Antidiabetic effect of d-limonene, a monoterpene in streptozotocin-induced diabetic rats

Hesperidin, a citrus flavonoid ameliorates hyperglycemia by regulating key enzymes of carbohydrate metabolism in streptozotocin-induced diabetic rats

The present study investigated the protective effect of hesperidin on carbohydrate metabolizing enzymes in streptozotocin-induced diabetic rats. Hesperidin was administered to streptozotocin-induced (40 mg/kg b.w.) diabetic rats at different dosages of (25, 50, 100 mg/kg b.w.) respectively for 30 days to evaluate its effect on fasting plasma glucose, insulin, glycosylated hemoglobin, hemoglobin, and carbohydrate metabolic enzymes. The plasma glucose levels were significantly reduced in a dose-dependent manner in hesperdin-treated group of rats when compared to the diabetic control rats. In addition, concomitant increase in hemoglobin and insulin levels and a decrease in glycosylated hemoglobin were observed in treated group of rats. The activities of the hepatic key enzymes of carbohydrate metabolism such as hexokinase and glucose-6-phosphate dehydrogenase were significantly increased, whereas glucose-6-phosphatase and fructose-1,6-bisphosphatase were significantly decreased. Furthermore, hesperidin administration prevented the loss in body weight and improved the glycogen content in the hepatic tissue of diabetic animals by reinstating the activities of glycogen synthase and glycogen phosphorylase. These results showed that hesperidin has potential antihyperglycemic activity in streptozotocin-induced diabetic rats. This was further supported by the histological studies of pancreas and liver.

Zingerone (4-(4-hydroxy-3-methylphenyl)butan-2-one) ameliorates renal function via controlling oxidative burst and inflammation in experimental diabetic nephropathy

Development of diabetic nephropathy (DN) is directly linked to oxidative stress and inflammation. In this context, inflammatory and oxidative markers have gained much attention as targets for therapeutic intervention. We studied the effect of zingerone in a streptozotocin/high fat diet (STZ/HFD)-induced type 2 diabetic Wistar rat model. Zingerone also known as vanillyl acetone is a pharmacologically active compound present usually in dry ginger. STZ/HFD caused excessive increase in ROS and inflammation in experimental animals. The treatment with zingerone markedly abrogated ROS levels, inhibited the NF-кB activation and considerably reduced level of other downstream inflammatory molecules (TNF-α, IL-6, IL-1β), furthermore, zingerone treatment improved renal functioning by significantly decreasing the levels of kidney toxicity markers KIM-1, BUN, creatinine, and LDH and suppressed TGF-β. Collectively, these findings indicate that zingerone treatment improved renal function by anti-hyperglycaemic, anti-oxidant, and anti-inflammatory effects, suggesting the efficacy of zingerone in the treatment of DN.

First ethnobotanical inventory and phytochemical analysis of plant species used by indigenous people living in the Maromizaha forest, Madagascar

ETHNOPHARMACOLOGICAL RELEVANCE

Characterized by one of the highest rates of endemism and biodiversity in the world, Madagascar provides a wide variety of medicinal plants, that could represent a potential source of new drugs. The main aim of this study was to investigate the potential medicinal properties of the plant species used by indigenous people in Maromizaha forest and to provide the first ethnobotanical inventory of the area.

MATERIALS AND METHODS

Data were collected through open semi-structured interviews with local informants, the reported plants were collected and identified to create a specimen herbarium. Informant Consensus Factor (ICF) was calculated for each ailment category mentioned in the use-reports. A selection of seven medicinal plants was submitted to phytochemical and antimicrobial analysis. The results were discussed and compared with those described in ethnobotanical and pharmacological literature.

RESULTS

One hundred and three villagers were interviewed and a total of 509 use-reports were recorded. Information on 117 plant species belonging to 57 botanical families were provided. 12 categories of indigenous uses were recognized, among them the higher ICF values were recorded for cardiovascular complaints (0.75), general and unspecific diseases (0.74), digestive disorders (0.69), and diseases of the skin (0.55). The traditional medicinal uses of 18 species (15 endemic) were described for the first time. In total, 22 different bioactive compounds were identified; polyphenols, monoterpenes, organic acids, and vitamin C were observed in the chemical composition of all the analyzed samples. Macaranga perrieri showed the highest values of both total polyphenolic compounds and antioxidant activity. Antimicrobial activity was observed in leaf and bark extracts of Dilobeia thouarsii.

CONCLUSION

These results confirmed the importance of investigating the traditional use of plant species, suggesting the crucial role of ethnobotanical studies for rural development, biodiversity conservation, and the sustainable use of plant resources in the studied area.

Effects of phytochemicals against diabetes

Diabetes mellitus, a chronic metabolic disease, characterized by elevated levels of blood glucose and insufficiency in production and action of insulin is the seventh leading cause of death worldwide. Numerous studies have shown that diabetes mellitus is associated with increased formation of free radicals and decrease in antioxidant potential. In the patients with diabetes mellitus, the levels of antioxidant parameters are found to decrease, hence in many studies phytochemicals which can exert antioxidant and free radical scavenging activities, are suggested to improve the insulin sensitivity. Several phytoactive compounds such as flavonoids, lignans, prophenylphenols, are also found to combat the complications of diabetes. This chapter mainly focuses on the relationship between diabetes mellitus and preventive roles of various phytochemicals on diabetes via their antioxidant properties.

Feasibility and acceptability of a beverage intervention for Hispanic adults: results from a pilot randomized controlled trial

OBJECTIVE

To assess the feasibility and acceptability of a beverage intervention in Hispanic adults.

DESIGN

Eligible individuals identified as Hispanic, were 18-64 years old and had BMI 30·0-50·0 kg/m2. Participants were randomized 2:2:1 to one of three beverages: Mediterranean lemonade (ML), green tea (GT) or flavoured water control (FW). After a 2-week washout period, participants were asked to consume 32 oz (946 ml) of study beverage daily for 6 weeks and avoid other sources of tea, citrus, juice and sweetened beverages; water was permissible. Fasting blood samples were collected at baseline and 8 weeks to assess primary and secondary efficacy outcomes.

SETTING

Tucson, AZ, USA.ParticipantsFifty-two participants were recruited over 6 months; fifty were randomized (twenty-one ML, nineteen GT, ten FW). Study population mean (sd) age 44·6 (sd 10·2) years, BMI 35·9 (4·6) kg/m2; 78 % female.

RESULTS

Forty-four (88 %) completed the 8-week assessment. Self-reported adherence was high. No significant change (95 % CI) in total cholesterol (mg/dl) from baseline was shown -1·7 (-14·2, 10·9), -3·9 (-17·2, 9·4) and -13·2 (-30·2, 3·8) for ML, GT and FW, respectively. Mean change in HDL-cholesterol (mg/dl) -2·3 (-5·3, 0·7; ML), -1·0 (-4·2, 2·2; GT), -3·9 (-8·0, 0·2; FW) and LDL-cholesterol (mg/dl) 0·2 (-11·3, 11·8; ML), 0·5 (-11·4, 12·4; GT), -9·8 (-25·0, 5·4; FW) were also non-significant. Fasting glucose (mg/dl) increased significantly by 5·2 (2·6, 7·9; ML) and 3·3 (0·58, 6·4; GT). No significant change in HbA1c was demonstrated. Due to the small sample size, potential confounders and effect modifiers were not investigated.

CONCLUSIONS

Recruitment and retention figures indicate that a larger-scale trial is feasible; however, favourable changes in cardiometabolic biomarkers were not demonstrated.

Hydroxyl Group and Vasorelaxant Effects of Perillyl Alcohol, Carveol, Limonene on Aorta Smooth Muscle of Rats

The present study used isometric tension recording to investigate the vasorelaxant effect of limonene (LM), carveol (CV), and perillyl alcohol (POH) on contractility parameters of the rat aorta, focusing in particular on the structure-activity relationship. LM, CV, and POH showed a reversible inhibitory effect on the contraction induced by electromechanical and pharmacomechanical coupling. In the case of LM, but not CV and POH, this effect was influenced by preservation of the endothelium. POH and CV but not LM exhibited greater pharmacological potency on BayK-8644-induced contraction and on electromechanical coupling than on pharmacomechanical coupling. In endothelium-denuded preparations, the order of pharmacological potency on electrochemical coupling was LM < CV < POH. These compounds inhibited also, with grossly similar pharmacological potency, the contraction induced by phorbol ester dibutyrate. The present results suggest that LM, CV and POH induced relaxant effect on vascular smooth muscle by means of different mechanisms likely to include inhibition of PKC and IP3 pathway. For CV and POH, hydroxylated compounds, it was in electromechanical coupling that the greater pharmacological potency was observed, thus suggesting a relative specificity for a mechanism likely to be important in electromechanical coupling, for example, blockade of voltage-dependent calcium channel.

Five traditional Nigerian Polyherbal remedies protect against high fructose fed, Streptozotocin-induced type 2 diabetes in male Wistar rats

BACKGROUND

This present study sought to assess the modulatory effects of five Nigerian traditional polyherbal in high fructose-fed, streptozotocin-induced (HF-STZ) Type 2 diabetes (T2D) in rats. T2D was achieved via fructose feeding (20%^W/V) ad libitum for 2 weeks and streptozotocin (STZ, 40 mg/kg) (15th Day) intraperitoneally.

METHODS

Seventy-two hours after STZ injection, fourty-eight diabetic rats were divided into eight of 6 rats/group: Diabetic normal untreated, glibenclamide (GBLI, 0.07 mL/kg) or yoyo (YB, 0.43), ruzu (RB, 0.08), fajik (FJB, 0.20), oroki (OB, 0.16), and fidson (FB, 0.43)/ mL/kg bitters respectively. Controls normal and diabetic untreated groups received intragastric carboxylmethylcellulose (CMC, 1 mL/kg) for eleven days.

RESULTS

T2D was characterized in rats by an increased (p < 0.001-0.05) blood glucose levels (BGL), total cholesterol, triglycerides, low-density lipoprotein and alanine aminotransferase compared with control CMC group. Similarly, hepatic and pancreatic malondialdehyde (MDA) were increased by 180 and 97% respectively. Polyherbal treatments demonstrated efficacies on BGL as follow: YB (55.6%, 160.7 mg/dL); RB (59.7%, 145.2 mg/dL); FJB (59.8%, 243.4 mg/dL); OB (60.8%, 194.5 mg/dL) and FB (61.3%, 203.3 mg/dL) respectively by day 11 (versus GBLI, 65.1%) compared with control untreated diabetic rats. Also, elevated TC, LDL cholesterol, ALT were lowered (p < 0.05) by YB, FJB, and FB respectively in rats. YB, FJB, and OB lowered MDA levels in treated rats. Further, YB, RB, FJB and FB restored changes in liver, and pancreas histopathology. Predominant non-polar bioactive include oleic, hexadecanoic, octadecanoic among others following gas chromatography-mass spectrophotometry analyses.

CONCLUSION

Overall, these present results demonstrate anti-hyperglycemic potentials, although with cautions, of some polyherbal in T2D rats, which may, in part, be antioxidants mediated.

Antifibrotic effects of D-limonene (5(1-methyl-4-[1-methylethenyl]) cyclohexane) in CCl4 induced liver toxicity in Wistar rats

This study was designed to assess the potential antifibrotic effect of D-Limonene-a component of volatile oils extracted from citrus plants. D-limonene is reported to have numerous therapeutic properties. CCl₄ -intduced model of liver fibrosis in Wistar rats is most widely used model to study chemopreventive studies. CCl₄ -intoxication significantly increased serum aminotransferases and total cholesterol these effects were prevented by cotreatment with D-Limonene. Also, CCl₄ -intoxication caused depletion of glutathione and other antioxidant enzymes while D-Limonene preserved them within normal values. Hydroxyproline and malondialdehyde content was increased markedly by CCl₄ treatment while D-Limonene prevented these alterations. Levels of TNF-α, TGF-β, and α-SMA were also assessed; CCl₄ increased the expression of α-SMA, NF-κB and other downstream inflammatory cascade while D-Limonene co-treatment inhibited them. Collectively these findings indicate that D-Limonene possesses potent antifibrotic effect which may be attributed to its antioxidant and anti-inflammatory properties.

Antidiabetic Potential of Monoterpenes: A Case of Small Molecules Punching above Their Weight

Monoterpenes belong to the terpenoids class of natural products and are bio-synthesized through the mevalonic acid pathway. Their small molecular weight coupled with high non-polar nature make them the most abundant components of essential oils which are often considered to have some general antioxidant and antimicrobial effects at fairly high concentrations. These compounds are however reported to have antidiabetic effects in recent years. Thanks to the ingenious biosynthetic machinery of nature, they also display a fair degree of structural complexity/diversity for further consideration in structure-activity studies. In the present communication, the merit of monoterpenes as antidiabetic agents is scrutinized by assessing recent in vitro and in vivo studies reported in the scientific literature. Both the aglycones and glycosides of these compounds of rather small structural size appear to display antidiabetic along with antiobesity and lipid lowering effects. The diversity of these effects vis-à-vis their structures and mechanisms of actions are discussed. Some key pharmacological targets include the insulin signaling pathways and/or the associated PI3K-AKT (protein kinase B), peroxisome proliferator activated receptor-γ (PPARγ), glucose transporter-4 (GLUT4) and adenosine monophosphate-activated protein kinase (AMPK) pathways; proinflammatory cytokines and the NF-κB pathway; glycogenolysis and gluconeogenesis in the liver; glucagon-like-1 receptor (GLP-1R); among others.

Geraniol, a natural monoterpene, ameliorates hyperglycemia by attenuating the key enzymes of carbohydrate metabolism in streptozotocin-induced diabetic rats

CONTEXT

Geraniol, an acyclic monoterpene alcohol is found in medicinal plants, is used traditionally for several medical purposes including diabetes.

OBJECTIVES

The present study evaluates the antihyperglycemic potential of geraniol on key enzymes of carbohydrate metabolism in streptozotocin (STZ)-induced diabetic rats.

MATERIALS AND METHODS

Diabetes was induced in experimental rats, by a single intraperitoneal (i.p) injection of STZ [40 mg/kg body weight (b.w.)]. Different doses of geraniol (100, 200 and 400 mg/kg b.w.) and glyclazide (5 mg/kg b.w.) were administrated orally to diabetic rats for 45 days. Body weight, food intake, plasma glucose, insulin, blood haemoglobin (Hb), glycosylated haemoglobin (HbA_1c), hepatic glucose metabolic enzymes and glycogen were examined.

RESULTS

The LD₅₀ value of geraniol is 3600 mg/kg b.w. at oral administration in rats. Administration of geraniol in a dose-dependent manner (100, 200, 400 mg/kg b.w.) and glyclazide (5 mg/kg b.w.) for 45 days significantly improved the levels of insulin, Hb and decreased plasma glucose, HbA_1C in diabetic-treated rats. Geraniol at its effective dose (200 mg/kg b.w.) ameliorated the altered activities of carbohydrate metabolic enzymes near normal effects compared with two other doses (100 and 400 mg/kg b.w.). Geraniol treatment to diabetic rats improved hepatic glycogen content suggesting its anti-hyperglycemic potential. Geraniol supplement was found to preserve the normal histological appearance of hepatic cells and pancreatic β-cells in diabetic rats.

DISCUSSION AND CONCLUSIONS

The present findings suggest that geraniol can potentially ameliorate key enzymes of glucose metabolism in experimental diabetes even though clinical studies used to evaluate this possibility are warranted.

d-limonene ameliorates diabetes and its complications in streptozotocin-induced diabetic rats

It is known that diabetes causes some complications including alterations in lipid profile, hepatic enzyme levels but also it causes oxidative stress. Limonene, a major component of Citrus oils, has important health beneficial effects in lowering the level of oxidative stress due to its antioxidant activity. The aim of this study was to investigate the effects of D-limonene on streptozotocin (STZ)-induced diabetes in Wistar albino rats. For this purpose, DNA damage was evaluated by alkaline comet assay. Changes in the activities of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GSHPx) and the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), total glutathione (GSH), malondialdehyde (MDA), insulin, total bilirubin and BCA protein, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT), high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol and triglyceride were also evaluated. D-limonene treatment was found to significantly decrease DNA damage, GR enzyme activities and MDA levels and significantly increase GSH levels and CAT, SOD and GSH-Px enzyme activities and altered lipid and liver enzyme parameters in diabetic rats. According to our results, it seems that D-limonene might have a role in the prevention of the complication of diabetes in rats.

Physio-pharmacological Investigations About the Anti-inflammatory and Antinociceptive Efficacy of (+)-Limonene Epoxide

D-limonene epoxidation generates (+)-limonene epoxide, an understudied compound in the pharmacologically point of view. Herein, we investigated the anti-inflammatory and antinociceptive potentialities of (+)-limonene epoxide and suggested a mechanism of action. The anti-inflammatory potential was analyzed using agents to induce paw edema, permeability, and myeloperoxidase (MPO) activity. Pro-inflammatory cytokines and cell migration of peritoneal cells were also assessed. Antinociceptive effects were evaluated by writhing test induced by acetic acid, formalin, and hot plate assays and contribution of opioid pathways. Pretreated animals with (+)-limonene epoxide showed reduced carrageenan-induced paw edema in all doses (25, 50, and 75 mg/kg) (P < 0.05). At 75 mg/kg, it suppressed edema provoked by compound 48/80, histamine, prostaglandin E₂, and serotonin and reduced permeability determined by Evans blue and MPO activity. It also reduced leukocytes, neutrophils, and IL-1β levels in the peritoneal cavity in comparison with carrageenan group (P < 0.05). (+)-Limonene epoxide diminished abdominal contortions induced by acetic acid (78.9%) and paw licking times in both 1 (41.8%) and 2 (51.5%) phases and a pretreatment with naloxone (3 mg/kg) reverted the antinociceptive action in morphine- and (+)-limonene epoxide-treated groups (P < 0.05). Additionally, it enlarged response times to the thermal stimulus after 60 and 90 min. In conclusion, (+)-limonene epoxide inhibited release/activity of inflammatory mediators, vascular permeability, migration of neutrophils and displayed systemic and peripheral analgesic-dependent effects of the opioid system.

Molecular Modeling and Physicochemical Properties of Supramolecular Complexes of Limonene with α- and β-Cyclodextrins

This study evaluated three different methods for the formation of an inclusion complex between alpha- and beta-cyclodextrin (α- and β-CD) and limonene (LIM) with the goal of improving the physicochemical properties of limonene. The study samples were prepared through physical mixing (PM), paste complexation (PC), and slurry complexation (SC) methods in the molar ratio of 1:1 (cyclodextrin:limonene). The complexes prepared were evaluated with thermogravimetry/derivate thermogravimetry, infrared spectroscopy, X-ray diffraction, complexation efficiency through gas chromatography/mass spectrometry analyses, molecular modeling, and nuclear magnetic resonance. The results showed that the physical mixing procedure did not produce complexation, but the paste and slurry methods produced inclusion complexes, which demonstrated interactions outside of the cavity of the CDs. However, the paste obtained with β-cyclodextrin did not demonstrate complexation in the gas chromatographic technique because, after extraction, most of the limonene was either surface-adsorbed by β-cyclodextrin or volatilized during the procedure. We conclude that paste complexation and slurry complexation are effective and economic methods to improve the physicochemical character of limonene and could have important applications in pharmacological activities in terms of an increase in solubility.

Ethnopharmacological appraisal of culturally important medicinal plants and polyherbal formulas used against communicable diseases in Rodrigues Island

ETHNOPHARMACOLOGICAL RELEVANCE

The tropical island of Rodrigues is one of three islands that constitute the Mascarene archipelago in the Indian Ocean. Currently considered as a biodiversity hotspot, the island has also a resilient history in the use of traditional medicine. However, there has been no ethnopharmacological study to document quantitatively such traditional practice against communicable diseases (CD), which currently accounts for 6.61% annual death and 30.7% attendances in public hospitals. The aim of the present study was to collect, analyse, and document traditionally used medicinal plants (MP) and polyherbal formulas from key informants and traditional medicine practitioners (TMP) in Rodrigues to treat and/or manage common CD.

MATERIALS AND METHODS

Data was collected via face-to-face interviews with MP users (n=113) and TMP (n=9) from 17 key sites. Seven quantitative ethnopharmacological indices, namely family use value (FUV), use value (UV), informant agreement ratio (IAR), relative frequency of citation (RFC), fidelity level (FL), relative importance (RI), and ethnobotanicity index (EI) were calculated.

RESULTS

Ninety-seven plants belonging to 49 families were recorded to be in common use as monotherapy (80 plants) and/or as part of polyherbal preparation (23 plants) for the treatment and/or management of 16 different CD. Thirteen MPs were found to have a maximum FL of 100% for CD. The highest IAR (0.98) was observed for diseases of the eye and adnexa and skin and subcutaneous tissue. The highest FUV was for Arecaceae. Ayapana triplinervis (Vahl) R.M. king et H.Rob. scored the highest UV (UV=2.72). Seven endemic medicinal plants have been recorded to be employed in cultural rituals for the management of common CDs, whereas 14 polyherbal preparations were used to treat and/or manage 6 different types of CDs. Side effects were also reported following use of some these medicinal plants.

CONCLUSION

Given the dearth of updated information on traditional medicine from Rodrigues, this work has provided an opportunity to establish valuable primary information on the different MP used by the local people. Further research is needed to probe into the possible active constituents that could open new perspectives for further pharmacological research and hence be the basis of an evidence-based investigation to discover new drugs.

Myrtenal alleviates hyperglycaemia, hyperlipidaemia and improves pancreatic insulin level in STZ-induced diabetic rats

CONTEXT

Myrtenal is monoterpene a constituent of essential oils found mainly in herbs such as mint, pepper, cumin, etc. It exerts admirable pharmacological activities against many diseases including diabetes. Hyperlipidaemia is a secondary complication of diabetes and also a major risk factor for cardiovascular diseases.

OBJECTIVE

The present study investigated the possible antihyperlipidaemic efficacy of myrtenal on plasma glucose, pancreatic insulin, plasma and tissue lipid levels in streptozotocin (STZ) induced diabetic rats.

MATERIALS AND METHODS

Diabetes was induced in male Wistar rats by a single intraperitoneal injection of STZ (40 mg/kg b.w.). Myrtenal (80 mg/kg) was administered orally to diabetic rats for a period of 28 d. Plasma glucose, pancreatic insulin, TC, TGs, FFAs, PLs, LDL-C, HDL-C, VLDL, atherogenic index, (HMG-CoA) reductase, LPL, LCAT and liver histology were analyzed.

RESULTS

Diabetic rats showed significantly (p < 0.05) increased plasma glucose (273.18 mg/dL), total cholesterol (142 mg/dL), triglycerides (126 mg/dL), free fatty acids (118 mg/dL), phospholipids (153 mg/dL), low-density lipoprotein (88.07 mg/dL), very low-density lipoprotein (25.2 mg/dL), atherogenic index, whereas a decrease in the levels of pancreatic insulin (97.48 ng/mg) and high-density lipoprotein (29.12 mg/dL). In addition, the activity of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase (0.94 HMG-CoA ratio/(mevalonate) increased significantly in contrast to the activities of lipoprotein lipase (4.87 μmoles of glycerol liberated/h/L) and lecithin cholesterol acyltransferase (54.61 μmoles of cholesterol esterified/h/L) in diabetic rats. Treatment with myrtenal significantly (p < 0.05) improved the levels of plasma glucose, pancreatic insulin and lipid profiles. Moreover, the histopathological analysis of liver was also in agreement with the biochemical findings.

DISCUSSION AND CONCLUSIONS

The present study indicates that myrtenal possess antihyperglycaemic and antihyperlipidemic properties, and could potentially be a useful phytochemical in treating diabetes.

Chemical Composition andα-Glucosidase Inhibitory Activity of VietnameseCitrusPeels Essential Oils

Background. Inhibition ofα-glucosidase is an important factor to control postprandial hyperglycemia in type 2 diabetes mellitus.Citrusessential oils (CEO) are among the most widely used essential oils, and some of them exhibited promising antidiabetic effect. However, theα-glucosidase inhibition of CEO has not been investigated so far. The present work aims to evaluate theα-glucosidase inhibition of essential oils from six VietnameseCitruspeels.Methods. The chemical composition of essential oils obtained by hydrodistillation from sixCitruspeels was analyzed by GC-MS. All essential oils were tested for their inhibitory activity onα-glucosidase usingp-nitrophenyl-α-D-glucopyranoside as substrate.Results. In Buddha’s hand and lime peels, the major components were limonene (59.0–61.31%) andγ-terpinene (13.98–23.84%) while limonene (90.95–95.74%) was most abundant in pomelo, orange, tangerine, and calamondin peels. Among the essential oils, the Buddha’s hand oil showed the most significantα-glucosidase inhibitory effect with the IC50value of 412.2 μg/mL. The combination of the Buddha’s hand essential oil and the antidiabetic drug acarbose increased the inhibitory effect.Conclusions. The results suggested the potential use of Buddha’s hand essential oil as an alternative in treatment of type 2 diabetes mellitus.

Ethnopharmacological analysis of medicinal plants used against non-communicable diseases in Rodrigues Island, Indian Ocean

ETHNOPHARMACOLOGICAL RELEVANCE

Rodrigues is an autonomous outer island that form part of the Republic of Mauritius and one of three islands that constitute the Mascarene archipelago in the Indian Ocean. Though herbal medicine is in common use in Rodrigues, there has been no ethnopharmacological study to document quantitatively such traditional practise particularly against non-communicable diseases (NCD) which is currently a growing major health issue on the island. The aim of the present study was to collect, analyse and document traditionally used medicinal plants (MP) from key informants and traditional medicine practitioners (TMP) in the tropical island of Rodrigues to treat and/or manage common NCD.

MATERIALS AND METHODS

Data was collected via face-to-face interviews with MP users (n=113) and TMP (n=9). Seven quantitative ethnopharmacological indices, namely family use value (FUV), use value (UV), informant agreement ratio (IAR), relative frequency of citation (RFC), fidelity level (FL), relative importance (RI) and ethnobotanicity index (EI) were calculated.

RESULTS

Hundred and three plants belonging to 55 families were recorded for the treatment and/or management of 27 different NCD. Three of the MP (Terminalia bentzoë (L.) L.F, Sarcostemma cf. adontolepis Balf.f. and Clerodendrum laciniatum Balf.f.) recorded are endemic to Rodrigues and 2 (Carissa xylopicron Thouars., Phyllanthus casticum Willemet f.) endemic to the Mascarene Islands. The most solicited MP family was Asteraceae with a total of 8 species. Citrus aurantifolia (Christm.) Swingle scored the highest RFC (RFC=1.02) value. Ten plants were found to score 100% FL and the highest IAR (0.98) was observed for the disease category of certain conditions originating in the perinatal period. Arecaceae scored the highest FUV value and Ayapana triplinervis (Vahl) R.M. King et H.Rob highest UV (UV= 2.72).

CONCLUSION

Given the dearth of updated information on traditional medicine of Rodrigues, this study can provide an opportunity to establish valuable primary information on the different MP used by the local people and hence can open new perspectives for further pharmacological research.

Self-nanoemulsifying drug delivery system of trans-cinnamic acid: formulation development and pharmacodynamic evaluation in alloxan-induced type 2 diabetic rat model

The objective of this study was to formulate a self-nanoemulsifying oral drug delivery system (SNEDDS) for the poorly water-soluble trans-Cinnamic acid (t-CA SNEDDS) that could be evaluated for its antihyperglycemic efficacy in comparison to the parent t-CA in an alloxan-induced diabetic rat model. A SNEDDS formulation consisting of 60% surfactant (Kolliphor EL), 10% co-surfactant (PEG 400) and 30% oil (isopropyl myristate) proved to be optimal. t-CA SNEDDS (80 mg/kg, p.o.), t-CA suspension (80 mg/kg, p.o.), and Metformin Hydrochloride Tablets (230 mg/kg, p.o.) were administer qdfor 30 days to diabetic rats. After treatment the body weight of diabetic rats was increased, blood glucose levels, total cholesterol, and triglyceride in the serum tended to be normalized, while the levels of alanine aminotransferase and aspartate aminotransferase were markedly decreased. The effects of t-CA SNEDDS were superior to that of the t-CA suspension. The present study demonstrated that t-CA was effective in attenuating the effects of alloxan treatment and that t-CA SNEDDS with a more favorable absorption and enhanced bioavailability is more effective than t-CA.

Phytochemicals and their potential usefulness in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract with unclear etiology, namely ulcerative colitis and Crohn's disease. Various drug therapies including aminosalicylates and immunomodulators have been approved for use; they have shown to produce diverse side effects. To overcome these limitations of the current therapeutics for IBD, extensive research is underway to identify drugs that are effective and free of undesirable side effects. Recently, various naturally occurring phytochemicals that cover a wide range of chemical entities such as polyphenols, terpeniods, flavonoids, and alkaloids have received attention as alternative candidates for IBD therapy. These phytochemicals act by modulating the immune response, various transcription factors, or reduce cytokine secretion. This review summarizes the findings of recent studies on phytochemicals as therapeutic agents in the management of IBD.

Formation and stability of D-limonene organogel-based nanoemulsion prepared by a high-pressure homogenizer

D-limonene organogel-based nanoemulsion was prepared by high-pressure homogenization technology. The organogelator type had a major role on the formation of the formulations, in which stearic acid has given nanoemulsions with the smallest droplet size. The surfactant type and concentration also had an appreciable effect on droplet formation, with Tween 80 giving a mean droplet diameter (d ≈ 112 nm) among a range of non-ionic surfactants (Tween 20, 40, 60, 80, and 85). In addition, high-pressure homogenization conditions played a key role in the nanoemulsion preparation. The stability of d-limonene organogel-based nanoemulsion was also investigated under two different temperatures (4 and 28 °C) through 2 weeks of storage. Results showed a good stability of the formulations, which is maybe due to the incorporation of D-limonene into the organogel prior to homogenization. This study may have a valuable contribution for the design and use of organogel-based nanoemulsion as a delivery system in food.

In vitro α-amylase inhibitory activity and in vivo hypoglycemic effect of methanol extract of Citrus macroptera Montr. fruit

OBJECTIVE

To investigate the therapeutic effects of methanol extract of Citrus macroptera Montr.fruit in α-amylase inhibitory activity (in vitro) and hypoglycemic activity in normal and glucose induced hyperglycemic rats (in vivo).

METHODS

Fruits of Citrus macroptera without rind was extracted with pure methanol following cold extraction and tested for presence of phytochemical constituents, α-amylase inhibitory activity, and hypoglycemic effect in normal rats and glucose induced hyperglycemic rats.

RESULTS

Presence of saponin, steroid and terpenoid were identified in the extract. The results showed that fruit extract had moderate α-amylase inhibitory activity [IC50 value=(3.638±0.190) mg/mL] as compared to acarbose. Moreover at 500 mg/kg and 1 000 mg/kg doses fruit extract significantly (P<0.05 and P<0.01 respectively) reduced fasting blood glucose level in normal rats as compared to glibenclamide (5 mg/kg). In oral glucose tolerance test, 500 mg/kg dose significantly reduced blood glucose level (P<0.05) at 2 h but 1 000 mg/kg dose significantly reduced blood glucose level at 2 h and 3 h (P<0.05 and P<0.01 respectively) whereas glibenclamide (5 mg/kg) significantly reduced glucose level at every hour after administration. Overall time effect is also considered extremely significant with F value=23.83 and P value=0.0001 in oral glucose tolerance test.

CONCLUSION

These findings suggest that the plant may be a potential source for the development of new oral hypoglycemic agent.

Short-term caraway extract administration improves cardiovascular disease risk markers in streptozotocin-induced diabetic rats: a dose-response study

OBJECTIVE

This study examined the effects of caraway plant on blood levels of glucose, lipid profile, and C-reactive protein in diabetic rats.

METHODS

Thirty two male Wistar rats were randomly divided into four groups: group 1: nondiabetic control rats, group 2: diabetic rats, group 3, and 4 (caraway treated diabetic groups): each rat was treated with caraway at doses of 1 g/kg in group 3 and 2 g/kg in group 4. Diabetes was induced by a single intraperitoneal injection of 60 mg/kg streptozotocin. Caraway was administered as aqueous extract orally once a day for 3 weeks. Finally, blood samples were collected and fasting blood glucose, serum lipid profile, and C-reactive protein levels were determined. Data were analyzed statistically by one-way Analysis of Variance and considered to be significant when p < .05.

RESULTS

Diabetic rats receiving 1 and 2 g/kg caraway extracts had significantly lower total cholesterol (p = .036 and p = .010, respectively), low-density lipoprotein (p = .001 and p = .002, respectively), non-HDL-C (p = .003 and p = .007, respectively), LDL-C to HDL-C ratio (p = .002) and atherogenic index (p = .001) than that of diabetic control rats. Moreover, there were significant changes in fasting blood glucose in diabetic groups treated with 1 and 2 g/kg caraway extracts (p = .001 and p = .027, respectively) compared with the diabetic control. However, caraway did not have any significant effect on C-reactive protein level in diabetic rats.

CONCLUSION

This study suggests that caraway can exhibit blood glucose and lipid lowering activities in diabetes, without any effect on C-reactive protein level.