Hypoglycaemic effect of Artemisia herba alba. II. Effect of a valuable extract on some blood parameters in diabetic animals.

Artemisia herba alba is widely used in Iraqi folk medicine for the treatment of diabetes mellitus. However, very few scientific and medical studies were carried out to assess the efficacy and toxicity of A. herba alba. In this study feeding diabetic rats and rabbits with 0.39 g/kg body weight of the aqueous extract of the aerial parts of the plant for 2-4 weeks shows a significant reduction in blood glucose level, prevents elevation of glycosylated haemoglobin level and possesses a hypoliposis effect, in addition to the protection against body weight loss of diabetic animals.

Hypoglycaemic effect of Artemisia herba alba. I. Effect of different parts and influence of the solvent on hypoglycaemic activity.

Artemisia herba alba is widely used in Iraqi folk medicine for the treatment of diabetes mellitus. Oral administration of 0.39 g/kg body weight of the aqueous extract of the leaves or barks produced a significant reduction in blood glucose level, while the aqueous extract of roots and the methanolic extract of the aerial parts of the plant produce almost no reduction in blood glucose level. The extract of the aerial parts of the plant seem to have minimal adverse effect and high LD50 value.

Hypoglycemic activity of Artemisia herba alba.

Artemisia herba alba has been widely used in Iraqi folk medicine for the treatment of diabetes mellitus. Oral administration of an aqueous extract (0.39 g/kg) of the aerial parts of this plant to normoglycemic and to alloxan-diabetic rabbits produced significant hypoglycemic activity, which was consistent and time-dependent.

Toxicologic and histopathologic studies of Pleurotus ostreatus mushroom in mice.

The edible mushroom Pleurotus ostreatus (with locally reported toxic properties) was identified and collected 1-4 days after raining in the city of Baghdad. It was freshly extracted with distilled water at room temperature. Both oral and intraperitoneal routes were used for acute and subacute toxicity studies on mice. In spite of important toxicologic signs and findings on treated animals, the estimated 24-h LD50 values exceeded 3 g/kg for both routes of administration. However, the 30-day LD50 values were 319 mg/kg for oral and 1143 mg/kg for i.p. administration. Gross examination of the dissected organs revealed marked haemorrhages in the intestine, liver, lung and the kidney. Histopathologic examination revealed significant changes mainly in the liver, which took the form of inflammation and microabscesses. The present results were consistent with clinical findings available after human and animal ingestion of this mushroom in Iraq.

Some pharmacological, toxicological and phytochemical investigations on Centaurea phyllocephala.

Centaurea phyllocephala Boiss. has been used in folkloric medicine as an antidiabetic agent. Present investigations on various extracts of C. phyllocephala revealed that basal plasma glucose concentration and plasma glucose response to glucose load were either elevated or unchanged by the i.v. administration of these extracts in anaesthetized rats or by i.p. or oral administration of the extracts in conscious rats. The predominant effect of C. phyllocephala is the toxicity in rats and mice and this indicates the presence of some toxic or active compounds which merit phytochemical isolation. Further, C. phyllocephala extracts also caused either an initial brief hypotension followed by a delayed hypertension or produced no changes when injected i.v. in the rats. The hypotensive effect was inhibited by atropine whereas the hypertensive effect was prevented by phentolamine or guanethidine but not by hexamethonium. The alcoholic extract also induced an initial brief negative inotropic effect, followed by delayed prolonged positive inotropic and negative chronotropic effects on the spontaneous inotropic and negative chronotropic effects on the spontaneous contractions of the guinea pig right atrium. The initial depressing effect and the delayed positive inotropic effect were inhibited by pretreatment with atropine. The extract of C. phyllocephala also produced a contractile activity on guinea pig ileum strips and this could be prevented by atropine. No significant diuretic effect was produced by the extract. Phytochemical screening revealed that C. phyllocephala contains tertiary and quaternary alkaloids, sesquiterpene lactones, methylated flavones and their glycosides, as well as leuco- and proanthocyanidines. Further studies on sesquiterpene lactones and methylated flavones resulted in the isolation of lactones with alpha-methylene gamma-lactone and methylene side chain on the cyclopentyl ring as well as of four methylated flavones (hispidulin, nepetin, cirsiliol, jaceosidin) structurally closely related to the cytotoxic flavonoids of other Compositae plants.

Evaluation of combined adrenal demedullation and chronic guanethidine treatment as a sympathectomy procedure for metabolic studies.

The usefulness of a combination of adrenal demedullation and treatment with guanethidine (25 mg kg-1 day-1, i.p. for 14 days) as a sympathectomy procedure for metabolic studies was investigated in the rat. The procedure reduced markedly or abolished pressor and positive chronotropic responses to tyramine, nicotine or electrical stimulation of the sympathetic spinal outflow. Hyperglycaemic responses to nicotine or spinal sympathetic stimulation were abolished. Nicotine infusion in intact animals reduced glucose-induced hyperinsulinaemia. On the other hand nicotine infusion in sympathectomized animals produced a marked elevation in glucose-induced hyperinsulinaemia relative to that seen in intact animals. The early hyperinsulinaemic response to glucose infusion during sympathetic stimulation was markedly greater in sympathectomized rats compared with that seen in intact rats. The sympathectomy procedure did not modify the glycaemic responses to adrenaline or insulin or glucose-induced hyperinsulinaemia.

Some factors modifying the insulinotropic and cardiovascular effects of isoprenaline in the rat.

The effects of L-isoprenaline on plasma immunoreactive insulin (IRI) and glucose concentrations were examined in pentobarbitone anaesthetized rats. When given by bolus injection hyperinsulinaemia was produced only by very large doses of isoprenaline (100-200 micrograms/kg). Infusion of isoprenaline allowed the demonstration of hyperinsulinaemia at low dose rates (0.07-0.7 microgram kg-1 min-1). Pretreatment with phentolamine or production of a functional sympathectomy by bilateral adrenal demedullation and chronic guanethidine treatment augmented the hyperinsulinaemic effect of isoprenaline. Isoprenaline-induced hyperglycaemia was attenuated by sympathectomy and by phentolamine pretreatment, this attenuation being attributed to the augmented hyperinsulinaemic effect of isoprenaline under these conditions. The increase in heart rate and reduction in blood pressure produced by isoprenaline were also augmented in sympathectomized rats.