[Medicinal plants and diabetes mellitus]. / Lécivé rostliny a diabetes mellitus.

Diabetes mellitus is a group of chronic metabolic disorders. Hyperglycaemia and other related disturbances in the body's metabolism can result in serious damage to many of the body's systems, especially the blood vessels and nerves. Across the globe, there are an estimated 150 million people suffering from diabetes mellitus, which causes about 5 % of all deaths globally each year. From many reports it is clear that diabetes will be one of the major diseases in the coming years. Existing treatment options are costly, and have limited palliative effects. It stimulates finding new medicines or suitable prophylactic treatments. Plant-based medicinal products known since ancient times have been used to control diabetes in the traditional medicinal systems. Numerous medicinal plants have been studied and validated for their hypoglycaemic properties using diabetic animal models but not so often in clinical studies. Testing of many plant extracts and plant substances continue. This review paper presents selected information on the hypoglycemic and antihyperglycaemic activities of tested preparations of plant origin.

[Protective effects of the flavonoids osajin and pomiferin on heart ischemia-reperfusion]. / Protektivní efekt flavonoidu osajinu a pomiferinu na ischémii-reperfuzi srdce.

The study was undertaken to evaluate the cardioprotective potential of the flavonoids osajin and pomiferin against ischemia-reperfusion induced injury in rat hearts as a model of antioxidant-based composite therapy. Studies were performed with isolated, modified Langendorff-perfused rat hearts and ischemia of the heart was initiated by stopping the coronary flow for 30 min followed by 60 min of reperfusion (14 ml x min(-1)). Wistar rats were divided into four groups. The treated groups received osajin or pomiferin (5 mg/kg/day in 0.5% Avicel), the placebo group received only 0.5 Avicel; the intact group was left without any applications. Biochemical indicators of oxidative damage--malondialdehyde, superoxide dismutase, glutathione peroxidase, total antioxidant activity in serum and the myocardium have been evaluated. We also examined the effect of osajin and pomiferin on cardiac function: left ventricular end-diastolic pressure, left ventricular pressure, and peak positive dP/dt. Our results demonstrate that the flavonoids osajin and pomiferin attenuate the myocardial dysfunction provoked by ischemia-reperfusion. This was confirmed by an increase in both the antioxidant enzyme values and the total antioxidant activity. The cardioprotection provided by osajin and pomiferin treatment results from the suppression of oxidative stress and correlates with the improved ventricular function.

Protective effects of osajin in ischemia-reperfusion of laboratory rat kidney.

The aim of this study was to analyze the antioxidative effect of osajin during prophylactic administration. The pathological model for in vivo experiment was the unilateral ischemia-reperfusion of kidney of the laboratory rat. The animals were randomly divided into five groups. Osajin was administrated orally in doses of 5, 10 and 20 mg/kg once a day to three premedicated groups. Placebo--0.5% solution of Avicel--was given to the fourth group and the fifth group was completely intact. The premedication lasted 15 days and subsequently the ischemia of the left kidney was incited in general anaesthesia for 60 min. The reperfusion lasted 10 min and it was finished by blood collection from the left ventricle and the reperfused kidney was recovered. Selected biochemical markers were assessed in blood: superoxide dismutase, glutathion peroxidase, total antioxidative capacity and malondialdehyde. The kidney tissue samples were used for histopathological examination. Laboratory and histopathological results confirmed supposed effects of osajine. The dependence between the effect and the applied dose of osajin was linear. The best biochemical results were reached after administration of osajin at the dose of 5 mg/kg. The best histopathological results were reached after administration of osajin at the dose of 10 mg/kg.

[Morin in the therapy of the ischemia-reperfusion damage model of the rat kidney]. / Morin v terapii ischemicko-reperfuzního poskození ledvinné tkáne laboratorního potkana.

The aim of this study was to analyze the protective effects of morin administered during the therapy of reperfusion injury of the laboratory rat kidney. Animals were randomly divided into five groups (n= 10). One group was left intact. Three medicated groups and one placebo group were subjected to ischemia (60 min) and reperfusion of the left kidney. Morin was suspended in a 2 ml of 0.5% Avicel solution and administered orally by a gastric probe at doses of 5, 10, and 20 mg.kg(-1) once a day for 15 days. The placebo group was given only 2 ml of 0.5% Avicel in the same way. On the 15th day, all the animals were exsanguinated and the reperfused kidneys were recovered. Selected biochemical markers in blood were assessed: superoxide dismutase, glutathion peroxidase, total antioxidative capacity, malondialdehyde, creatinine, urea, and uric acid. Creatinine, urea, and total protein were analyzed in urine, and a 24-hour diuresis was recorded. The kidney tissue samples were used for histopathological examination. Morin supported the organism's own defensive reactions against free radicals and decreased lipid peroxidation in the cell membranes and contributed to the recovery of kidney functions. The histopathological results confirm 20 mg x kg(-1) as the most effective dose.

[Prophylactic administration of homoisoflavonoid in ischemic-reperfusion damage of the renal tissue in the laboratory rat]. / Profylaktické podávání homoizoflavonoidu u ischemicko- reperfuzního poskození ledvinné tkáne laboratorního potkana.

The study aimed to examine the antioxidizing effect of homoisoflavonoid in prophylactic administration under the conditions of renal ischemia-reperfusion in the laboratory rat. The pathological model for the in vivo experiment was unilateral renal ischemia-reperfusion of the laboratory rat. The animals were randomized into 5 groups. Homoisoflavonoid was administered to treated groups orally in doses of 5, 10 and 20 mg/kg once a day in 0.5% Avicel solution. The placebo group received Avicel only, and the intact group was without medication and intervention. On day 15 of the experiment, renal tissue ischemia/reperfusion (60/10 mins) was induced in the treated and placebo groups. Then the animals were exsanguinated, biochemical parameters in the blood (superoxidismutase, glutathionperoxidase, total antioxidizing capacity and malondialdehyde) were assayed, and renal samples were withdrawn for histopathological examination. A biochemical examination demonstrated a dependence of the effect of homoisoflavonoid on the dose administered. An obvious effect was demonstrated in the values of GSHPx, AOC, and MDA. On the other hand, a negative dependence was found between the dose of administered homoisoflavonoid and SOD and GSHPx values. The results of biochemical examination correlate with the histopathological pictures of the renal tissue and support the assumption about a protective effect of homoisoflavonoid under the conditions of artificially induced pathological state--renal tissue ischemia-reperfusion.

[Natural substances as chemoprotective agents]. / Prírodní látky jako chemoprotektiva.

The fate of xenobiotics in the organism and their toxic or therapeutic influence have been under intensive investigation in recent years. The compounds are searched for which affect as preventive agents cancerogenesis and other disorders caused by procancerogens and pro-mutagens from the environment. The main focus is on the compounds able to modulate the activity of enzymes of the Ist and IInd phase of xenobiotic detoxication or compounds with antioxidative activity. In the following review, compounds of natural origin are presented which possess an ability to modulate the processes connected with detoxication of xenobiotics. These compounds could be usable as preventive agents against some diseases or as supportive pharmaceuticals during chemotherapy.

Chemoprotective potentials of homoisoflavonoids and chalcones of Dracaena cinnabari: modulations of drug-metabolizing enzymes and antioxidant activity.

A series of homoisoflavonoids and chalcones, isolated from the endemic tropical plant Dracaena cinnabari Balf. (Agavaceae), were tested for their potential to inhibit cytochrome P4501A (CYP1A) enzymes and Fe-enhanced in vitro peroxidation of microsomal lipids in C57B1/6 mouse liver. The effects of the polyphenolic compounds were compared with those of prototypal flavonoid modulators of CYP1A and the well-known antioxidant, butylated hydroxytoluene. 2-Hydroxychalcone and partly 4,6-dihydroxychalcone were found to be strong inhibitors of CYP1A-dependent 7-ethoxyresorufin O-deethylase (EROD) activity in vitro comparable to the effects of quercetin and chrysin. The first screening of flavonoids and chalcones of Dracaena cinnabari for antioxidant activity was done in an in vitro microsomal peroxidation assay. While chalcones were shown to be poor antioxidants, 7,8-methylenedioxy-3(4-hydroxybenzyl) chromane, as one of the tested homoisoflavonoids, exhibited a strong antioxidant activity comparable to that of the strongest flavonol antioxidant, quercetin.

Chemoprotective activity of boldine: modulation of drug-metabolizing enzymes.

Possible chemoprotective effects of the naturally occurring alkaloid boldine, a major alkaloid of boldo (Peumus boldus Mol.) leaves and bark, including in vitro modulations of drug-metabolizing enzymes in mouse hepatoma Hepa-1 cell line and mouse hepatic microsomes, were investigated. Boldine manifested inhibition activity on hepatic microsomal CYP1A-dependent 7-ethoxyresorufin O-deethylase and CYP3A-dependent testosterone 6 beta-hydroxylase activities and stimulated glutathione S-transferase activity in Hepa-1 cells. In addition to the known antioxidant activity, boldine could decrease the metabolic activation of other xenobiotics including chemical mutagens.

Separation of structurally related flavonoids by GC/MS technique and determination of their polarographic parameters and potential carcinogenicity.

The present study deals with the investigation of the naturally occurring derivatives of the benzo[b]pyran-4-one - flavonoids - chrysin, tectochrysin and galangin, and with the effect of minor changes in their chemical structure on their separation using GC/MS. In the relation to their close chemical structure, their basic polarographic parameters were also investigated. Their potential carcinogenicity index tg alpha was determined by DC polarography experiments in the presence of alpha-lipoic acid. The tg alpha values for chrysin, tectochrysin and galangin were all under 0.180. This indicates a very minor carcinogenic potential that does not prevent the use of the investigated flavonoids in human.

[Antioxidants of biological origin]. / Antioxidanty biogenního puvodu.

Diseases due to free radical are the subject of intensive study. The search aims to find substances preventing the origin of free radicals, substances capable of rendering the developed free radicals harmless, or substances capable of removing the damage of molecules which has already taken place. The present paper briefly surveys the metabolites of biogenic origin, mainly from higher plants, which show in vitro antioxidant activity and are potentially usable in a number of diseases.

Potential carcinogenicity of homoisoflavanoids and flavonoids from Resina sanguinis draconis (Dracaena cinnabari Balf.).

Polarographic behavior of three homoisoflavanoids and four flavanoids isolated from the dragon's blood (Resina sanguinis draconis. Dracaena cinnabari Balf.), collected at Sokotra, was investigated in aprotic solution and an index of potential carcinogenicity tg alpha was determined. Generally, homoisoflavanoids and flavanoids were reduced in two two-electron steps, the first being reversible and the second one irreversible. The parameter tg alpha values indicated that the majority of these compounds possesses no or only marginal potential carcinogenic activity. However, it was demonstrated that some structural modifications in basic flavonoid structure lead to changed electrochemical properties and a substantial increase of derivative potential carcinogenicity.

Floral volatiles ofTanacetum vulgare L. attractive toLobesia botrana den. et schiff. females.

The European grapevine moth (EGVM),Lobesia botrana, is a major pest of grapes in Europe. Females are attracted to a nonhost plant: tansy (Tanacetum vulgare L.), which is a common weed in Slovakian vineyards. A steam distillate extract of tansy flowers was analyzed by means of a GC-EAG technique to screen constituents detected by the olfactory receptors of EGVM females. From more than 200 GC peaks, nine peaks corresponding to monoterpenoids released an EAG response in more than 70% of the females (N=15):p-cymene,d-limonene,α-thujene,α-thujone,ß-thujone, thujyl alcohol, terpinene-4-ol, (Z)-verbenol, and piperitone. The steam distillate of tansy as well as a synthetic blend of identified compounds released consistent attraction in a field cage. The use of nonhost plants and host plant odors in integrated pest management is discussed.

[Propolis allergy]. / Zur Frage der Propolisallergie.

The incidence of propolis contact sensitivity was 1.2-3.3% among 7483 hospital patients during the period 1981-1987, while the prevalence among 1,558 healthy volunteers was 0.64%. A group of 26 patients with contact allergy to propolis was challenged with identified substances isolated from propolis. The mixture of 3-methyl-2-butenylester (3M2B) and 3-methyl-3-butenylester (3M3B) from caffeic acid caused a positive reaction in 7 patients, and in 5 of 9 patients there was a positive reaction to the mixture of 3M2B and 3M3B from diacetyl-caffeic acid. Among the 19 patients challenged with the flavonoid group, 3 had positive reactions, and individual derivatives of cinnamic acid caused positive reactions in 3 and 4 patients each. When five components taken from poplar buds were tested, the one that provoked the largest number of positive reactions was the methanol component (15 of 19 patients). The results show that propolis contact allergy is not caused by one main allergen, but by several allergens varying in chemical composition; the presence of these in propolis depends on the nature of the source plant and the place and time of collection by the bees.