Pharmacological studies on aerial parts of Calotropis procera

The decoction of the aerial part of Calotropis procera is commonly used in Saudi Arabian traditional medicine for the treatment of variety of diseases including fever, joint pain, muscular spasm and constipation. The present investigation was undertaken to confirm its claimed activity in traditional medicine. The ethanol extract of the plant was tested on laboratory animals for its antipyretic, analgesic, anti-inflammatory, antibacterial, purgative and muscle relaxant activities. The results of this study showed a significant antipyretic, analgesic and neuromuscular blocking activity. On smooth muscle of guinea pig ileum, the extract produced contractions which was blocked by atropine supporting its use in constipation. The extract failed to produce significant anti-inflammatory and antibacterial activities. Our phytochemical studies on the aerial parts of C. procera showed the presence of alkaloids, cardiac glycosides, tannins, flavonoids, sterols and/or triterpenes. However, the chemical constituents responsible for the pharmacological activities remains to be investigated. The safety evaluation studies revealed that the use of extract in single high doses (up to 3 g/kg) does not produce any visible toxic symptoms or mortality. However, prolong treatment (90 days) causes significantly higher mortality as compared to control group.

Gastric antiulcer and cytoprotective effects of dipyridamole in rats

Dipyridamole has been studied for its ability to inhibit gastric secretion and to protect gastric mucosa against the injuries caused by hypothermic restraint stress, indomethacin and various necrotizing agents including 80% ethanol, 0.6 M HCl, 0.2 M NaOH and 25% NaCl in rats. The results of this study demonstrate that dipyridamole has both prophylactic and curative effects on various experimentally induced gastric ulcers. It produced inhibition of normal and histamine-stimulated gastric secretion in rats. The intensity of gastric lesions induced by indomethacin and hypothermic restraint stress was reduced significantly by dipyridamole. Our findings also showed that dipyridamole protect gastric wall against hypothermic restraint stress-induced mucus depletion. It produced marked cytoprotective effect against all the necrotizing agents used in this study. The cytoprotective effect of dipyridamole against 80% ethanol was reversed significantly by prior treatment with a dose of indomethacin that inhibits prostaglandin biosynthesis. These data indicate that dipyridamole inhibits the formation of gastric lesions by mucosal generation of prostaglandins. The concentration of nonprotein sulfhydryls were decreased significantly in gastric mucosa after administration of 80% ethanol. Treatment with dipyridamole replenish the reduced level of gastric mucosal nonprotein sulfhydryls, thus suggesting the mediation of its protective effect through sulfhydryls. Our findings show that dipyridamole possesses both antisecretory and antiulcer effects. Further studies are required to determine its role in the prophylaxis and or the treatment of gastric ulcer disease.

An evaluation of the male reproductive toxicity of cathinone

(-)-Cathinone is the major psychoactive component of khat plant (Catha edulis Forssk.). Khat has been shown to produce reproductive toxicity in human beings and experimental animals. However, the chemical constituents of khat leaves responsible for sexual dysfunction are not known. In the present study cathinone enantiomers have been investigated for their reproductive toxicity in rats. Cathinone produced a dose-dependent decrease in food consumption and suppressed the gain in body weight. There was a significant decrease in sperm count and motility and increase in the number of abnormal sperms in cathinone treated animals. Histopathological examination of testes revealed degeneration of interstitial tissue, cellular infiltration and atrophy of Sertoli and Leydig's cells in cathinone treated animals. Cathinone also produced a significant decrease in plasma testosterone levels of the rats. Although both enantiomers of cathinone produced deleterious effects on male reproductive system, (-)-cathinone was found to be more toxic. From this study it may be concluded that the cathinone content in khat may be partially or totally responsible for the reproductive toxicity in khat chewers.

The induction of dominant lethal mutations upon chronic administration of khat (Catha edulis) in albino mice

The mutagenicity of a methanolic extract of khat has been evaluated on male germ cells using the dominant lethal test in albino mice. An aqueous solution of khat extract was administered orally in doses of 50, 100 and 200 mg/kg body wt., respectively, to 3 different groups of male mice for a period of 6 weeks. At the end of treatment each male mouse was allowed to mate with 2 different groups of 3 females each, on 2 consecutive weeks. These females were necropsied on the 13th day of their presumptive mating, and the number of implants in each female and the ratio of live and dead embryos were determined. The results of this study showed that the treatment of male mice over a period of 6 weeks produced a dose-dependent reduction in the rate of fertility in the first week after mating, which was irreversible in the second week at the highest dose (200 mg/kg). Khat extract also induced post-implantation loss during the first week following treatment. However, a comparison of the results of the first and second weeks showed a reversible pattern of dominant lethality.

Comparison of intravenous and nasal bioavailability of clonidine in rodents

The bioavailability and cardiac depressant activity of 3H-clonidine was studied following intravenous and nasal administration in rodents. The drug is rapidly absorbed by nasal route, and the peak blood concentration is reached within 10 minutes. The area under the blood concentration-time curve, following intravenous and nasal routes, was found to be 3.55 x 10(5) counts/g/min and 3.75 x 10(5) counts/g/min respectively. The drug was found to eliminate slowly from blood. The t1/2 beta, following intravenous and nasal administration, was found to be 8.8 hr and 8.0 hr respectively. Our electrocardiographic studies, to compare myocardial depression following intravenous and nasal administration of clonidine, revealed that a bolus intravenous clonidine in the dose of 10 micrograms, 30 micrograms, and 100 micrograms/kg body weight produced a significant and transient decrease in heart rate in a dose dependent manner. One rat developed arrhythmia after receiving a higher dose of 100 micrograms/kg body weight of clonidine by intravenous route. However, only a mild decrease in heart rate was observed following nasal administration of clonidine. The examination of the nasal cavity one hour after the single dose of 100 micrograms/kg body weight of clonidine in rats showed no sign of erythema, oedema or lesions. These findings suggest that the nasal route may be a good substitute for I.V. administration of clonidine.

Effect of khatamines and their enantiomers on plasma triiodothyronine and thyroxine levels in normal Wistar rats

The effect of cathinone and N-formylnorephedrine, two psychoactive amines of khat (Catha edulis Forsk.) and their enantiomers have been studied on plasma levels of triiodothyronine (T3) and thyroxine (T4) in male Wistar rats. The rats were injected with 5, 10 and 30 mg/kg, body weight of four khatamines and the blood samples were collected 2 h after their administration. In the separate set of experiments the effect of these khatamines at 1, 2 and 4 h after their administration was also examined. All the khatamines failed to produce a significant dose dependent increase in T3 and T4 levels in the dose of 5 mg/kg. However, all of these compounds produced a significant dose dependent increase in T3 and T4 levels at higher doses but only T4 levels were increased following the dose of 10 mg/kg. Our studies on the effect of khatamines in T3 and T4 levels at various times showed a significant increase in T4 levels in all the four groups treated with various khatamines and the peak effect was observed at 2 h in case of (-)- and (+)-cathinone and 4 h in case of (-) and (+)N-formylnorephedrine. This study suggests that the symptoms observed in khat chewers including hyperthermia, anorexia, and metabolic changes may to some extent be attributed to the thyroid stimulating effect of khatamines. However, further studies are needed to establish the mechanism of release of thyroid hormones by these compounds and their involvement in the pharmacological effects.

Cyclopeptide alkaloids: further studies on mauritine-C and sativanine-C

The 14-membered cyclopeptide alkaloid mauritine-C and the 13-membered cyclopeptide alkaloid sativanine-C were isolated from Zizyphus spinea-christi and Zizyphus sativa commonly used in the Saudi Folklor medicine. The N-formyl derivatives of these compounds were prepared and their corresponding spectral data was analyzed. Fundamental differences were observed in the mass spectrometric fragmentation of the newly formed derivatives as compared to the parent compounds mass spectrometry was found a useful tool to substantiate the fragmentation pattern proposed for these potential natural products.

Studies on herbal aphrodisiacs used in Arab system of medicine

Toxicity studies were conducted on Brassica rapa, Prunus amygdalus and Zingiber officinale, used as aphrodisiacs in Arab Medicine. During acute toxicity test observations were made for 24 h where all these plants showed no toxicity. The animals were treated for 3 months in chronic treatment. External morphological changes, visceral toxicity, haematological changes, effects on average body weight, vital organ weight, sperm contents, sperm motility and sperm abnormalities were recorded. The average body weight increase was significant in B. rapa and P. amygdalus treated animals. Haematological studies revealed reduction in WBC level in these groups. These changes were not significant in Z. officinale treated animals. In all three groups the visceral condition was normal and the percent lethality was insignificant as compared to the control. All these plant extracts significantly increased the sperm motility and sperm contents in the epididymides and vas deferens without producing any spermatotoxic effect.

Saudi folk medicine: phytochemical and antimicrobial screening

Plants of 25 families, encompassing 30 species were selected on the basis of their folklore uses and literature data for the present screening. Besides phytochemical screening the plant extracts were prepared and tested for their antimicrobial activity. The result of the testing showed that about 77% of these plants exhibited some level of antibacterial activity. The most common chemical constituents found in these plants were sterols and/or triterpenes, falvonoids, alkaloids and tannins. Volatile oils, volatile bases, saponins, coumarins, anthraquinones and cardiac glycosides were also detected.

Comparative study of cathinone and amphetamine on brown adipose thermogenesis

The effect of cathinone and amphetamine on brown adipose tissue thermogenesis and its modification with propranolol and timolol has been studied in rats. Both cathinone and amphetamine produced significant dose dependent increases in intracapsular brown adipose tissue (IBAT) and rectal temperatures. Amphetamine was found to be three times more potent as compared to cathinone, on a dose basis. Pretreatment of animals with propranolol and timolol individually inhibited cathinone and amphetamine induced hyperthermia. These findings suggest the involvement of beta adrenergic receptors in cathinone and amphetamine induced thermogenesis.

Gastroprotective activity of ginger zingiber officinale rosc., in albino rats

The cytoprotective and gastric anti-ulcer studies of ginger have been carried out in albino rats. Cytodestruction was produced by 80% ethanol, 0.6M HC1, 0.2M NaOH and 25% NaCl. Whereas gastric ulcers were produced by ulcerogenic agents including indomethacin, aspirin and reserpine, beside hypothermic restraint stress and by pylorus ligated Shay rat technique. The results of this study demonstrate that the extract in the dose of 500 mg/kg orally exert highly significant cytoprotection against 80% ethanol, 0.6M HC1, 0.2M NaOH and 25% NaCl induced gastric lesions. The extract also prevented the occurrence of gastric ulcers induced by non-steroidal anti-inflammatory drugs (NSAIDs) and hypothermic restraint stress. These observations suggest cytoprotective and anti-ulcerogenic effect of the ginger.

Genetic effects of chronic treatment with cathinone in mice

The mutagenicity of (-)-cathinone has been evaluated in the germ cells of male albino mice using a dominant lethal test. An aqueous solution of cathinone was administered orally at doses of 5, 20 or 40 mg/kg body wt, respectively to three different groups of male mice for a period of six weeks. After treatment, each male was allowed to mate with two different groups of three females each, on two consecutive weeks. These females were necropsied on the 17th day after mating. The number of implants in each female and the ratio of live and dead embryos was determined. The results of this study showed that treatment of male mice over a period of 6 weeks produced a dose-dependent reduction in fertility with total sterility at a dose of 40 mg/kg body wt. Cathinone also induced dose-dependent post-implantation loss during the first week following treatment. However, no dominant lethality was detected during the second week of mating.

Cytological effects of khat (Catha edulis) in somatic and male germ cells of mice

Cytological effects of khat (Catha edulis), a popular drug of abuse from Southern Arabia and Eastern Africa, have been studied in Swiss albino mice. The studies on the somatic system involved the use of micronucleus test and the cytological analysis of the mitotic index in the femoral cells of mice. In the micronucleus test, the mice were treated with different doses of khat extract (125, 250 and 500 mg/kg, p.o.) 30 and 6 hours before sacrificing the animals. The polychromatic erythrocytes were screened for the induction of micronuclei. For the analysis of bone marrow cytotoxicity, the mice were treated with the dose of 125, 250 and 500 mg/kg, body weight, p.o. daily for 5 consecutive days. The animals were sacrificed and the femoral cells were microscopically examined for the mitoses. Following the same schedule of treatment, studies on the cytogenetic analysis of meiotic chromosomal aberrations and the sperm head abnormality were undertaken. Khat extract significantly increased the frequency of micronucleated polychromatic erythrocytes, induced bone marrow depression and reduced the mitotic index of the somatic cells. It induced significant chromosomal aberrations viz., aneuploids, autosomal univalents, univalents of the sex chromosomes and polyploids. The frequency of abnormal sperms was also increased.

Gastric anti-ulcer and cytoprotective effect of vitamin E in rats

Effect of vitamin E on the gastric mucosal damage induced by hypothermic restraint stress, indomethacin, reserpine, hydrochloric acid, sodium chloride and ethanol has been studied in rats. The results demonstrate that pretreatment of animals with vitamin E produces a significant inhibition of gastric lesions induced by above mentioned agents. An increase in the synthesis of prostaglandins, and high level of glutathione in tissues of vitamin E treated animals have been suggested as a possible mechanism of anti-ulcer activity of -tocopherol. However, further studies are required to confirm these effects and to determine the role of vitamin E in the prophylaxis and treatment of peptic ulcer disease.

Effect of some new prostaglandin synthetase inhibitors on the endotoxin induced mortality and biochemical changes in experimental animals

The protective effect of some novel nonsteroidal anti-inflammatory agents has been studied on the endotoxin (lipopolysaccharide B) shock induced mortality in mice and biochemical changes in rats. All the three compounds included in this report, namely isoxicam, fentiazac and ketoprofen have been found to produce significant protection against the endotoxin mortality in mice. Isoxicam and fentiazac have been found effective in antagonizing some of the biochemical changes induced by endotoxin in rats. On the other hand isoxicam and ketoprofen exacerbated the increase in serum aminotransferases induced by endotoxin. It is suggested that mechanisms other than the prostaglandin synthetase inhibition may be involved in the protective effect of these drugs.

Bioavailability of indenolol by nasal and intravenous routes

The blood levels of indenolol were determined in rats following nasal and intravenous administration of 5 mg/kg body weight of the drug. The results indicate that the peak drug levels reach within 10 minutes of nasal administration. The areas under the curve for nasal and intravenous routes were found to be 65.67 (ng x hr)/ml and 65.32 (ng x hr)/ml respectively. The results suggest that nasal route may be of practical value for the administration of indenolol.

Gastric anti-ulcer and cytoprotective effect of selenium in rats

Selenium, a trace element, in the form of sodium selenite has been studied for its ability to protect the gastric mucosa against the injuries caused by hypothermic restraint stress, aspirin, indomethacin, reserpine, dimaprit, and various other gastric mucosal-damaging (necrotizing) agents in rats. The results demonstrate that oral administration of sodium selenite produces a significant inhibition of the gastric mucosal damage induced by all the procedures used in this study. Selenium, in a nonantisecretory dose, produced a marked cytoprotective effect against all the necrotizing agents. The cytoprotective effect of selenium against the effects of 80% ethanol and 0.6 M HCl was significantly reversed by prior treatment with a dose of indomethacin that inhibits prostaglandin biosynthesis. These data indicate that sodium selenite inhibits the formation of these lesions by the mucosal generation of prostaglandins. The concentrations of nonprotein sulfhydryls (NP-SH) were significantly decreased in the gastric mucosa following the administration of necrotizing agents--80% ethanol and 0.6 M HCl. Treatment with sodium selenite, which significantly reduced the intensity of gastric lesions, did not replenish the reduced levels of gastric mucosal NP-SH, thus ruling out the mediation of its protective effect through sulfhydryls. The antisecretory effect of sodium selenite, which becomes evident only in the high dose of 20 mumol/kg, may be responsible for the inhibition of gastric lesions induced by aspirin, indomethacin, reserpine, and dimaprit. Our findings show that selenium possesses significant anti-ulcer and adaptive cytoprotective effects. However, further detailed studies are required to confirm these effects, to establish its mechanism(s) of action, and to determine its role in the prophylaxis and treatment of peptic ulcer disease.

Proglumide, a cholecystokinin receptor antagonist, exacerbates alloxan-induced diabetes mellitus in Swiss mice

The effect of proglumide ((+/-)-4-benzamido-N,N-dipropyl-glutaramic acid), a gastrin and cholecystokinin receptor antagonist, has been studied on the fasting plasma glucose (FPG) and insulin levels in normal and alloxan-diabetic mice. In normal mice, proglumide, administered as a single oral dose or twice daily for five consecutive days, did not produce any alteration in those parameters. Injection of alloxan monohydrate (70 mg kg-1 i.v.) produced a significant decrease in plasma insulin and a significant elevation of FPG levels on the 5th day after its administration as evidence of diabetes mellitus. Proglumide sodium, given as a single acute dose on the 5th day of alloxan injection, or as a twice daily dose for 5 days immediately after alloxan injection, significantly exacerbated the hyperglycaemia and further decreased the plasma insulin levels thus worsening the diabetogenic effect of alloxan. These observations point to a possible involvement of cholecystokinin (CCK) in alloxan-induced diabetes and indicate a need for monitoring the levels of FPG in diabetic patients being treated with a high dose of proglumide or other CCK-antagonists.

Gastric cytoprotection: a critical appraisal of the concept, methodology, implications, mechanisms and future research prospects

Gastric cytoprotection is the property of certain substances, particularly prostaglandins, when used in non-antisecretory doses, to protect the gastric mucosa from becoming inflamed and necrotic on being exposed to noxious agents. An association between alterations in endogenous prostaglandins and gastric mucosal damage induced by a number of drugs has also been observed. The process of adaptive cytoprotection in which mild irritants protect the gastric mucosa against the damaging effects of various necrotizing agents has been shown to be prostaglandin mediated. However, the exact mechanisms underlying this cytoprotective activity have still not been elucidated although a number of hypotheses have been proposed. Recently, thromboxanes, leukotrienes and endogenous sulfhydryls have also been suggested to be involved in the pathogenesis of gastric mucosal damage induced by various necrotizing agents. This review attempts to provide an up-to-date appraisal of the concept, methodology, mechanisms and implications of this phenomenon and suggests that prostaglandins and endogenous sulfhydryls may play a significant role in the pathogenesis of gastric ulceration and may serve an important function in maintaining normal gastric mucosal integrity.

Effect of thromboxane A2 and leukotriene C4 inhibitors on the experimentally induced gastric lesions in the rat

Effects of OKY-046, a thromboxane synthetase inhibitor; BM 13.177, a thromboxane A2-receptor antagonist and FPL 55712, a leukotriene antagonist have been studied on gastric lesions induced by necrotizing agents (80% ethanol, 0.6 M HCl, 0.2 M NaOH, 25% NaCl and 100 mM sodium taurocholate), aspirin, indomethacin, reserpine and hypothermic restraint stress in rats. Ro 22-6923, a synthetic trimethyl prostanoid has been used for comparison. OKY-046, FPL 55712 and Ro 22-6923 produced dose dependent inhibition of gastric lesions induced by necrotizing agents and reduced the severity of aspirin, indomethacin, reserpine and hypothermic restraint stress induced lesions. BM 13.177 was not found effective against any of the models used in this study. These observations indicate towards the role of thromboxane A2 and leukotriene C4 in the genesis of gastric lesions induced by different methods. FPL 55712 required considerably lower doses than those of OKY-046 to display its protective effects in these models. Further studies on the levels of thromboxane A2 and leukotriene C4 in the gastric mucosa, are suggested to substantiate these observations.

Studies on the possible mechanism of morphine-induced potentiation of the gastroulcerogenic effect of indomethacin in rats

Morphine has been shown to produce a significant potentiation of indomethacin-induced gastric lesions in rats. The exact mechanism of this response has still not been worked out. Hence, in the present study, the effects of pirenzepine, cimetidine, disodium cromoglycate, OKY-046 (a thromboxane A2 synthesis inhibitor), BM 13.177 (a thromboxane A2 receptor antagonist), FPL 55712 (a leukotriene C4 antagonist) and a synthetic trimethylprostanoid, Ro 22-6923 have been studied on the gastric ulcers produced by indomethacin and its combination with morphine in rats. Only naloxone, FPL 55712 and Ro 22-6923 significantly reduced the morphine-potentiated ulcerogenic response of indomethacin as compared to the indomethacin ulcers in the groups pretreated with these drugs. It is, therefore, proposed that the potentiating effect of morphine is mediated through the opiate receptors, which, in some way, increase leukotriene C4 and decrease prostaglandin-like activities in the gastric mucosa. Further studies on the levels of leukotriene C4 and endogenous prostaglandins are suggested to substantiate these findings.

Effect of a low-dose endotoxin pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine in rats

The effect of endotoxin pretreatment (1 mg/kg body weight, i.p., once daily for 2 days) on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine has been studied in albino rats. When given alone, endotoxin did not produce any visibly discernible gastric lesions. It produced a significant augmentation of the gastric lesions produced by phenylbutazone and reserpine but did not significantly alter the ulcerogenicity of aspirin. The involvement of endogenous histamine formation and its release following phenylbutazone and reserpine administration and also in response to endotoxin pretreatment may be responsible for the exacerbation of gastric lesions induced by these drugs. Recent reports indicate the involvement of endorphins and platelet activating factor (PAF) in the ulcerogenic activity of endotoxin when used in high doses and their role in the potentiation of phenylbutazone- and reserpine-induced gastric lesions has to be worked out.

Gastric and duodenal antiulcer and cytoprotective effects of proglumide in rats

Proglumide has been studied for its ability to inhibit gastric secretion and to protect the gastroduodenal mucosa against the injuries caused by pyloric ligation, hypothermic restraint stress, acetic acid, nonsteroid anti-inflammatory drugs, reserpine, cysteamine and the cytodestructing agents: 80% ethanol, 0.6 M HCl, 0.2 M NaOH, 25% NaCl and 30 mg of acetylsalicylic acid in 0.35 M HCl in rats. The results of this study demonstrate that proglumide has both prophylactic and curative effects on various experimentally induced ulcers. It produced a dose-dependent inhibition of gastric secretion in the pylorus-ligated rats and reduced significantly the intensity of gastric lesions induced by pyloric ligation, hypothermic restraint stress, acetic acid, mucosal damaging agents and that of duodenal ulcers induced by cysteamine. The intensity of gastric lesions induced by nonsteroid anti-inflammatory drugs and reserpine was also reduced significantly by proglumide. Cimetidine, which was used as a standard antiulcer drug for comparison, also produced a similar protective effect in most of the models used by us. It was found to have a more potent antisecretory effect but failed to protect the rats against the gastric mucosal damage induced by hyperthermic restraint stress and 0.2 M NaOH. Our findings suggest that proglumide exerts these antiulcer effects by its antisecretory, gastric mucosal resistance increasing and cytoprotective activities. Further studies are required to find out its exact mechanism of action and therapeutic usefulness.

Clastogenic evaluation of cathinone and amphetamine in somatic cells of mice

Clastogenic effects of cathinone, the active principle from khat (Catha edulis) and amphetamine, a compound having similar chemical structure and pharmacological activity, have been studied on the somatic cells of mice. Both of them produced marked clastogenic activity and affected the cell proliferation in the bone marrow of mice. They induced a significant increase in the frequency of micronucleated polychromatic erythrocytes at higher doses. These results substantiate our earlier observations on the clastogenic and mitodepressive activity of cathinone on the meristematic region of Allium cepa, and indicate that cathinone may be responsible for the mutagenic effect of khat reported by other workers. The clastogenic effects of amphetamine are being reported for the first time. Further studies are required to substantiate these findings and to study whether cathinone and amphetamine produce a direct clastogenic effect or whether they act as spindle poisons.

Evaluation of Artemisia inculta for anti-inflammatory activity in rats

The ethanolic extract of Artemisia inculta has been screened for anti-inflammatory, analgesic and antipyretic activities on suitable experimental models. It has been found to produce significant inhibition of carrageenan induced paw edema and cotton pellet induced granuloma pouch and a significant decrease in the prothrombin time in rats. It failed to produce any analgesic or antipyretic activity on the hot plate reaction time and yeast induced hypyrexia tests in mice. It also did not produce any effect on the platelet aggregation and fibrinogen level in the rats. Amongst the phytoconstituents detected in this plant, flavonoids may be responsible for the observed anti-inflammatory effect of the ethanolic extract.

Some central effects of indenolol in experimental animals

Indenolol, a relatively new beta-adrenergic blocking drug, was tested for its effect on the central nervous system. The parameters included its effects on spontaneous motor activity, conditioned avoidance response (CAR) acquisition, pentobarbitone hypnosis, amphetamine induced motor excitation, analgesic activity and rectal temperature in experimental animals. Indenolol was found to significantly decrease the spontaneous motor activity in mice and CAR acquisition in rats. It potentiated the pentobarbitone induced hypnosis and antagonized amphetamine induced excitatory behaviour in mice. It did not show a marked analgesic effect of its own but potentiated the analgesia induced by the subanalgesic dose of morphine. It also produced a significant hypothermic effect in mice. All the effects except on CAR acquisition were obtained in the dose of 50-75 mg/kg body weight administered intraperitoneally. It enhanced CAR acquisition in the specific dose of 5 mg/kg. These observations indicate that indenolol possesses an anxiolytic effect similar to that reported for propranolol and some other beta-blocking drugs.

Gastric antisecretory, gastric and duodenal anti-ulcer and cytoprotective properties of Ro 22-6923, a synthetic trimethyl prostanoid in rats

Ro 22-6923, a synthetic trimethyl prostanoid, has been studied for its ability to inhibit gastric secretion and to protect the gastroduodenal mucosa against the injuries caused by pyloric ligation, hypothermic restraint stress, nonsteroidal anti-inflammatory drugs (NSAIDs), reserpine, dimaprit, cysteamine and the cytodestructing agents--80% ethanol, 0.6 M HCl, 0.2 M NaOH, 25% NaCl, aspirin 30 mg in 0.35 M HCl and 100 mM sodium taurocholate in 0.2 M HCl. The results of this study demonstrate that Ro 22-6923 has both prophylactic and curative effects on various experimental models. It produces a dose dependent inhibition of the gastric mucosal damage induced by pyloric ligation, hypothermic restraint stress, NSAIDs, reserpine, dimaprit and cytodestructing agents and that of duodenal ulcers induced by cysteamine. It also produces a dose dependent healing of the acetic acid induced chronic gastric ulcers. These observations suggest that Ro 22-6923 exerts its anti-ulcer effects by its antisecretory, gastric mucosal resistance increasing and cytoprotective activities and that it may be a useful therapeutic agent for the treatment of peptic ulcer disease in humans.

Evaluation of genotoxic potential of khat (Catha edulis) in Swiss albino mice

Genotoxicity of the methanolic extract of khat (Catha edulis) has been evaluated on the male germ cells using the dominant lethal assay procedure in Swiss albino mice. The extract was administered at a dose of 500 mg/kg orally once daily, for five days. Following this sub-acute dose regimen, the effect of khat was studied during the different stages of spermatogenic cycle on the rate of pregnancy and post-implantation losses. Khat reduced the percent pregnancy rates and increased the mean post-implantation losses in the treated group. The increase was found to be statistically significant in the post-meiotic stages.

Effect of nicotine and alcohol pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats

The effect of nicotine and alcohol pretreatment by feeding nicotine (2.5 mg/100 ml), alcohol (25%, v/v) and their combination (nicotine 2.5 mg/100 ml + alcohol 25%, v/v) in drinking water ad libitum for 21 days was studied on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats. When given alone, neither nicotine nor alcohol produced any visibly discernible gastric lesions. Their concurrent administration, however, produced minor injury to the gastric mucosa appearing as 5-7 circular ulcers of less than 1 mm in diameter. Pretreatment with nicotine, alcohol, and their combination resulted in the significant augmentation of gastric ulcers produced by aspirin, phenylbutazone, and reserpine. The augmentation of gastric lesions in the group pretreated with the combination of nicotine and alcohol was significantly greater than in the groups treated by either of them alone. The effect of nicotine on the mucus neck cell population of the gastric mucosa and pancreatic bicarbonate secretion, and the gastric mucosal damaging effect of chronic alcohol treatment may be responsible for the potentiation of ulcerogenic effects of aspirin, phenylbutazone, and reserpine.

Anti-inflammatory activity of some Saudi Arabian medicinal plants

Five plants which have been used for the treatment of rheumatism, arthritis and gout in the traditional medicine of Saudi Arabia, were evaluated for their anti-inflammatory properties. Of these the ethanolic extract of Capparis decidua and the aqueous extract of Capparis spinosa were found to possess significant anti-inflammatory activity against carrageenan induced oedema in rats. These two plants were also tested for their antipyretic and analgesic activity. C. decidua was found to possess significant antipyretic effect. Both of them are devoid of analgesic activity.

Anti-inflammatory activity of Commiphora molmol

The petroleum ether extract of the oleo-gum resin of Commiphora molmol, at a dose of 500 mg/kg body weight, produced significant inhibition of carrageenan induced inflammation and cotton pellet granuloma. The extract also showed significant antipyretic activity in mice. Further studies on the fractionation of phytoconstituents and their mechanism of action are in progress.

The antidiabetic activity of aloes: preliminary clinical and experimental observations

The dried sap of the aloe plant (aloes) is one of several traditional remedies used for diabetes in the Arabian peninsula. Its ability to lower the blood glucose was studied in 5 patients with non-insulin-dependent diabetes and in Swiss albino mice made diabetic using alloxan. During the ingestion of aloes, half a teaspoonful daily for 4-14 weeks, the fasting serum glucose level fell in every patient from a mean of 273 +/- 25 (SE) to 151 +/- 23 mg/dl (p less than 0.05) with no change in body weight. In normal mice, both glibenclamide (10 mg/kg twice daily) and aloes (500 mg/kg twice daily) induced hypoglycaemia after 5 days, 71 +/- 6.2 and 91 +/- 7.6 mg/dl, respectively, versus 130 +/- 7 mg/dl in control animals (p less than 0.01); only glibenclamide was effective after 3 days. In the diabetic mice, fasting plasma glucose was significantly reduced by glibenclamide and aloes after 3 days. Thereafter only aloes was effective and by day 7 the plasma glucose was 394 +/- 22.0 versus 646 +/- 35.9 mg/dl, in the controls and 726 +/- 30.9 mg/dl in the glibenclamide treated group (p less than 0.01). We conclude that aloes contains a hypoglycaemic agent which lowers the blood glucose by as yet unknown mechanisms.

Decrease by naloxone of some electrocardiographic and biochemical changes following endotoxin induced shock in rats

Administration of endotoxin, a lipopolysaccharide extracted from cell walls of gram negative bacteria, elicited alterations in various metabolic parameters and in the electrocardiogram of rats. Cardiac glycogen and serum glucose were decreased, while serum pyruvate and acid phosphatase levels were increased. There was initial tachycardia followed by significant bradycardia and elevation of the ST segment in the animals with shock. Erythrocyte count, haemoglobin and haematocrit were not changed after shock. Treatment with naloxone caused significant decreases in the metabolic and electrocardiographic changes induced by endotoxin.

Anti-inflammatory activity of the flavonoid fraction of khat (Catha edulis Forsk)

The administration of the flavonid fraction, isolated from Khat (Catha edulis Forsk), in a dose of 200 mg/kg orally, produced a significant anti-inflammatory activity against the carrageenan induced paw oedema and cotton pellet granuloma in albino rats. The results were comparable with the standard anti-inflammatory drug oxyphenbutazone.

Pharmacological studies on Salvia haematodes Wall

The aqueous extract of the root of Salvia haematodes has been investigated for its pharmacological actions on the cardiovascular and central nervous system. It was found to possess significant cardiotonic and anticonvulsant activities. It was not found toxic up to the dose of 5 g/kg given orally in order to evaluate its acute toxicity.

Effect of nicotine, alcohol and caffeine pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine in rats

The effects of nicotine (2.5 mg/100 ml), alcohol (25% v/v) and caffeine (30 mg/100 ml base) and their combination (nicotine, 2.5 mg/100 ml; alcohol, 25% v/v; and caffeine, 30 mg/100 ml base) fed in drinking water ad libitum for 21 days were studied on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine in rats. When given alone, none of them produced any visibly discernible gastric lesions. Their concurrent administration, however, produced some injury to the gastric mucosa which was far less severe than the lesions induced by any of the ulcerogenic drugs used in this study. Pretreatment with nicotine, alcohol and caffeine and their combination resulted in a significant augmentation of gastric lesions produced by aspirin, phenylbutazone and reserpine. These results establish an association between nicotine, alcohol and caffeine in the pathogenesis of gastric ulcers and also implicate them as modifying factors in the genesis of gastric lesions induced by aspirin, phenylbutazone and reserpine.

Effect of nicotine and caffeine pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats

The effect of nicotine and caffeine pretreatment by feeding nicotine (2.5 mg %), caffeine (30 mg % base), and their combination (nicotine 2.5 mg % + caffeine 30 mg %) in drinking water ad libitum for 21 days was studied on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats. When given alone, neither nicotine nor caffeine produced any visibly discernible gastric lesions. Their concurrent administration too, did not produce any gastric mucosal injury. Pretreatment with nicotine, caffeine, and their combination resulted in significant augmentation of gastric ulcers produced by aspirin, phenylbutazone, and reserpine. However, caffeine administration produced a comparatively less profound augmentation of experimentally induced gastric lesions than that produced by nicotine pretreatment. The enhancement of gastric ulcers in the groups pretreated with the combination of nicotine and caffeine followed by one of the drugs was significantly greater than in the groups treated by either of them alone. The effect of nicotine on the mucus neck cell population of the gastric mucosa and on pancreatic bicarbonate secretion and the gastric secretory effect of caffeine may be responsible for the potentiation of the ulcerogenic effects of aspirin, phenylbutazone, and reserpine.

Effect of bromocriptine, a dopamine receptor agonist, on the experimentally induced gastric ulcers in albino rats

The effect of bromocriptine, a dopamine receptor agonist, has been studied on the aspirin, phenylbutazone and reserpine induced gastric ulcers in rats. A single dose of bromocriptine 4 mg/kg s.c. produced a significant exacerbation of gastric ulcers induced by all the three ulcerogenic drugs, whereas in the same dose administered once daily for 5 consecutive days, it produced a marked protective effect in all the models. A review of the literature shows that different mechanisms may be involved in the opposite effects of acutely and chronically administered bromocriptine observed in this study. The study also points towards a role of dopamine in the pathogenesis of gastroduodenal ulceration.

Effect of sucralfate on the bioavailability of indenolol

Effect of concurrent administration of sucralfate on the bioavailability of indenolol in rats has been investigated. Albino rats were administered with lg/kg body weight of sucralfate just before the oral administration of indenolol solution (10 mg/kg), blood samples were collected at 0,15,30,45,60,120,240 and 360 minutes after the administration of drugs. Indenolol concentration was determined spectrofluorometrically, 2,4, and 6-hour Area Under the Curve (AUC) was calculated. The peak indenolol blood concentration was observed at 45th minute of drug administration. The level in rats treated with indenolol alone (2.46 +/- 0.07 microgram/ml) and indenolol along with sucralfate (1.21 +/- 0.06 microgram/ml) suggested more than a 50% decrease. There were 36.4%, 27.2% and 20.4% decrease in 2-hour AUC, 4-hour AUC and 6-hour AUC respectively. The data suggest that sucralfate significantly decreased the absorption of indenolol, especially in the early phase after administration and clinically significant interaction may occur due to concurrent administration of indenolol with sucralfate.

The effect of nicotine pretreatment on the gastric mucosal damage induced by aspirin and reserpine in rats

The effect of nicotine pretreatment by feeding nicotine (5mcg/ml) in drinking water ad libitum for 10 days was studied on the aspirin and reserpine induced gastric mucosal damage in rats. The administration of nicotine resulted in the significant augmentation of aspirin (P less than 0.01) and reserpine (P less than 0.05) induced gastric ulcers. The mechanism(s) involving the sensitization of gastric mucosa towards the ulcerogenic effect of aspirin and reserpine may be responsible for the increased intensity of gastric ulcers in both the groups. The study indicates the possibility of a similar interaction in heavy smokers who ingest these drugs.