furthermore, SOR 11, SOR 17 and SOR 33 exhibited significantly higher percentage inhibitory activity of α-glucosidase and α-amylase (IC₅₀ = 14.71, 32.98, 24.93 µg/ml and 27.6, 23.84, 45.01 µg/ml, respectively) compared to acarbose (IC₅₀ = 59.34 and 27.73 µg/ml, respectively). Similarly, SOR 17, SOR 11 and SOR 33 showed significantly potent inhibition of AGEs formation with IC₅₀ values of 14.19, 18.23 and 26.31 µg/ml, respectively, compared to aminoguanidine (AG) (52.30 µg/ml). Flavones, isoflavones and dihydroflavonols were the predominant flavonoids identified in SOR 11, SOR 17 and SOR 33 genotypes. Therefore, these sorghum grains are potential candidates for the development of functional foods.

The Potential of Anti-Diabetic Rākau Rongoā (Māori Herbal Medicine) to Treat Type 2 Diabetes Mellitus (T2DM) Mate Huka: A Review

T2DM (type 2 diabetes mellitus, or Māori term “mate huka”) is a major long-term health issue in New Zealand particularly among the Māori community. Non-insulin drugs commonly used in New Zealand for the treatment of T2DM have limits to their efficacy as well as side effects, which are of concern for diabetics. As such, the potential for natural products such as traditional rākau rongoā are of interest for potentially preventing the development of T2DM or improving the treatment of the disease. In particular, anti-diabetic effects have been reported for rākau rongoā such as karamu, kūmarahou, and kawakawa. Natural products have been identified in karamu, kūmarahou, and kawakawa that have documented potential effects on glucose metabolism that could contribute to the anti-diabetic effect of these rākau rongoā. As such, this could provide scientific insight into the mātauranga (traditional knowledge) developed over generations by Māori. However, detailed laboratory based and clinical studies would be required to understand and validate these properties of karamu, kūmarahou, and kawakawa, and to understand how they can be used in T2DM treatment. Social determinants of indigenous health such as language, culture, traditional knowledge, and identity, are important in understanding the relationship Māori have with their land and the mātauranga they developed of the medicinal properties within their rākau rongoā, over many centuries. Interestingly, traditional Māori views towards scientific research using animal models to test rākau rongoā are varied but supportive. Furthermore, cultural issues surrounding Māori mana motuhake (self-determination) of traditional rongoā Māori healing practices and the inequity faced by many kairongoā (rongoā Māori practitioners) and tohunga (healers) compared to mainstream health are a current issue within the New Zealand health system. As such, a cultural holistic approach for T2DM care among Māori would be advantageous. This review will outline the available evidence supporting the anti-diabetic efficacy of karamu, kūmarahou, and kawakawa. Currently though there is a lack of molecular research to understand the mechanisms of this efficacy, as such this review will also outline Te Reo Tipu Research, a kaupapa Māori framework for molecular and genomic research on taonga flora.

Toxic, Radical Scavenging, and Antifungal Activity of Rhododendron tomentosum H. Essential Oils

The chemical composition of eight (seven shoot and one inflorescence) essential oils (EOs) of Rh. tomentosum H. plants growing in Eastern Lithuania is reported. The plant material was collected during different phases of vegetation (from April to October). The oils were obtained by hydrodistillation from air-dried aerial parts (leaves and inflorescences). In total, up to 70 compounds were identified by GC−MS and GC (flame-ionization detector, FID); they comprised 91.0 ± 4.7%–96.2 ± 3.1% of the oil content. Sesquiterpene hydrocarbons (54.1 ± 1.5%–76.1 ± 4.5%) were found to be the main fraction. The major compounds were palustrol (24.6 ± 2.6%–33.5 ± 4.4%) and ledol (18.0 ± 2.9%–29.0 ± 5.0%). Ascaridol isomers (7.0 ± 2.4%–14.0 ± 2.4% in three oils), myrcene (7.2 ± 0.3% and 10.1 ± 1.3%), lepalol (3.3 ± 0.3% and 7.9 ± 3.0%), and cyclocolorenone isomers (4.1 ± 2.5%) were determined as the third main constituents. The toxic activity of marsh rosemary inflorescence and shoot oils samples was evaluated using a brine shrimp (Artemia sp.) bioassay. LC₅₀ average values (11.23–20.50 µg/mL) obtained after 24 h of exposure revealed that the oils were notably toxic. The oil obtained from shoots gathered in September during the seed-ripening stage and containing appreciable amounts of palustrol (26.0 ± 2.5%), ledol (21.5 ± 4.0%), and ascaridol (7.0 ± 2.4%) showed the highest toxic activity. Radical scavenging activity of Rh. tomentosum EOs depended on the plant vegetation stage. The highest activities were obtained for EOs isolated from young shoots collected in June (48.19 ± 0.1 and 19.89 ± 0.3 mmol/L TROLOX (6-hydroxy-2,5,7,8-tetra-methylchromane-2-carboxylic acid) equivalent obtained by, respectively, ABTS^•+ (2,2′-amino-bis(ethylbenzothiazoline-6-sulfonic acid) diammonium salt) and DPPH^•(2,2-diphenyl-1-picrylhydrazyl) assays). Agar disc diffusion assay against pathogenic yeast Candida parapsilosis revealed the potential antifungal activity of EOs. An alternative investigation of antifungal activity employed mediated amperometry at yeast Saccharomyces cerevisiae-modified electrodes. The subjection of yeast cells to vapors of EO resulted in a three to four-fold increase of electrode responses due to the disruption of yeast cell membranes.

Phenolic Profile, Antioxidant, and Antidiabetic Potential Exerted by Millet Grain Varieties

This study evaluated the potential antioxidant and antidiabetic properties in vitro of four millet grain varieties cultivated in South Korea. The free fractions were tested for their total antioxidant capacity using 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS⁺) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays, followed by α-glucosidase, α-amylase, and advanced glycation endproducts (AGEs) formation inhibition assays. The total phenolics, flavonoids, and condensed tannins in the free fractions ranged from 107.8 to 136.4 mg ferulic acid equivalent (FAE)/100 g, 101.3 to 115.8 mg catechin equivalent (CE)/100 g, and 17.65 to 59.54 mg catechin equivalent (CE)/100 g, respectively. Finger Italian millet had the highest total phenolic content (136.4 mg FAE/100 g) and flavonoid content (115.8 mg CE/100 g). Barnyard and finger Italian millet showed the highest DPPH (IC₅₀ = 359.6 µg/mL and 436.25 µg/mL, respectively) and ABTS radical scavenging activity (IC₅₀ = 362.40 µg/mL and 381.65 µg/mL, respectively). Similarly, finger Italian millet also exhibited significantly lower IC₅₀ values for the percentage inhibition of α-glucosidase (18.07 µg/mL) and α-amylase (10.56 µg/mL) as compared with acarbose (IC₅₀ = 59.34 µg/mL and 27.73 µg/mL, respectively) and AGEs formation (33.68 µg/mL) as compared with aminoguanidine (AG) (52.30 µg/mL). All eight phenolic compounds identified in finger Italian millet were flavonoids, with flavanols being the predominant subclass. Taken together, millet flavonoids play important roles in the prevention and management of type 2 diabetes, and hence finger Italian millet has the potential to be developed as a functional food.

Unraveling the Inhibition of Intestinal Glucose Transport by Dietary Phenolics: A Review

Background:

Glucose transport across the intestinal brush border membrane plays a key role in metabolic regulation. Depending on the luminal glucose concentration, glucose is mainly transported by the sodium- dependent glucose transporter (SGLT1) and the facilitated-transporter glucose transporter (GLUT2). SGLT1 is apical membrane-constitutive and it is active at a low luminal glucose concentration, while at concentrations higher than 50 mM, glucose is mainly transported by GLUT2 (recruited from the basolateral membrane). Dietary phenolic compounds can modulate glucose homeostasis by decreasing the postprandial glucose response through the inhibition of SGLT1 and GLUT2.

Methods:

Phenolic inhibition of intestinal glucose transport has been examined using brush border membrane vesicles from rats, pigs or rabbits, Xenopus oocytes and more recently Caco-2 cells, which are the most promising for harmonizing in vitro experiments.

Results:

Phenolic concentrations above 100 µM has been proved to successfully inhibit the glucose transport. Generally, the aglycones quercetin, myricetin, fisetin or apigenin have been reported to strongly inhibit GLUT2, while quercetin-3-O-glycoside has been demonstrated to be more effective in SGLT1. Additionally, epigallocatechin as well as epicatechin and epigallocatechin gallates were observed to be inhibited on both SGLT1 and GLUT2.

Conclusion:

Although, valuable information regarding the phenolic glucose transport inhibition is known, however, there are some disagreements about which flavonoid glycosides and aglycones exert significant inhibition, and also the inhibition of phenolic acids remains unclear. This review aims to collect, compare and discuss the available information and controversies about the phenolic inhibition of glucose transporters. A detailed discussion on the physicochemical mechanisms involved in phenolics-glucose transporters interactions is also included.

Evaluation of Antioxidant, Antidiabetic and Antiobesity Potential of Selected Traditional Medicinal Plants

This study evaluated potential antidiabetic and antiobesity properties in vitro of selected medicinal plants. The hot water (WE) and ethanol extracts (EE) of sweet gale (Myrica gale L.), roseroot (Rhodiola rosea L.), sheep sorrel (Rumex acetosa L.), stinging nettles (Utrica dioica L.) and dandelion (Taraxacum officinale L.) were tested for total antioxidant capacity using ferric reducing antioxidant power (FRAP) and DPPH^• scavenging capacity assays, followed by α-amylase, α-glucosidase and formation of advanced glycation end products (AGE) inhibition assays in vitro. Myrica gale EE had the highest total phenolic content (12.4 mmol GAE/L), FRAP value (17.4 mmol TE/L) and DPPH^• scavenging activity (IC₅₀ = 3.28 mg/L). Similarly, Myrica gale also exhibited significantly lower IC₅₀ values for the percentage inhibition of α-amylase (IC₅₀ = 62.65 mg/L) and α-glucosidase (IC₅₀ = 27.20 mg/L) compared to acarbose (IC₅₀ = 91.71 mg/L; IC₅₀ = 89.50 mg/L, respectively) (p ≤ 0.05). The 3T3-L1 preadipocyte study also revealed that Myrica gale EE (54.8%) and stinging nettles (62.2% EE; 63.2% WE) significantly inhibited the adipogenesis in adipocytes in vitro (p ≤ 0.05). Polyphenols present in these medicinal plants have the potential to use in managing type 2 diabetes and obesity.

Banana flour phenolics inhibit trans-epithelial glucose transport from wheat cakes in a coupledin vitrodigestion/Caco-2 cell intestinal model

A 10% replacement of wheat flour with banana flour subjected to different processing conditions resulted in from 45.0 to 54.5% higher glucose transport inhibition.

Intestinal Saturated Long-Chain Fatty Acid, Glucose and Fructose Transporters and Their Inhibition by Natural Plant Extracts in Caco-2 Cells

The intestinal absorption of fatty acids, glucose and fructose is part of the basic requirements for the provision of energy in the body. High access of saturated long-chain fatty acids (LCFA), glucose and fructose can facilitate the development of metabolic diseases, particularly the metabolic syndrome and type-2 diabetes mellitus (T2DM). Research has been done to find substances which decelerate or inhibit intestinal resorption of these specific food components. Promising targets are the inhibition of intestinal long-chain fatty acid (FATP2, FATP4), glucose (SGLT1, GLUT2) and fructose (GLUT2, GLUT5) transporters by plant extracts and by pure substances. The largest part of active components in plant extracts belongs to the group of polyphenols. This review summarizes the knowledge about binding sites of named transporters and lists the plant extracts which were tested in Caco-2 cells regarding uptake inhibition.

Action of Phytochemicals on Insulin Signaling Pathways Accelerating Glucose Transporter (GLUT4) Protein Translocation

Diabetes is associated with obesity, generally accompanied by a chronic state of oxidative stress and redox imbalances which are implicated in the progression of micro- and macro-complications like heart disease, stroke, dementia, cancer, kidney failure and blindness. All these complications rise primarily due to consistent high blood glucose levels. Insulin and glucagon help to maintain the homeostasis of glucose and lipids through signaling cascades. Pancreatic hormones stimulate translocation of the glucose transporter isoform 4 (GLUT4) from an intracellular location to the cell surface and facilitate the rapid insulin-dependent storage of glucose in muscle and fat cells. Malfunction in glucose uptake mechanisms, primarily contribute to insulin resistance in type 2 diabetes. Plant secondary metabolites, commonly known as phytochemicals, are reported to have great benefits in the management of type 2 diabetes. The role of phytochemicals and their action on insulin signaling pathways through stimulation of GLUT4 translocation is crucial to understand the pathogenesis of this disease in the management process. This review will summarize the effects of phytochemicals and their action on insulin signaling pathways accelerating GLUT4 translocation based on the current literature.

Rosemary (Rosmarinus officinalis) essential oil components exhibit anti-hyperglycemic, anti-hyperlipidemic and antioxidant effects in experimental diabetes

INTRODUCTION

The present study aims to investigate the protective effects of Rosemary (Rosmarinus officinalis L.) essential oils (ROEO) against alloxan-induced diabetes and oxidative stress in rats.

METHODS

The animals were divided into four groups: Healthy Control (HC); Diabetic Control (DC); Healthy+ROEO (H+ROEO) and Diabetic+ROEO (D+ROEO).

RESULTS

The use of GC/MS technique has allowed us to identify fifteen compounds in ROEO. We have found that alloxan administration induced hyperglycaemia, lipid metabolic parameters deregulation as well as liver and kidney dysfunctions. Alloxan administration has also induced an oxidative stress status as assessed by malondialdehyde (MDA) content increase, thiol groups (-SH) level decrease and antioxidant enzyme activities depletion such as catalase (CAT), total superoxide dismutase (SOD), Cu/Zn-SOD, Mn-SOD and Fe-SOD in both liver and kidney tissues. More importantly subacute (15days) ROEO administration has significantly corrected all biochemical alterations induced by alloxan intoxication.

CONCLUSIONS

We propose that Rosmarinus officinalis essential oils exhibit protective effects in alloxan-induced hyperglycaemia as well as protecting against liver and kidney oxidative stress in rats, reflecting its antioxidant properties.

Effect of Glycosin alkaloid from Rhizophora apiculata in non-insulin dependent diabetic rats and its mechanism of action: In vivo and in silico studies

BACKGROUND AND AIM

Diabetes mellitus is a complex multifactorial disorder that remains a great challenging task in the clinical practice. Rhizophora apiculata from Indian medicinal mangrove is widely used to treat inflammation, wound healing and diabetes. Bioassay guided fractionation was followed to isolate Glycosin from the ethanolic extract of R. apiculata. The antidiabetic effect of Glycosin in diabetic rats was investigated and determined their possible mechanism of action.

METHODS

Diabetes was induced in adult Wistar rats by a single intraperitoneal injection of streptozotocin and nicotinamide. Based on the oral glucose tolerance test, Glycosin (50mg/kg b.wt.) was orally administrated to diabetic rats for a period of 45 days. In different intervals, blood glucose and body weight were recorded. After 45 days, blood samples were collected to determine serum lipid profile, level of plasma insulin, hemoglobin, liver, and kidney functions using the appropriate tests. In addition the levels of carbohydrate metabolic enzymes in the liver homogenate were also measured. To determine the molecular mechanism of action, we followed the molecular docking of Glycosin in its possible targets, dipeptidyl peptidase-IV (DPP-IV), Peroxisome proliferator-activated receptor gamma (PPARγ), phosphorylated insulin receptor, and protein tyrosine phosphatase 1B (PTP-1B).

RESULTS

Glycosin treatment significantly (p<0.01) reduced the blood-glucose level, increased the body weight, increase hemoglobin, high-density lipoprotein and insulin level, protein, in addition the activity of hexokinase when compared to untreated rats. Decreased activities of liver function enzymes as well as level of urea, and creatinine were observed in Glycosin treated rats. Docking simulation confirmed that Glycosin interacted with DPP-IV, Insulin receptor and PTP-1B and PPARγ with more affinity and binding energy.

CONCLUSION

Glycosin acts as antihyperglycemic agent, associated with antihyperlipidemic and possibility function as a ligand for proteins that are targets for antidiabetes drugs.

Exploring the anti-diabetic potential of Australian Aboriginal and Indian Ayurvedic plant extracts using cell-based assays

BACKGROUND

Plant-derived compounds have been used clinically to treat type 2 diabetes for many years as they also exert additional beneficial effects on various other disorders. The aim of the present study was to investigate the possible mechanism of anti-diabetic activity of twelve (seven Australian Aboriginal and five Indian Ayurvedic) plant extracts.

METHODS

The ethanolic plant extracts were investigated for glucose uptake and adipogenesis in murine 3T3-L1 adipocytes. Cytotoxicity studies were also carried out against two cancerous cell lines, HeLa and A549, to investigate the potential anti-cancer activities of the extracts.

RESULTS

Of the seven Australian Aboriginal plant extracts tested, only Acacia kempeana and Santalum spicatum stimulated glucose uptake in adipocytes. Among the five Indian Ayurvedic plant extracts, only Curculigo orchioides enhanced glucose uptake. With respect to adipogenesis, the Australian plants Acacia tetragonophylla, Beyeria leshnaultii and Euphorbia drumondii and the Indian plants Pterocarpus marsupium, Andrographis paniculata and Curculigo orchioides reduced lipid accumulation in differentiated adipocytes. Extracts of Acacia kempeana and Acacia tetragonophylla showed potent and specific activity against HeLa cells.

CONCLUSIONS

The findings suggest that the plant extracts exert their anti-diabetic properties by different mechanisms, including the stimulation of glucose uptake in adipocytes, inhibition of adipogenesis or both. Apart from their anti-diabetic activities, some of the extracts have potential for the development of chemotherapeutic agents for the treatment of cervical cancer.

The transport and efflux of glycosylated luteinising hormone-releasing hormone analogues in caco-2 cell model: contributions of glucose transporters and efflux systems

Luteinising hormone-releasing hormone (LHRH) analogues have wide therapeutic applications in the treatment of prostate cancers and endocrine disorders. The structure of LHRH was modified using a glycosylation strategy to increase the permeability of the peptide across biological membranes. Lactose, galactose and glucose units were coupled to LHRH peptide, and the impact of glucose transporters, GLUT2 and SGLT1, was investigated in the transport of the analogues. Results showed the contribution of both transporters in the transport of all LHRH analogues. In the presence of glucose transporter inhibitors, reduction in the apparent permeability (Papp ) was greatest for compound 6, which contains a glucose unit in the middle of the sequence (Papp = 58.54 ± 4.72 cm/s decreased to Papp = 1.6 ± 0.345 cm/s). The basolateral to apical flux of the glycosylated derivatives and the impact of two efflux pumps was also examined in Caco-2 cell monolayers. The efflux ratios (ERs) of all LHRH analogues in Caco-2 cells were in the range of 0.06-0.2 except for compound 4 (galactose modified, ER = 8.03). We demonstrated that the transport of the glycosylated peptides was facilitated through glucose transporters. The proportion of glucose and lactose derivatives pumped out by efflux pumps did not affect the Papp values of the analogues.

Effects of ursolic acid derivatives on Caco-2 cells and their alleviating role in streptozocin-induced type 2 diabetic rats

In this study, the effect and mechanism of a series of ursolic acid (UA) derivatives on glucose uptake were investigated in a Caco-2 cells model. Their effect on hyperglycemia, hyperlipidemia and oxidative stress were also demonstrated in streptozocin (STZ)-induced diabetic rats. 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-glucose (2-NBDG) was used as a fluorescein in Caco-2 cells model to screen UA derivatives by glucose uptake and expression of glucose transporter protein (SGLT-1, GLUT-2). Moreover, STZ-induced diabetic rats were administered with these derivatives for 4 weeks of treatment. The fasting blood glucose (FBG), insulin levels, biochemical parameters, lipid levels, and oxidative stress markers were finally evaluated. The results of this study indicated that compounds 10 and 11 significantly inhibited 2-NBDG uptake under both Na+-dependent and Na+-independent conditions by decreasing SGLT-1 and GLUT-2 expression in the Caco-2 cells model. Further in vivo studies revealed that compound 10 significantly reduced hyperglycemia by increasing levels of serum insulin, total protein, and albumin, while the fasting blood glucose, body weight and food intake were restored much closer to those of normal rats. Compounds 10 and 11 showed hypolipidemic activity by decreasing the total amounts of cholesterol (TC) and triglycerides (TG). Furthermore, compound 10 showed antioxidant potential which was confirmed by elevation of glutathione (GSH) and superoxide dismutase (SOD) and reduction of malondialdehyde (MDA) levels in the liver and kidney of diabetic rats. It was concluded that compound 10 caused an apparent inhibition of intestinal glucose uptake in Caco-2 cells and hypoglycemia, hypolipidemia and augmented oxidative stress in STZ-induced diabetic rats. Thus, compound 10 could be developed as a potentially complementary therapeutic or prophylactic agent for diabetics mellitus and its complications.

Mechanisms of Action of Indigenous Antidiabetic Plants from the Boreal Forest of Northeastern Canada

Indigenous populations in Canada possess a wealth of native traditional knowledge. However, their rates of Type 2 diabetes mellitus (T2DM), a disease that was unheard of in their midst 50 years ago, are the highest in the country. In an effort to cut the impact of T2DM epidemic on Indigenous health, the Canadian Institutes of Health Research funded the “CIHR Team in Aboriginal Antidiabetic Medicines (CIHR-TAAM).” The goal was to explore Boreal forest medicinal plants stemming from Indigenous Traditional Medicine to be included in T2DM care. Six out of nine communities of the Cree of Eeyou Istchee (CEI) participated in ethnobotanical studies that resulted in the identification of 17 potential antidiabetic plant species. These species were screened for antidiabetic activities using a platform of in vitro bioassays and in vivo models of T2DM. This paper summarizes results on the 10 most promising plant species, their active constituents, and the mechanisms behind their antidiabetic activities. In addition, potential herb-drug interactions were examined at the level of drug-metabolizing enzymes, notably the cytochrome P450 family. This review serves as a canvas onto which is discussed the value of Indigenous medicinal plants, future avenues of research, and the ethical approach required in this field.

Medicinal plants of the Russian Pharmacopoeia; their history and applications

ETHNOPHARMACOLOGICAL RELEVANCE

Due to the location of Russia between West and East, Russian phytotherapy has accumulated and adopted approaches that originated in European and Asian traditional medicine. Phytotherapy is an official and separate branch of medicine in Russia; thus, herbal medicinal preparations are considered official medicaments. The aim of the present review is to summarize and critically appraise data concerning plants used in Russian medicine. This review describes the history of herbal medicine in Russia, the current situation and the pharmacological effects of specific plants in the Russian Pharmacopoeia that are not included in the European Pharmacopoeia.

MATERIALS AND METHODS

Based on the State Pharmacopoeia of the USSR (11(th) edition), we selected plant species that have not yet been adopted in Western and Central Europe (e.g., selected for inclusion in the European Pharmacopoeia) and systematically searched the scientific literature for data using library catalogs, the online service E-library.ru, and databases such as Medline/Pubmed, Scopus, and the Web of Science regarding species, effectiveness, pharmacological effects, and safety.

RESULTS

The Russian Federation follows the State Pharmacopoeia of the USSR (11(th) edition), which contains 83 individual plant monographs. Fifty-one of these plants are also found in the European Pharmacopoeia and have been well studied, but 32 plants are found only in the Pharmacopoeia of the USSR. Many articles about these medicinal plants were never translated in English, and much of the information collected by Russian scientists has never been made available to the international community. Such knowledge can be applied in future studies aimed at a safe, evidence-based use of traditional Russian medicinal plants in European and global phytopharmacotherapy as well as for the discovery of novel leads for drug development.

CONCLUSION

The review highlights the therapeutic potential of these Russian phytopharmaceuticals but also highlights cases where concern has been raised about product safety and tolerability, which would aid in supporting their safe use.

Cooperative anti-diabetic effects of deoxynojirimycin-polysaccharide by inhibiting glucose absorption and modulating glucose metabolism in streptozotocin-induced diabetic mice

We had previously shown that deoxynojirimycin-polysaccharide mixture (DPM) not only decreased blood glucose but also reversed the damage to pancreatic β-cells in diabetic mice, and that the anti-hyperglycemic efficacy of this combination was better than that of 1-deoxynojirimycin (DNJ) or polysachharide alone. However, the mechanisms behind these effects were not fully understood. The present study aimed to evaluate the therapeutic effects of DPM on streptozotocin (STZ)-induced diabetic symptoms and their potential mechanisms. Diabetic mice were treated with DPM (150 mg/kg body weight) for 90 days and continued to be fed without DPM for an additional 30 days. Strikingly, decrease of blood glucose levels was observed in all DPM treated diabetic mice, which persisted 30 days after cessation of DPM administration. Significant decrease of glycosylated hemoglobin and hepatic pyruvate concentrations, along with marked increase of serum insulin and hepatic glycogen levels were detected in DPM treated diabetic mice. Results of a labeled (13)C6-glucose uptake assay indicated that DPM can restrain glucose absorption. Additionally, DPM down-regulated the mRNA and protein expression of jejunal Na(+)/glucose cotransporter, Na(+)/K(+)-ATPase and glucose transporter 2, and enhanced the activities as well as mRNA and protein levels of hepatic glycolysis enzymes (glucokinase, phosphofructokinase, private kinase and pyruvate decarboxylas E1). Activity and expression of hepatic gluconeogenesis enzymes (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) were also found to be attenuated in diabetic mice treated with DPM. Purified enzyme activity assays verified that the increased activities of glucose glycolysis enzymes resulted not from their direct activation, but from the relative increase in protein expression. Importantly, our histopathological observations support the results of our biochemical analyses and validate the protective effects of DPM on STZ-induced damage to the pancreas. Thus, DPM has significant potential as a therapeutic agent against diabetes.

Rhododendron tomentosum (Ledum palustre). A review of traditional use based on current research

Rhododendron tomentosum Harmaja (previously: Ledum palustre) is a fragrant evergreen shrub found in peaty soils in northern Europe, Asia and North America, commonly referred to as wild rosemary, marsh tea, marsh rosemary or northern Labrador tea. At least since the eighteenth century it has been used in ethnomedicine for the treatment of various ailments, such as rheumatism, cough, cold and insect bites, as well as a repellent. The essential oil of wild rosemary with the rich polyphenolic fraction possesses analgesic, anti-inflammatory, antimicrobial, antiviral, antifungal and insecticidal potential, demonstrated by in vivo and in vitro studies. In addition, recent scientific research reported the promising antidiabetic, antioxidant and anticancer properties. This review summarizes the information concerning taxonomy, botany, ecology, chemical composition, biological activities, toxicology and traditional and contemporary application of Rhododendron tomentosum plants.

Larix laricina, an Antidiabetic Alternative Treatment from the Cree of Northern Quebec Pharmacopoeia, Decreases Glycemia and Improves Insulin Sensitivity In Vivo

Larix laricina K. Koch is a medicinal plant belonging to traditional pharmacopoeia of the Cree of Eeyou Istchee (Eastern James Bay area of Canada). In vitro screening studies revealed that, like metformin and rosiglitazone, it increases glucose uptake and adipogenesis, activates AMPK, and uncouples mitochondrial function. The objective of this study was to evaluate the antidiabetic and antiobesity potential of L. laricina in diet-induced obese (DIO) C57BL/6 mice. Mice were subjected for eight or sixteen weeks to a high fat diet (HFD) or HFD to which L. laricina was incorporated at 125 and 250 mg/kg either at onset (prevention study) or in the last 8 of the 16 weeks of administration of the HFD (treatment study). L. laricina effectively decreased glycemia levels, improved insulin resistance, and slightly decreased abdominal fat pad and body weights. This occurred in conjunction with increased energy expenditure as demonstrated by elevated skin temperature in the prevention study and improved mitochondrial function and ATP synthesis in the treatment protocol. L. laricina is thus a promising alternative and complementary therapeutic approach for the treatment and care of obesity and diabetes among the Cree.

In vitro modulation of oxidative burst via release of reactive oxygen species from immune cells by extracts of selected tropical medicinal herbs and food plants

OBJECTIVE

To evaluate in vitro immunomodulating properties and potential cytotoxicity of six tropical medicinal herbs and food plants namely Antidesma madagascariense (Euphorbiaceae) (AM), Erythroxylum macrocarpum (Erythroxylaceae) (EM), Faujasiopsis flexuosa (Asteraceae) (FF), Pittosporum senacia (Pittosporaceae) (PS), Momordica charantia (Cucurbitaceae) (MC) and Ocimum tenuiflorum (Lamiaceae) (OT).

METHODS

Initially, the crude water and methanol extracts were probed for their capacity to trigger immune cells' NADPH oxidase and MPO-dependent activities as measured by lucigenin- and luminol-amplified chemiluminescence, respectively; as compared to receptor-dependent (serum opsonised zymosan- OPZ) or receptor-independent phorbol myristerate acetate (PMA).

RESULTS

Preliminary screening on whole human blood oxidative burst activity showed significant and concentration-dependent immunomodulating properties of three plants AM, FF and OT. Further investigations of the fractions on isolated human polymorphonuclear cells (PMNs) and mice monocytes using two different pathways for activation of phagocytic oxidative burst showed that ethyl acetate fraction was the most potent extract. None of the active samples had cell-death effects on human PMNs, under the assay conditions as determined by the trypan-blue exclusion assay. Since PMA and OPZ NADPH oxidase complex is activated via different transduction pathways, these results suggest that AM, FF and OT does not affect a specific transductional pathway, but rather directly inhibit a final common biochemical target such as the NADPH oxidase enzyme and/or scavenges ROS.

CONCLUSIONS

Our findings suggest that some of these plants extracts/fractions were able to modulate significantly immune response of phagocytes and monocytes at different steps, emphasizing their potential as a source of new natural alternative immunomodulatory agents.

Influence of the traditional Brazilian drink Ilex paraguariensis tea on glucose homeostasis

In this study we examined the acute in vivo effect and short- and long-term in vitro effects of samples from native and commercial Ilex paraguariensis on glucose homeostasis. Also, the potential effect of I. paraguariensis on serum insulin secretion was investigated. The chemical identification and quantification of methyl xanthines and polyphenols in CH₂Cl₂, EtOAc and n-BuOH fractions of native I. paraguariensis as well as infusions of green and roasted I. paraguariensis from a commercial source was verified by high-performance liquid chromatography. The results for the serum glucose-lowering indicated that both fractions and both infusions were able to improve significantly the oral glucose tolerance curve. Additionally, both the EtOAc and n-BuOH fractions induced-insulin secretion, but EtOAc induced an early (at 15 min) and late (at 60 min) biphasic peak of insulin secretion similar to glipizide stimulatory effect. Both fractions increased liver glycogen content compared with fasted normal rats. Also, EtOAc and n-BuOH fractions inhibited in vitro disaccharidases activities after an acute treatment. The maximum inhibitory effect of the EtOAc and n-BuOH fractions on maltase activity (at 5 min) was around 35%. The evident reduction of protein glycation by glucose or fructose with EtOAc and n-BuOH fractions increased from 7 to 28 days of in vitro incubation. Inhibition of bovine serum albumin glycation by glucose and fructose, by around 50% and 90%, respectively, was observed. Additionally, the green and roasted mate infusions reduced the formation of AGEs in a characteristic long-term effect. In conclusion, this study shows that I. paraguariensis has an anti-hyperglycemic potential role able to improve the diabetic status and is probably a source of multiple hypoglycemic compounds.

Comprehensive evidence-based assessment and prioritization of potential antidiabetic medicinal plants: a case study from canadian eastern james bay cree traditional medicine

Canadian Aboriginals, like others globally, suffer from disproportionately high rates of diabetes. A comprehensive evidence-based approach was therefore developed to study potential antidiabetic medicinal plants stemming from Canadian Aboriginal Traditional Medicine to provide culturally adapted complementary and alternative treatment options. Key elements of pathophysiology of diabetes and of related contemporary drug therapy are presented to highlight relevant cellular and molecular targets for medicinal plants. Potential antidiabetic plants were identified using a novel ethnobotanical method based on a set of diabetes symptoms. The most promising species were screened for primary (glucose-lowering) and secondary (toxicity, drug interactions, complications) antidiabetic activity by using a comprehensive platform of in vitro cell-based and cell-free bioassays. The most active species were studied further for their mechanism of action and their active principles identified though bioassay-guided fractionation. Biological activity of key species was confirmed in animal models of diabetes. These in vitro and in vivo findings are the basis for evidence-based prioritization of antidiabetic plants. In parallel, plants were also prioritized by Cree Elders and healers according to their Traditional Medicine paradigm. This case study highlights the convergence of modern science and Traditional Medicine while providing a model that can be adapted to other Aboriginal realities worldwide.