In Vitro Antidiabetic Activity and Mechanism of Action of Brachylaena elliptica (Thunb.) DC

Use of Various Sugarcane Byproducts to Produce Lipid Extracts with Bioactive Properties: Physicochemical and Biological Characterization

Sugarcane, a globally cultivated crop constituting nearly 80% of total sugar production, yields residues from harvesting and sugar production known for their renewable bioactive compounds with health-promoting properties. Despite previous studies, the intricate interplay of extracts from diverse sugarcane byproducts and their biological attributes remains underexplored. This study focused on extracting the lipid fraction from a blend of selected sugarcane byproducts (straw, bagasse, and filter cake) using ethanol. The resulting extract underwent comprehensive characterization, including physicochemical analysis (FT-IR, DSC, particle size distribution, and color) and chemical composition assessment (GC-MS). The biological properties were evaluated through antihypertensive (ACE), anticholesterolemic (HMG-CoA reductase), and antidiabetic (alpha-glucosidase and Dipeptidyl Peptidase-IV) assays, alongside in vitro biocompatibility assessments in Caco-2 and Hep G2 cells. The phytochemicals identified, such as β-sitosterol and 1-octacosanol, likely contribute to the extract's antidiabetic, anticholesterolemic, and antihypertensive potential, given their association with various beneficial bioactivities. The extract exhibited substantial antidiabetic effects, inhibiting α-glucosidase (5-60%) and DPP-IV activity (25-100%), anticholesterolemic potential with HMG-CoA reductase inhibition (11.4-63.2%), and antihypertensive properties through ACE inhibition (24.0-27.3%). These findings lay the groundwork for incorporating these ingredients into the development of food supplements or nutraceuticals, offering potential for preventing and managing metabolic syndrome-associated conditions.

Research-based Analytical Procedures to Evaluate Diabetic Biomarkers and Related Parameters: In Vitro and In Vivo Methods

BACKGROUND

The degenerative tendency of diabetes leads to micro- and macrovascular complications due to abnormal levels of biochemicals, particularly in patients with poor diabetic control. Diabetes is supposed to be treated by reducing blood glucose levels, scavenging free radicals, and maintaining other relevant parameters close to normal ranges. In preclinical studies, numerous in vivo trials on animals as well as in vitro tests are used to assess the antidiabetic and antioxidant effects of the test substances. Since a substance that performs poorly in vitro won't perform better in vivo, the outcomes of in vitro studies can be utilized as a direct indicator of in vivo activities.

OBJECTIVE

The objective of the present study is to provide research scholars with a comprehensive overview of laboratory methods and procedures for a few selected diabetic biomarkers and related parameters.

METHOD

The search was conducted on scientific database portals such as ScienceDirect, PubMed, Google Scholar, BASE, DOAJ, etc. Conclusion: The development of new biomarkers is greatly facilitated by modern technology such as cell culture research, lipidomics study, microRNA biomarkers, machine learning techniques, and improved electron microscopies. These biomarkers do, however, have some usage restrictions. There is a critical need to find more accurate and sensitive biomarkers. With a few modifications, these biomarkers can be used with or even replace conventional markers of diabetes.

Synthesis and bioactivity assessment of Coccinia grandis L. extract encapsulated alginate nanoparticles as an antidiabetic drug lead

AIM

This study aimed to prepare, characterise, and evaluate the antidiabetic activity of Coccinia grandis (L.) extracts encapsulated alginate nanoparticles.

METHODS

Alginate nanoparticles were prepared using the ionic gelation method and characterised by encapsulation efficiency %w/w, loading capacity %w/w, particle size analysis, zeta potential, Fourier transform infra-red spectroscopy (FTIR), and scanning electron microscopy (SEM). In vitro antidiabetic activity was also evaluated.

RESULTS

Encapsulation efficiency %w/w, loading capacity %w/w, mean diameter, zeta potential of C. grandis encapsulated alginate nanoparticles ranged from 10.51 ± 0.51 to 62.01 ± 1.28%w/w, 0.39 ± 0.04 to 3.12 ± 0.11%w/w, 191.9 ± 76.7 to 298.9 ± 89.6 nm, -21.3 ± 3.3 to -28.4 ± 3.4 mV, respectively. SEM and FTIR confirmed that particles were in nano range with spherical shape and successful encapsulation of plant extracts into an alginate matrix. The antidiabetic potential of aqueous extract of C. grandis encapsulated alginate nanoparticles (AqCG-ANP) exhibited inhibition in α-amylase, α-glucosidase and dipeptidyl peptidase IV enzymes of 60.8%c/c, 19.1%c/c, and 30.3%c/c, respectively, compared to the AqCG.

CONCLUSION

The AqCG-ANP exerted promising antidiabetic potential as an antidiabetic drug lead.

Bael (Aegle marmelos L. Correa) fruit extracts encapsulated alginate nanoparticles as a potential dietary supplement with improved bioactivities

Nanoencapsulated bael fruit (Aegle marmelos L. Correa (Family: Rutaceae)) extracts reveal novel prospects in the development of dietary supplements with improved biological activities in the field of the food industry. The main objectives of this study were to prepare and characterize aqueous, ethanol, 50% ethanol, and 50% acetone extracts of bael fruit encapsulated alginate nanoparticles and investigate the effect of encapsulation on in vitro release of polyphenols, antidiabetic, antioxidant, and anti-inflammatory activities, and their stability. Bael fruit extracts encapsulated alginate nanoparticles were prepared using the ionic gelation method. Characterization, in vitro release profiles of polyphenols, determination of antidiabetic, anti-inflammatory, antioxidant activity, and accelerated stability were conducted. The results of the characterization confirmed the successful encapsulation of extracts of bael fruit in the alginate matrix. The aqueous extract of bael fruit encapsulated alginate nanoparticles exhibited a more controlled slow-release profile, accounting for 21.82% ± 1.17% and 48.14% ± 0.52% of polyphenols at solutions of pH 1.2 and pH 6.8, respectively. In general, the results of the bioactivity assessment suggested that nanoencapsulation could facilitate the enhancement of its antidiabetic, antioxidant, and anti-inflammatory properties. The results of thermogravimetric analysis and thin layer chromatography fingerprint showed the stability of aqueous bael fruit extract encapsulated alginate nanoparticles at 27 and 4°C over a month. In summary, the results of this study revealed the potency of nanoencapsulated aqueous extract of bael fruit to develop a dietary supplement with improved antidiabetic, antioxidant, and anti-inflammatory activities. PRACTICAL APPLICATION: The encapsulation of bael fruit extracts into a nanocarrier enhances bioactivities and promotes the controlled release of bioactive compounds. This could be useful in the future food industry, based on scientifically proven data, and inspire the market by means of the development of dietary supplements. Overall, the results would facilitate the formulation of novel commercially elegant nanoencapsulated dietary supplements with improved potential to manage a healthy life.

The antidiabetic effect of methanolic extract of Holarrhena pubescens seeds is mediated through multiple mechanisms of action

Holarrhena pubescens is widely used in Indian and Chinese medicine in the treatment of diabetes. The current work determined the oral hypoglycemic and antidiabetic effects of seed extract in rats. The probable mechanism of action was evaluated in-vitro by α - glucosidase inhibition, glucose metabolism in insulinoma (INS-1) cells to reflect secretion of insulin, and protein glycation inhibition. Its potential for herb-drug interaction was evaluated in the cytochrome P450 3A4 (CYP3A4) inhibition assay. The seed extract increased serum insulin levels and reduced serum blood glucose levels in the oral glucose tolerance test. It also reduced the serum glucose levels in streptozocin-induced diabetes. The extract also inhibited α -glucosidase enzyme activity and demonstrated that it can increase the secretion of insulin from INS to 1-rat insulinoma cell line cells in-vitro in a concentration-dependent manner. However, it had a very weak inhibitory effect on protein glycation and it did not affect the activity of CYP3A4. The results of the study showed that H. pubescens seed extract increases insulin secretion and inhibits glucose absorption both in-vivo and in-vitro with a weak protein glycation inhibitory effect. The herb is devoid of CYP3A4 inhibitory effect indicating that it may not have pharmacokinetic interaction with the drug metabolized by this enzyme.

Anti-Inflammatory and Anti-Diabetic Activity of Ferruginan, a Natural Compound from Olea ferruginea

Inflammation is a complex response of the human organism and relates to the onset of various disorders including diabetes. The current research work aimed at investigating the anti-inflammatory and anti-diabetic effects of ferruginan, a compound isolated from Olea ferruginea. Its in vitro anti-inflammatory activity was determined by using the heat-induced hemolysis assay, while the anti-diabetic effect of the compound was studied by the yeast cell glucose uptake assay. Ferruginan exhibited a maximum of 71.82% inhibition of inflammation and also increased the uptake of glucose by yeast cells by up to 74.96% at the highest tested concentration (100 µM). Moreover, ferruginan inhibited α-amylase dose-dependently, by up to 75.45% at the same concentration. These results indicated that ferruginan possesses promising anti-inflammatory and anti-diabetic properties in vitro, even if at high concentrations. To provide preliminary hypotheses on the potentially multi-target mechanisms underlying such effects, docking analyses were performed on α-amylase and on various molecular targets involved in inflammation such as 5′-adenosine monophosphate-activated protein kinase (AMPK, PDB ID 3AQV), cyclooxygenase (COX-1, PDB ID 1EQG, and COX-2, 1CX2), and tumor necrosis factor alpha (TNF-α, PDB ID 2AZ5). The docking studies suggested that the compound may act on α-amylase, COX-2, and AMPK.

Antidiabetic Medicinal Plants Used in the Eastern Cape Province of South Africa: An Updated Review

Oral antidiabetic drugs are usually costly and are associated with several adverse side effects. This has led to the use of medicinal plants that are considered to have multiple therapeutic targets and are readily accessible. In the Eastern Cape province of South Africa, the number of people using medicinal plants for the management of diabetes has been climbing steadily over the past two decades due to their cultural acceptability, accessibility, affordability, efficacy, and safety claims. In this study, a review of antidiabetic medicinal plants used in the Eastern Cape province of South Africa was conducted. A comprehensive literature survey was thoroughly reviewed using several scientific databases, ethnobotanical books, theses and dissertations. About forty-eight (48) plant species were identified as being used to treat diabetes by the people of Eastern Cape province. Among the plant species, only eight (8) species have not been scientifically evaluated for their antidiabetic activities and twenty antidiabetic compounds were isolated from these medicinal plants. This review has confirmed the use and potential of the antidiabetic medicinal plants in the Eastern Cape province and identified several promising species for further scientific investigation.

Carpachromene Ameliorates Insulin Resistance in HepG2 Cells via Modulating IR/IRS1/PI3k/Akt/GSK3/FoxO1 Pathway

Insulin resistance contributes to several disorders including type 2 diabetes and cardiovascular diseases. Carpachromene is a natural active compound that inhibits α-glucosidase enzyme. The aim of the present study is to investigate the potential activity of carpachromene on glucose consumption, metabolism and insulin signalling in a HepG2 cells insulin resistant model. A HepG2 insulin resistant cell model (HepG2/IRM) was established. Cell viability assay of HepG2/IRM cells was performed after carpachromene/metformin treatment. Glucose concentration and glycogen content were determined. Western blot analysis of insulin receptor, IRS1, IRS2, PI3k, Akt, GSK3, FoxO1 proteins after carpachromene treatment was performed. Phosphoenolpyruvate carboxykinase (PEPCK) and hexokinase (HK) enzymes activity was also estimated. Viability of HepG2/IRM cells was over 90% after carpachromene treatment at concentrations 6.3, 10, and 20 µg/mL. Treatment of HepG2/IRM cells with carpachromene decreased glucose concentration in a concentration- and time-dependant manner. In addition, carpachromene increased glycogen content of HepG2/IRM cells. Moreover, carpachromene treatment of HepG2/IRM cells significantly increased the expression of phosphorylated/total ratios of IR, IRS1, PI3K, Akt, GSK3, and FoxO1 proteins. Furthermore, PEPCK enzyme activity was significantly decreased, and HK enzyme activity was significantly increased after carpachromene treatment. The present study examined, for the first time, the potential antidiabetic activity of carpachromene on a biochemical and molecular basis. It increased the expression ratio of insulin receptor and IRS1 which further phosphorylated/activated PI3K/Akt pathway and phosphorylated/inhibited GSK3 and FoxO1 proteins. Our findings revealed that carpachromene showed central molecular regulation of glucose metabolism and insulin signalling via IR/IRS1/ PI3K/Akt/GSK3/FoxO1 pathway.

Aegle marmelos Leaf Extract Phytochemical Analysis, Cytotoxicity, In Vitro Antioxidant and Antidiabetic Activities

For many years, Aegle marmelos (A. marmelos) has been used medicinally and as a dietary supplement. Despite this, there are minimal research data on A. marmelos phytochemical properties and pharmacological effects. This study aimed to explore the phytoconstituents, cytotoxicity, glucose uptake, and antioxidant and antidiabetic potential of an alcoholic extract of A. marmelos leaf. The cytotoxicity of A. marmelos in HepG2 cells was tested in vitro, and the results revealed that it has strong cytocompatibility and cytoprotective properties. The extract's antioxidant activities were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. Antioxidant potential was shown to be quite impressive. The enzymes α-amylase and α-glycosidase were found to be substantially inhibited by A. marmelos, with IC₅₀ values of 46.21 and 42.07 mg/mL, respectively. In HepG2 cells, A. marmelos significantly reduced ROS levels that were elevated due to high glucose and enhanced glucose consumption (p < 0.05). These activities might be due to the enrichment of bioactive phytoconstituents analyzed chromatographically using GC/MS and HPLC. The findings of this study show that A. marmelos could be an effective restorative therapy for diabetes and related diseases.

Formulation and characterization of rutin loaded chitosan-alginate nanoparticles: Antidiabetic and cytotoxicity studies

BACKGROUND

The rutin loaded chitosan-alginate nanoparticles (RCANP) were prepared using an ion gelation method. The optimized RCANP4 formulation composed of rutin: alginate: chitosan with the ratio of 1.24:5:2. The particle size, zeta potential, and entrapment efficiency of RCANP4 formulation were found to be 168.4 ± 11.23 nm, -24.7 ± 1.5 mV, and 91.23 ± 1.1%, respectively. The in vitro drug release of RCANP4 formulation was found to be 88.89 ± 2.9% within 24 h. The Fourier transform infrared spectroscopy (FT-IR) of RCANP4 revealed all characteristic groups of rutin, confirming the successful loading of rutin into the nanoparticles. <P> Background: The rutin loaded chitosan-alginate nanoparticles (RCANP) were prepared using an ion gelation method. The optimized RCANP4 formulation composed of rutin: alginate: chitosan with the ratio of 1.24:5:2. The particle size, zeta potential, and entrapment efficiency of RCANP4 formulation were found to be 168.4 ± 11.23 nm, -24.7 ± 1.5 mV, and 91.23 ± 1.1%, respectively. The in vitro drug release of RCANP4 formulation was found to be 88.89 ± 2.9% within 24 h. The Fourier transform infrared spectroscopy (FT-IR) of RCANP4 revealed all characteristic groups of rutin, confirming the successful loading of rutin into the nanoparticles. <P> Results: The results obtained for glucose uptake in HepG2 cells, the RCANP4 caused a significant (P < 0.05) increase in glucose uptake in contrast to rutin. In vitro cytotoxicity results explained that RCANP4 could significantly (P < 0.05) reduce the cells viability rate compared with rutin. It may be due to the internalization of RCANP4 formulations in systemic circulation. <P> Conclusion: The results also showed that RCANP4 could significantly reduce cell viability over 24 h and 48 h compared to free rutin.

Dipeptidyl peptidase-IV inhibitory action of Calebin A: An in silico and in vitro analysis

BACKGROUND

Dipeptidyl peptidase-IV (DPP-IV) inhibitors, the enhancers of incretin are used for the treatment of diabetes. The non-glycaemic actions of these drugs (under developmental stage) also proved that repurposing of these molecules may be advantageous for other few complicated disorders like cardiovascular diseases, Parkinson's disease, Alzheimer's disease, etc. OBJECTIVE: The present study was aimed to investigate the DPP-IV inhibitory potential of Calebin-A, one of the constituents of Curcuma longa.

MATERIAL AND METHODS

The phytoconstituent was subjected for various in silico studies (using Schrödinger Suite) like, Docking analysis, molecular mechanics combined with generalized Born model and solvent accessibility method (MMGBSA) and Induced fit docking (IFD) after validating the protein using Ramachandran plot. Further, the protein-ligand complex was subjected to molecular dynamic simulation studies for 50 nanoseconds. And finally, the results were confirmed through enzyme inhibition study.

RESULTS

Insilico results revealed possible inhibitory binding interactions in the catalytic pocket (importantly Glu205, Glu206 and Tyr 662 etc.) and binding affinity in terms of glide g-score and MMGBSA dG bind values were found to be -6.2 kcal/mol and -98.721 kcal/mol. Further, the inhibitory action towards the enzyme was confirmed by an enzyme inhibition assay, in which it showed dose-dependent inhibition, with maximum % inhibition of 55.9 at 26.3 μM. From molecular dynamic studies (50 nanoseconds), it was understood that Calebin A was found to be stable for about 30 nanoseconds in maintaining inhibitory interactions.

CONCLUSION

From the in silico and in vitro analysis, the current research emphasizes the consideration of Calebin A to be as a promising or lead compound for the treatment of several ailments where DPP-IV action is culprit.

Cytotoxicity, Anti-Obesity and Anti-Diabetic Activities of Heteromorpha arborescens (Spreng.) Cham Leaves

This study investigated the cytotoxicity, anti-obesity and anti-diabetic potentials of blanched, aqueous and ethanol extracts of Heteromorpha arborescens (Spreng.) Cham leaves. The results revealed that both ethanol and aqueous extracts exhibited considerable inhibition against α-glucosidase (IC50 of 627.29 ± 4.62 µg/mL and 576.46 ± 3.21 µg/mL respectively), while the blanched extract showed weak α-glucosidase inhibition (IC50; 855.38 ± 4.29 µg/mL) and the aqueous extract showed the best α-amylase inhibition (IC50; 583.74 ± 5.87 µg/mL). However, weak α-amylase inhibition was observed in the ethanol (IC50; 724.60 ± 4.33 µg/mL) and blanched extracts (IC50; 791.63 ± 3.76 µg/mL). The toxicity of the extracts is indicated by LC50 values as 154.75 µg/mL, 125 µg/mL and 90.58 µg/mL for ethanol, aqueous and blanched extracts respectively, indicating the blanched extract to be the most toxic. Moderate glucose utilization in both C3A and L6 cells was also observed for the aqueous and ethanol extracts which may be attributed to the relatively lower toxicity levels present. However, glucose utilization was very weak for the blanched extract, which may be due to higher level of cytotoxicity it possessed. Relatively weaker lipase inhibition was observed for the ethanol (IC50; 699.3 ± 1.33 µg/mL), aqueous (IC50; 811.52 ± 3.52 µg/mL) and blanched extracts (IC50; 1152.7 ± 4.61 µg/mL) compared to orlistat (IC50; 56.88 ± 0.11 µg/mL). However, there was no reasonable reduction in lipid accumulation observed in all the extract treated cells. These observations suggest that ethanol and aqueous extracts of H. arborescens leaf are promising as new agents for the treatment of diabetes and its acclaimed anti-obesity potentials are likely due to its lipase, α-amylase and α-glucosidase inhibition.

Cytotoxic, Cellular Antioxidant, and Antiglucuronidase Properties of the Ethanol Leaf Extract from Bulbine asphodeloides

Bulbine asphodeloides (L.) Spreng (Xanthorrhoeaceae family), popularly known in South Africa as “ibhucu” or “Balsamkopieva,” is a perennial plant traditionally used to treat skin diseases, including sunburns, rough skin, dressing burns, itches, and aging. The present study reports the cytotoxic, cellular antioxidant, and antiglucuronidase properties of the ethanol leaf extract from B. asphodeloides. The cytotoxic effect of the plant extract on human dermal fibroblast (MRHF) cells was evaluated by the bis-Benzamide H 33342 trihydrochloride/propidium iodide (Hoechst 33342/PI) dual-staining method. A validated biological cell-based assay was used to determine the cellular antioxidant activity of the extract. The antiglucuronidase and metal chelating activities were evaluated using standard in vitro methods. Lipopolysaccharide- (LPS-) induced RAW 264.7 cell model was used to determine the anti-inflammatory effect of the plant extract, and the immune-modulatory activity was performed using RAW 264.7 cells. The extract demonstrated no cytotoxic effect towards the MRHF cells at all the tested concentrations. Furthermore, the extract also possessed significant cellular antioxidant and antiglucuronidase activities, but a weak effect of metal chelating activity in a dose-dependent manner. However, the extract showed no significant anti-inflammatory and immune-stimulatory activities. Overall, the results showed that B. asphodeloides may be a useful therapeutic agent for the treatment of skin diseases, therefore supporting its ethnomedicinal usage.

Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching

Pumpkin leaves (Cucurbita moschata Duchesne ex Poir.) are popularly consumed in Sub-Saharan Africa and Asia. Blanching the leaves before drying is a method of preservation during off-season. In this study, different blanching treatments and media are used to test the changes in non-targeted phenolic compounds, antioxidant capacity (FRAP and ABTS activity), in vitro α-glucosidase activity and cell cytotoxicity of pumpkin leaves. Steam blanching in plain water led to the highest retention of total phenolic content and reduced the loss of quercetin 3-glucoside 7-rhamnoside (Rutin), kaempferol 7-neohesperidoside, isoorientin 2″-O-rhamnoside, isorhamnetin-3-O-rutinoside, quercetin 3-galactoside, coumaroyl glucaric acid, isorhamnetin-3-galactoside-6″-rhamnoside, 2-caffeoylisocitric acid, quercetin 3-galactoside 7-rhamnoside by (3.04%), (7.37%), (10.65%), (10.97%), (14.88%), (16.1%), (16.73%), (18.88%), and (23.15%), respectively, and coumaroyl isocitrate increased by 14.92%. Candidate markers, 2-O-caffeoylglucaric acid, 2-(E)-O-feruloyl-D-galactaric acid, quercetin 3-galactoside 7-rhamnoside (rutin) and unidentified compounds ([(M-H) 677.28 and at RT 21.78] were responsible for the separation of the steam blanched samples in plain water from the other blanching treatments. Steam blanching in plain water increased the antioxidant capacity (FRAP and ABTS activity). There were no cytotoxic effect or inhibitory effect of α-glucosidase activity detected in the raw or blanched pumpkin leaves. Thus, this study recommends steam blanching in plain water for African cuisine, and confirms it is safe to consume pumpkin leaves frequently.

Impact of Household Cooking Techniques on African Nightshade and Chinese Cabbage on Phenolic Compounds, Antinutrients, in vitro Antioxidant, and β-Glucosidase Activity

Different household cooking techniques (boiling, steaming, stir frying, and microwave) were tested on the changes of targeted phenolic compounds, antioxidant property (ferric reducing-antioxidant power (FRAP) activity), α-glucosidase activity, antinutritive compounds, and sensory properties in commonly consumed traditional leafy vegetables in Southern Africa, the non-heading Chinese cabbage (Brassica rapa L. subsp. chinensis) and African nightshade (Solanum retroflexum Dun). Stir frying increased kaempferol-3-O-hydroxyferuloyl-trihexoside, kaempferol-dihexoside, sinapoyl malate, rutin, and isorhamnetin-O-dihexoside in Chinese cabbage leaves, followed by steaming. Similarly, stir frying increased kaempferol-3-O-rutinoside, chlorogenic acid, caffeoylmalic acid, and quercetin-3-O-xylosyl-rutinoside in nightshade, followed by steaming. Biomarkers, sinapoyl malate (Chinese cabbage) and caffeoylmalic acid (nightshade), separated the stir frying from the other cooking techniques. Steaming and stir-frying techniques significantly increased the FRAP activity; whereas boiling and microwaving reduced the tannin, oxalate, and phytate contents in both leafy vegetables and steroidal saponins in nightshade. Stir-fried nightshade leaf extract showed the most effective inhibition against α-glucosidase activity, with an IC₅₀ of 26.4 μg ml^-1, which was higher than acarbose, a synthetic compound (positive control; IC₅₀ 69.83 μg ml^-1). Sensory panelists preferred the stir-fried Chinese cabbage and nightshade leaves, followed by steamed, microwaved, and boiled vegetables.

Hypoglycemic and Antihyperglycemic Activities of 80% Methanol Root Extract of Acanthus polystachyus Delile (Acanthaceae) in Type 2 Diabetic Rats

Background

The morbidity and mortality rate from diabetic mellitus are increasing in the world especially in low- and middle-income countries; hence, it is necessary to evaluate the efficacy and safety of medicinal plants to support existing drugs in treating diabetes mellitus. Therefore, the aim of this study was to evaluate the hypoglycemic effect of 80% methanol root extract of Acanthus polystachyus in normoglycemic, hyperglycemic, and streptozotocin–nicotinamide induced diabetic rats.

Methods

Male albino Wistar rats were divided into five groups (n=6) in all three models. In all models, group one rats served as a negative control and were received vehicle (10mL/kg distilled water), whereas group two (APRE100), three (APRE200), and four (APRE400) were treated with 100, 200, and 400mg/kg of extract, respectively, and group five were treated with glibenclamide (5mg/kg) and served as a positive control. Blood glucose levels were measured at different time points by taking blood from their tails. Data were analyzed using one-way ANOVA followed by Tukey’s post hoc test to carry out comparisons between and within-group and P < 0.05 was considered as statistically significant.

Results

The root of Acanthus polystachyus reduces peak blood sugar levels significantly after the loading of oral glucose at all tested doses. In streptozotocin–nicotinamide-induced type 2 diabetic rats, the daily oral administration of the crude extracts showed a significant reduction of blood glucose level at all tested doses compared to the negative control group. However, the extract did not reduce blood glucose levels in normoglycemic rats at all tested doses compared to both negative and positive control.

Conclusion

From this study, it can be concluded that the root extract of Acanthus polystachyus showed an antihyperglycemic effect in hyperglycemic and diabetic rats but lack hypoglycemic effect in normoglycemic rats. Hence, the plant root may be a good candidate for the development of new antidiabetic drugs.

In vitro evaluation of the anti-diabetic potential of Helichrysum petiolare Hilliard & B.L. Burtt using HepG2 (C3A) and L6 cell lines

Background:Helichrysum petiolare Hilliard & B.L. Burtt has been listed in a survey of plants used in traditional medicine for the treatment of type 2 diabetes in the Eastern Cape of South Africa. In this study, the antidiabetic potentials of ethanol, cold aqueous (CAQ) and boiled aqueous (BAQ) extracts of H. petiolare were investigated. Methods: The cytotoxic and glucose utilization effects of the extracts were evaluated using L6 myocytes and HepG2 (C3A) hepatocytes. α-amylase, α-glucosidase and lipase inhibition assays were also carried out. Results: The ethanol extract showed significant cytotoxic effects in the treated cells. Both BAQ and CAQ extracts significantly increased glucose uptake in L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α-amylase and α-glucosidase than CAQ. The activities were not significantly different from acarbose. However, BAQ showed lower lipase inhibition than acarbose (p<0.05). Conclusions: The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus.

In vitro evaluation of the anti-diabetic potential of Helichrysum petiolare Hilliard & B.L. Burtt using HepG2 (C3A) and L6 cell lines

Background:Helichrysum petiolare Hilliard & B.L. Burtt has been listed in a survey of plants used in traditional medicine for the treatment of type 2 diabetes in the Eastern Cape of South Africa. In this study, the antidiabetic potentials of ethanol, cold aqueous (CAQ) and boiled aqueous (BAQ) extracts of H. petiolare were investigated. Methods: The cytotoxic and glucose utilization effects of the extracts were evaluated using L6 myocytes and HepG2 (C3A) hepatocytes. α-amylase, α-glucosidase and lipase inhibition assays were also carried out. Results: The ethanol extract showed significant cytotoxic effects in the treated cells. Both BAQ and CAQ extracts significantly increased glucose uptake in L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α-amylase and α-glucosidase than CAQ. The activities were not significantly different from acarbose. However, BAQ showed lower lipase inhibition than acarbose (p<0.05). Conclusions: The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus.

Comparison of Phenolic Compounds, Carotenoids, Amino Acid Composition, In Vitro Antioxidant and Anti-Diabetic Activities in the Leaves of Seven Cowpea (Vigna unguiculata) Cultivars

Cowpea is a well-known nutrition rich African leafy vegetable that has potential to sustain food and nutrition insecurity in sub-Saharan Africa. Consumption of cowpea legumes is associated with reduced risk of type 2 diabetes mellitus. Therefore, the present study was designed to evaluate the (i) variation in phenolic metabolites in seven cowpea cultivars (VOP1, VOP2, VOP3, VOP4, VOP5, VOP7, and VOP8 using UHPLC coupled with high resolution Q-TOF-MS technique, (ii) in vitro antioxidant activity using ferric reducing/antioxidant capacity (FRAP) assay (iii) in vitro anti-diabetic effects and (iv) composition of carotenoids and amino acids of theses cowpea cultivars. The results of this study demonstrated that gentisic acid 5-O-glucoside, quercetin 3-(2G-xylosylrutinoside) and Quercetin 3-glucosyl-(1->2)-galactoside were highest in VOP1 VOP4 and VOP5, respectively. High inhibition (>50%) of α-glucosidase and α-amylase activities was shown by the leaf extracts (50 and 25 mg/mL) of VOP1 and VOP4. Cowpea cultivars VOP1 and VOP4 demonstrated the highest gene expression levels of regulation of glucose transporter GLUT4 in C2C12 skeletal muscle cells, similar to insulin. A positive correlation exited between the phenolic components and the inhibitory effect of antidiabetic enzymes and FRAP activity. Cytotoxic effect was not detected in vitro in any cowpea cultivar. Lutein (124.6 mg/100 g) and all-trans-beta-carotene (92.6 mg/100 g) levels were highest in VOP2 and VOP1, respectively. Cowpea cultivars VOP3 and VOP4 showed potential to fulfil the daily requirements of essential amino acids. Thus, based on this information, cowpea (leaves) genotypes/cultivars can be selected and propagated for the further development of supplementary foods or functional food ingredients.

Inhibition of HIV-1 Protease by Carpobrotus edulis (L.)

Carpobrotus edulis (L.) is a plant commonly found in the Eastern Cape Province of South Africa and is used for the general treatment of infections relating to the human immunodeficiency virus (HIV). HIV-1 protease plays an important role during HIV replication and maturation to its infectious form, and therefore inhibition of the enzyme is one of the main focus areas in drug development. The inhibitory effect of a water extract of C. edulis leaves against HIV-1 protease activity was determined using the SensoLyte® 520 HIV-1 protease assay fluorimetric kit and employing a HiLyte Fluor™488/QXL™520 fluorescence resonance energy transfer (FRET) peptide. Cytotoxicity of the extract towards HeLa Chang cell lines was determined using an in vitro MTT assay, and the phytochemical profile of the extract was determined with FT-IR and LC-MS. HIV-1 protease activity was inhibited 83.06% (IC₅₀ 1.6 mg/ml) (p < 0.0001) by the pepstatin A inhibitor control. Treatment with all C. edulis extract concentrations (16, 1.6, 0.16, and 0.016 mg/ml) inhibited HIV-1 protease activity significantly (p < 0.0001) in a typical dose response manner. With regards to cytotoxicity, the negative controls containing untreated HeLa Chang cells exhibited high formazan formation rates in contrast with the positive controls, containing curcumin, which reduced formazan formation significantly (p < 0.001), exhibiting cytotoxicity towards the cells. There was no significant (p > 0.05) difference in the formazan formation rates between the negative controls and 1, 0.5, 0.125, 0.065, 0.031, and 0.015 mg/ml plant extract, confirming no toxicity of C. edulis extracts towards HeLa Chang cells. Major functional phytochemical compounds identified included alcohols, phenols, alkanes, amines, carboxylic acids, and esters. LC-ESI-TOF/MS analysis revealed the putative identities of main compounds present in the aqueous leaves extract, including some that contribute to its anti-HIV-1 protease action.

Extraction of Phenolic Compounds from Tabernaemontana catharinensis Leaves and Their Effect on Oxidative Stress Markers in Diabetic Rats

The aim of this study was to evaluate the most effective extraction condition (temperature, solvent type and time) for recovery of high-value phytochemicals present in the Tabernaemontana catharinensis leaves (TC) and to assess their effect on biochemical parameters in streptozotocin-induced diabetic rats. The extraction of phenolic compounds from TC using a factorial design (FD) 2³, high performance liquid chromatography (HPLC), response surface methodology (RSM) and principal component analysis (PCA) were studied. It was found that the optimal conditions for extraction of phenolics were higher temperature (65 °C) and time (60 min) using ethanol as extractor solvent. In this condition of extraction (A8), total phenolic compounds (TPC) and antioxidant activity (AA) were determined. Additionally, this extract was used to evaluate their effect on antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)) as well as lipid peroxidation (LP) and protein thiols level (PSH) in the liver and kidneys of normal and diabetic rats. As result, T. catharinensis extract presented TPC content of 23.34 mg EAG/g (equivalent gallic acid) and AA of 34.26 μmol Trolox/g. Phenolic acids (ferulic acid and coumaric acid) and flavonoids (quercetin, rutin and pinocembrin) could be recovered and identified by HPLC. This study indicated an important role of the T. catharinensis extract on free radical inactivation and on the antioxidant defense system in diabetic rats. In fact, the use of T. catharinensis extract restored the normal activity of SOD (p < 0.05) and suppressed malondialdehyde levels in liver and kidney tissues. Thus, the T. catharinensis extract, rich in phenolic compounds, can be responsible for the recover the enzymatic changes in the liver and kidney tissues provoked by diabetes in rats. In addition, the lipid peroxidation rate decreased in the diabetic rats treated with T. catharinensis.

Anti-Melanogenesis, Antioxidant and Anti-Tyrosinase Activities of Scabiosa columbaria L

Scabiosa columbaria is a plant traditionally used to treat skin ailments, such as scabies, wound bruises, sores and hyperpigmentation. To find a novel skin depigmenting agent, the present study was investigated to determine the possible anti-melanogenesis, antioxidant and anti-tyrosinase effects of methanol extract of S. columbaria leaves. Cytotoxicity towards human dermal fibroblast (MRHF) cells was assessed using the live-cell fluorescence imaging microscopy. The inhibitory effects of the extract on tyrosinase, collagenase and melanin synthesis were also investigated using standard in vitro method, while ferric reducing power (FRAP) was used to determine the antioxidant potential of the plant extract. The effect of the extract on collagen content in MRHF cells was also investigated. The plant extract displayed no meaningful cytotoxicity towards MRHF cells and no significant cell death was recorded at all the tested concentrations. The extract (25–100 µg/mL) effectively decreased melanin content in B16F10 (mouse melanoma) cells with moderate inhibition of tyrosinase enzyme in a dose-dependent manner. However, the extract also demonstrated no significant effect on collagenase and collagen content in MRHF cells, but showed strong antioxidant activity at the concentrations tested. The results suggest that S. columbaria could be a promising candidate in the treatment of skin hyperpigmentation disorders

Aqueous extract from Mangifera indica Linn. (Anacardiaceae) leaves exerts long-term hypoglycemic effect, increases insulin sensitivity and plasma insulin levels on diabetic Wistar rats

BACKGROUND

Diabetes mellitus is one of the most common todays public health problems. According to a survey by the World Health Organization, this metabolic disorder has reached global epidemic proportions, with a worldwide prevalence of 8.5% in the adult population.

OBJECTIVES

The present study aimed to investigate the hypoglycemic effect of aqueous extract of Mangifera indica (EAMI) leaves in streptozotocin-induced diabetic rats.

METHODS

Sixty male rats were divided into 2 groups: Normoglycemic and Diabetic. Each group was subdivided into negative control, glibenclamide 3 or 10 mg/kg, EAMI 125, 250, 500, and 1000 mg/kg. Intraperitoneal injection of streptozotocin 100 mg/kg was used to DM induction. The hypoglycemic response was assessed acutely after two and four weeks of treatment. After a 6-hour fasting period, the fasting blood glucose of animals was verified, and 2.5 g/kg glucose solution was orally administered. The insulin tolerance test and plasma insulin levels assessment were performed in the morning after fasting of 12 to 14 hours.

RESULTS AND CONCLUSION

The chemical analysis of EAMI showed high levels of phenolic compounds. There was no significant difference in fasting blood glucose between normoglycemic and diabetic groups, and that EAMI did not have an acute effect on diabetes. After two and four weeks of treatment, the extract significantly reduced blood glucose levels, exceeding glibenclamide effects. EAMI was effective in maintaining the long-term hypoglycemic effect, as well as, significantly increased the sensitivity of diabetic animals to insulin and the plasma insulin level.

Understanding glycaemic control and current approaches for screening antidiabetic natural products from evidence-based medicinal plants

Type 2 Diabetes Mellitus has reached epidemic proportions as a result of over-nutrition and increasingly sedentary lifestyles. Current therapies, although effective, are not without limitations. These limitations, the alarming increase in the prevalence of diabetes, and the soaring cost of managing diabetes and its complications underscores an urgent need for safer, more efficient and affordable alternative treatments. Over 1200 plant species are reported in ethnomedicine for treating diabetes and these represents an important and promising source for the identification of novel antidiabetic compounds. Evaluating medicinal plants for desirable bioactivity goes hand-in-hand with methods in analytical biochemistry for separating and identifying lead compounds. This review aims to provide a comprehensive summary of current methods used in antidiabetic plant research to form a useful resource for researchers beginning in the field. The review summarises the current understanding of blood glucose regulation and the general mechanisms of action of current antidiabetic medications, and combines knowledge on common experimental approaches for screening plant extracts for antidiabetic activity and currently available analytical methods and technologies for the separation and identification of bioactive natural products. Common in vivo animal models, in vitro models, in silico methods and biochemical assays used for testing the antidiabetic effects of plants are discussed with a particular emphasis on in vitro methods such as cell-based bioassays for screening insulin secretagogues and insulinomimetics. Enzyme inhibition assays and molecular docking are also highlighted. The role of metabolomics, metabolite profiling, and dereplication of data for the high-throughput discovery of novel antidiabetic agents is reviewed. Finally, this review also summarises sample preparation techniques such as liquid-liquid extraction, solid phase extraction, and supercritical fluid extraction, and the critical function of nuclear magnetic resonance and high resolution liquid chromatography-mass spectrometry for the dereplication, putative identification and structure elucidation of natural compounds from evidence-based medicinal plants.

Mechanism of Action of Mangifera indica Leaves for Anti-Diabetic Activity

Diabetes is a major metabolic disorder whose prevalence is increasing daily. Medicinal plants have played an important role in the prevention and treatment of type 2 diabetes via prophylactic and therapeutic management. In this study, Mangifera Indica leaf (MIL) extract was investigated for its promising anti-diabetic activity via an in vitro model. It was found that MIL extract possessed significant inhibition on alpha-amylase activity up to (51.4 ± 2.7)% at a concentration of 200 µg/mL. Moreover, glucose adsorption capacity of MIL was identified at (2.7 ± 0.19) mM glucose/g extract. Furthermore, the extract caused a significant increase in glucose uptake up to (143 ± 9.3)% in LO-2 liver cells. Notably, MIL extract was effective in scavenging (63.3 ± 2.1)% 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and (71.6 ± 4.3)% 2,2-azinobis-3-ethyl benzothiazoline-6-sulfonic acid (ABTS)+ radicals and inhibiting (66 ± 4.9)% NO production from RAW264.7 cells without any cytotoxicity effects. Accordingly, M. indica leaves are suggested as a promising material for development of hypoglycemic products.