Identification of hypoglycaemic compounds from berries of Juniperus oxycedrus subsp. oxycedrus through bioactivity guided isolation technique

Bioassay-guided isolation of anti-inflammatory and antinociceptive metabolites among three Moroccan Juniperus leaves extract supported with in vitro enzyme inhibitory assays

ETHNOPHARMACOLOGICAL RELEVANCE

Herbs of the genus Juniperus (family Cupressaceae) have been commonly used in ancestral folk medicine known as "Al'Araar" for treatment of rheumatism, diabetes, inflammation, pain, and fever. Bioassay-guided isolation of bioactives from medicinal plants is recognized as a potential approach for the discovery of novel drug candidates. In particular, non-addictive painkillers are of special interest among herbal phytochemicals.

AIM OF THE STUDY

The current study aimed to assess the safety of J. thurifera, J. phoenicea, and J. oxycedrus aqueous extracts in oral treatments; validating the traditionally reported anti-inflammatory and analgesic effects. Further phytochemical investigations, especially for the most bioactive species, may lead to isolation of bioactive metabolites responsible for such bioactivities supported with in vitro enzyme inhibition assays.

MATERIALS AND METHODS

Firstly, the acute toxicity study was investigated following the OECD Guidelines. Then, the antinociceptive, and anti-inflammatory bioactivities were evaluated based on chemical and mechanical trauma assays and investigated their underlying mechanisms. The most active J. thurifera n-butanol fraction was subjected to chromatographic studies for isolating the major anti-inflammatory metabolites. Moreover, several enzymatic inhibition assays (e.g., 5-lipoxygenase, protease, elastase, collagenase, and tyrosinase) were assessed for the crude extracts and isolated compounds.

RESULTS

The results showed that acute oral administration of the extracts (300-500 mg/kg, p. o.) inhibited both mechanically and chemically triggered inflammatory edema in mice (up to 70% in case of J. thurifera) with a dose-dependent antinociceptive (tail flick) and anti-inflammatory pain (formalin assay) activities. This effect was partially mediated by naloxone inhibition of the opioid receptor (2 mg/kg, i. p.). In addition, 3-methoxy gallic acid (1), quercetin (2), kaempferol (3), and ellagic acid (4) were successfully identified being involved most likely in J. thurifera extract bioactivities. Nevertheless, quercetin was found to be the most potent against 5-LOX, tyrosinase, and protease with IC50 of 1.52 ± 0.01, 192.90 ± 6.20, and 399 ± 9.05 μM, respectively.

CONCLUSION

J. thurifera extract with its major metabolites are prospective drug candidates for inflammatory pain supported with inhibition of inflammatory enzymes. Interestingly, antagonism of opioid and non-opioid receptors is potentially involved.

Juniper Berries Regulate Diabetes and Obesity Markers Through Modulating PPARα, PPARγ, and LXR: In Vitro and In Vivo Effects

The berries of Juniperus communis have been traditionally used for therapeutic purposes. They have been reported to possess various pharmacological effects such as anti-inflammatory, hypoglycemic and hypolipidemic activities. In this study, a methanolic extract of J. communis berries (JB) was evaluated for its effects on peroxisome proliferator-activated receptors alpha and gamma (PPARα and PPARγ), liver X receptor (LXR), glucose uptake and lipid accumulation using various cellular systems. At a concentration of 25 μg/mL, JB caused 3.77-fold activation of PPARα, 10.90-fold activation of PPARγ, and 4.43-fold activation of LXR in hepatic cells. JB inhibited (11%) the adipogenic effect induced by rosiglitazone in adipocytes and increased glucose uptake (90%) in muscle cells. In high-fat diet (HFD) fed mice, JB at a dose of 25 mg/kg body weight exhibited a 21% decrease in body weight. Fasting glucose levels in mice treated with 12.5 mg/kg of JB were significantly decreased (39%) indicating its efficacy in regulating hyperglycemia and obesity induced by HFD thus ameliorating the symptoms of type 2 diabetes. A series of energy metabolic genes, including Sirt1 (2.00-fold) and RAF1 (2.04-fold), were upregulated by JB, while rosiglitazone regulated the hepatic PPARγ only. Phytochemical analysis of JB indicated presence of a number of flavonoids and biflavonoids which seem to be responsible for the observed activity. It was concluded that JB acted as a multiple agonist of PPARα, PPARγ and LXR without the undesired effect of adipogenesis and exhibited the property of enhancing glucose uptake. The regulation of PPARα, PPARγ and LXR seems to be through Sirt1 and RAF1. In vivo results confirmed the antidiabetic and antiobesity potential of JB and indicated its utility in metabolic disorder and type 2 diabetes.

Naturally-occurring carboxylic acids from traditional antidiabetic plants as potential pancreatic islet FABP3 inhibitors. A molecular docking-aided study

The antidiabetic action of traditional plants is mostly attributed to their antioxidant and anti-inflammatory properties. These plants are still having some secrets, making them an attractive source that allows for investigating new drugs or uncovering precise pharmacologic antidiabetic functions of their constituents. In diabetes, which is a lipid disease, long-term exposure of pancreatic islet beta cells to fatty acids (FAs) increases basal insulin release, reduces glucose-stimulated insulin secretion, causes islet beta cell inflammation, failure and apoptosis. Pancreatic islet beta cells express fatty acid binding protein 3 (FABP3) that receives long-chain FAs and traffics them throughout different cellular compartments to be metabolized and render their effects. Inhibition of this FABP3 may retard FA metabolism and protect islet beta cells. Since FAs interact with FABPs by their carboxylic group, some traditionally-known antidiabetic plants were reviewed in the present study, searching for their components that have common features of FABP ligands, namely carboxylic group and hydrophobic tail. Many of these carboxylic acids were computationally introduced into the ligand-binding pocket of FABP3 and some of them exhibited FABP3 ligand possibilities. Among others, the naturally occurring ferulic, cleomaldeic, caffeic, sinapic, hydroxycinnamic, 4-p-coumaroylquinic, quinoline-2-carboxylic, chlorogenic, 6-hydroxykynurenic, and rosmarinic acids in many plants are promising candidates for being FABP3-specific inhibitors. The study shed light on repurposing these phyto-carboxylic acids to function as FABP inhibitors. However, more in-depth biological and pharmacological studies to broaden the understanding of this function are needed.

Comprehensive Analysis of the Herbal Mixture Made of Juniperus oxycedrus L. Berries, Inner Bark of Betula pendula Roth., and Grains of Avena sativa L

This is the first report of the high-performance liquid chromatography and gas chromatography–mass spectrometry profile of a herbal mixture (HM) made of Juniperus oxycedrus L. (redberry juniper) berries, inner bark of Betula pendula Roth. (silver birch), and grains of Avena sativa L. (oat), and its effect on the No. of micronuclei (MN) in human lymphocytes and toxicity toward Artemia salina. Constituents represented by over 1000 µg per g of methanol dry extract were gallic acid, protocatechuic acid, and amentoflavone. The methanol extract of the HM at a concentration of 2.0 μg/mL decreased MN frequency by 38.3%, which was more than 3 times greater than that of the radioprotectant amifostine. The essential oil isolated from the HM was composed mainly of β-myrcene (32%) and showed weaker toxicity toward Artemia salina than the positive control after both incubation periods (24 h and 48 h). These findings suggest that the examined HM, beside its ethnopharmacological relevance on the elimination of renal calculi, also significantly reduces the No. of MN in human lymphocytes.

Essential Oils and Extracts of Juniperus macrocarpa Sm. and Juniperus oxycedrus L.: Comparative Phytochemical Composition and Anti-Proliferative and Antioxidant Activities

In this work, we conducted a comparative phytochemical, chemotaxonomic, and biological study of essential oils (EOs) and extracts (ethyl acetate and methanol) obtained from the leaves of Juniperusmacrocarpa and J. oxycedrus. The dominant compounds of J. macrocarpa EO, analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), are α-pinene, sabinene, manoyl oxide, and germacrene D, whereas α-pinene, limonene, (Z,E)-farnesol, β-pinene, and γ-cadinene are the most representative volatiles of J. oxycedrus EOs. A multivariate analysis of EOs, included a selection of literature data comparing our samples to samples of J. oxycedrus/macrocarpa/deltoides from the Mediterranean area, was performed. As evident by high-performance liquid chromatography (HPLC) analyses, apigenin, (−)-epicatechin, and luteolin were abundant in J. oxycedrus extracts, while gallic acid, kaempferol-3-O-glucoside, and protocatechuic acid were the dominant constituents of J. macrocarpa extracts. EOs and extracts have been investigated for their potential antioxidant properties and anti-proliferative activity against lung adenocarcinoma (A549), breast cancer (MCF-7 and MDA-MB-231), and lung large cell carcinoma (COR-L23) human cell lines. The methanol and ethyl acetate extracts of J. oxycedrus exerted the most valuable antioxidant activity and exhibited the most promising activity against the COR-L23 cell line with an IC₅₀ of 26.0 and 39.1 μg/mL, respectively, lower than that obtained with the positive control (IC₅₀ of 45.5 μg/mL). To the best of our knowledge, this is the first report highlighting the anti-proliferative activity of J. oxycedrus and J. macrocarpa extracts against this lung cancer cell line. Our results indicate that J. oxycedrus may be considered a source of natural compounds with antioxidant and anti-proliferative effects that could be suitable for future applications.

Standardization of Juniperus macrocarpa Sibt. & Sm. and Juniperus excelsa M. Bieb. Extracts with Carbohydrate Digestive Enzyme Inhibitory and Antioxidant Activities

Juniperus species growing in Turkey are used for various medicinal purposes in traditional folk medicine. We aimed to evaluate in-vitro antidiabetic (α-glucosidase and α-amylase inhibition assays), antiobesity (pancreatic lipase inhibition assay), and antioxidant (ABTS and DPPH radical scavenging activities, ferric reducing activity, metal chelating activity, and phosphomolybdenum assay) activities of the extracts obtained from branches, leaves, and fruits of Juniperus macrocarpa and Juniperus excelsa. The branch (IC₅₀ = 67.1 ± 1.7 µg/mL) and leaf ethyl acetate extracts (IC₅₀ = 83.4 ± 0.8 µg/mL) of J. macrocarpa exhibited the strongest activity on the α-glucosidase enzyme. Besides that, J. excelsa leaf methanol extract exerted remarkable α-amylase inhibitory activity (IC₅₀ = 950.1 ± 3.5 µg/mL). Only J. macrocarpa branch and J. excelsa leaf ethyl acetate extract slightly inhibited pancreatic lipase enzyme with 2963.3 ± 736.4 and 2343 ± 557.8 µg/mL IC₅₀ values, respectively. The RP-HPLC-DAD analysis results demonstrated that the more active J. macrocarpa extracts are richer in agathisflavone, amentoflavone, and umbelliferone than J. excelsa extracts. With this study, it is concluded that J. macrocarpa branch and leaf ethyl acetate extracts may be a new source of α-glucosidase enzyme inhibitory activity and agathisflavone, amentoflavone can be used in the standardization of the extracts.

Effects of oleanolic acid on inflammation and metabolism in diabetic rats

Diabetes mellitus (DM) is a chronic metabolic disease that threatens the health of the world population. We investigated the effects of oleanolic acid (OA) administration on inflammation status and metabolic profile in streptozotocin (STZ) induced diabetic rats. Four experimental groups were established: healthy rats not administered OA, healthy rats administered OA, diabetic rats not administered OA, diabetic rats administered OA. OA, 5 mg/kg, was administered by oral gavage for 21 days. Serum samples collected at the end of the experiment and analyzed for toll-like receptor-9, interleukin-18, nuclear factor kappa B, malondialdehyde MDA, glucose, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, calcium, phosphorus, magnesium and potassium. Pancreas tissue was examined for pathology. Induction of DM caused increased serum concentrations of inflammation and oxidative damage markers. DM also caused hyperglycemia-hyperlipidemia and decreased serum concentration of minerals. The islets of Langerhans were degenerated and necrotic. Administration of OA reversed the adverse effects of DM. OA treatment can ameliorate inflammation and oxidative damage due to DM by normalizing hyperglycemia and decreasing TLR-9, IL-18, NF-κB and MDA levels.

Volatiles and Antifungal-Antibacterial-Antiviral Activity of South African Salvia spp. Essential Oils Cultivated in Uniform Conditions

Spontaneous emissions of S. dentata Aiton and S. scabra Thunb., as well as the essential oil (EO) composition of the cited species, together with S. aurea L., were investigated. The chemical profile of the first two species is reported here for the first time. Moreover, in vitro tests were performed to evaluate the antifungal activity of these EOs on Trichophyton mentagrophytes, Microsporum canis, Aspergillus flavus, Aspergillus niger, and Fusarium solani. Secondly, the EO antibacterial activity against Escherichia coli, Staphylococcus aureus, and Staphylococcus pseudointermedius was examined, and their antiviral efficacy against the H1N1 influenza virus was assessed. Leaf volatile organic compounds (VOCs), as well as the EOs obtained from the arial part of Salvia scabra, were characterized by a high percentage of sesquiterpene hydrocarbons (97.8% and 76.6%, respectively), mostly represented by an equal amount of germacrene D (32.8% and 32.7%, respectively). Both leaf and flower spontaneous emissions of S. dentata, as well as the EO composition, showed a prevalence of monoterpenes divided into a more or less equal amount of hydrocarbon and oxygenated compounds. Interestingly, its EO had a non-negligible percentage of oxygenated sesquiterpenes (29.5%). S. aurea EO, on the contrary, was rich in sesquiterpenes, both hydrocarbons and oxygenated compounds (41.5% and 33.5%, respectively). S. dentata EO showed good efficacy (Minimal Inhibitory Concentration (MIC): 0.5%) against M. canis. The tested EOs were not active against E. coli and S. aureus, whereas a low inhibition of S. dentata EO was observed on S. pseudointermedius (MIC = 10%). Once again, S. dentata EO showed a very good H1N1 inhibition; contrariwise, S. aurea EO was completely inactive against this virus. The low quantity of S. scabra EO made it impossible to test its biological activity. S. dentata EO exhibited interesting new perspectives for medicinal and industrial uses.

Middle East Medicinal Plants in the Treatment of Diabetes: A Review

Diabetes is a global health problem, and the number of diabetic patients is in continuous rise. Conventional antidiabetic therapies are associated with high costs and limited efficiency. The use of traditional medicine and plant extracts to treat diabetes is gaining high popularity in many countries. Countries in the Middle East region have a long history of using herbal medicine to treat different diseases, including diabetes. In this review, we compiled and summarized all the in vivo and in vitro studies conducted for plants with potential antidiabetic activity in the Middle East region. Plants of the Asteraceae and Lamiaceae families are the most investigated. It is hoped that this review will contribute scientifically to evidence the ethnobotanical use of medicinal plants as antidiabetic agents. Work has to be done to define tagetes, mechanism of action and the compound responsible for activity. In addition, safety and pharmacokinetic parameters should be investigated.

Sequential extracts of red honeybush (Cyclopia genistoides) tea: Chemical characterization, antioxidant potentials, and anti-hyperglycemic activities

The antioxidant, antidiabetic, and anti-obesogenic potentials of different extracts (dichloromethane, ethyl acetate, ethanol, and aqueous) of the red honeybush (Cyclopia genistoides) tea were investigated in vitro and ex vivo. All extracts exhibited significant scavenging and reducing power activities, with the aqueous and ethyl acetate extracts being the most potent. In vitro antidiabetic analysis revealed the extracts to be potent inhibitors of α-glucosidase and lipase activities. All extracts increased catalase and SOD activities, and glutathione level in oxidative pancreatic injury. GC-MS analysis revealed the presence of fatty acids, fatty acid ester, phytols, sterols, saccharide, ketones, and triterpenes. These results imply that the sequential extracts of honeybush tea (particularly the aqueous and ethyl acetate extracts) may not only exhibit antioxidant potentials but also mediate anti-hyperglycemia activities by inhibiting lipid and carbohydrate digestion. PRACTICAL APPLICATIONS: Red honeybush tea is enjoyed widely in South Africa and around the world due to its no caffeine and very low tannin content, as well as many healthcare attributes. There are however no scientific reports for its sequential extraction of different solvents on antidiabetic effects. The different extracts of honeybush tea (particularly the aqueous and ethyl acetate extracts) inhibited lipid and carbohydrate digestive enzymes linked to type 2 diabetes (T2D), as well as modulate oxidative pancreatic injury. These findings will promote its utilization as a potential nutraceutical in the management of diabetes and its complications.

Pharmacokinetics of Shikimic Acid Following Intragastric and Intravenous Administrations in Rats

Shikimic acid, a critical starting material for the semi-total synthesis of oseltamivir to treat and prevent influenza, exerts many pharmacological effects. However, the optimal bioanalytical method has not been adequately defined. We used liquid chromatography-tandem mass spectrometry to quantitate shikimic acid in rat plasma and studied its pharmacokinetics after intragastric and intravenous administration. Plasma was spiked with an internal standard, and the proteins were precipitated with acetonitrile, followed by solvent evaporation and reconstitution of the mobile phase. Shikimic acid was separated on a hydrophilic reverse-phase column and showed a mass transition ([M-H]⁻) at m/z 173.4→136.6. Shikimic acid exhibited bi-exponential decay after intravenous dosing, with a rapid distribution (5.57 h⁻¹) up to 1 h followed by slow elimination (0.78 h⁻¹). The steady state distribution and clearance volumes were 5.17 and 1.79 L/h/kg, respectively. After intragastric administration, the shikimic acid level peaked at about 3 h, and the material then disappeared mono-exponentially with a half-life of 1.3 h. A double peak phenomenon was observed. The absolute oral bioavailability was about 10% in rats. We explored the relationship between the pharmacokinetics and pharmacodynamics of shikimic acid.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Potential of Juniperus communis L as a nutraceutical in human and veterinary medicine

Plants have been used for thousands of years as medicine for treating variety of diseases and medical complaints by most of the civilizations. Juniperus communis L. is an evergreen aromatic shrub with high therapeutic potential for the treatment of diseases in human and animals. The plant is rich in aromatic oils, invert sugars, resins, catechin, organic acid, terpenic acids, leucoanthocyanidin, alkaloids, flavonoids, tannins, gums, lignins, wax, etc. Juniper berries or extract of the plant has traditionally been used as diuretic, anti-arthritis, anti-diabetes, antiseptic as well as for the treatment of gastrointestinal and autoimmune disorders. The essential oil and extracts of juniper have been experimentally documented to have antioxidant, antibacterial, antiviral and antifungal activities. Recent studies have also found anti-inflammatory, cytotoxic, hypoglycemic and hypolipidemic effects of berries in experimental models. Further, the essential oil incorporation retarded lipid peroxidation in preserved meat due to its high antioxidant effect which not only improved meat product quality but also improved shelf life of the product. Thus natural antioxidant such as juniper can be used in place synthetic antioxidant for the preservation and improving self-life of meat products. New well designed clinical trials in human and animals using well-characterized J. communis extract or oil need to be conducted so that additional information is generated which can support the use of this natural product as a nutraceutical.

The Current Status of the Pharmaceutical Potential of Juniperus L. Metabolites

Background: Plants and their derived natural compounds possess various biological and therapeutic properties, which turns them into an increasing topic of interest and research. Juniperus genus is diverse in species, with several traditional medicines reported, and rich in natural compounds with potential for development of new drugs. Methods: The research for this review were based in the Scopus and Web of Science databases using terms combining Juniperus, secondary metabolites names, and biological activities. This is not an exhaustive review of Juniperus compounds with biological activities, but rather a critical selection taking into account the following criteria: (i) studies involving the most recent methodologies for quantitative evaluation of biological activities; and (ii) the compounds with the highest number of studies published in the last four years. Results: From Juniperus species, several diterpenes, flavonoids, and one lignan were emphasized taking into account their level of activity against several targets. Antitumor activity is by far the most studied, being followed by antibacterial and antiviral activities. Deoxypodophyllotoxin and one dehydroabietic acid derivative appears to be the most promising lead compounds. Conclusions: This review demonstrates the Juniperus species value as a source of secondary metabolites with relevant pharmaceutical potential.

Phytochemical and biological studies on Alnus glutinosa subsp. glutinosa, A. orientalis var. orientalis and A. orientalis var. pubescens leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Alnus species have been used for the treatment of rheumatism, hemorrhoids and for wound healing in folk medicine.

MATERIALS AND METHODS

Aqueous and methanol extracts of A. glutinosa (L.) Gaertner subsp. glutinosa, A. orientalis Decne. var. orientalis and A. orientalis var. pubescens Dippel leaves were evaluated for their wound healing, anti-inflammatory and antioxidant activities. In vivo wound models of linear incision and circular excision were performed. "Inhibition of acetic acid-induced capillary permeability", "carrageenan-induced hind paw edema" and T"PA-induced ear edema" assays were applied to determine the anti-inflammatory effects. For the antioxidant activity assessment, DPPH and ABTS radicals scavenging effect, reducing power and denaturation of nonspecific hydroxyl radical-targeted 2-deoxyribose were used. In vitro inhibitory effects on enzymes hyaluronidase, collagenase and elastase were evaluated. The methanol extract of the leaves of A. glutinosa subsp. glutinosa (MB), the most potent extract, was fractionated by bioassay-guided fractionation technique. The structure of the isolated compound was determined as shikimic acid by using NMR and IR analyses.

RESULTS

MB increased the wound tension by 42.79% value and provided a contraction by 51.58%. Wound tension, contraction capacity and tissue hydroxyproline levels were increased with the application of the fraction EtOAc: MeOH (Fr. D), subfraction D_27-38 and shikimic acid. In the "inhibition of acetic acid-induced capillary permeability" assay, MB, Fr. D, subfraction D_27-38 and shikimic acid inhibited the permeability with significant inhibition values of 30.22%, 32.46%, 38.24% and 27.19%, respectively. In carrageenan-induced hind paw edema model, MB displayed 29.1% inhibition. Likewise, Fr. D, subfraction D_27-38, and shikimic acid were found to exhibit remarkable anti-inflammatory and antioxidant effects. Shikimic acid exhibited significant inhibitory effect (38.24%) on the hyaluronidase enzyme.

CONCLUSIONS

This is the first and unique study that investigates wound healing, anti-inflammatory and antioxidant effects of some Alnus taxons growing in Turkey. According to the results, shikimic acid was found to be the major compound responsible from the activity.

Shikimic acid inhibits LPS-induced cellular pro-inflammatory cytokines and attenuates mechanical hyperalgesia in mice

BACKGROUND AND AIMS

Shikimic acid (SA) is present in a wide variety of plants and microorganisms used in traditional and folk medicine and also is an essential starting material for the synthesis of the antiviral drug Oseltamivir (Tamiflu®). Some pharmacological actions observed in SA-enriched products include antioxidant and anti-inflammatory activities. Here, we investigated the anti-inflammatory and antinociceptive actions of isolated SA.

METHODS

RAW 264.7 macrophage cells were treated with bacterial LPS (1μg/mL) and the effect of SA on the modulation of cell viability, nitric oxide (NO) production, TNF-α, and IL-1β content and MAPK (ERK1/2 and p38) activation was evaluated. Besides, the anti-hyperalgesic actions of SA on in vivo model of mechanical hyperalgesia induced by carrageenan (CG), dopamine (DA), TNF-α and prostaglandin (PGE2) were assessed.

RESULTS

In RAW 264.7 cells, SA suppressed LPS-induced decrease in cell viability and nitrite accumulation to control values and inhibited up-regulation of TNF-α (65%) and IL-1β (39%). These effects may be mediated at least in part by inhibition of LPS-induced ERK 1/2 (22%) and p38 (17%) phosphorylation. In mice, SA at 50, 100, and 200mg/kg decreased formalin-induced nociceptive behavior (around 50%) and inhibited the inflammatory nociception induced by TNF-α and PGE2 (50 to 75% each). Moreover, SA (100 and 200mg/kg) significantly attenuated the mechanical hyperalgesia induced by CG and DA (25 to 40% each).

CONCLUSIONS

These results indicate that SA presents anti-inflammatory actions with potential for development of drugs to treat pro-inflammatory and painful conditions.

DNA protection, antioxidant, antibacterial and enzyme inhibition activities of heartwood and sapwood extracts from juniper and olive woods

In this study, DNA protective, antioxidant, antibacterial and enzyme inhibiting properties of methanol extracts obtained from juniper and olive heartwood and sapwood were determined.

Antidiabetic effect of flavonoids from Malus toringoides (Rehd.) Hughes leaves in diabetic mice and rats

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf of Malus toringoides (Rehd.) Hughes is a traditional folk medicine in Tibet, China, which is called "E Se" in Tibetan language. This original plant grows on snow mountains at an attitude of 3000 to 3700 m. It is primarily used to treat hypertension, hyperlipidemia, hyperglycemia, indigestion and other diseases. This study aimed to evaluate the antidiabetic effect of flavonoids extracted from E Se (ESF) and to explore the potential mechanism in streptozotocin (STZ) or alloxan (ALX) induced diabetic mice and STZ-induced diabetic rats.

MATERIALS AND METHODS

72 h after the establishment of a diabetic model, STZ or ALX induced diabetic mice and STZ-induced diabetic rats were treated daily with ESF at doses of 45, 90, 180 mg/kg and 37.5, 75, 150 mg/kg, respectively. Both mice and rats were fasted for 5h before administration and the blood glucose (BG) levels were tested 1h after treatment. Body weight was determined every other day. For STZ-induced rats, glycosylated hemoglobin (Hb1Ac), serum insulin and c-peptide, hepatic glycogen, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in liver were assessed on the fourth day after BG level detection.

RESULTS

Compared with the model group, the general behavior of mice treated with ESF (90, 180 mg/kg) and rats treated with ESF (75, 150 mg/kg) became better and BG levels were significantly reduced (P<0.05). Significant decrease (P<0.05) in Hb1Ac level was observed in ESF-treated rats compared with diabetic rats. Significant increase (P<0.05 ) in serum insulin and c-peptide were detected in ESF-treated rats. The treatment also significantly (P<0.05) elevated SOD activity and reduced MDA level in the liver of diabetic rats. Besides, ESF 150 mg/kg had a trend of rising hepatic glycogen content of diabetic rats.

CONCLUSIONS

The findings of this study suggest that flavonoids from the Malus toringoides (Rehd.) Hughes leaves may possess an antidiabetic activity in animals with established diabetes.

A bioactivity guided study on the antidiabetic activity of Juniperus oxycedrus subsp. oxycedrus L. leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Juniperus (Cupressaceae) species are widely used as folk medicine in spreading countries. Decoction of Juniperus oxycedrus subsp. oxycedrus L. leaves is used internally to lower blood glucose levels in Turkey.

AIM OF THE STUDY

To determine hypoglycaemic and antidiabetic activities of Juniperus oxycedrus subsp. oxycedrus leaves and to identify active compounds through bioactivity guided isolation technique.

MATERIALS AND METHODS

Ethanol and water extracts of Juniperus oxycedrus subsp. oxycedrus (Joso), leaves on oral administration were studied using in vivo models in normal, glucose-hyperglycemic and streptozotocin-induced diabetic rats. Through in vivo bioactivity-guided fractionation processes, a nonpolar fraction was separated from the n-hexane subextract by silica gel column chromatography as the main active fraction. Subfractions of this fraction was found to possess antidiabetic activity and their chemical composition was investigated by GC-FID and GC-MS, simultaneously.

RESULTS

This is the first report on the antidiabetic constituents of Joso leaves. Fatty acids, such as palmitic, linoleic and linolenic acid were found as the major compounds in subfractions.

CONCLUSION

Results indicated that Joso leaf extract and its active constituents might be beneficial for diabetes mellitus.