Rahman M. Hafizur

Modulation of pancreatic β-cells in neonatally streptozotocin-induced type 2 diabetic rats by the ethanolic extract of Momordica charantia fruit pulp

Effective doses of the Momordica charantia fruit pulp (MCF) ethanolic extract on pancreatic β-cells modulation in neonatally streptozotocin-induced type 2 diabetic rats were studied. Diabetic rats (n = 8) were treated with MCF extract (400 mg kg−1 day−1) or glibenclamide (5 mg kg−1) for 28 days. Control rats (n = 11) and untreated diabetic rats (n = 8) received only water. Fasting glucose, serum insulin (by ELISA) and β-cell function (HOMA %B by homeostasis model assessment) were measured. β- and α-cells were identified by immunostaining, nuclei by DAPI, and β-cell size and number by morphometry. Significant improvement of fasting blood glucose, serum insulin and β-cell function was observed with the MCF extract for the diabetic rat model. The islet size, total β-cell area and number of β-cells were increased to almost double in the diabetic rats treated with MCF extract as compared to the untreated diabetic rats. The number of α-cells did not change significantly. Insulin granules in β-cells were notably reduced in diabetic islets as compared to control islets. However, extract-treated diabetic rat β-cells were abundant with insulin granules, which was comparable to non-diabetic control islets. The modulation of pancreatic β-cells may be involved in the experimental observation of anti-diabetic effects of M. charantia extract.

Antiglycation, antioxidant and toxicological potential of polyphenol extracts of alligator pepper, ginger and nutmeg from Nigeria

OBJECTIVE To evaluate the antioxidant and antiglycation potential of polyphenols from three spices; alligator pepper, ginger and nutmeg. METHODS Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay, phytotoxicity test, DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation assay. RESULTS Results obtained showed that polyphenol extract of ginger has the highest antioxidant potential with IC50 0.075 and 0.070 mg/mL for DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC50 0.125 mg/mL. However, nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD50 4359.70 and 1490 µg/mL respectively. CONCLUSIONS It can be concluded that the polyphenol extracts of alligator pepper, ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are safe for consumption.

Iridoid Glycoside from the Leaves of Clerodendrum volubile Beauv. Shows Potent Antioxidant Activity Against Oxidative Stress in Rat Brain and Hepatic Tissues

ABSTRACT Aim: This study aims at reporting the isolation, structure elucidation, and antioxidant potentials of ajugoside from C. volubile leaves in sodium nitroprusside (SNP)-induced oxidative stressed rat brain and hepatic tissues. Materials and Method: An iridoid monoterpene, ajugoside was isolated from the n-butanol fraction of C. volubile and evaluated for its antioxidant protective potential on brain and liver tissues of male Wister rats in an ex vivo model. Two molar concentrations (6.4 × 10−4 M and 1.28 × 10−3 M) of the metabolite and SNP were incubated with the tissues homogenate at 37°C for 2 hr prior to the test and assayed for catalase, superoxide dismutase (SOD) activities, and lipid peroxidation. α tocopherol (6.4 × 10−4 M) was used as standard. Results: Both molar concentrations exhibited high catalase activity in the tissues. However, 6.4 × 10−4 M ajugoside exhibited a very high SOD activity (liver: 96.45 and brain: 96.30%) and inhibition of lipid peroxidation (liver: 88.11 and brain: 93.27%) compared to the standard. 1.28 × 10−3 M ajugoside also exhibited good activities but lower than that of the standard and 6.4 × 10−4 M ajugoside. Discussion and Conclusion: Ajugoside showed potent antioxidant activities as evidenced by the synergistic high activities of SOD and catalase as well as inhibition of lipid peroxidation in the studied tissues.

Two new compounds from the aerial parts of Bergenia himalaica Boriss and their anti-hyperglycemic effect in streptozotocin-nicotinamide induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE Bergenia himalaica Boriss is mainly distributed in the temperate Himalayas between altitudes of 900 and 3000m ranging from the southeastern regions in central Asia and northern regions in South Asia. The plant has a long history of its use in traditional medicine for the treatment of various diseases such as diabetes, urinary complaints, kidney stones, hemorrhagic diseases and epilepsy. The aim of this study is to isolate pure compounds from Bergenia himalaica Boriss, elucidate their structures and determine their blood glucose lowering activity to obtain additional scientific evidence for its usage in traditional medicine for the management of diabetes. MATERIALS AND METHODS The crude methanolic extract from the aerial parts of Bergenia himalaica Boriss was separated into EtOAc and water sub-extracts and the EtOAc sub-extract was further divided into petroleum ether soluble and insoluble fractions. The pet-ether insoluble fraction was subjected to fractionation through column chromatography followed by prep. TLC. The blood glucose lowering activity of the 2 new compounds was evaluated in streptozotocin-nicotinamide induced diabetic rats. Additionally, glucose-stimulated insulin secretion was measured on isolated mice islets. RESULTS Two new compounds bergenicin and bergelin were isolated and their structures determined on the basis of spectral analysis. Significant decrease of blood glucose was observed at 1-h (1.0mg/kg) and 2-h (0.5mg/kg), after bergenicin administration to the diabetic rats and at 2-h (1.0mg/kg) and 3-h (0.5mg/kg), after bergelin administration. Bergenicin, but not bergelin, enhanced glucose-stimulated insulin secretion in isolated pancreatic islets. CONCLUSIONS In the present studies two new compounds, bergenicin and bergelin were isolated from Bergenia himalaica Boriss and their structures were elucidated. Both the compounds showed anti-hyperglycemic effects in streptozotocin-nicotinamide induced diabetic rats. Bergenicin showed insulinotropic effect; suggesting that the anti-hyperglycemic effect is mostly due to enhancement of insulin secretion from pancreatic β-cells.

Dietary Fatty Acids from Leaves of Clerodendrum Volubile Induce Cell Cycle Arrest, Downregulate Matrix Metalloproteinase-9 Expression, and Modulate Redox Status in Human Breast Cancer

ABSTRACT The antiproliferative effect of the fatty acid components of Clerodendrum volubile leaves as well as its antioxidant effect on MCF-7 and MDA-MB-231 human breast cancer cell lines were investigated. Fatty acids extracted from C. volubile leaf oil were subjected to gas chromatography mass spectrometry (GCMS) analysis. The cells were cultured and treated with the fatty acids for 48 h, after which the antiproliferation effect was ascertained via MTT assay and cell viability analysis using BD fluorescence activated cells sorting (FACS) Calibur. Cell cycle was analyzed by flow cytometry on FACS Calibur. Western blotting was used in determining expression of proteins in the cell lines. The treated cell lines were assessed for reduced glutathione level, catalase, superoxide dismutase, and lipid peroxidation. The fatty acids significantly inhibited cell proliferation, arrested G0/G1 phase, downregulated the expression of MMP-9, and attenuated oxidative stress in of MCF-7 cell lines but had little or no effect on MDA-MB-231 cell lines. These results indicate the therapeutic potential of the fatty acids components of the leaves of C. volubile on human breast cancer, which may be explored further in drug development.

The antidiabetic effect of Geigeria alata is mediated by enhanced insulin secretion, modulation of β-cell function and improvement of antioxidant activity in streptozotocin-induced diabetic rats

In Sudanese folk medicine, Geigeria alata roots have been used for the management of diabetes for a long time. However, its antidiabetic activity is unreported. In this study, G. alata methanolic extract was tested for its antidiabetic, antioxidant, and β-cell modulatory effects in a streptozotocin-induced diabetic rat model. In this model of diabetic rats, the oral glucose tolerance test with G. alata extract at 125, 250, and 500  mg/kg doses revealed the efficacy of the 250  mg/kg dose in improving glucose tolerance comparable to the standard drug glibenclamide. Diabetic rats were treated with a 250  mg/kg dose of G. alata extract orally for 2  h (acute) or 14 days (chronic). In the case of acute treatment, the extract lowered blood glucose levels significantly at 120  min both in nondiabetic and diabetic rats. Chronic treatment of diabetic rats with 250  mg/kg of G. alata extract resulted in a significant decrease in blood glucose level closer to that of nondiabetic rats. Interestingly, increased serum insulin, improved β-cell function, and antioxidant status were observed in G. alata-treated diabetic rats. G. alata also showed strong antioxidant and α-glucosidase inhibitory activities in in vitro assays. These data show direct evidence that G. alata has antidiabetic activity and suggest that the antidiabetic activity is due to enhanced insulin secretion, modulation of β-cell function, and improvement of antioxidant status.

Anti-diabetic effect of the ethyl acetate fraction of Clerodendrum volubile: protocatechuic acid suppresses phagocytic oxidative burst and modulates inflammatory cytokines

The antidiabetic effects of the ethyl acetate (EtOAc) fraction of Clerodendrum volubile leaves was investigated in this study. EtOAc extract was also fractionated to isolate the active compounds. The structure of the isolated compound (Protocatechuic acid) was established using 1H and 13C NMR spectroscopies and mass spectrometry. Protocatechuic acid was investigated for its anti-oxidative burst in polymorphonuclear neutrophils (PMNs) and macrophages. It was also docked with α-glucosidase and TNF-α. Acute treatment with EtOAc fraction of Clerodendrum volubile leaves significantly (p<0.05) decreased blood glucose level and hepatic biomarkers, and significantly (p<0.05) increased serum insulin level and β-cell function. It had little or no effect on serum lipid profile and atherogenic indices. Protocatechuic acid significantly (p<0.05) suppressed phagocytic oxidative burst and docked well with α-glucosidase and TNF-α. These results indicate the therapeutic effect of EtOAc fraction of C. volubile on type 2 diabetes and its complications, which can be attributed to the main bioactive compound, protocatechuic acid.

Potent Insulin Secretagogue from Scoparia dulcis Linn of Nepalese Origin

Ethno‐botanical inspired isolation from plant Scoparia dulcis Linn. (Sweet Broomweed) yielded six compounds, coixol (1), glutinol (2), glutinone (3), friedelin (4), betulinic acid (5), and tetratriacontan‐1‐ol (6). There structures were identified using mass and 1D‐ and 2D‐NMR spectroscopy techniques. Compounds 1–6 were evaluated for their insulin secretory activity on isolated mice islets and MIN‐6 pancreatic β‐cell line, and compounds 1 and 2 were found to be potent and mildly active, respectively. Compound 1 was further evaluated for insulin secretory activity on MIN‐6 cells. Compound 1 was subjected to in vitro cytotoxicity assay against MIN‐6, 3T3 cell lines, and islet cells, and in vivo acute toxicity test in mice that was found to be non‐toxic. The insulin secretory activity of compounds 1 and 2 supported the ethno‐botanic uses of S. dulcis as an anti‐diabetic agent. Copyright

Insulin releasing effect of some pure compounds from Moringa oleifera on mice islets

The anti-diabetic activity of extracts, fractions and compounds of Moringa oleifera have been reported; however, several constituents from this well known medicinal plant are not yet screened for bio-perspecting role for diabetes. Current studies demonstrated the anti-diabetic properties of five chemical constituents of the plant viz, 4-hydroxyphenylacetonitrite (1), fluoropyrazine (3), methyl-4-hydroxybenzoate (4), vanillin (5), and 4-α-L-rhamnopyranosyloxybenzyl isothiocyanate (6) along with one related compound 3,4-dihydroxy benzonitrile (2) for the first time in vitro and in vivo. Furthermore, the mechanism of action of compounds was predicted by utilizing molecular docking with protein kinase A (PKA) and exchange protein activated by cAMP (Epac2A). The structure of compounds was elucidated by UV, IR, MS, and 1H NMR. The compounds 1, 3–5 induced significant insulin secretion at stimulatory (16.7 mM) glucose, but not at basal (3 mM) glucose concentration, and compound 3 seems to be the most active. Compounds 1, 3–5 showed dose-dependent insulin secretory activity with optimum response at 200 μM. In silico studies revealed that compound 3 has a noticeable electrostatic and hydrophobic interaction with protein kinase A (PKA). In vitro studies also showed that there was significant reduction of compounds 1–3 mediated insulin secretion in the presence of PKA inhibitor suggesting that there is a possible role of PKA signaling pathway on insulin secretion. Upon oral administration of 1, 3–5 to diabetic rats, compounds 1 and 3 significantly reduced blood glucose level in diabetic rats in a dose- and time-dependent manner. The oral glucose tolerance test in diabetic rats showed that compound 3 significantly enhanced plasma insulin and improved beta-cell function. In cytotoxicity assay, compounds 1, 3–5 did not show any toxic effect upto 200 μM. The insulin releasing characteristic of different constituents from M. oleifera conceivably correlate the lowering of blood glucose in in vivo diabetic rats by triggering glucose-induced insulin secretion from pancreatic islets possibly by PKA-mediated insulin secretory pathway.

Suppressive Effects of Clerodendrum volubile P Beauv. [Labiatae] Methanolic Extract and Its Fractions on Type 2 Diabetes and Its Complications

Type 2 diabetes is the most prominent of all diabetes types, contributing to global morbidity and mortality. Availability and cost of treatment with little or no side effect especially in developing countries, remains a huge burden. This has led to the search of affordable alternative therapies especially from medicinal plants. In this study, the antidiabetic effect of the methanolic extract, dichloromethane (DCM), butanol (BuOH) and aqueous fractions of Clerodendrum volubile leaves were investigated in type 2 diabetic rats for their effect on glucose homeostasis, serum insulin level and hepatic biomarkers, lipid profile, pancreatic redox balance and Ca2+ levels, and β-cell distribution and function. The DCM was further fractionated to isolate the active compounds, biochanin and 5,7,4′-trimethoxykaempferol. They were investigated for their toxicity and ADMET properties, α-glucosidase and angiotensin I converting enzyme (ACE) inhibitory activities in silico. There were significant (p < 0.05) decrease in blood glucose, cholesterol, LDL-C, vLDL-C, triglyceride, AST and ALT levels in all treated groups, with DCM fraction showing the best activity. All treated rats showed significantly (p < 0.05) improved anti-oxidative activities. Treatment with the DCM fraction led to significant (p < 0.05) increased serum insulin and pancreatic Ca2+ levels, as well as improved β-cell distribution and function. DCM fraction also showed improved glucose tolerance. DCM fraction dose-dependently inhibited ACE activity. The toxicity class of the isolated compounds was predicted to be 5. They were also predicted to be potent inhibitors of cytochrome P (CYPs) 1A2, 2D6 and 3A4. They docked well with α-glucosidase and ACE. These results indicate the therapeutic potential of the plant against type 2 diabetes, with the DCM fraction being the most potent which may be attributed to the isolated flavones. It further suggests antihypertensive potentials of the DCM fraction. However, inhibition of CYPs by the flavones may suggest caution in usage with other prescribed drugs metabolized by these enzymes.