In vitro inhibition activity of polyphenol-rich extracts from Syzygium aromaticum (L.) Merr. & Perry (Clove) buds against carbohydrate hydrolyzing enzymes linked to type 2 diabetes and Fe(2+)-induced lipid peroxidation in rat pancreas

Phytochemicals-linked food safety and human health protective benefits of the selected food-based botanicals

Phytochemicals-rich food-based botanicals including traditional or under-utilized plant-based ingredients can serve a dual functional role to help counter food contamination of bacterial origin, while also addressing the rise of diet-linked non-communicable chronic diseases (NCDs) such as type 2 diabetes, chronic hypertension and the associated oxidative stress. Hence the screening of these food-based botanicals for their phenolic content and profile, as well as antimicrobial, antioxidant, anti-hyperglycemic and anti-hypertensive properties has relevant merit. Using in vitro assay models, hot water extracts of different forms (slice, pickle, or powder) of amla (Phyllanthus emblica), clove (Syzygium aromaticum), kokum (Garcinia indica), and garlic (Allium sativum) were analyzed for their total soluble phenolic content (TSP) and phenolic profile as well as antimicrobial activity against strains of Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli that are associated with food-borne disease outbreaks. In addition, the antioxidant, anti-hyperglycemic and anti-hypertensive activity of the extracts were also determined using in vitro assay models, with the goal of establishing a dual functional role of the food safety and health protective benefits of these botanicals. A high baseline TSP content was observed in all the extracts and the major phenolic phytochemicals detected were gallic, cinnamic, ellagic, benzoic, dihydroxybenzoic, protocatechuic, and p-coumaric acid along with catechin and rutin. All extracts displayed significant antimicrobial activity against most of the bacterial strains tested and the antimicrobial activity was specific for each strain targeted in this study. Furthermore, significant antioxidant, anti-hyperglycemic and antihypertensive activity were observed among the botanical extracts, especially among the amla and kokum extracts. These results indicate that phytochemicals enriched botanicals, including amla and kokum, can be integrated into modern-day food preservation and dietary support strategies aimed at improving the food safety and health protective benefits of the food matrix.

Therapeutic potential of Thai herbal formula for cognitive impairment: A metabolomics approach for Comprehensive Insights

Chronic cerebral ischemia hypoperfusion plays a role in the initiation and progression of vascular dementia, which causes changes in metabolites. Currently, there is no standard treatment to treat, prevent and reduce the severity of this condition. Thai herbal Yahom no.20 (YHF20) is indicated for fatigue and dizziness. The components of YHF20 have been found to have pharmacological effects related to the pathology of chronic cerebral ischemia hypoperfusion. This study aimed to investigate metabolomic changes after YHF20 administration in a rat model of permanent bilateral common carotid artery occlusion (2-VO) induced chronic cerebral ischemia hypoperfusion, and to explore its impact on spatial learning and memory. Albino Wistar rats were randomly allocated to 5 groups; sham, 2-VO, 2-VO+ 100 mg/kg YHF20, 2-VO+300 mg/kg YHF20, and 2-VO+1000 mg/kg YHF20. The rats were administered YHF20 daily by oral gavage for 56 days after 2-VO induction. Plasma was collected weekly for metabolome change analysis using LC-MS/QTof and toxicity study. The rats were evaluated for spatial learning and memory using the Morris water maze. The results showed that 78 known metabolites and 10 tentative pathways altered after chronic cerebral hypoperfusion, although it was not able to determine the effect on memory and learning behaviors of rats. Glutathione and glutathione metabolism might be metabolite-pathway that were the affect after YHF20 administration in cerebral ischemic condition. The 4 known metabolites may be the metabolites from the constituents of YHF20 could be considered and confirmed for quality control purpose. In conclusion, YHF20 administration might contribute to metabolic changes related to cerebral ischemia condition without the effect on spatial learning and memory, including hepatotoxicity and nephrotoxicity after 56 days of treatment. Alterations in the potential metabolites may provide data support for elucidating dementia pathogenesis and selecting pathways for intervention.

The most commonly used spices in Thai traditional medicine: in vitro evaluation of anti-hyperglycemic, antioxidant, polyphenol content, and nitric oxide production inhibitory activities

Background and purpose

Diabetes mellitus is a persistent hyperglycemic condition. Thai cuisine and medicine incorporate spices: nutmeg, mace, clove buds, cardamom, cinnamon, and coriander. The in vitro impacts of these spices on anti-diabetic, antioxidant, anti-inflammatory, and total phenolic and flavonoid content were assessed.

Experimental approach

Alpha-amylase and alpha-glucosidase inhibition assays were conducted. Antioxidant potential was measured through DPPH and ABTS assays. Anti-inflammatory activity was determined by inhibiting nitric oxide generation in RAW 264.7 cells. Total phenolic content was quantified using the Folin Ciocalteu method, while total flavonoid content was estimated via the aluminum chloride colorimetric method.

Findings/Results

Ethanolic and aqueous extracts of a blend of spices (Siam cardamom, nutmeg, mace, and clove buds), denoted as 4-GlurE and 4-GlurA, displayed concentration-dependent inhibition of alpha-glucosidase, with IC50 values of 0.373 and 0.435 mg/mL, respectively. 4-GlurE and 4-GlurA exhibited antioxidant activity, by ABTS·+ radical and DPPH scavenging capabilities. 4-GlurE demonstrated anti-inflammatory potential by reducing nitric oxide generation (IC50: 43.95 ± 2.47 μg/mL). 4-GlurE and 4-GlurA possessed total phenolic content (TPC) of 122.47 ± 1.12 and 148.72 ± 0.14 mg GAE/g, respectively. 4-GlurE exhibited a higher total flavonoid content (TFC) compared to the aqueous extract (340.33 ± 4.77 and 94.17 ± 3.36 mg QE/g). Cinnamon and clove aqueous extracts were more potent than acarbose in alpha-glucosidase inhibition with the highest antioxidant activity. Polyphenol levels (TPC and TFC) exhibited strong correlations with antioxidant capacity.

Conclusions and implications

Findings are consistent with the traditional use of 4-Glur, with cinnamon, for diabetes prevention and treatment.

Chemical Characterization of Different Extracts from Artemisia annua and Their Antioxidant, Enzyme Inhibitory and Anti-Inflammatory Properties

Artemisia annua L. (Asteraceae Family) is an important plant in Asia that has been used for treating different diseases, including fever due to malaria, wounds, tubercolisis, scabues, pain, convulsions, diabetes, and inflammation. In this study we aimed to evaluate the effects of different polarity extracts (hexane, dichloromethane, ethyl acetate, ethanol, ethanol/water (70 %) and water) from A. annua against the burden of inflammation and oxidative stress occurring in colon tissue exposed to LPS. In parallel, chemical composition, antiradical, and enzyme inhibition effects against α-amylase, α-glucosidase, tyrosinase, and cholinesterases were evaluated. The water extract contained the highest content of the total phenolic with 34.59 mg gallic acid equivalent (GAE)/g extract, while the hexane had the highest content of the total flavonoid (20.06 mg rutin equivalent (RE)/g extract). In antioxidant assays, the polar extracts (ethanol, ethanol/water and water) exhibited stronger radical scavenging and reducing power abilities when compared to non-polar extracts. The hexane extract showed the best AChE, tyrosinase and glucosidase inhibitory effects. All extracts revealed effective anti-inflammatory agents, as demonstrated by the blunting effects on COX-2 and TNFα gene expression. These effects seemed to be not related to the only phenolic content. However, it is worthy of interest to highlight how the higher potency against LPS-induced gene expression was shown by the water extract ; thus suggesting a potential phytotherapy application in the management of clinical symptoms related to inflammatory colon diseases, although future in vivo studies are needed to confirm such in vitro and ex vivo observations.

The α-glucosidase inhibitory activity of avicularin and 4-O-methyl gallic acid isolated from Syzygium myrtifolium leaves

Diabetes Mellitus is the main cause of death on a global scale. In 2019, there were 463 million people with diabetes, and WHO predicts that by 2030, there will be 578 million. As an antidiabetic agent, α-glucosidase inhibitors are one of the methods employed to reduce the prevalence of diabetes. Diabetes is traditionally treated with Syzygium as a primary material, medicine, fruit, ornamental plant, and source of carpentry. This investigation aimed to examine the inhibitory effect of seven species of Syzygium against α-glucosidase enzyme using an in vitro assay and isolate active substances and ascertain their concentrations in each sample. As a solvent, ethanol was used in maceration to extract the substance. Afterward, the extract underwent a series of fractionation techniques, including liquid-liquid extraction, vacuum liquid chromatography, column chromatography, and preparative Thin Layer Chromatography (TLC) for purification and isolation. The compound's structures were elucidated using TLC, UV-Visible spectrophotometry, and nuclear magnetic resonance (NMR) spectroscopy. Based on concentrations of 100 and 200 µg/mL, Syzygium myrtifolium exhibited the most significant inhibitory effect, followed by other species of Syzygium. The proportion of ethyl acetate had the strongest activity (IC₅₀ 0.40 ± 0.02 µg/mL) contrasted to positive control acarbose (IC₅₀ 55.39 ± 0.67 g/mL) and quercitrin (IC₅₀ 6.47 ± 0.40 µg/mL). Avicularin and 4-O-methyl gallic acid were discovered in the ethyl acetate fraction of Syzygium myrtifolium with IC₅₀ values of 17.05 ± 0.75 µg/mL and 25.19 ± 0.21 µg/mL, respectively. As α-glucosidase inhibitory, the results of this study indicate Syzygium myrtifolium can be used as a dietary supplement to manage hyperglycemia.

Theaflavin-3,3'-Digallate Inhibits Erastin-Induced Chondrocytes Ferroptosis via the Nrf2/GPX4 Signaling Pathway in Osteoarthritis

There is evidence that osteoarthritis (OA) is associated with ferroptosis which is a kind of lipid peroxidation-related cell death. Theaflavin-3,3'-digallate(TF3), a polyphenol compound extracted from black tea, possesses antioxidative and anti-inflammatory properties, but its effects on chondrocyte ferroptosis in osteoarthritis (OA) remain unclear. Our present study aims at exploring the protective role and underlying mechanisms of TF3 against erastin-induced chondrocyte ferroptosis in OA. In human primary chondrocytes treated with erastin alone or combined with different doses of TF3, cell viability was assessed by MTS. Ferroptosis-related proteins, including Gpx4, HO-1, and FTH1, were detected by western blot. The levels of lipid peroxidation and Fe2⁺ were determined by fluorescence staining. Meanwhile, the change of related proteins in the Nrf2/Gpx4 signaling pathway was determined by western blot. siRNA-mediated Nrf2 knockdown and the Gpx4 inhibitor RSL3 were used to explore molecular mechanisms for TF3-induced ferroptosis in OA chondrocyte. The magnetic resonance imaging (MRI), HE staining, Masson's staining, and immunohistochemistry were used to evaluate articular cartilage damages in the rat OA model. The results showed that Gpx4 expression was markedly downregulated in the chondrocytes of OA patients. TF3 reversed erastin-induced ferroptosis of human cultured chondrocytes, lipid ROS, and Fe2⁺ production in mitochondria. Moreover, the expression of Gpx4, HO-1, FTH1, and Nrf2 was markedly induced by TF3 in the erastin-treated chondrocytes. The antiferroptotic effect of TF3 was related to enhance Nrf2/Gpx4 signaling pathway. Finally, TF3 inhibited OA progression by alleviating in vivo cartilage damage related to chondrocyte ferroptosis. Thus, TF3 significantly inhibits chondrocyte ferroptosis by activating the Nrf2/Gpx4 signaling pathway, suggesting that TF3 serves as a potential therapeutic supplement for OA treatment.

Evaluation of Major Constituents of Medicinally Important Plants for Anti-Inflammatory, Antidiabetic and AGEs Inhibiting Properties: In Vitro and Simulatory Evidence

Diabetes mellitus (DM) is a global health concern that is associated with several micro- and macrovascular complications. We evaluated several important medicinal plant constituents, including polyphenols and flavonoids, for α-glucosidase inhibition, AGEs’ inhibitory activities using oxidative and no-oxidative assays, the inhibition of protein cross link formation, 15-lipoxydenase inhibition and molecular docking. The molecular docking studies showed high binding energies of flavonoids for transcriptional regulars 1IK3, 3TOP and 4F5S. In the α-glucosidase inhibition assay, a significant inhibition was noted for quercitrin (IC₅₀ 7.6 µg/mL) and gallic acid (IC₅₀ 8.2 µg/mL). In the AGEs inhibition assays, quercetin showed significant results in both non-oxidative and (IC₅₀ 0.04 mg/mL) and oxidative assays (IC₅₀ 0.051 mg/mL). Furthermore, quercitrin showed inhibitory activity in the non-oxidative (IC₅₀ 0.05 mg/mL) and oxidative assays (IC₅₀ 0.34 mg/mL). A significant inhibition of protein cross link formation was observed by SDS-PAGE analysis. Quercitrin (65%) and quercetin (62%) showed significant inhibition of 15-lipoxygenase. It was thus concluded that flavonoids and other polyphenols present in plant extracts can be effective in management of diabetes and allied co-morbidities.

Screening of Aqueous Extract of Persea americana Seeds for Alpha-Glucosidase Inhibitors

Activity of α-glucosidase enzyme in the gastrointestinal tract has been implicated in postprandial hyperglycaemia. If not properly controlled, postprandial hyperglycaemia might progress to diabetes mellitus, a metabolic syndrome. Diabetes is associated with many complications such as retinopathy, heart attack, nephropathy, neuropathy, stroke, and lower limb amputation. Antidiabetic medications presently in use have little effect on postprandial glycaemic excursion and hence do not bring down the blood glucose level to baseline. This study extracted, fractionated, and screened the aqueous extract of Persea americana seeds for hypoglycaemic potential. Inhibitory effects of the fractions and subfractions of the extract on α-glucosidase activity were investigated. The most active subfraction was subjected to Fourier transform infrared (FTIR) and gas chromatography mass spectroscopy (GC-MS) analysis to elucidate the active components. The active subfraction showed a significant inhibition (p < 0.05) on α-glucosidase. The subfraction competitively inhibits α-glucosidase (with IC50 = 09.48 ± 0.58 μg/mL), though less potent than the standard drug, acarbose (IC50 = 06.45 ± 0.47 μg/mL). FTIR analysis of the subfraction showed the presence of carbonyl group, hydroxy group, carboxyl group, double bonds, methylene, and methyl groups. GC-MS analysis suggests the presence of cis-11,14-eicosadienoic acid, catechin, and chlorogenic acid as the active components. In conclusion, the components obtained from this study can be synthesised in the laboratory to further confirm their hypoglycaemic activity. The most active subfraction can be explored further to confirm its inhibitory activity against the enzyme and to determine its extent in the treatment of diabetes mellitus in vivo.

Culinary Spices in Food and Medicine: An Overview of Syzygium aromaticum (L.) Merr. and L. M. Perry [Myrtaceae]

Spices-dried aromatic parts of plants (leaves, seeds, bark, roots, rhizomes, buds, etc) used to enhance flavour, taste and colour (sensory quality) of foods, are increasingly finding other useful roles in healthcare beyond their primary use as culinary organoleptic enhancers. Several spices are currently being investigated for their potential health benefits, because of the failing efficacy, toxicity and high cost associated with conventional drugs. One such spice: Syzygium aromaticum (L.) Merr. and L.M.Perry [Myrtaceae] (Clove), has a multi-dimensional role in diet, medicine, functional foods and nutraceuticals, agriculture, among other industries. Peer-reviewed articles, mostly from PubMed and Google Scholar, were consulted for the purpose of this review. The nutritional and phytochemical contents, selected biological activities as well as some functional foods and beverages of clove and their uses for human health are presented. Although these observations are largely empirical, the efficacious attributes have led to their pharmacological applications in the indigenous system of medicine all over the world and bridge between food, diet and medicine. Considering the GRAS status of clove, more studies on bioavailability, accumulation, toxicity, dosage and efficacy of clove as a spice drug or functional foods in biological systems especially in humans are required. Meanwhile, clove and its products can be used as co-adjuvants in the prevention, treatment and management of chronic diseases. Further, many applications of clove in food, health, cosmetics, pharmaceutics, nanoparticles and agricultural industries are still open for investigations.

Exploring the Regulation of Jiangtang Tiaozhi Formula on the Biological Network of Obese T2DM Complicated With Dyslipidemia Based on Clinical Transcriptomics

OBJECTIVE

To use systems biology to explore the biomolecular network mechanism of the Jiangtang Tiaozhi Recipe (JTTZR) in the intervention of obese Type 2 diabetes (T2DM) patients with dyslipidemia.

METHODS

Twelve patients with obese type 2 diabetes mellitus and dyslipidemia (traditional Chinese medicine syndrome differentiation was excess heat syndrome of the stomach and intestines) were treated with JTTZR for 24 weeks, and 12 patients were included in the healthy control group. First, blood samples from 6 patients in each group (disease group before treatment, disease group after treatment, and healthy control group) were collected for RNA microarray analysis. Quantitative polymerase chain reaction (qPCR) was used to validate these target lncRNAs and mRNAs. Finally, a detailed analysis of the differences in the disease group before treatment vs. the healthy control group and the disease group after treatment vs. the disease group before treatment was undertaken. In addition, we focused on disease-related pathways and analyzed the correlation between the differential expression of target lncRNAs and clinical indicators.

RESULTS

(1) Disease group before treatment vs. healthy control group: There were 557 up-regulated lncRNAs, 273 down-regulated lncRNAs, 491 up-regulated mRNAs, and 1639 down-regulated mRNAs. GO analysis and pathway analysis showed that T2DM may be related to cell proliferation in the forebrain, post-embryonic organ development, calcium signaling pathway. qPCR validation showed that the expression of XLOC-005590 and HNF1A-AS1 as target lncRNAs increased, and this was verified by gene chip analysis. (2) Disease group after treatment vs. disease group before treatment: 128 lncRNAs were upregulated, 32 lncRNAs were downregulated, 45 mRNAs were upregulated, and 140 mRNAs were downregulated. GO analysis and pathway analysis showed that JTTZR may treat T2DM through endosome transport, the insulin signaling pathway, and glycine, serine, and threonine metabolism. qPCR validation showed that in the healthy control group, XLOC_005590 was upregulated, whereas the downstream gene (ECI2) was downregulated in the disease group before treatment. However, after 24 weeks of intervention with JTTZR, XLOC_005590 was downregulated and ECI2 was upregulated compared with the disease group before treatment (0 weeks) (P <0.05).

CONCLUSION

JTTZR may interfere in patients with obese T2DM with dyslipidemia by regulating pathways such as fatty acid degradation, glycolysis/gluconeogenesis, and pyruvate metabolism.

Phytochemical Characterization and Evaluation of the Antioxidant and Anti-Enzymatic Activity of Five Common Spices: Focus on Their Essential Oils and Spent Material Extractives

The essential oil industry of aromatic herbs and spices is currently producing a significant amount of by-products, such as the spent plant materials remaining after steam or hydrodistillation, that are simply discarded. The aim of this study was to comparatively investigate the phytochemical composition, antioxidant and multi-enzymatic inhibitory potential of the essential oils and spent plant material extractives obtained from cinnamon, cumin, clove, laurel, and black pepper. The essential oils were characterized by the presence of several phytochemical markers (cinnamaldehyde, cuminaldehyde, eugenol, eucalyptol, α-terpinene, limonene, β-caryophyllene or β-pinene). On the other hand, the LC-HRMS/MS profiling of the spent material extracts allowed the annotation of species specific and non-specific metabolites, such as organic acids, phenolic acids, flavonoids, proanthocyanidins, hydrolysable tannins, fatty acids, or piperamides. All samples exhibited very strong antioxidant effects, with the clove essential oil displaying the strongest radical scavenging (525.78 and 936.44 mg TE/g in DPPH and ABTS assays), reducing (2848.28 and 1927.98 mg TE/g in CUPRAC and FRAP), and total antioxidant capacity (68.19 mmol TE/g). With respect to the anti-acetylcholinesterase (0.73-2.95 mg GALAE/g), anti-butyrylcholinesterase (0-3.41 mg GALAE/g), anti-tyrosinase (0-76.86 mg KAE/g), anti-amylase and anti-glucosidase (both 0-1.00 mmol ACAE/g) assays, the spice samples showed a modest activity. Overall, our study reports that, not only the volatile fractions of common spices, but also their spent plant materials remaining after hydrodistillation can be regarded as rich sources of bioactive molecules with antioxidant and multi-enzymatic inhibitory effects.

Phytochemical Constituents and Biological Activities of the Unexplored Plant Rhinanthus angustifolius subsp. grandiflorus

In the present study, a total of 12 extracts of Rhinanthus angustifolius subsp. grandiflorus, an understudied hemiparasitic species, were obtained using different extraction techniques, namely, homogenizer-assisted extraction (HAE), maceration (MAC), soxhlet (SOX), infusion, and solvents (ethyl acetate, methanol, ethanol, and water), and were evaluated for their in vitro antioxidant and enzyme-inhibiting properties. Additionally, untargeted profiling based on high-resolution mass spectrometry targeted different phytochemical classes, namely, polyphenols, terpenoids, and alkaloids. The highest total phenolic and flavonoid contents were detected using methanol as the extraction solvent. Multivariate statistics following the untargeted profiling revealed that the extraction solvent had a hierarchically higher impact than the extraction method when considering the recovery of bioactive compounds. The methanolic extracts displayed the highest radical-scavenging antioxidant capacity, as provided by CUPRAC and FRAP assays. On the other hand, the water extracts (MAC and HAE) and the infusion extract showed the highest activity as metal chelators (25.66–27.51 mg EDTAE/g). Similarly, the water extract obtained by HAE and the infusion extract revealed the highest phosphomolybdenum activity (3.92 ± 0.14 and 3.71 ± 0.01 mmol TE/g, respectively). The different extracts also exhibited different enzyme inhibition potentials. For instance, HAE and MAC ethanolic extracts inhibited only α-amylase (0.69 ± 0.01 and 0.70 ± 0.01 mmol ACAE/g), while all the other extracts showed a dual inhibition against both carbohydrate-hydrolyzing enzymes tested (i.e., α-amylase: 0.07–0.69 mmol ACAE/g; α-glucosidase: 0.03–1.30 mmol ACAE/g). Nevertheless, the other extracts inhibited acetyl-, butyryl-cholinesterases, or both; MAC–water extract displayed no inhibition against the enzymes. Additionally, all the studied extracts were found to inhibit tyrosinase, ranging from 10.62 to 52.80 mg KAE/g. In general, the water extracts showed weaker inhibition towards the enzymes than the other extracts. This study demonstrated that R. angustifolius is an excellent source of natural antioxidants and enzyme inhibitors that could be further investigated and exploited for pharmaceutical purposes.

Hypoglycemic Effects of Licochalcone A on the Streptozotocin-Induced Diabetic Mice and Its Mechanism Study

Type 2 diabetes mellitus (T2DM) is a type of metabolic illness based on relatively insufficient insulin secretion and insulin resistance (IR) as pathophysiological bases. Currently, it is the main type of diabetes. Hypoglycemic and hypolipidemic effects of licochalcone A (LicA) on high-fat diet and streptozocin-caused T2DM were studied. LicA can remarkably decline the IR index and blood glucose and serum lipid levels. Also, the treatment of LicA can improve the "three more and one less" phenomenon in T2DM mice, such as excessive drinking, eating, urine, and weight loss. In addition, LicA can improve oral glucose tolerance, pancreatic injury, and liver enlargement in T2DM mice. Network pharmacology analysis demonstrated that the observed pharmacological effects were mediated by regulating the insulin signal transduction pathway. Therefore, the PI3K/Akt-signaling pathway was selected for verification; it was demonstrated that LicA could improve the insulin-signaling pathway, protect islet cells, improve IR, reduce blood glucose levels, and alleviate lipid metabolism disorder. Its mechanism of influence may be closely related to LicA up-regulating the liver and pancreas IRS-2/PI3K/AKT-signaling pathway. Among them, the high-dose group of LicA had the best effect, which provided an idea for the use of LicA as a nutritional agent in the cure of T2DM.

Phytochemical profile, antioxidant, α-amylase inhibition, binding interaction and docking studies of Justicia carnea bioactive compounds with α-amylase

The present study investigated the antioxidant and invitro antidiabetic capacities of Justicia carnea aqueous leaf extract (JCAE) using α-amylase inhibition model. α-Amylase binding-interaction with JCAE was also investigated using fluorescence spectroscopy and molecular docking. Phytochemical screening and Gas Chromatography-Mass Spectrometry (GC-MS) analysis indicated presence of bioactive compounds. Phenolic (132 mg GAE/g) and flavonoid contents (31.08 mg CE/g) were high. JCAE exhibited high antioxidant capacity and effectively inhibited α-amylase activity (IC50, 671.43 ± 1.88 μg/mL), though lesser than acarbose effect (IC50, 108.91 ± 0.61 μg/mL). α-Amylase intrinsic fluorescence was quenched in the presence of JCAE. Ultraviolet-visible and FT-IR spectroscopies affirmed mild changes in α-amylase conformation. Synchronous fluorescence analysis indicated alterations in the microenvironments of tryptophan residues near α-amylase active site. Molecular docking affirmed non-polar interactions of compounds 6 and 7 in JCAE with Asp-197 and Trp-58 residues of α-amylase, respectively. Overall, JCAE indicated potential to prevent postprandial hyperglycemia by slowing down carbohydrate hydrolysis.

Effect of eugenol treatment in hyperglycemic murine models: A meta-analysis

Diabetes is a highly prevalent health condition affecting many people worldwide. In vitro studies have described the positive effects of cloves and its major compound, eugenol, in the treatment of diabetes. However, it is unclear whether the effects of this compound are negative, neutral, or positive, on hyperglycemic animals. Therefore, a meta-analytical review was conducted to determine the magnitude of effects of eugenol on variables directly and indirectly related to diabetes. This study revealed that eugenol treatment decreased the glucose levels and the activity of carbohydrate-metabolizing enzymes, ameliorated the lipid profile, and reduced the oxidative, renal, and hepatic damages in hyperglycemic rodents. Moreover, eugenol alleviated the weight loss and restored the activity of the antioxidant defense system. Insulin levels was not affected by eugenol treatment. Also, mixed model analyses revealed that the use of purified or non-purified eugenol and the concentrations administered significantly affected the treatment outcome. In conclusion, our findings indicate that eugenol may have potential therapeutic effects in the treatment of diabetes. Furthermore, this study can direct future preclinical and clinical trials, with important implications for human health.

Antidiabetic Potential of Syzygium sp.: An Overview

Diabetes, characterized by hyperglycemia, is one of the most significant metabolic diseases, reaching alarming pandemic proportions. It can be due to the defects in insulin action, or secretion, or both. The global prevalence of diabetes is estimated at 425 million people in 2017, and expected to rise to 629 million by 2045 due to an increasing trend of unhealthy lifestyles, physical inactivity, and obesity. Several treatment options are available to diabetics, however, some of the antidiabetic drugs result in adverse side effects such as hypoglycemia. Hence, there has been a proliferation of studies on natural products with antidiabetic effects, including plants from the Myrtaceae family, such as Psidium guajava, Eucalyptus globulus,Campomanesia xanthocarpa, and more significantly, Syzygium sp. Previous studies have shown that a number of Syzygium species had potent antidiabetic effects and were safe for consumption. This review aims to discuss the antidiabetic potential of Syzygium sp., based on in vitro and in vivo evidence.

Evaluation of the Anti-Diabetic Activity of Some Common Herbs and Spices: Providing New Insights with Inverse Virtual Screening

Culinary herbs and spices are widely used as a traditional medicine in the treatment of diabetes and its complications, and there are several scientific studies in the literature supporting the use of these medicinal plants. However, there is often a lack of knowledge on the bioactive compounds of these herbs and spices and their mechanisms of action. The aim of this study was to use inverse virtual screening to provide insights into the bioactive compounds of common herbs and spices, and their potential molecular mechanisms of action in the treatment of diabetes. In this study, a library of over 2300 compounds derived from 30 common herbs and spices were screened in silico with the DIA-DB web server against 18 known diabetes drug targets. Over 900 compounds from the herbs and spices library were observed to have potential anti-diabetic activity and liquorice, hops, fennel, rosemary, and fenugreek were observed to be particularly enriched with potential anti-diabetic compounds. A large percentage of the compounds were observed to be potential polypharmacological agents regulating three or more anti-diabetic drug targets and included compounds such as achillin B from yarrow, asparasaponin I from fenugreek, bisdemethoxycurcumin from turmeric, carlinoside from lemongrass, cinnamtannin B1 from cinnamon, crocin from saffron and glabridin from liquorice. The major targets identified for the herbs and spices compounds were dipeptidyl peptidase-4 (DPP4), intestinal maltase-glucoamylase (MGAM), liver receptor homolog-1 (NR5A2), pancreatic alpha-amylase (AM2A), peroxisome proliferator-activated receptor alpha (PPARA), protein tyrosine phosphatase non-receptor type 9 (PTPN9), and retinol binding protein-4 (RBP4) with over 250 compounds observed to be potential inhibitors of these particular protein targets. Only bay leaves, liquorice and thyme were found to contain compounds that could potentially regulate all 18 protein targets followed by black pepper, cumin, dill, hops and marjoram with 17 protein targets. In most cases more than one compound within a given plant could potentially regulate a particular protein target. It was observed that through this multi-compound-multi target regulation of these specific protein targets that the major anti-diabetic effects of reduced hyperglycemia and hyperlipidemia of the herbs and spices could be explained. The results of this study, taken together with the known scientific literature, indicated that the anti-diabetic potential of common culinary herbs and spices was the result of the collective action of more than one bioactive compound regulating and restoring several dysregulated and interconnected diabetic biological processes.

Evaluation of In Vitro Antioxidant and Antidiabetic Activities of Aristolochia longa Extracts

Oxidative stress plays a major role in diabetic physiopathology; hence, the interest of using natural antioxidants as therapeutic tools exists. The aim of this study was the evaluation of in vitro antioxidant activity and inhibitory potential of organic extracts from Aristolochia longa roots against key enzymes linked to hyperglycemia. Antioxidant activity was performed using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals and ferric reducing/antioxidant power (FRAP) methods. The α-Glucosidase and β-Galactosidase inhibitory activities were investigated using an in vitro model. Moreover, phytochemical analysis of tested extracts was carried out. The aqueous fraction of this herb exhibited the highest antioxidant activity for both DPPH and ABTS methods, IC₅₀=125.40±2.40 μg/mL and IC₅₀=65.23±2.49 μg/mL, respectively. However, the ethyl acetate fraction possessed the strongest inhibitory effect towards α-Glucosidase (IC₅₀=1.112±0.026 mg/mL). Furthermore, the result showed high levels of phenolic content. The results showed that this plant could be a significant source of medically important natural compounds.

Identification of Bioactive Compounds and Analysis of Inhibitory Potential of the Digestive Enzymes from Syzygium sp. Extracts

Diabetes and obesity represent major public health problems worldwide. High cost of medicines and drug treatments propose the research for less expensive alternatives, such as enzymatic inhibitors present in medicinal plants from natural sources. An example of such medicinal plant is the jambolan Syzygium sp., which is referred to be hypoglycemic and efficient in weight loss. With this in mind, we identified the bioactive compounds from Syzygium sp. commercial teas and evaluated the inhibitory potential and the antioxidant activity of digestive enzymes from a simulated gastric fluid. Syzygium sp. samples showed low percentages of enzymatic inhibition at 1 : 200 dilution. Antioxidant activity was significant, although it was not expressive of the contents of total phenolic compounds, tannins, flavonoids, flavones, and alkaloids. Maldi-Tof spectroscopy suggested the presence of luteolin in Syzygium sp. samples. Molecular docking predicted that luteolin binds at the α-amylase catalytic site in a similar manner as acarbose, the carbohydrate inhibitor from the enzyme crystallographic structure. The phytochemical content and biological activity were distinct among samples from commercial teas. Thus, additional studies should be conducted to elucidate efficacy and safety of Syzygium sp. extracts, especially in vivo experiments. Syzygium sp. might be in the near future recommended as a medicinal plant in low cost diabetes and obesity treatments.

Restorative Effect of Semecarpus Anacardium on Altered Energy Metabolism in Type-2 Diabetes Mellitus-Induced Cardiac Dysfunction in Rats

Semecarpus anacardium is an important herbal drug that has been used against various ailments. To evaluate the cardioprotective effect of the drug against altered cardiac energy metabolism in type-2 diabetes rats, type-2 diabetes was induced in rats by feeding them with a high-fat diet for 2 weeks followed by intraperitoneal injection of streptozotocin (STZ) 35 mg/kg body weight twice 24 h apart and left for 12 weeks to develop cardiovascular complication. The effects of the nut milk extract on the glucose metabolizing enzymes and mitochondrial complex enzymes were studied using biochemical assays. The drug effectively ameliorated the alteration in cardiac energy metabolism in diabetic rats. The cardioprotective effect may be mediated through the ability of the drug to enhance glucose utilization and control the oxidative stress under diabetic conditions.

A panoramic view of medicinal plants traditionally applied for impotence and erectile dysfunction in Persian medicine

Erectile dysfunction (ED) and impotence are common male sexual problems, and they are highly prevalent in male adults with a history of hypertension or diabetes mellitus. This review aims to bring together the standpoints of the early Persian physicians on these disorders and to identify the respective medication in comparison with conventional contemporary medicine. The main medical and pharmaceutical manuscripts of traditional Persian medicine (TPM) are from 9th-18th century AD. Besides the medieval findings, the current knowledge on ED and impotence, and the related effects of the cited medicinal herbs were studied. In the medieval and traditional literature, male potency is called bāh. According to the TPM approaches, the first step in the mitigation of impotence focuses on the treatment of the main body organs including the heart, brain, and liver. The TPM approaches for diagnosis and treatment include the evaluation of the quality of semen, sexual habit, and quality of urine. The treatment strategies in TPM involve lifestyle modification and prescription of natural medicaments. Many medicinal herbs have been traditionally used for the mitigation of impotency. There could be numerous possibilities for bringing out new natural medicaments with aphrodisiac effects supported by the early medical literature.

In Vitro Inhibition of α-Amylase and α-Glucosidase by Extracts from Psiadia punctulata and Meriandra bengalensis

BACKGROUND

This research assessed the in vitro antidiabetic activity and phytochemical constituents of the traditionally used medicinal plants, Psiadia punctulata and Meriandra bengalensis.

METHOD

The leaves of both plants were subjected to cold extraction method using 70% ethanol and hot Soxhlet extraction using n-hexane, chloroform, methanol, and distilled water. The extracts were studied for their effect on glucose transport across yeast cells and inhibition of α-amylase and α-glucosidase enzyme activities. Thin-layer chromatographic analysis of ethanol extract was also undertaken.

RESULTS

The results of yeast glucose uptake assay revealed that extracts from both plants had a maximum increase in glucose uptake at the 25mM glucose concentration with a maximum dose of 2000μg/ml plant extract. The ethanol extract of P. punctulata and aqueous extract of M. bengalensis showed a high activity of 68% and 96%, respectively, at 25mM and 2000μg/ml of glucose and extract concentration. P. punctulata exerted peak inhibition activity of α-amylase of 37.5 ± 3% mg/dl (IC50 = 0.523 mg/dl) for methanol and distilled water extract at 0.5 mg/dl, respectively. M. bengalensis methanol extract exhibited the highest inhibition activity of 38 ± 8 % mg/dl (IC50 = 0.543 mg/dl) at 0.5 mg/dl. In the α-glucosidase inhibition assay, the methanolic extract of P. punctulata exhibited the highest inhibitory activity of 17.29 ± 9% mg/dl (IC50 = 0.761 mg/dl) at 0.5mg/dl. The chloroform extract of M. bengalensis had the highest inhibitory activity of 30 ± 5% mg/dl (IC50 = 0.6mg/dl) at 0.5 mg/dL. Phytochemical analysis of the different extracts of P. punctulata and M. bengalensis revealed the presence of flavonoids, alkaloids, tannins, saponins, phytosterols, and carbohydrates. Thin-layer chromatography analysis of ethanolic extract of both plants indicated presence of 15 and 17 spots for P. punctulata and M. bengalensis respectively.

CONCLUSION

P. punctulata and M. bengalensis extracts have moderate inhibitory activity against pancreatic α-amylase and relatively low inhibitory activities against α-glucosidase. The observed effects may be associated with the presence of flavonoids, saponins, and alkaloids. Additional in vivo analysis, toxicological studies, isolation, and structural characterization of the phytomolecules identified in this study and molecular docking studies should be undertaken.

Identification of Bioactive Peptides with α-Amylase Inhibitory Potential from Enzymatic Protein Hydrolysates of Red Seaweed (Porphyra spp)

Inhibition of α-amylase enzyme is one therapeutic approach in lowering glucose level in the blood to manage diabetes mellitus. In this study α-amylase inhibitory peptides were identified from proteolytic enzymes hydrolysates of red seaweed laver ( Porphyra species) using consecutive chromatographic techniques. In the resultant fractions from RP-HPLC (D₁-₁₀), D₂ inhibited α-amylase activity (88.67 ± 1.05%) significantly ( p ≤ 0.5) at 1 mg/mL protein concentration. A mass spectrometry (ESI-Q-TOF- MS) analysis was used to identify peptides from this fraction. Two novel peptides were identified as Gly-Gly-Ser-Lys and Glu-Leu-Ser. To validate their α-amylase inhibitory activity, these peptides were synthesized chemically. The peptides were demonstrated inhibitory activity at IC₅₀ value: 2.58 ± 0.08 mM (Gly-Gly-Ser-Lys) and 2.62 ± 0.05 mM (Glu-Leu-Ser). The inhibitory kinetics revealed that these peptides exhibited noncompetitive binding mode. Thus, laver can be a potential source of novel ingredients in food and pharmaceuticals in diabetes mellitus management.

Synthesis of biosurfactant‐coated magnesium oxide nanoparticles for methylene blue removal and selective Pb2+ sensing

Dyes and lead (Pb2+) are toxic compounds that can contaminant water. In this study, magnesium oxide (MgO) nanoparticles (NPs) prepared using clove, i.e. Syzygium aromaticum extract [clove extract (CE)] were used for methylene blue (MB) removal and Pb2+ ion sensing in aqueous solution. Maximum 90% MB removal was achieved using MgO NPs. The MB adsorption on MgO NPs surface followed second‐order kinetics and Langmuir isotherm. MB dye was adsorbed as a monolayer on the surface of MgO NPs with maximum adsorption capacity, 5555 mg g−1. MgO NPs were also able to selectively detect lead (Pb2+) in 1 nM–200 µM range with 24 µM (3σ) limit of detection. So, CE prepared MgO NPs are useful for MB dye adsorption and metal ion sensing applications.

Olive Polyphenols and the Metabolic Syndrome

Here, the effects of consuming polyphenol-rich olive products, including olive leaves, their crude extract, and extra virgin olive oil, on aspects of the metabolic syndrome are reviewed. We have sought to summarize the available scientific evidence from dietary intervention trials demonstrating a role for these phytochemicals in ameliorating aberrant glucose metabolism, high blood pressure and elevated blood lipids, and we discuss the potential mechanisms underpinning these observations. Searches for relevant literature published in English were conducted via PubMed and Science Direct. Based on published dietary intervention studies, there is convincing evidence to show that olive polyphenols, independently of olive lipids, reduce risk factors for metabolic syndrome, in particular by improving blood sugar and blood pressure control, and in reducing low density lipoprotein oxidation. There is more limited evidence to suggest that the consumption of olive polyphenols or related products can reduce body weight and visceral fat or impede weight gain, and similarly there are some limited data suggesting improved lipid profiles. There is some mechanistic data to support observations made in human volunteers, but further work is needed in this area. The consumption of olive polyphenols within the context of a healthy pattern of food intake may, in part, explain the reduced risk of metabolic disease associated with adherence to the Mediterranean diet.

Ashanti pepper (Piper guineense Schumach et Thonn) attenuates carbohydrate hydrolyzing, blood pressure regulating and cholinergic enzymes in experimental type 2 diabetes rat model

BACKGROUND

Ashanti pepper (Piper guineense Schumach et Thonn) seed is well known in folkloric medicine in the management of type 2 diabetes (T2DM) with little or no scientific documentation for its action. This study investigated the effect of Ashanti pepper seed on some enzymes relevant to carbohydrate hydrolysis, blood regulation and the cholinergic system, as well as the blood glucose level, lipid profile, antioxidant parameters, and hepatic and renal function markers in T2DM rats.

METHODS

T2DM was induced by feeding rats with high-fat diet (HFD) for 14 days followed by a single intraperitoneal dose of 35 mg/kg body weight of streptozotocin (STZ). Three days after STZ induction, diabetic rats were placed on a dietary regimen containing 2%-4% Ashanti pepper.

RESULTS

Reduced blood glucose level with decreased α-amylase, α-glucosidase and angiotensin I converting enzyme (ACE) activities were observed in Ashanti pepper seed and acarbose-treated rat groups when compared to that of the diabetic control rat group. Furthermore, the results revealed that inclusion of 2%-4% Ashanti pepper seed in diabetic rat fed group diets may ameliorate the lipid profile, antioxidant status, and hepatic and renal function in T2DM rats as much as in the acarbose-treated groups. In addition, a chromatographic profile of the seed revealed the presence of quercitrin (116.51 mg/g), capsaicin (113.94 mg/g), dihydrocapsaicin (88.29 mg/g) and isoquercitrin (74.89 mg/g).

CONCLUSIONS

The results from this study clearly suggest that Ashanti pepper could serve as a promising source of phenolic compounds with great alternative therapeutic potentials in the management of T2DM.

Postprandial Antihyperglycemic And Antioxidant Activities of Acalypha indica Linn Stem Extract: An In-vivo Study

BACKGROUND

α-glucosidase inhibitors controls postprandial hyperglycemia (PPHG) by lowering sharp rise in blood glucose levels after ingestion of carbohydrate rich meal in type 2 diabetic (T2D) individuals. Acalypha indica commonly known as Indian copper leaf is used in traditional medicinal system to treat various diseases. In our previous in-vitro investigation, methanolic extract of A. indica stems (AIS) proved to be an effective a-glucosidase inhibitor, antioxidant, and well tolerated in acute and subchronic toxicity studies in albino wistar rats.

OBJECTIVE

In this perspective, this study was designed to evaluate postprandial antihyperglycemic potential of AIS in maltose, sucrose, and glucose loaded streptozotocin (STZ)-induced normal and diabetic rats. As, the acute hyperglycemia at postprandial period has more triggering effect on oxidative stress, study was also aimed to evaluate the antioxidant potential of AIS on STZ-induced Albino-Wistar rats.

MATERIALS AND METHODS

Rats were treated with AIS (300-600 mg/kg b.w.) to investigate effect of AIS in controling PPHG after carbohydrate loading. Hepatoprotective activity of AIS is evaluated in diabetic rats by treating them at the dosages 300-600 mg/kg b.w.

RESULTS

Studies revealed 69.10 and 80.35% blood glucose-lowering effect of AIS in maltose and sucrose loaded diabetic rats in comparison with the diabetic control group. AIS recovered the liver damage caused by streptozotocin.

CONCLUSION

The present study confirmed high potential of AIS in controling PPHG by inhibiting a-glucosidase enzyme in maltose and sucrose loaded diabetic rats. AIS also exhibited hepatoprotective activity in STZ-induced diabetic rats. Thus, AIS could be used as a nutraceutical supplement to treat T2D effectively.

SUMMARY

AIS extract is effective in suppressing maltose and sucrose-induced postprandial hyperglycemic spikes in ratsAIS treat ment showed a 69.10 and80.35% blood glucose-lowering effect in maltose and sucrose loaded diabetic rats in comparison with the diabetic control group.AIS also improved the antioxidant status in diabetic rats and also has recovered the liver damage caused by streptozotocin.The α-glucosidase inhibitor isolated from AIS is a good supplement to control postprandial blood glucose level in the management of type 2 diabetes. Abbreviations used: AIS: Acalypha indica Stems, ALP: Alkaline Phosphatase, b/w: Body Weight, PPHG: Postprandial hyperglycemia, SE: Standard Error, SGOT: Serum glutamate oxaloacetate transaminase, SGPT: Serum glutamate pyruvate transaminase, SOD: Superoxide dismutase, STZ: Streptozotocin, TB: Total Bilirubin, T2D: Type 2 diabetes.

Blanching influences the phenolics composition, antioxidant activity, and inhibitory effect of Adansonia digitata leaves extract on α-amylase, α-glucosidase, and aldose reductase

Adansonia digitata (A. digitata) leaves serve as food and has several medicinal uses in many parts of the world. This study evaluated the influence of blanching on the phenolics composition, antioxidant activity, and inhibitory effect of methanol extract of A. digitata leaves on the activities of some key enzymes (α‐amylase, α‐glucosidase, and aldose reductase) implicated in type 2 diabetes (T2D) in vitro. Reverse‐phase HPLC analysis revealed that the leaves had appreciable levels of flavonoids and phenolic acids, including catechin, epicatechin, rutin, quercitrin, quercetin, kaempferol, and luteolin (flavonoids); gallic, chlorogenic, caffeic, and ellagic acids (phenolic acids). Blanching caused significant (P < 0.05) decrease in the flavonoids and phenolic acids contents; DPPH* (2,2 diphenyl‐1‐picrylhydrazyl radical) and ABTS*⁺ [2,2‐azinobis (3‐ethyl‐benzothiazoline‐6‐sulfonic acid) radical cation] scavenging ability; reducing power; and Fe²⁺‐induced lipid peroxidation inhibitory capacity of the extract. Similarly, the inhibitory effect of the extract on the activities of α‐amylase, α‐glucosidase, and aldose reductase was significantly (P < 0.05) reduced due to blanching. Thus, A. digitata leaves extract could be effective for the management of T2D due to its flavonoids and phenolic acids content, antioxidant properties, and inhibitory potency on the activities of α‐amylase, α‐glucosidase, and aldose reductase. However, blanching militated against the levels of these functional attributes of the leaves and, therefore, may not be recommended for their optimal retention.

Safety and anti-ulcerogenic activity of a novel polyphenol-rich extract of clove buds (Syzygium aromaticum L)

Despite the various reports on the pharmacology of Clove bud [Syzygium aromaticum]-derived essential oil and its major component eugenol, systematic information on the bioactivity of clove polyphenols is very limited. Clove buds being one of the richest sources of dietary polyphenols with many traditional medicinal uses, the present contribution attempted to derive their standardized polyphenol-rich extracts as a water soluble free flowing powder (Clovinol) suitable for functional food applications, without the issues of its characteristic pungency and aroma. The extract was characterized by electrospray ionization-time of flight mass spectrometry (ESI-TOF-MS), and investigated for in vivo antioxidant, anti-inflammatory and anti-ulcerogenic activities. Clovinol showed significant antioxidant and anti-inflammatory effects as measured by cellular antioxidant levels, and the ability to inhibit carrageenan-induced paw swelling in mice. Further investigations revealed its significant anti-ulcerogenic activity (>97% inhibition of ethanol-induced stomach ulcers in Wistar rats when orally administered at 100 mg per kg b.w.) and up regulation of in vivo antioxidants such as superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT). Clovinol also reduced the extent of lipid peroxidation among ulcer induced rats, indicating its usefulness in ameliorating oxidative stress and improving gastrointestinal health, especially upon chronic alcohol consumption. The extract was also shown to be safe and suitable for further investigations and development upon acute toxicity studies at 5 g per kg body weight and 28 days of repeated dose toxicity studies at 2.5 g per kg b.w.

Screening of antidiabetic and antioxidant activities of medicinal plants

Diabetes is a common metabolic disorder characterized by abnormally increased plasma glucose levels. Postprandial hyperglycemia plays an essential role in development of type-2 diabetes. Inhibitors of carbohydrate-hydrolyzing enzymes (such as α-glucosidase and α-amylase) offer an effective strategy to regulate/prevent hyperglycemia by controlling starch breakdown. Natural α-amylase and α-glucosidase inhibitors, as well as antioxidants from plant-based sources, offer a source of dietary ingredients that affect human physiological function in order to treat diabetes. Several research studies have investigated the effectiveness of plant-based inhibitors of α-amylase and α-glucosidase, as well as their antioxidant activity. The aim of this review is to summarize the antidiabetic and antioxidant properties of several medicinal plants around the world. Half inhibitory concentration (IC50, for enzyme suppression) and half effective concentration (EC50, for antioxidant activity) values of less than 500 μg/mL were defined as the most potent plant-based inhibitors (in vitro) and are expected to provide interesting candidates for herbal treatment of diabetes, as foods, supplements, or refined drugs.

Antioxidant properties of aqueous extracts of unripe Musa paradisiaca on sodium nitroprusside induced lipid peroxidation in rat pancreas in vitro

OBJECTIVE

To evaluate and compare antioxidant activities of the aqueous extracts of unripe plantain (Musa paradisiaca), assess their inhibitory action on sodium nitroprusside induced lipid peroxidation in rat pancreas in vitro and to characterize the main phenolic constituents of the plantain products using gas chromatography analysis.

METHODS

Aqueous extracts of plantain products (raw, elastic pastry, roasted and boiled) flour of 0.1 g/mL (each) were used to determine their total phenol, total flavonoid, 1,1 diphenyl-2 picrylhydrazyl (DPPH) and hydroxyl (OH) radical scavenging ability. The inhibitory effect of the extracts on sodium nitroprusside induced lipid peroxidation was also determined.

RESULTS

The results revealed that all the aqueous extracts showed antioxidant activity. The boiled flour had highest DPPH and OH radical scavenging ability while raw flour had the highest Fe(2+) chelating ability, sodium nitroprusside inhibitory effect and vitamin C content. The antioxidant results showed that elastic pastry had the highest total phenol and total flavonoid content. Characterization of the unripe plantain products for polyphenol contents using gas chromatography showed varied quantity of apigenin, myricetin, luteolin, capsaicin, isorhaemnetin, caffeic acid, kampferol, quercetin, p-hydroxybenzoic acid, shogaol, glycitein and gingerol per product on the spectra.

CONCLUSIONS

Considering the antioxidant activities and ability to inhibit lipid peroxidation of unripe plantain, this could justify their traditional use in the management/prevention of diseases related to stress.

Antidiabetic potential of some less commonly used plants in traditional medicinal systems of India and Nigeria

The incidence of diabetes mellitus continue to rise annually all over the world with India and Nigeria having recorded cases of 65.1 and 3.9 million respectively in 2013 and expected to increase by a large amount in 2035. Hyperglycemia is a pre-condition for the development of diabetic complications and is accompanied by an increase in the production of free radicals. The present available treatment option for diabetes like sulfonylurea, metformin and alpha-glucosidase are restricted by their limited actions, secondary failure rates, and side-effects; and unaffordable to the majority of the population. Hence, the need to screen for more medicinal plants with antidiabetic ability due to the fact that plants are; biodegradable, safe and cheap with fewer side-effects. In this review article, we have presented the current status of diabetes in India and Nigeria and the role of some less commonly used medicinal plants from both countries that have antidiabetic potential.

The brown seaweed Sargassum hemiphyllum exhibits α-amylase and α-glucosidase inhibitory activity and enhances insulin release in vitro

Diabetes is one of the most prevalent chronic diseases globally. In this study, major polyphenols (17.35 ± 0.93-36.66 ± 2.01 mg/g) and minor fucoxanthin (non detected 15.12 ± 0.09 mg/g) were isolated from water, ethanol, and acetone extracts (WES, EES, and AES, respectively) of Sargassum hemiphyllum. Inhibition of α-amylase, α-glucosidase, sucrose, and maltase activities and stimulation of insulin secretion was greater with AES than with WES or EES and correlated with polyphenol and fucoxanthin concentrations in extracts. Moreover, 250 μg/ml EES and AES significantly increased insulin secretion in the presence of 25 mg/ml glibenclamide to higher levels than those obtained with 50 mg/ml glibenclamide. None of the extracts exhibited cytotoxicity, exacerbated the side effects of glibenclamide, or inhibited glibenclamide-induced insulin secretion. These results suggested that the S. hemiphyllum extracts WES, EES, and AES could be used as pharmaceuticals and functional foods to reduce dosages of synthetic diabetes drugs.

Antihyperglycemic, hypolipidemic, hepatoprotective and antioxidative effects of dietary clove (Szyzgium aromaticum) bud powder in a high-fat diet/streptozotocin-induced diabetes rat model

BACKGROUND

Syzygium aromaticum (L.) Merr. & Perry (clove) bud is an important spice used in the preparation of several delicacies and in folklore for diabetes management. The present study was convened to assess the effects of dietary clove bud powder (CBP) on biochemical parameters in a type 2 diabetes rat model, induced by a combination of high-fat diet and low-dose streptozotocin (35 mg kg⁻¹) for 30 days.

RESULTS

Diabetic rats were placed on dietary regimen containing 20-40 g kg⁻¹ clove bud powder. The results revealed that there was no significant (P > 0.05) difference in the average feed intake and weight changes between the rat groups. Furthermore, supplementation with CBP gradually reduced blood glucose level in diabetic rat compared to control diabetic rats without CBP supplementation (DBC). Moreover, reduced activity of α-glucosidase was observed in CBP and metformin-treated rat groups when compared to that of the DBC rat group. In addition, the DBC group had significantly (P < 0.05) higher lipid concentrations (except for high-density lipoprotein cholesterol) when compared to all other groups. Furthermore, CBP had significantly (P < 0.05) reduced activity of liver enzymes (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) and showed elevated levels of antioxidant status (glutathione, ascorbic acid, superoxide dismutase and catalase).

CONCLUSION

The results suggest that the clove bud diet may attenuate hyperglycemia, hyperlipidemia, hepatotoxicity and oxidative stress in the type 2 diabetic condition.

Protein glycation inhibitory activity and antioxidant capacity of clove extract

Syzygium aromaticum (L.) (clove) is one of the most widely cultivated spices in many tropical countries. The aim of this study was to determine the phytochemical content, the antioxidant properties and the antiglycation properties of aqueous extract of clove against fructose-mediated protein glycation and oxidation. The result showed that the content of total phenolics and flavonoids in clove extract was 239.58 ± 0.70 mg gallic acid equivalents/g dried extract and 65.67 ± 0.01 mg catechin equivalents/g dried extract, respectively. In addition, clove exhibited antioxidant properties including DPPH radical scavenging activity (IC50 = 0.29 ± 0.01 mg/ml), Trolox equivalent antioxidant capacity (4.69 ± 0.03 μmol Trolox equivalents/mg dried extract), ferric reducing antioxidant power (20.55 ± 0.11 μmol ascorbic acid equivalents/mg dried extract), Oxygen radical absorbance capacity (31.12 ± 0.21 μmol Trolox equivalents/mg dried extract), hydroxyl radical scavenging activity (0.15 ± 0.04 mg Trolox equivalents/mg dried extract), and superoxide radical scavenging activity (18.82 ± 0.50 mg Trolox equivalents/mg dried extract). The aqueous extract of clove (0.25-1.00 mg/ml) significantly inhibited the formation of fluorescent advanced glycation end products (AGEs) and non-fluorescent AGEs (N(ɛ)-(carboxymethyl) lysine (CML)) in glycated BSA during 4 weeks of incubation. The extract also markedly prevented oxidation-induced protein damage by decreasing protein carbonyl formation and protecting against the loss of protein thiol group. These results clearly demonstrated that a polyphenol enriched clove extract, owing to its antioxidant, was capable to inhibit the formation of AGEs and protein glycation. The findings might lead to the possibility of using the clove extract for targeting diabetic complications.

Exploration of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays

AIM

To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.

METHODS

The leaf extracts of the three different Eucalyptus species [E. globulus (EG), E. citriodora (EC), E. camaldulensis (ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors (NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.

RESULTS

Major bioactive compounds like polyphenols (341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids (4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation (R(2) = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.

CONCLUSION

These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.

Exploration of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays

AIM

To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.

METHODS

The leaf extracts of the three different Eucalyptus species [E. globulus (EG), E. citriodora (EC), E. camaldulensis (ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors (NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.

RESULTS

Major bioactive compounds like polyphenols (341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids (4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation (R(2) = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.

CONCLUSION

These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.

Inhibition of key enzymes related to diabetes and hypertension by Eugenol in vitro and in alloxan-induced diabetic rats

The present study investigated the effect of treating diabetic rats with eugenol (EG). In vitro enzyme activity was measured in the presence of eugenol, and it was found to inhibit pancreatic α-amylase (IC(50) = 62.53 µg/mL) and lipase (IC(50) = 72.34 µg/mL) as well as angiotensin converting enzyme (ACE) activity (IC50 = 130.67 µg/mL). In vivo, EG reduced the activity of amylase in serum, pancreas and intestine also the peak level of glucose by 60% compared to diabetic rats. Furthermore, eugenol similar to acarbose reduced serum glycosylated hemoglobin (HbA1c), lipase and ACE levels. In addition, treatments with EG showed notable decrease in serum total-cholesterol, triglycerides and low density lipoprotein-cholesterol levels with an increase of high density lipoprotein-cholesterol. Overall, EG significantly reverted back to near normal the values of the biochemical biomarkers such as transaminases (AST&ALT), alkaline phosphatase (ALP), creatine phosphokinase (CPK) and gamma-glutamyl transpeptidase (GGT) activities, total-bilirubin, creatinine, urea and uric acid rates.

Chemo-profiling of eucalyptus and study of its hypoglycemic potential

Constant escalations in the number of diabetics world-wide and the failure of conventional therapy to restore normoglycemia without adverse effects, in spite of tremendous strides in modern medicine, calls for naturopathy and alternative medicine. Because diabetes is multi-factorial and has secondary complications, prevention of hyperglycemia is the central dogma for its management. To date, no oral hypoglycemic exists which can achieve tight glycemic control without side effects. Dietary adjuncts, lifestyle interventions and a resurgence of interest in phyto-therapy have consequently gained ground. Natural hypoglycemics have attracted attention due to ease of incorporation in everyday diet, affordability, less adverse effects, and long term safety. Ethno botanical literature reports more than 800 anti-diabetic plants species. Eucalyptus is well represented in the Aboriginal Pharmacopoeias for its various pharmacological activities. Its hot aqueous decoction has been used as a hypoglycemic in various regions of world. This editorial attempts to summarize the data on the hypoglycemic potential of the different eucalyptus species, highlight the value of its natural biomolecules for the prophylaxis and treatment of type 2 diabetes, describe their mechanistic actions, shed light on the posology and safety aspects of eucalyptus and assess its applicability as a reinforcement to currently used therapy.