Evaluation of the inhibition of carbohydrate hydrolysing enzymes, antioxidant activity and polyphenolic content of extracts of ten African Ficus species (Moraceae) used traditionally to treat diabetes

Anti-diabetic, anti-pancreatic lipase, and anti-protein glycation potential of Irvingia gabonensis stem bark extracts: in vitro and in silico studies

Diabetes mellitus is a chronic metabolic disorder that affects glucose, lipid, and protein metabolism. Targeting these metabolic derangements can optimize the therapeutic strategies for this disease. Utilizing in vitro and in silico models, this study investigated the ability of aqueous and ethanol extracts of Irvingia gabonensis to inhibit α-amylase, α-glucosidase, pancreatic lipase, and protein glycation. High-performance liquid chromatography (HPLC) was used to identify the compounds found in the stem bark of I. gabonensis. In silico analysis determined the binding mode and mechanism of interactions between the enzymes and phytochemicals. With an IC50 value of 11.47 µg/ml, the aqueous extract demonstrated higher inhibitory efficacy against α-amylase compared to the ethanol extract (IC50 19.88 µg/ml). However, the ethanol extract had stronger inhibitory activities against α-glucosidase, pancreatic lipase, and protein glycation compared to the aqueous extract (IC50 values of 3.05, 32.85, 0.0014 versus 25.72, 332.42, 0.018 µg/ml respectively). Quercetin ranked highest in binding energy with α-amylase (-6.6 kcal/mol), α-glucosidase (-6.6 kcal/mol), and pancreatic lipase (-5.6 kcal/mol). This was followed by rhamnetin (6.5, 6.5, and 6.1 kcal/mol respectively). Hydrogen bonding, hydrophobic interactions, and pi-pi stacking are forces responsible for the binding of quercetin and rhamnetin to these enzymes. Molecular dynamics simulation showed that the lead phytochemicals formed stable and energetically stabilized complexes with the target proteins. This study showed that the extracts of I. gabonensis stem bark had significant in vitro anti-diabetic, anti-pancreatic lipase, and anti-protein glycation activities. The strong binding affinities of some of the identified compounds could be responsible for the inhibitory potential of the extracts. I. gabonensis stem bark could be further explored as a natural remedy for the treatment of diabetes mellitus and its complications.

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

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

The inhibition mechanism of bound polyphenols extracted from mung bean coat dietary fiber on porcine pancreatic α-amylase: kinetic, spectroscopic, differential scanning calorimetric and molecular docking

The inhibitory mechanisms of purified bound polyphenols extracted from mung bean coat dietary fiber (pMBDF-BP) on porcine pancreatic α-amylase (PPA) were investigated through inhibition kinetics, fluorescence spectroscopy, circular dichroism, differential scanning calorimetry and molecular docking. It was shown that pMBDF-BP exerted significant reversible inhibition on PPA in a mixed-type inhibition manner (IC50 = 18.57 ± 0.30 μg/mL), and the combination of the three major components exhibited a synergistic inhibitory effect on PPA. Further, pMBDF-BP bound to the active site or form a polyphenol-enzyme complex at the inactive site through hydrogen bonding and hydrophobic forces, via enhancing the hydrophobicity of the microenvironment surrounding tryptophan and tyrosine residues and promoting the secondary structure of PPA towards a more stable conformation, eventually reducing the enzyme activity. This study provided theoretical evidences for the utilization of bound polyphenols extracted from mung bean coat dietary fiber as a functional component in natural inhibitors of α-amylase.

Antidiabetic Activity, Molecular Docking, and ADMET Properties of Compounds Isolated from Bioactive Ethyl Acetate Fraction of Ficus lutea Leaf Extract

Diabetes contributes to the rising global death rate. Despite scientific advancements in understanding and managing diabetes, no single therapeutic agent has been identified to effectively treat and prevent its progression. Consequently, the exploration for new antidiabetic therapeutics continues. This study aimed to investigate the antidiabetic bioactive ethyl acetate fraction of F. lutea at the molecular level to understand the molecular interactions and ligand-protein binding. To do this, the fraction underwent column chromatography fractionation to yield five compounds: lupeol, stigmasterol, α-amyrin acetate, epicatechin, and epiafzelechin. These compounds were evaluated in vitro through α-glucosidase inhibition and glucose utilization assays in C2C12 muscle and H-4-11-E liver cells using standard methods. In silico analysis was conducted using molecular docking and ADMET studies. Epicatechin exhibited the most potent α-glucosidase inhibition (IC50 = 5.72 ± 2.7 µg/mL), while epiafzelechin stimulated superior glucose utilization in C2C12 muscle cells (33.35 ± 1.8%) and H-4-11-E liver cells (46.7 ± 1.2%) at a concentration of 250 µg/mL. The binding energies of the isolated compounds for glycogen phosphorylase (1NOI) and α-amylase (1OSE) were stronger (<-8.1) than those of the positive controls. Overall, all tested compounds exhibited characteristics indicative of their potential as antidiabetic agents; however, toxicity profiling predicted epiafzelechin and epicatechin as better alternatives. The ethyl acetate fraction and its compounds, particularly epiafzelechin, showed promise as antidiabetic agents. However, further comprehensive studies are necessary to validate these findings.

Investigation of the Potential Phlorotannins and Mechanism of Six Brown Algae in Treating Type II Diabetes Mellitus Based on Biological Activity, UPLC-QE-MS/MS, and Network Pharmacology

Type 2 diabetes mellitus (T2DM) has developed into an important health concern worldwide. The discovery of phlorotannins and their efficacy in the treatment of T2DM has become a hotspot for research in various fields. In this study, the potential phlorotannins and mechanism of six brown algae against T2DM were in-depth investigated using biological activity assays, LC-MS, and network pharmacology. First, the ethyl acetate fraction (EA frac.) showed high polyphenolic content and possessed significantly antioxidant and enzyme inhibitory abilities. Further, a total of fifty-nine peaks were obtained from six EA fracs. via UPLC-QE-MS/MS analysis, and fifteen of them were identified as phlorotannins and their isomers or derivatives. In detail, the chemical structures of six phlorotannins were inferred as dibenzodioxine-1,3,6,8-tetraol, bifuhalol, dioxinodehydroeckol, eckol, fucofurodiphlorethol, and fucotriphlorethol; three phlorotannin isomers were deduced to be fucophlorethol, trifucol, triphlorethol A, or triphlorethol B; and the phlorotannin derivative of m/z 263 was determined to be dibenzodioxine-1,2,3,6,8-pentanol or dibenzodioxine-1,2,4,5,7-pentanol. Moreover, 43 T2DM-related targets acted on by these chemicals were identified, and the function of phlorotannin to prevent and treat T2DM was elucidated in a holistic way based on the established compound-target-disease network, and GO function and KEGG pathway enrichment analysis.

Anti-Diabetic Activities of Hydro-Methanolic Crude Extract and Solvent Fractions of Heteromorpha arborescens (Apiaceae) Leaves in Mice

Background

Heteromorpha arborescens has been used to treat diabetes traditionally. There was no in vivo study to support the claim. This study aimed to confirm anti-diabetic activity of 80% methanol in water extract and solvent fractions of H. arborescens leaves in mice.

Methods

H. arborescens leaves were macerated and extracted in 80% methanol in water. Hydro-methanol extract of H. arborescens leaves were tested in mice models. Overnight fasted mice were randomly divided into five groups for normoglycemic and glucose-loaded models as a negative control, positive control, and three tested groups, whereas, in streptozotocin-induced diabetic models, the mice were grouped into six groups each comprised six mice: diabetic negative control and normal negative control groups treated with 10 mL/kg distilled water, diabetic positive control group treated with Glibenclamide 5 mg/kg and three diabetic tested groups treated with extract at 100, 200, and 400 mg/kg doses. A one-way ANOVA was performed to analyze the data, and the post hoc Tukey's test was utilized for multiple comparisons. The P-value <0.05 was considered statistically significant.

Results

Hydro-methanol extract of H. arborescens leaves at 400 mg/kg in normoglycemic mice significantly lowered blood glucose levels (BGLs) (P< 0.01). Mice with oral glucose-loaded test lowered BGLs at dosages of 200 mg/kg (P < 0.05) and 400 mg/kg (P < 0.01) respectively. Single-dose of ethyl acetate, n-hexane fractions and hydro-methanol extract at 100 mg/kg, 400 mg/kg and 200 mg/kg reduced BGLs (P < 0.05, P < 0.001, and P < 0.01) respectively. BGL drops in diabetic mice given daily repeated doses of 200 mg/kg of hydro-methanol extract and 400 mg/kg of ethyl acetate fraction (P < 0.001). Diabetic mice gained weight at a 400 mg/kg hydro-methanol extract and ethyl acetate fraction (P < 0.05 and P < 0.01) respectively. Hydro-methanol extract and ethyl acetate fraction and at 200 mg/kg decreased total cholesterol, triglycerides, and low-density lipoprotein and increased high-density lipoprotein (P < 0.001).

Conclusion

80% methanol in water extract and solvent fractions of H. arborescens leaves showed anti-diabetic effects and significantly reduced hyperlipidemia in diabetics, this study supported the traditional usage of H. arborescens for treating diabetes; however, species variation could also limit such a straightforward extrapolation of the findings of this study in humans.

A Phase I, Randomized, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Safety and Tolerance of Oil Palm Phenolics (OPP) in Healthy Volunteers

Background and aim: Oil palm aqueous by-products rich in phenolic content are known as oil palm phenolics (OPP), and pre-clinical research has shown that OPP has great potential to be further developed as an anti-hyperlipidemic agent. Hence, in order to introduce OPP into market, its safety profile needs to be established by undergoing a phase I clinical trial on healthy humans.

Methods: A parallel, placebo-controlled, randomized, and double-blinded clinical trial was conducted for 2 months on 100 healthy subjects aged 20–40 years old. This trial was registered at clinicaltrials.gov (NCT04164446). The subjects were randomly allocated to four treatment arms with 25 participants each: placebo, 250, 1,000, and 1,500 mg of OPP. During the trial, subjects were required to consume four capsules simultaneously per day. Withdrawal of fasting blood for hematology, liver and renal function analysis, and medical examination were conducted at baseline (day 1), day 30, and day 60. For monitoring, vital signs (blood pressure and pulse rate) and weight measurements were taken during each visit.

Results: Minor adverse events (AEs) were reported in all groups especially at high dose (1,500 mg) but none were serious adverse events (SAEs). Fasting blood parameters between control and all OPP-treated groups demonstrated no statistically significant difference from baseline to day 60.

Conclusion: With no major AEs and SAEs reported and no abnormal findings in biochemistry and hematology results, OPP supplementation in capsule form is safe to be taken up to 1,500 mg a day.

Molecular Docking and Molecular Dynamics Studies of Antidiabetic Phenolic Compound Isolated from Leaf Extract of Englerophytum magalismontanum (Sond.) T.D.Penn

Englerophytum magalismontanum, a medicinal plant with ethnopharmacology use, has a dearth of information regarding its antidiabetic properties. This study evaluated the crude methanol leaf extract of E. magalismontanum and its fractions for total phenolic content, antioxidant activity, and digestive enzymes (α-amylase and α-glucosidase) inhibitory activity using standard methods. The total phenolic content (56.53 ± 1.94 mg GAE/g dry extract) and DPPH Trolox antioxidant equivalent (TAE) (1.51 ± 0.66 µg/mL) of the methanol fraction were the highest among the fractions. The IC₅₀ values of the methanol fraction against α-amylase (10.76 ± 1.33 µg/mL) and α-glucosidase (12.25 ± 1.05 µg/mL) activities were also high. Being the most active, the methanol fraction was subjected to bio-assay guided column chromatography-based enzyme inhibition to obtain a pure compound. The phenolic compound isolated and identified as naringenin inhibited α-amylase and α-glucosidase with IC₅₀ of 5.81 ± 2.14 µg/mL and 4.77 ± 2.99 µg/mL, respectively. This is the first study to isolate naringenin from E. magalismontanum extract. The molecular docking and molecular dynamics studies demonstrated naringenin as a promising lead compound in comparison to acarbose for the treatment of diabetes through the inhibition of α-glucosidase activity.

Comparative in-vitro anti-inflammatory, anticholinesterase and antidiabetic evaluation: computational and kinetic assessment of succinimides cyano-acetate derivatives

This research was planned to synthesize cyano-acetate derivatives of succinimide and evaluate its comparative biological efficacy as anti-inflammatory, anti-cholinesterase and anti-diabetic, which was further validated by molecular docking studies. The three cyano-acetate derivatives of succinimide including compound 23 Methyl 2-cyano-2-(2,5-dioxopyrrolidin-3-yl)acetate, compound 31 Methyl 2-cyano-2-(1-methyl-2,5-dioxopyrrolidin-3-yl)acetate and compound 44 Methyl 2-cyano-2-(1-ethyl-2,5-dioxopyrrolidin-3-yl) acetate were synthesized. The mentioned compounds were checked for in vitro anti-inflammatory, anti-cholinesterase and anti-diabetic (α-amylase inhibition) activity. To validate the in vitro results, computational studies were carried out using molecular operating environment to analyse the BE, i.e. binding energies of all synthesized compounds against the respective enzymes. The Compounds 23, 31, 44 exhibited anti-inflammatory via inhibiting COX-2 (IC50 value of 204.08, 68.60 and 50.93 µM, respectively), COX-1 (IC50 value of 287, 185, and 143 µM, respectively) and 5-LOX (IC50 value of 138, 50.76 and 20, 87 µM respectively). They exhibited choline-mimetic potential, such as compound 23, 31 and 44 inhibited AChE enzyme (IC50 value of 240, 174, and 134 µM, respectively) and BChE enzyme (IC50 value of 203, 134 and 97 µM, respectively). The Compounds 23, 31, 44 exhibited anti-diabetic effect via inhibiting α-amylase enzyme (IC50 values of 250, 106 and 60 µM, respectively). Molecular docking studies revealed that the synthesized compounds have good binding affinity in the binding pockets of AChE, BChE, COX-2, 5-LOX and α-amylase enzyme and showed high binding energies. The synthesized succinimide derivatives, i.e. compound 23, 31, 44 showed marked inhibitory activities against cyclooxygenase, lipoxygenase, α-amylase and cholinesterase enzymes. Among these three, compound 44 and 31 showed strong anti-inflammatory and anti-diabetic activity while they displayed moderate anti-cholinesterase activity supported by molecular docking results.Communicated by Ramaswamy H. Sarma.

Ficus natalensis extract alleviates Cadmium chloride-induced testicular disruptions in albino rats

BACKGROUND

Cadmium is a potential environmental pollutant with worldwide health problems. Many Ficus species are reported to have an extensive diversity of traditional uses, among them the treatment of reproductive toxicity.

OBJECTIVES

This study set out to evaluate the effect of Ficus natalensis extract on the testicular impairments induced by cadmium chloride (CdCl₂) and investigated the potential mechanisms associated with its treatment.

METHODS

Thus, 40 male albino rats were categorized into 4 groups (n = 10); group I (control), group II (cadmium-treated group) orally received 5 mg/kg/day CdCl₂ for one month, group III (cadmium + Ficus natalensis extract) orally received 5 mg/kg/day CdCl₂ for one month plus 200 mg/kg/day Ficus natalensis extract for another month, and group IV (cadmium + reference drug (mesterolone) orally received 5 mg/kg/day CdCl₂ for one month plus 4.16 mg/kg/day mesterolone for another month.

RESULTS

At the end of experiment, CdCl₂ administration markedly induced histological and histo-morphometric changes with a substantial (p < 0.05) decrease in the sperm count, sperm motility, serum TAC, serum testosterone, downregulation in the mRNA expression levels of testicular 17β-HSD and StAR, in addition to a significant increase in serum TNF-α and testicular MDA level compared to the control group. Conversely, the treatment with Ficus natalensis methanolic extract as well as the reference drug significantly ameliorated the above-mentioned adverse effects induced by CdCl₂.

CONCLUSIONS

Our results suggested that Ficus natalensis extract can attenuate the CdCl₂-induced testicular impairments via inhibiting the oxidative cell damage and inflammation that contributed to CdCl₂ toxicity.

Ficus glumosa Del. reduces phenylhydrazine-induced hemolytic anaemia and hepatic damage in Wistar rats

OBJECTIVES

Anemia is a direct or indirect consequence of oxidative stress via free radicals on erythrocytes and subsequently on other tissues like liver. Ficus glumosa constitute a rich pharmacologically compound that can prevent or repair oxidative damage. Therefore, this study seeks to evaluate the effect of F. glumosa on phenylhydrazine-induced hemolytic anemia and hepatic damage in rats.

METHODS

Twenty-four (24) albino Wistar rats were assigned to four (4) experimental groups (n=6) as follows: Group I (non-anemic control) and Group 2 (anemic control) received normal saline, while Group III and IV (test groups) 200 and 400 mg/kg of aqueous leaf extract of F. glumosa (ALEFG), respectively. All the groups were treated orally (via a cannula) for seven consecutive days. Intraperitoneal (IP) injection of phenylhydrazine (PHZ) at 40 mg/kg for two consecutive days induced hemolytic anemia in group II to IV before treatment. Rats of all groups were anaesthetized and sacrificed 24 h after the last treatment. Blood and liver samples were collected for some hematological indices, liver function test, antioxidant parameter and histological analysis.

RESULTS

The LD₅₀ of ALEFG was assessed orally in rats and found to be above 5,000 mg/kg body weight. Significant (p<0.05) decreases in the level of red blood cell (RBC), hemoglobin (HGB) concentrations and packed cell volume (PCV) by 50% after 2 days of PHZ induction, were attenuated by more than 50% after 7 days administration of ALEFG at 200 and 400 mg/kg. The percentage change in body weight increased significantly (p<0.05) after 7 days post PHZ-induced anemia, but those that received oral administration of ALEFG (at 200 and 400 mg/kg) for 7 days increased significantly (p<0.05) by more than 2%, dose-dependently compared to anemic untreated group. Increased level of serum ALT, AST, ALP and GGT in PHZ-induced anemic animals, were significantly (p<0.05) attenuated in the groups that received oral administration of ALEFG (at 200 and 400 mg/kg) for 7 days. Decreased level of catalase (CAT) and superoxide dismutase (SOD) activities with concomitant increase in malondialdehyde (MDA) content from PHZ-induced untreated group, were significantly (p<0.05) mitigated in the rats that received oral administration of ALEFG (at 200 and 400 mg/kg) for 7 days. Histopathological analysis showed that ALEFG could remarkably though not completely mitigated PHZ-induced hepatic damage.

CONCLUSIONS

Our data suggests that the leaves of F. glumosa contain important antioxidant(s) that could effectively reduce hemolytic anemia and hepatic damage, especially during phenylhydrazine-induced toxicity.

Barbeya oleoides Leaves Extracts: In Vitro Carbohydrate Digestive Enzymes Inhibition and Phytochemical Characterization

This study investigated the in vitro inhibitory potential of different solvent extracts of leaves of Barbeya oleoides on key enzymes related to type 2 diabetes mellitus (α-glucosidase and α-amylase) in combination with an aggregation assay (using 0.01% Triton X-100 detergent) to assess the specificity of action. The methanol extract was the most active in inhibiting α-glucosidase and α-amylase, with IC₅₀ values of 6.67 ± 0.30 and 25.62 ± 4.12 µg/mL, respectively. However, these activities were significantly attenuated in the presence of 0.01% Triton X-100. The chemical analysis of the methanol extract was conducted utilizing a dereplication approach combing LC-ESI-MS/MS and database searching. The chemical analysis detected 27 major peaks in the negative ion mode, and 24 phenolic compounds, predominantly tannins and flavonol glycosides derivatives, were tentatively identified. Our data indicate that the enzyme inhibitory activity was probably due to aggregation-based inhibition, perhaps linked to polyphenols.

In vitro antidiabetic, antioxidant activities and GC-MS analysis of Rhynchostylis Retusa and Euphorbia Neriifolia leaf extracts

This study aimed to assess the antidiabetic, and antioxidant potential of Rhynchostylis retusa and Euphorbia neriifolia, well known for traditional ethnomedicinal uses in North-east India. Leaf extracts prepared in water, methanol and petroleum ether were evaluated for in vitro antidiabetic and antioxidant assay using α-amylase inhibition, glucose diffusion method and DPPH radical scavenging activity. The α-amylase inhibition with E. neriifolia methanolic extract at 400 μg/ml (66.67%) and R. retusa aqueous extract at 300 μg/ml (58.15%) were stronger than in equivalent concentrations of acarbose, i.e., 62.17, and 51.52%, respectively. Aqueous extract R. retusa showed a maximum 67.65% inhibition of glucose diffusion at 180 min in comparison to control without leaf extract. The DPPH radical scavenging activity of E. neriifolia extract in methanol was significantly better than equivalent aqueous or ether extract. However, the solvent choice had little impact on antioxidant activity in R. retusa. GC-MS analysis revealed the presence of a large number of phytochemicals in methanol fraction of E. neriifolia aqueous extracts in comparison to R. retusa. Though the in vitro α-amylase inhibition or glucose diffusion retardation implied potential medicinal use of endangered orchid R. retusa and E. neriifolia, further investigation may be warranted for identification of relevant bio-active compounds and in vivo validation of their pharmacological properties.

Alotaibi A, Al-zharani M, Ziyyat A, Mekhfi H, Legssyer A, Aziz M, Bnouham M. Opuntia dillenii (Ker Gawl.) Haw., Seeds Oil Antidiabetic Potential Using In Vivo, In Vitro, In Situ, and Ex Vivo Approaches to Reveal Its Underlying Mechanism of Action

Opuntia dillenii Ker Gawl. is one of the medicinal plants used for the prevention and treatment of diabetes mellitus (DM) in Morocco. This study aims to investigate the antihyperglycemic effect of Opuntia dillenii seed oil (ODSO), its mechanism of action, and any hypoglycemic risk and toxic effects. The antihyperglycemic effect was assessed using the OGTT test in normal and streptozotocin (STZ)-diabetic rats. The mechanisms of action were explored by studying the effect of ODSO on the intestinal absorption of d-glucose using the intestinal in situ single-pass perfusion technique. An Ussing chamber was used to explore the effects of ODSO on intestinal sodium-glucose cotransporter 1 (SGLT1). Additionally, ODSO’s effect on carbohydrate degrading enzymes, pancreatic α-amylase, and intestinal α-glucosidase was evaluated in vitro and in vivo using STZ-diabetic rats. The acute toxicity test on mice was performed, along with a single-dose hypoglycemic effect test. The results showed that ODSO significantly attenuated the postprandial hyperglycemia in normal and STZ-diabetic rats. Indeed, ODSO significantly decreased the intestinal d-glucose absorption in situ. The ex vivo test (Ussing chamber) showed that the ODSO significantly blocks the SGLT1 (IC₅₀ = 60.24 µg/mL). Moreover, ODSO indu\ced a significant inhibition of intestinal α-glucosidase (IC₅₀ = 278 ± 0.01 µg/mL) and pancreatic α-amylase (IC₅₀ = 0.81 ± 0.09 mg/mL) in vitro. A significant decrease of postprandial hyperglycemia was observed in sucrose/starch-loaded normal and STZ-diabetic ODSO-treated rats. On the other hand, ODSO had no risk of hypoglycemia on the basal glucose levels in normal rats. Therefore, no toxic effect was observed in ODSO-treated mice up to 7 mL/kg. The results of this study suggest that ODSO could be suitable as an antidiabetic functional food.

Antioxidant and Antiproliferative Potentials of Ficus glumosa and Its Bioactive Polyphenol Metabolites

Ficus glumosa Delile (Moraceae), a reputed plant that is used in herbal medicine, is of high medicinal and nutritional value in local communities primarily ascribed to its phytochemical profile. Currently, there are hardly any fine details on the chemical profiling and pharmacological evaluation of this species. In this study, the flavonoids and phenolics contents of the ethanol extracts and four extracted fractions (petroleum ether (PE), ethyl acetate (EA), n-butanol, and water) of the stem bark of Ficus glumosa were firstly quantified. Further, their antioxidant and antiproliferative potentials were also evaluated. The quantitative determination indicated that the EA and n-butanol fractions possessed the highest total flavonoids/phenolics levels of 274.05 ± 0.68 mg RE/g and 78.87 ± 0.97 mg GAE/g, respectively. Similarly, for the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric-reducing antioxidant power (FRAP) assays, the EA fraction exhibited high potency in both DPPH and ABTS⁺ scavenging activities with IC₅₀ values of 0.23 ± 0.03 mg/mL, 0.22 ± 0.03 mg/mL, and FRAP potential of 2.81 ± 0.01 mg Fe²⁺/g, respectively. Furthermore, the EA fraction displayed high cytotoxicity against human lung (A549) and colon (HT-29) cancer cells. Additionally, the liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was employed in order to characterize the chemical constituents of the EA fraction of Ficus glumosa stem bark. Our findings revealed 16 compounds from the EA fraction that were possibly responsible for the strong antioxidant and anti-proliferative properties. This study provides edge-cutting background information on the exploitation of Ficus glumosa as a potential natural antioxidant and anti-cancer remedy.

Pharmacological Potential and Chemical Characterization of Bridelia ferruginea Benth.-A Native Tropical African Medicinal Plant

To avail the possible pharmacological actions of Brideliaferruginea Benth., the present investigation was designed to quantitatively analyze the total flavonoid and phenolic contents and assess the various antioxidant and enzyme inhibition properties of leaf and stem bark extracts (ethyl acetate, water and methanolic) of B. ferruginea. Anti-proliferative effect was also investigated against human colon cancer cells (HCT116) as well as the antimicrobial potential against multiple bacterial and fungal (yeasts and dermatophytes) strains. The methanolic and water extracts of the stem bark demonstrated the highest phenolic content (193.58 ± 0.98 and 187.84 ± 1.88 mg/g, respectively), while the leaf extracts showed comparatively higher flavonoid contents (24.37-42.31 mg/g). Overall, the methanolic extracts were found to possess the most significant antioxidant potency. Compared to the other extracts, methanolic extracts of the B. ferruginea were revealed to be most potent inhibitors of acetyl- and butyryl-cholinesterases, tyrosinase α-amylase, except α-glucosidase. Only the ethyl acetate extracts were found to inhibit glucosidase. Additionally, the stem bark methanolic extract also showed potent inhibitory activity against E. coli and gram-positive bacteria (MIC (minimum inhibitory concentration): 2.48-62.99 µg/mL), as well as all the tested fungi (MIC: 4.96-62.99 µg/mL). In conclusion, B. ferruginea can be regarded as a promising source of bioactive compounds displaying multifunctional pharmacological activities and thus is a potential candidate for further investigations in the endeavor to develop botanical formulations for pharmaceutical and cosmeceutical industries.

Ethnobotanical study of plants used by the traditional healers to treat malaria in Mogovolas district, northern Mozambique

INTRODUCTION

Malaria is an important parasitic disease that affects mostly the African continent. Traditional medicine is very important in Mozambique and traditional healers play a key role in the primary health care services, particularly in rural areas. We aim to report the results of an ethnobotanical survey undertaken in Mogovolas district, northern region of Mozambique. We recorded and identified the medicinal plants used by traditional healers for treatment of malaria, as well as the mode of preparation and administration.

METHODS

The study was conducted in 14 villages from Mogovolas between June and August 2015. Sixteen traditional healers were interviewed using semi-structured questionnaires. Under their guidance, we collected medicinal plants and prepared herbarium specimens that were sent and kept at Eduardo Mondlane University Herbarium for scientific identification. We searched for information on the in vitro and in vivo studies of the cited plants for antiplasmodial activity.

RESULTS

Traditional healers from Mogovolas district reported the use of 37 plants to treat malaria, belonging to 22 families. The most used species are Ochna kirkii Oliv. (5 citations), Ehretia amoena Klotzsch and Pteleopsis myrtifolia (M.A.Lawson) Engl. & Diels (both with 3 citations). These plants belong to Ochnaceae, Boraginaceae and Combretaceae families, respectively. The herbal remedies are prepared using leaves (22/37), roots (18/37), stem barks (16/37) and stems (3/37). The administration of the herbal remedies was made essentially by oral route and bathing.

CONCLUSION

The ethnobotanical data resulted from this study can be the starting point for further chemical and pharmacological studies aiming to identify medicinal species with antimalarial activity, thus, open the insights for the discovery of new antimalarial substances, as well as better integration of the traditional medicine into the national health systems, particularly in developing countries, as the health system coverage is limited.

The genus Ficus (Moraceae) used in diet: Its plant diversity, distribution, traditional uses and ethnopharmacological importance

ETHNOPHARMACOLOGICAL RELEVANCE

A new field of enthnopharmacology has opened, where pharmacological studies draw their attention from the conventional only-medicine approach towards the dietary dimension. The uses of Ficus species in the human diet have been extensively documented by ethnobotanical field surveyors. Overlap commonly exist between the dietary and medicinal selection of Ficus species but not for choices of the plant parts and development stages, which leave a large space for ethnopharmacological study.

AIMS OF THE STUDY

1) To review published works on the dietary uses of Ficus species and their food-medicine overlap based on traditional uses, and 2) to spark interest in ethnopharmacological studies on the dietary uses of Ficus species.

MATERIALS AND METHODS

Data was collected and analyzed from many sources, including published and unpublished ethnobotanical field surveys, taxonomic and distribution information, international journals, books, thesis, floras, reports and professional databases. The possible biases arising from data sources are assessed to make sure that the dataset are global representative.

RESULTS

A total of 132 Ficus species are reported for dietary uses, including one subspecies and four varieties. Those species are found across all of the six subgenera of the genus Ficus. For distribution, 98 species from the Indo-Australasian region, 27 species from the African tropics (with one species, F. palmata, from both the two regions) and 8 from the Neotropics. The parts most commonly used are the figs (i.e. syconium or fruits) (110 species) and leaves (67 species), in various growth stages. It is also found that the certain plant parts of 78 species are used both for dietary and medicinal purpose. Among which the figs are frequently cited in the treatment of diarrhea and oligogalactia, the leaves in the treatment of diarrhea, stomach complaintsas, antidote and diabetes, the latex in the treatment of intestinal worms and wounds, and the barks in the treatment of diarrhea.

CONCLUSIONS

We demonstrate that throughout its area of distribution, the genus Ficus is generally used as a dietary plant, although use of a individual species seems uncommon. Furthermore, we highlight the diet-medicine overlap of the uses of this genus, which should enable further understanding of the potential for broader health benefits, rather than limiting studies in this genus to its only-medicinal properties.

Antioxidant Status, Antidiabetic Properties and Effects on Caco-2 Cells of Colored and Non-Colored Enriched Extracts of Sweet Cherry Fruits

This study aimed to compare three different extracts of Saco sweet cherry, namely the non-colored fraction, colored fraction, and total extract concerning phenolic composition, antioxidant and antidiabetic potential, and erythrocytes’ protection and effects on Caco-2 cells. Twenty-two phenolic compounds were identified using high-performance liquid chromatography with diode-array detection. Hydroxycinnamic acids were the most predominant in both the non-colored fraction and total extract, while cyanidin-3-O-rutinoside was the main anthocyanin found in the colored fraction. The total extract was the most effective against 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, and superoxide radicals, and in the inhibition of α-glucosidase enzyme. The colored fraction revealed the best activity against hemoglobin oxidation and hemolysis. Regarding to Caco-2 cells, the colored extract exhibited the highest cytotoxic effects, while the total extract was the most efficient in protecting these cells against oxidative damage induced by tert-butyl hydroperoxide.

Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management

Strategies to avoid lactose malabsorption, which affects 70% of the world's population, are focused on the restriction of milk and dairy products or the use of non-human β-galactosidases or probiotics endowed with β-galactosidase activity added at mealtime. Our evaluation of a commercial blend of probiotics and enzymes (protease, lactase, lipase and amylase) and its potential application in lactase non-persistence management is described in this work. Recommended amounts (460-1000 mg) of the commercial probiotics-enzyme blend were shown to be adequate for performing in vitro lactose hydrolysis in standard solutions (0.25-5%) and commercial dairy products, namely milks (5% lactose) and yogurts (3% lactose), reaching hydrolysis values between 44 and 96%. According to these percentages, the use of the enzymatic preparation would guarantee the intake of less than 12 g, the recommendation of the EFSA for lactose intolerance. Furthermore, formation of prebiotic galactooligosaccharides was also detected, increasing the potential benefits of the enzymatic preparation in the gastrointestinal system.

In vitro biological screening of a critically endangered medicinal plant, Atropa acuminata Royle Ex Lindl of north western Himalaya

Atropa acuminata Royle Ex Lindl (Atropa acuminata) under tremendous threat of extinction in its natural habitat. However, the antimicrobial, antileishmanial and anticancer effects of the plant’s extracts have not been reported yet. In the current study, an attempt has been made to evaluate the pharmacological potential of this plant’s extracts against microbes, Leishmania and cancer. The roots, stems and leaves of Atropa acuminata were ground; then, seven different solvents were used alone and in different ratios to prepare crude extracts, which were screened for pharmacological effects. The aqueous, methanolic and ethanolic extracts of all parts carried a broad spectrum of anti-bacterial activities, while no significant activity was observed with combined solvents. Three types of cytotoxicity assays were performed, i.e., haemolytic, brine shrimp and protein kinase assays. The aqueous extract of all the parts showed significant haemolytic activity while n-hexane extracts of roots showed significant activity against brine shrimp. The acetone extracts strongly inhibited protein kinase while the methanolic extracts exhibited significant cytotoxic activity of roots and stem. The anti-leishmanial assays revealed that the methanolic extract of leaves and roots showed significant activity. These findings suggest that this plant could be a potential source of natural product based drugs.

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.

A role of Ficus species in the management of diabetes mellitus: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus is one of the most common global health concerns, with a rapidly increasing incidence. A variety of medicinal plants, particularly those belonging to the genus Ficus (Moraceae), and their active compounds have been used to treat diabetes and related chronic disorders since ancient times.

AIM OF THE STUDY

The aim of this review is to provide information regarding traditional and scientific knowledge of Ficus species with antidiabetic activity to researchers.

MATERIALS AND METHODS

A literature search was conducted to obtain information about the antidiabetic properties of Ficus from the electronic databases. Common and scientific names of various Ficus species were used as keywords for the search, along with the terms antidiabetic, hypoglycemic and diabetes.

RESULTS

Among the assorted species of Ficus that were included in our search, F. benghalensis, F. carica, F. glomerata, F. glumosa, F. racemosa, and F. religiosa exhibited remarkable antidiabetic properties with various mechanisms of action. Moreover, Ficus species are versatile sources of bioactive metabolites such as flavonoids, phenolic acids, tannins, alkaloids, glycosides, coumarins, triterpenoids, sterols and vitamin E. These extracts and isolated compounds significantly have enhanced insulin secretion and subsequently reduced blood glucose level in various in vivo studies.

CONCLUSION

This review summarizes the antidiabetic potentials of the genus Ficus, including pharmacological studies with mechanisms of action as well as ethnobotanical uses. This review can help inform future scientific research towards the development of novel antidiabetic drugs.

Bioassay-guided fractionation and identification of α-amylase inhibitors from Syzygium cumini leaves

CONTEXT

Pancreatic α-amylase and α-glucosidase inhibitors serve as important strategies in the management of blood glucose. Even though Syzygium cumini (L.) Skeels (Myrtaceae) (SC) is used extensively to treat diabetes; scientific evidence on antidiabetic effects of SC leaves is scarce.

OBJECTIVE

SC leaf extract was investigated for α-amylase inhibitory effect and continued with isolation and identification of α-amylase inhibitors.

MATERIALS AND METHODS

Bioassay-guided fractionation was conducted using in vitro α-amylase inhibitory assay (with 20-1000 μg/mL test material) to isolate the inhibitory compounds from ethyl acetate extract of SC leaves. Structures of the isolated inhibitory compounds were elucidated using 1H NMR and 13C NMR spectroscopic analysis and direct TLC and HPLC comparison with authentic samples. Study period was from October 2013 to October 2015.

RESULTS

An active fraction obtained with chromatographic separation of the extract inhibited porcine pancreatic α-amylase with an IC50 of 39.9 μg/mL. Furthermore, it showed a strong inhibition on α-glucosidase with an IC50 of 28.2 μg/mL. The active fraction was determined to be a 3:1 mixture of ursolic acid and oleanolic acid. Pure ursolic acid and oleanolic acid showed IC50 values of 6.7 and 57.4 μg/mL, respectively, against α-amylase and 3.1 and 44.1 μg/mL respectively, against α-glucosidase.

DISCUSSION AND CONCLUSIONS

The present study revealed strong α-amylase and α-glucosidase inhibitory effects of ursolic acid and oleanolic acid isolated from SC leaves for the first time validating the use of SC leaves in antidiabetic therapy.

Ficus sycomorus extract reversed behavioral impairment and brain oxidative stress induced by unpredictable chronic mild stress in rats

BACKGROUND

Stress, regardless of its nature is nowadays recognized as one of the major risk factors for neuropsychiatric diseases, such as mood and anxiety disorders. The brain compared with other organs is more vulnerable to oxidative damage mainly due to its high rate of oxygen consumption, abundant lipid content, and relative insufficiency of antioxidant enzymes. Thus, the identification of neural mechanisms underlying resistance and vulnerability to stress is of crucial importance in understanding the pathophysiology of neuropsychiatric disorders and in developing new treatments, since the existing ones are for several reasons subject to increasing limitations. This study was aimed to assess the effects of hydromethanolic extract of Ficus sycomorus stem bark on depression, anxiety and memory impairment induced by unpredictable chronic mild stress (UCMS) in rats.

METHODS

These effects were studied using anxiety-related behavior, depression-related behavior, anhedonia-like behavior and the Y maze task. Sucrose test was performed twice (before and after UCMS) to assess anhedonia in rats. Liquid chromatography-mass spectrometry analysis of the extract were performed. The antioxidant activities of the extract were assessed using total glutathione (GSH) content and malondialdehyde (MDA) level (lipid peroxidation) in the rat temporal lobe homogenates.

RESULTS

The extract of F. sycomorus in a dose of 100 mg/kg significantly increased the sucrose consumption and the swimming time which had been reduced by the unpredictable chronic mild stress (p < 0.001). The extract also significantly reduced (p < 0.01) the latency time in the novelty-suppressed feeding test. In the elevated plus-maze, the extract (100 and 200 mg/kg) significantly reduced (p < 0.01) the time and the number of entries into the closed arms. The treatment with the extracts also significantly increased alternation in the Y-maze (p < 0.01 for 100 mg/kg). The extract significantly increased the total GSH content and reduced MDA level in rat temporal lobe. For the LC-MS analysis, the major compound in the extract was a flavonoid with formula C22H28O14.

CONCLUSIONS

F. sycomorus reversed the harmful effects of UCMS on mood and behaviors in rats and it possesses an antidepressant property that is at least in part mediated through the oxidative pathway.

Phenolic compounds as natural and multifunctional anti-obesity agents: A review

Prevalence of obesity worldwide has reached pandemic proportions. Despite the increasing evidence in the implication of phenolic compounds in obesity management, the real effect is not completely understood. The available in vitro and in vivo studies have demonstrated the implication of phenolic compounds in: lowering food intake, decreasing lipogenesis, increasing lipolysis, stimulating fatty acids β-oxidation, inhibiting adipocyte differentiation and growth, attenuating inflammatory responses and suppress oxidative stress. This review encompasses the most recent evidence in the anti-obesity effect of phenolic compounds from plants to different nutraceuticals and functional foods based on the in vitro, in vivo and clinical studies. For that, this review has been focused on popular plant-based products highly consumed today such as cocoa, cinnamon, and olive oil, beverages such as red wine, tea (green, white and black tea) and Hibiscus sabdariffa L. tea, among others.

Assessment of in Vitro Digestibility of Dietary Carbohydrates Using Rat Small Intestinal Extract

There are few studies on the assessment of digestibility of nondigestible carbohydrates, despite their increasingly important role in human health. In vitro digestibility of a range of dietary carbohydrates classified as digestible (maltose, sucrose, and lactose), well-recognized (lactulose, fructooligosaccharides (FOS), and two types of galactooligosaccharides (GOS) differing in the predominant glycosidic linkage), and potential (lactosucrose and GOS from lactulose, OsLu) prebiotics using a rat small intestinal extract (RSIE) under physiological conditions of temperature and pH is described. Recognized and potential prebiotics were highly resistant to RSIE digestion although partial hydrolysis at different extents was observed. FOS and lactulose were the most resistant to digestion, followed closely by OsLu and more distantly by both types of GOS and lactosucrose. In GOS, β(1 → 6) linkages were more resistant to digestion than β(1 → 4) bonds. The reported in vitro digestion model is a useful, simple, and cost-effective tool to evaluate the digestibility of dietary oligosaccharides.

Antihyperlipidemic and Antioxidant Activities of Edible Tunisian Ficus carica L. Fruits in High Fat Diet-Induced Hyperlipidemic Rats

The phenolic constituents of the aqueous-ethanolic extract of Tunisian Ficus carica (F. carica) fruit (FE) and its antihyperlipidemic and antioxidant activities in high-fat diet-induced hyperlipidemic rats (HFD) were evaluated. The obtained results demonstrated that the FE improved the lipid profile by decreasing the total cholesterol, triglyceride, low-density lipoprotein cholesterol and increasing high-density lipoprotein cholesterol levels. It also reduced the content of thiobarbituric acid-reactive substances and increased the antioxidant enzymes in liver, heart and kidney in HFD-fed rats. These antihyperlipidemic effects and in vivo antioxidative effects correlated with the in vitro phenolic content scavenging ability. Thus, the major phenolic compounds were identified using reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) coupled with two detection systems: diode-array detection (DAD) and quadrupole time-of-flight (QTOF) mass spectrometry (MS). Therefore, in the negative ionization mode, 28 phenolic compounds, including hydroxybenzoic acids, hydroxycinnamic acids, flavanoids and hydroxycoumarins were characterized. Dihydroxybenzoic acid di-pentoside, the flavonol quercetin 3-O-rutinoside and the flavone assigned as apigenin 8-C-glucoside were the main representative compounds in 'Tounsi' fruits. This work was complemented by the detection of seven other phenolic compounds in the positive ionization mode, including anthocyanins and furanocoumarins. Overall, these results have shown that the FE has a significant hypocholesterolemic effect and antioxidant activity in HFD-fed rats. This beneficial effect may be partly due to these phenolic constituents, especially vitexin, dihydroxybenzoic acid di-pentoside as well as rutin.

Evaluation of antioxidant, enzyme inhibition, and cytotoxic activity of three anthraquinones (alizarin, purpurin, and quinizarin)

OBJECTIVE

The aim of this work was to investigate the cytotoxic, antioxidative, and enzyme inhibition effects of alizarin, quinizarin, and purpurin, which are anthraquinones (AQ).

METHODS

Cytotoxic effects were evaluated with cell inhibition rate by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide assay. Different chemical assays, including free radical scavenging activity (1,1-diphenyl-2-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazloine-6-sulfonic acid)), phosphomolybdenum and reducing power (ferric reducing antioxidant power and cupric ion reducing activity), were used to evaluate the antioxidant properties. Moreover, enzyme inhibitory activities were analyzed against acetylcholinesterase, butrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase.

RESULTS

These components have antioxidant and enzyme inhibition activity. Especially, purpurin showed the strongest antioxidant and good enzyme inhibitory effects. According to our cytotoxicity results, alizarin, purpurin, and quinizarin induced dose- and time-dependent cell proliferation. Furthermore, when we applied AQs with mitomycin C (MC) on L929 cell line, we demonstrated that cell proliferation in MC-AQ groups compared with MC group was increased. The most effective component was alizarin at 100 µM concentration. These AQs showed positive effects on L929 cell lines with high half-maximal inhibitory concentration values.

CONCLUSION

Our results demonstrate that AQs may be used as antioxidative compounds in food and medicinal applications.

Antidiabetic activity of the ethyl acetate fraction of Ficus lutea (Moraceae) leaf extract: comparison of an in vitro assay with an in vivo obese mouse model

Background

Ficus lutea crude acetone leaf extracts were previously shown to stimulate glucose uptake and insulin secretion of established cells and, inhibit α-amylase and α-glucosidase activities.

Methods

For this study, F. lutea acetone extracts were subjected to solvent-solvent fractionation to yield fractions with differing polarities (hexane, chloroform, dichloromethane, ethyl acetate, n-butanol and water) in an attempt to obtain a more potent fraction with in vitro and probably in vivo activity.

Results

Among these fractions, the ethyl acetate fraction had the highest total polyphenol content (100.5 ± 1.6 mg GAE/g dried extract) and α-glucosidase inhibitory activity (126.8 ± 30.6 μg/ml). It also stimulated the highest glucose uptake of C2C12 muscle cells and decreased extracellular glucose concentration of H-4-II-E liver cells with low cytotoxic activity. The ethyl acetate fraction (10.88 ± 0.55 μg/L at 250 μg/ml) enhanced insulin secretion in RIN-m5F pancreatic β-cells to the same degree as the positive control glibenclamide (11.09 ± 0.07 μg/L at 1μM). While fractionation increased α-glucosidase inhibition and glucose uptake of cells, in the ethyl acetate fraction, the α-amylase inhibition and insulin secretion decreased. The weight reducing and glucose control potential of the ethyl acetate fraction in an obese mouse model, important factors in the amelioration of type II diabetes was determined. The extract had no statistical significant weight reducing activity.

Conclusion

A major finding was the decrease in the area under the curve of the glucose concentration over time in animals that were treated with both a change in diet and with the plant extract. This is linked to increased glucose uptake within the cells, the most likely mechanism is either an increased insulin response or increased insulin secretion.

α-glucosidase and glycation inhibitory effects of costus speciosus leaves

BACKGROUND

Hyperglycaemia is a salient feature of poorly controlled diabetes mellitus. Rate of protein glycation is increased with hyperglycaemia leading to long term complications of diabetes. One approach of controlling blood glucose in diabetes targets at reducing the postprandial spikes of blood glucose. The objectives of this study were to assess the in vitro inhibitory effects of Costus speciosus (COS) leaves on α-amylase and α-glucosidase activities, fructosamine formation, protein glycation and glycation-induced protein cross-linking.

METHODS

Methanol extracts of COS leaves were used. Inhibitory effects on enzyme activities were measured using porcine pancreatic α-amylase and α-glucosidase from Saccharomyces cerevisiae in the presence of COS extract. Percentage inhibition of the enzymes and the IC50 values were determined. In vitro protein glycation inhibitory effect of COS leaves on early and late glycation products were measured using bovine serum albumin or chicken egg lysozyme with fructose. Nitroblue tetrazolium was used to assess the relative concentration of fructosamine and polyacrylamide gel electrophoresis was used to assess the degree of glycation and protein cross-linking in the reaction mixtures.

RESULTS

α-Glucosidase inhibitory activity was detected in COS leaves with a IC50 of 67.5 μg/ml which was significantly lower than the IC50 value of Acarbose (p < 0.01). Amylase inhibitory effects occurred at a comparatively higher concentration of extract with a IC50 of 5.88 mg/ml which was significantly higher than the IC50 value of Acarbose (p < 0.01). COS (250 μg/ml) demonstrated inhibitory effects on fructosamine formation and glycation induced protein cross-linking which were in par with 1 mg/ml aminoguanidine were detected.

CONCLUSION

Methanol extracts of COS leaves demonstrated in vitro inhibitory activities on α-glucosidase, fructosamine formation, glycation and glycation induced protein cross-linking. These findings provide scientific evidence to support the use of COS leaves for hypoglycemic effects with an added advantage in slowing down protein glycation.

Herbal therapy: A review of emerging pharmacological tools in the management of diabetes mellitus in Africa

BACKGROUND

Diabetes mellitus is a chronic physiological glucose metabolic disorder. It has affected millions of people all over the world thereby having a significant impact on quality of life. The management of diabetes includes both nonpharmacological and conventional interventions. Drawbacks in conventional therapy have led to seeking alternative therapy in herbal medicine. Therefore, the need to review, elucidate and classify their mode of action in therapy for diabetes disease arises.

MATERIALS AND METHODS

Comprehensive literature reports were used to review all conventional agents and herbal therapy used in the management of diabetes. An online database search was conducted for medicinal plants of African origin that have been investigated for their antidiabetic therapeutic potentials.

RESULTS

The results showed that of the documented sixty five plants used, fourteen inhibit intestinal absorption of glucose, three exhibit insulin-mimetic properties, seventeen stimulate insulin secretion from pancreatic beta cells, twelve enhance peripheral glucose uptake, one promotes regeneration of beta-cell of islets of Langerhans, thirteen ameliorate oxidative stress and twenty induces hypoglycemic effect (mode of action is still obscure). Thirteen of these plants have a duplicate mode of actions while one of them has three modes of actions. These agents have a similar mechanism of action as the conventional drugs.

CONCLUSION

In conclusion, antidiabetic activities of these plants are well established; however, the molecular modulation remains unknown. It is envisaged that the use of herbal therapy will promote good health and improve the status of diabetic patients.

Antidiabetic, antioxidant, and TNF-α lowering properties of extract of the traditionally used plant Ixeris gracilis in alloxan-induced diabetic mice

CONTEXT

Ixeris gracilis DC. Stebbins (Asteraceae) is a plant considered to be medicinal by local communities of Meghalaya, India.

OBJECTIVE

To evaluate the antidiabetic potential, antioxidant activity, and effect of the 80% methanolic extract of the leaves of Ixeris gracilis on tumor necrosis factor-α (TNF-α) expression.

MATERIALS AND METHODS

Varying doses (250-1000 mg/kg body weight) were administered intraperitoneally to normoglycemic mice and their hypoglycemic properties noted for 24 h; the optimum dose observed was used to evaluate its antihyperglycemic activity and effect on glucose tolerance. In vitro antioxidant activity was analyzed by assessing the DPPH radicals scavenging ability of the extract and the total polyphenols, flavonoid, carbohydrate, and protein contents were determined. Diabetic mice were then subjected to daily intraperitoneal injections of the extract for 12 days after which the antioxidant enzyme activities in the tissues were assayed and serum TNF-α was evaluated by ELISA.

RESULTS

The extract displayed varying hypoglycemic activity. The dose of 250 mg/kg body weight exhibited potent antihyperglycemic activity and improved glucose tolerance. The extract was able to scavenge free radicals (IC50 57.544 µg/ml) and contained polyphenol (76.269 ± 0.204 mg GAE/g dry wt), flavonoid (70.070 ± 0.626 mg rutin equivalent/g dry wt), protein (4.368 ± 8.916 mg/g dry wt), and carbohydrate (558.189 ± 0.002 mg/g dry wt). TNF-α level and overall activity of glutathione peroxidase and superoxide dismutase in the liver, kidney, and brain of extract-treated diabetic mice were improved.

CONCLUSION

The study supports the inclusion of Ixeris gracilis in the list of plants with antidiabetic potential.

Antioxidant, α-glucosidase inhibitory activity and sub-chronic toxicity of Derris reticulata extract: its antidiabetic potential

Background

Antidiabetic activity of Derris reticulata extract on alloxan-induced diabetic rats has been reported. The extract was found to lower blood glucose and inhibit intestinal glucose absorption. The aim of this study was to further investigate mechanisms underlying the antihyperglycemic activity of D. reticulata extract in vitro.

Methods

The aqueous extract was obtained from D. reticulata stem. Phytochemical screening, total phenolic, and flavanoid contents were examined. ABTS and DPPH scavenging assays, and FRAP method were used to determine in vitro antioxidant activities. Measurement of cell viability on alloxan-induced cellular damage was performed in the insulin-secreting RINm5F cells by MTT assay. The effects of the extract on α-glucosidase activity and insulin release were studied. In addition, sub-chronic toxicity test in rats was also conducted.

Results

The results revealed that the extract, which consisted of terpenoids, saponins, tannins and flavonoids, possessed moderate radical scavenging activities. Pre-treatment of RINm5F cells with the extract was also found to exert moderate, but significant, in vitro protection against alloxan, an oxidative stress producing agent. Unlike glibenclamide, the extract did not stimulate insulin secretion. However, the extract was found to inhibit α-glucosidase activity similar to acarbose. It was found that in sub-chronic toxicity studies D. reticulata extract did not cause mortality or produce any remarkable haematological, biochemical and histopathological adverse effects in rats.

Conclusions

The data suggest that the possible mechanisms underlying antihyperglycemic activity of D. reticulata extract are cytoprotective effect on pancreatic cells, presumably by its antioxidant activity, and inhibition of α-glucosidase. Sub-chronic toxicity study also provides scientific evidence to corroborate the safety of this plant as an alternative antidiabetic agent.

Evaluation of the inhibition of carbohydrate hydrolyzing enzymes, the antioxidant activity, and the polyphenolic content of Citrus limetta peel extract

Type 2 diabetes mellitus is one of the most frequent causes of death in Mexico, characterized by chronic hyperglycemia. One alternative strategy for this metabolic abnormality is inhibiting the enzymes responsible for the metabolism of carbohydrates. We evaluated whether the aqueous Citrus limetta peel extract could inhibit the metabolism of carbohydrates. We found that this extract inhibited primarily the enzyme α-amylase by 49.6% at a concentration of 20 mg/mL and to a lesser extent the enzyme α-glucosidase with an inhibition of 28.2% at the same concentration. This inhibition is likely due to the high polyphenol content in the Citrus limetta peel (19.1 mg GAE/g). Antioxidant activity of the Citrus limetta peel demonstrated dose-dependent antioxidant activity, varying from 6.5% at 1.125 mg/mL to 42.5% at 20 mg/mL. The study of these polyphenolic compounds having both antihyperglycemic and antioxidant activities may provide a new approach to the management of type 2 diabetes mellitus.

The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system.

MATERIALS AND METHODS

Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. 'Diabetes' and 'Nigeria' were used as keywords for the primary searches; and then 'Plant name - accepted or synonyms', 'Constituents', 'Drug interaction' and/or 'Toxicity' for the secondary searches.

RESULTS

The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs.

CONCLUSION

This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb-drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided.

The potential role of GLUT4 transporters and insulin receptors in the hypoglycaemic activity of Ficus lutea acetone leaf extract

Background

Some Ficus species have been used in traditional African medicine in the treatment of diabetes. The antidiabetic potential of certain species has been confirmed in vivo but the mechanism of activity remains uncertain.

The aim was to investigate the hypoglycaemic potential of ten Ficus species focussing on glucose uptake, insulin secretion and the possible mechanism of hypoglycaemic activity.

Methods

The dried and ground leaves of ten Ficus species were extracted with acetone. The dried acetone extract was reconstituted with DMSO to a concentration of 100 mg/ml which was then serially diluted and used to assay for glucose uptake in muscle, fat and liver cells, and insulin secretion in pancreatic cells.

Results

Only the F. lutea extract was able to modulate glucose metabolism. In comparison to insulin in the primary muscle cells, the glucose uptake ability of the extract was 33% as effective. In the hepatoma cell line, the extract was as effective as metformin in decreasing extracellular glucose concentration by approximately 20%. In the pancreatic insulin secretory assay, the extract was 4 times greater in its secretory activity than commercial glibenclamide. With F. lutea extract significantly increasing glucose uptake in the primary muscle cells, primary fat cells, C2C12 muscle and H-4-II-E liver cells, the extract may act by increasing the activity of cell surface glucose transporters. When the 3T3-L1 pre-adipocytes were compared to the primary muscle, primary fat and C2C12 cells, the differences in the former’s ability to transport glucose into the cell may be due to the absence of the GLUT4 transporter, which on activation via the insulin receptor decreases extracellular glucose concentrations. Because the pre-adipocytes failed to show any active increase in glucose uptake, the present effect has to be linked to the absence of the GLUT4 transporter.

Conclusion

Only F. lutea possessed substantial in vitro activity related to glucose metabolism. Based on the effect produced in the various cell types, F. lutea also appears to be a partial agonist/antagonist of the insulin cell membrane receptor. While the clinical effectiveness of F. lutea is not known, this plant species does possess the ability to modify glucose metabolism.

Graphite catalyzed solvent free synthesis of dihydropyrimidin-2(1H)-ones/thiones and their antidiabetic activity

A solvent free three component condensation reaction between an aldehyde, ethyl acetoacetate and urea catalyzed by graphite, a green catalyst is described for the synthesis of dihydropyrimidin-2(1H)-ones. This protocol is scalable and the catalyst is reusable. This method is also applied for the synthesis of dihydropyrimidin-2(1H)-thiones. α-Amylase, a key enzyme in carbohydrate metabolism is generally targeted for management of type 2 diabetes. The therapeutic potential of the dihydropyrimidinones and dihydropyrimidinthiones to inhibit α-amylase activity was evaluated by in vitro assay. Of the synthesized compounds 3,4-dihydropyrimidin-2(1H)-thione (1k) demonstrated highest inhibition of α-amylase activity.