Comparative Evaluation of Medicinal Plant Extracts and Antimicrobial Magistrals.

The in vitro antimicrobial activity of the active ingredient in antimicrobial magistral drug formulations and plant extracts used in folk medicine were investigated comparatively. Borax, sulfur colloid, hydrogen peroxide, benzoic acid, rivanol, brilliant green and plant extracts as active ingredients, namely: Helianthus tuberosus tuber-H2O (aqueous extract), Cydonia oblonga leaves-H2O, Allium porrum whole plant-H2O, Cistus laurifolius leaves-EtOH, Solanum muricalum-H2O, and Fumaria cilicica leaves-EtOH were studied to determine their antimicrobial activity against different bacteria and fungi (S. pyogenes, S. aureus, S. epidermidis, E. faecalis, K. pneumonia, H. influenza, P. aeruginosa, A. baumannii, E. coli, Candida albicans, C. tropicalis, C. parapsilosis, C. krusei) by using the microdilution method. The active ingredients and plant extracts showed different activities as MIC between 1->128 µg/mL. Brilliant green and rivanol as active ingredients had MIC values of 1 µg/mL against all tested microorganisms. C. oblonga leaves-H2O as well as C. laurifolius leaves-EtOH as plant extracts were indicated as having the highest antimicrobial effect in MIC value of 16 µg/ml against A. baumannii and S. pyogenes, respectively. On the other hand, F. cilicica leaves-EtOH and C. laurifolius leaves-EtOH showed the highest antifungal activity (MIC; 16 µg/mL).

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.

Enzyme inhibitory and radical scavenging effects of some antidiabetic plants of Turkey.

OBJECTIVES: Ethnopharmacological field surveys demonstrated that many plants, such as Gentiana olivieri, Helichrysum graveolens, Helichrysum plicatum ssp. plicatum, Juniperus oxycedrus ssp. oxycedrus, Juniperus communis var. saxatilis, Viscum album (ssp. album, ssp. austriacum), are used as traditional medicine for diabetes in different regions of Anatolia. The present study was designed to evaluate the in vitro antidiabetic effects of some selected plants, tested in animal models recently. MATERIALS AND METHODS: α-glucosidase and α-amylase enzyme inhibitory effects of the plant extracts were investigated and Acarbose was used as a reference drug. Additionally, radical scavenging capacities were determined using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) ABTS radical cation scavenging assay and total phenolic content of the extracts were evaluated using Folin Ciocalteu method. RESULTS: H. graveolens ethanol extract exhibited the highest inhibitory activity (55.7 % ± 2.2) on α-amylase enzyme. Additionally, J. oxycedrus hydro-alcoholic leaf extract had potent α-amylase inhibitory effect, while the hydro-alcoholic extract of J. communis fruit showed the highest α-glucosidase inhibitory activity (IC50: 4.4 µg/ml). CONCLUSION: Results indicated that, antidiabetic effect of hydro-alcoholic extracts of H. graveolens capitulums, J. communis fruit and J. oxycedrus leaf might arise from inhibition of digestive enzymes.

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

ETHNOPHARMACOLOGICAL RELEVANCE: Decoction of Juniperus oxycedrus subsp. oxycedrus L. (Cupressaceae) berries is used internally as tea and pounded fruits are consumed to lower blood glucose levels in Turkey. AIM OF THE STUDY: To evaluate hypoglycaemic and antidiabetic activity of J. oxycedrus subsp. oxycedrus berries and to identify active compounds through bioactivity guided isolation technique. MATERIAL AND METHODS: Hypoglycaemic effect of J. oxycedrus subsp. oxycedrus (Joso) berry extracts on oral administration was studied using in vivo models in normal, glucose-hyperglycaemic rats. Streptozotocin induced diabetic rats were used to examine antidiabetic activity of Joso extracts, subextracts, fractions, subfractions and shikimic acid (SA). RESULTS: Through in vivo bioactivity-guided fractionation processes, shikimic acid, 4-O-ß-d-glucopyranosyl ferulic acid and oleuropeic acid-8-O-ß-d-glucopyranoside were isolated from the n-butanol subextract by silica gel and reverse phase column chromatography as the main active ingredient of the active subfraction. After 8 days administration of the major compound shikimic acid, blood glucose levels (24%), malondialdehyde levels in kidney tissues (63-64%) and liver enzymes (AST, ALT, ALP) of diabetic rats were decreased. CONCLUSION: Results indicated that Joso berry extract and its active constituents might be beneficial for diabetes and its complications.

In vivo activity assessment of a "honey-bee pollen mix" formulation.

Honey-bee pollen mix (HBM) formulation is claimed to be effective for the treatment of asthma, bronchitis, cancers, peptic ulcers, colitis, various types of infections including hepatitis B, and rheumatism by the herb dealers in northeast Turkey. In the present study, in vivo antinociceptive, anti-inflammatory, gastroprotective and antioxidant effects of pure honey and HBM formulation were evaluated comparatively. HBM did not show any significant gastroprotective activity in a single administration at 250 mg/kg dose, whereas a weak activity was observed after three days of successive administration at 500 mg/kg dose. On the other hand, HBM displayed significant antinociceptive (p <0.01) and anti-inflammatory (p <0.01) activities at 500 mg/kg dose orally without inducing any apparent acute toxicity or gastric damage. HBM was also shown to possess potent antilipidperoxidant activity (p <0.01) at 500 mg/kg dose against acetaminophen-induced liver necrosis model in mice. On the other hand, pure honey did not exert any remarkable antinociceptive, anti-inflammatory and gastroprotective activity, but a potent antilipidperoxidant activity (p <0.01) was determined. Results have clearly proved that mixing pure honey with bee pollen significantly increased the healing potential of honey and provided additional support for its traditional use. Total phenolic and flavonoid contents of HBM were found to be 145 and 59.3 mg/100 g of honey, which were estimated as gallic acid and quercetin equivalents, respectively.

Hypoglycemic activity and antioxidant potential of some medicinal plants traditionally used in Turkey for diabetes.

Cydonia oblonga Mill. (Rosaceae) leaves, Helianthus tuberosus L. (Asteraceae) tubers, and Allium porrum L. (Liliaceae) bulbs are used as a folk remedy for the treatment of diabetes and they are also consumed as food in Turkey. In the present study, the antidiabetic and antioxidant activities of the ethanol extracts of these plants were studied in normal and streptozotocin-induced diabetic rats for 5 days. All extracts were administrated orally to rats at the doses of 250 and 500 mg/kg. Blood glucose level was measured according to glucose oxidase method. In order to determine antioxidant activity, thiobarbituric acid reactive substance (TBARS) and reduced glutathione (GSH) levels in liver, kidney, and heart tissues were measured by using spectrophotometric methods. Oral administration of Cydonia oblonga (500 mg/kg) and Allium porrum (500 mg/kg) extracts for 5 days in diabetic rats caused a decrease in blood glucose levels by 33.8% and 18.0%, respectively. Moreover, Allium porrum and Cydonia oblonga extracts induced significant alleviation on only heart tissue TBARS levels (44.6 and 45.7%), Helianthus tuberosus and Allium porrum extracts showed an inhibitory effect on kidney tissue TBARS levels (24.5 and 14.8%). None of the extracts restored GSH levels in kidney, liver, and heart tissues of diabetic rats.

Antibacterial, antifungal, and antiviral activities of some flavonoids.

Antibacterial and antifungal activities of six plant-derived flavonoids representing two different structural groups were evaluated against standard strains of Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis and their drug-resistant isolates, as well as fungi (Candida albicans, C. krusei) using the microdilution broth method. Herpes simplex virus Type-1 and Parainfluenza-3 virus were employed for antiviral assessment of the flavonoids using Madin-Darby bovine kidney and Vero cell lines. Ampicillin, gentamycin, ofloxacin, levofloxacin, fluconazole, ketoconazole, acyclovir, and oseltamivir were used as the control agents. All tested compounds (32-128 microg/ml) showed strong antimicrobial and antifungal activities against isolated strains of P. aeruginosa, A. baumanni, S. aureus, and C. krusei. Rutin, 5,7-dimethoxyflavanone-4'-O-beta-D-glucopyranoside and 5,7,3'-trihydroxy-flavanone-4'-O-beta-D-glucopyranoside (0.2-0.05 microg/ml) were active against PI-3, while 5,7-dimethoxyflavanone-4'-O-[2''-O-(5'''-O-trans-cinnamoyl)-beta-D-apiofuranosyl]-beta-D-glucopyranoside (0.16-0.2 microg/ml) inhibited potently HSV-1.

A study of antidiabetic and antioxidant effects of Helichrysum graveolens capitulums in streptozotocin-induced diabetic rats.

Helichrysum graveolens (Bieb.) Sweet (Asteraceae) grows widely in Turkey. Capitulums of H. graveolens are used in the treatment of many diseases such as jaundice and wound healing and as a diuretic in the rural areas of Anatolia. The decoction from the capitulums of the plant is consumed for the symptoms of diabetes mellitus in folk medicine. In the present study, the hypoglycemic, antihyperglycemic, and antioxidant potentials of water and ethanol extracts of H. graveolens were evaluated by using in vivo methods in normal and streptozotocin-induced diabetic rats. Blood glucose levels of animals were measured by the glucose oxidase method. The antioxidant activity of these extracts was also studied in liver, kidney, and heart tissues. In order to determine antioxidant activity, tissue malondialdehyde and reduced glutathione levels were measured by using spectrophotometric methods. The experimental data obtained from water and ethanol extracts of capitulums confirmed the folkloric utilization. In order to discuss the role of polyphenolic components in the relevant activity, total phenol and flavonoid contents of each extract were also determined using the Folin-Ciocalteu reagent, and a positive correlation was observed.

Hepatoprotective effect of Vitis vinifera L. leaves on carbon tetrachloride-induced acute liver damage in rats.

The hepatoprotective effect of ethanolic extract and its four different fractions (CHCl(3), EtOAc, n-BuOH, and remaining water fraction) of Vitis vinifera L. leaves was investigated against carbon tetrachloride (CCl(4))-induced acute hepatotoxicity in rats. The ethanolic extract was found active at 125mg/kg dose (per os). The ethanolic extract was fractionated through successive solvent-solvent extractions and the n-BuOH fraction in 83mg/kg dose possessed remarkable antioxidant and hepatoprotective activities. Liver damage was assessed by using biochemical parameters (plasma and liver tissue MDA [malondialdehyde], transaminase enzyme levels in plasma [AST-aspartate transaminase, ALT-alanine transferase] and liver GSH [glutathione] levels). Additionally, the pathological changes in liver were evaluated by histopathological studies. Legalon 70 Protect was used as standard natural originated drug.

In-vivo assessment of antidiabetic and antioxidant activities of grapevine leaves (Vitis vinifera) in diabetic rats.

The acute and the subacute (15 days) hypoglycaemic and antihyperglycaemic effect of the two different doses (250, 500 mg/kg) of the aqueous extract from the leaves of Vitis vinifera L. were evaluated in this study. The aqueous extract was further fractionated through successive solvent extractions and the acute effect of different doses of its subfractions, 25 mg/kg for ethylacetate fraction, 80 mg/kg for n-butanol fraction and 375 mg/kg for remaining aqueous fraction were investigated using normal, glucose-hyperglycaemic and streptozotocin-induced diabetic rats. Blood glucose levels were measured according to the glucose oxidase method. Tolbutamide was used as a reference drug at a dose of 100 mg/kg. The antioxidant activity of the test samples was studied in the liver, kidney and heart tissues of diabetic rats by measuring malondialdehyde (MDA) and glutathion (GSH) levels. All results were compared to the diabetic control groups. The results showed that EtOAc Fr. was rich in polyphenolics and possessed a significant antihyperglycaemic and antioxidant activity equipotent with the reference hypoglycaemic agent (tolbutamide), when evaluated in diabetic rats.

Anti-inflammatory and antinociceptive activity of flavonoids isolated from Viscum album ssp. album.

Viscum album L. has been used in the indigenous systems of medicine for treatment of headache and some inflammatory diseases. In order to evaluate this information, antinociceptive and anti-inflammatory activities of the five flavonoids (5,7-dimethoxy naringenin or 4',6'-dimethoxy chalcononaringenin) derivatives, isolated from the ethyl acetate fraction of the extract from V. album ssp. album, were investigated, namely 5,7-dimethoxy-flavanone-4'-O-beta-D-glucopyranoside (1), 2'-hydroxy-4',6'-dimethoxy-chalcone-4-O-beta-D-glucopyranoside (2), 5,7-dimethoxy-flavanone-4'-O-[2"-O-(5"'-O-trans-cinnamoyl)-beta-D-apiofuranosyl]-beta-D-glucopyranoside (3), 2'-hydroxy-4',6'-dimethoxy-chalcone-4-O-[2"-O-(5"'-O-trans-cinnamoyl)-beta-Dapiofuranosyl]-beta-D-glucopyranoside (4), 5,7-dimethoxy-flavanone-4'-O-[beta-D-apiofuranosyl-(1 --> 2)]-beta-D-glucopyranoside (5). For the antinociceptive activity assessment the p-benzoquinone-induced writhing test and for the anti-inflammatory activity the carrageenan-induced hind paw edema model in mice were used. The ethyl acetate fraction in a dose of 250 mg/kg as well as compounds 2 and 5 in a 30 mg/kg dose were shown to possess remarkable antinociceptive and anti-inflammatory activities per os without inducing any apparent acute toxicity as well as gastric damage.

Effect of Cistus laurifolius L. leaf extracts and flavonoids on acetaminophen-induced hepatotoxicity in mice.

In this study, the effect of the flavonoids quercetin-3-methyl-ether (isorhamnetin) (1), quercetin-3,7-dimethyl-ether (2) and kaempferol-3,7-dimethyl-ether (3) isolated from Cistus laurifolius L. (cistaceae) leaves was assessed on lipid peroxidation (liver and plasma), cellular glutathione (GSH) level and plasma AST (aspartate aminotransferase), ALT (alanine aminotransferase) enzyme activities in acetaminophen-induced liver damage in mice. At 114 mg/kg oral dose quercetin-3,7-dimethyl-ether was shown to possess potent antioxidative activity.

Evaluation of the hypoglycemic effect and antioxidant activity of three Viscum album subspecies (European mistletoe) in streptozotocin-diabetic rats.

The acute hypoglycaemic effect of water and ethanolic extracts of three Viscum album subspecies, ssp. album, ssp. austriacum, ssp. abietis, were investigated in normoglycaemic and streptozotozocin-induced diabetic rats. Blood glucose level was measured according to glucose oxidase method. The antioxidant activity of these extracts was also studied in the liver, kidney and heart tissues of streptozotocin-induced diabetic rats after subacute administration. In order to determine antioxidant activity of extracts, tissue MDA and GSH levels were measured by using spectrophotometric methods. All results were compared with the diabetic control groups. The findings obtained in the experiments demonstrated that European mistletoe (Viscum album L.) subspecies possess potent antihyperglycaemic and antioxidant activity depending on host plant.

Evaluation of hepatoprotective effect of Gentiana olivieri herbs on subacute administration and isolation of active principle.

Hepatoprotective effect of Gentiana olivieri Griseb. (Gentianaceae) flowering herbs on subacute administration were studied using in vivo models in rats. For the activity assessment on carbon tetrachloride-induced hepatic damage following biochemical parameters were evaluated; plasma and hepatic tissue malondialdehyde formation, and liver tissue glutathione level, as well as plasma transaminase enzyme levels (aspartate transferase and alanine transferase). Results of biochemical tests were also confirmed by histopathological examination. Through bioassay-guided fractionation procedures isoorientin, a known C-glycosylflavone, was isolated from the ethyl acetate fraction as the active antihepatotoxic constituent by silica gel column chromatography. Isoorientin exhibited significant hepatoprotective effect at 15 mg/kg b.w. dose.