Showing papers in "Indian Journal of Experimental Biology in 1993"

Effect of leaf extract of Aegle marmelose in diabetic rats

Abstract: Alloxan induced animal model was used to evaluate the potential antidiabetic effect of A. marmelose leaf extract. The diabetic animals were given insulin injection and another group A. marmelose leaf extract orally. It maintained the weight of the animals near to the control rats but a significant decrease in weight was noted in diabetic animals without any treatment. The blood glucose level in treated animals were near to that of control ones. Also a significantly increased glucose tolerance was observed in animals orally given the leaf extract prior to the experiment. A significant decrease in liver glycogen (1.24 +/- .07 g/100 g of wet tissue) was observed in diabetic rats which was brought to almost the normal level (1.84 +/- .14 g/100 g) with leaf extract treatment. Blood urea and serum cholesterol increased (62.66 +/- 3.50 and 192.67 +/- 13.64 mg/dl) significantly in alloxan diabetic rats. The leaf extract treatment decreased the blood urea and serum cholesterol (37.83 +/- 3.97 and 99.20 +/- 8.43 mg/dl) to that of control ones. A similar effect was seen with insulin treatment. The results indicate that the active principle in A. marmelose leaf extract has similar hypoglycaemic activity to insulin treatment.

Hypoglycemic effect of Ocimum sanctum leaf extract in normal and streptozotocin diabetic rats.

Abstract: Oral administration of alcoholic extract of leaves of O. sanctum led to marked lowering of blood sugar level in normal, glucose fed hyperglycemic and streptozotocin induced diabetic rats. Further the extract potentiated the action of exogenous insulin in normal rats. The activity of the extract was 91.55 and 70.43% of that of tolbutamide in normal and diabetic rats respectively.

Antitumor and radiosensitizing effects of Withania somnifera (Ashwagandha) on a transplantable mouse tumor, Sarcoma-180.

Abstract: Antitumor and radiosensitizing effects of alcoholic root extract of W. somnifera and their modification by heat were studied in vivo on Sarcoma-180 grown on the dorsum of adult BALB/c mouse. Ashwagandha (AT) was injected (ip) at a dose of 500 mg/kg body wt for 10 consecutive days into mouse bearing tumor of 50 +/- 5 mm3, with or without a local treatment of 10 Gy gamma radiation (RT) or hyperthermia at 43 degrees C for 30 min (HT) or both on 5th day of AT. The response was assessed on the basis of tumor regression, growth delay, animal survival and changes in the tumor GSH content. Ashwagandha, RT and HT individually produced 18, 38 and 45% complete response (CR) respectively, but RT gave the best long term survival. Ashwagandha increased the effect of radiation on tumor regression as well as growth delay, but AT + HT gave a better tumor cure. However, both these combinations gave almost identical long term survival, which was not much higher than that produced by RT alone. The combination of Ashwagandha for 10 days with one local exposure to RT followed by HT significantly increased the tumor cure, growth delay of partially responding tumors and animal survival. This combination also significantly and synergistically depleted the tumor GSH level, with no recovery even at 3 hr after treatment. It is concluded that Ashwagandha, in addition to having a tumor inhibitory effect, also acts as a radiosensitizer and heat enhances these effects. The severe depletion in the tumor GSH content by the combination treatment must have enhanced the tumor response, as the inherent protection by the thiol will be highly reduced.

Anticholestatic effect of picroliv, active hepatoprotective principle of Picrorhiza kurrooa, against carbon tetrachloride induced cholestasis.

Abstract: Picroliv showed a dose (3-12 mg/kg, po for 7 days) dependent choleretic activity as evidenced by increase in bile flow and its contents (bile salts and bile acids). Significant anticholestatic activity was also observed against carbon tetrachloride induced cholestasis in conscious rat, anaesthetized guinea pig and cat. Picroliv was more active than the known hepatoprotective drug silymarin.

Antidiabetic effects of a glycoside of leucopelargonidin isolated from Ficus bengalensis Linn.

Abstract: Glycoside of leucopelargonidin isolated from the bark of F. bengalensis demonstrated significant hypoglycemic, hypolipidemic and serum insulin raising effects in moderately diabetic rats with close similarities to the effects of a minimal dose of glibenclamide. The main difference observed in their effects was that the former significantly enhanced the fecal excretion of sterols and bile acids while the later has no such action even though both controlled hypercholesteremia.

Mechanism of blood sugar lowering by a swerchirin-containing hexane fraction (swi) of swertia chirayita

Abstract: Mechanism of blood sugar lowering by the crude/impure swerchirin (SWI) isolated from the hexane fraction of Swertia chirayita was investigated. Single oral administration of SWI (50 mg/kg, body wt) to fed CF rats induced about 60% (max.) fall in blood glucose by 7 hr post-treatment. This was associated with marked depletion of aldehyde-fuchsin stained beta-granules and immunostained insulin in the pancreatic islets. In vitro, glucose uptake and glycogen synthesis by muscle (diaphragm) was significantly enhanced by the serum of SWI-treated rat. At 100, 10 and 1 microM final concentration, SWI greatly enhanced glucose (16.7 mM)-stimulated insulin release from isolated islets. It is therefore concluded that SWI lowers blood glucose level by stimulating insulin release from islets of Langerhans.

Antifilarial effect of two triterpenoid saponins isolated from Acacia auriculiformis.

Abstract: The active principle, isolated from the funicles of A. auriculiformis, consisted of two triterpenoid saponins, acaciaside A and acaciaside B which killed in vitro 97% microfilaria of Setaria cervi in 100 min at 4mg/ml concentration and 100% of adults in 35 min. The drug, when administered orally at 100 mg/kg on rats, in which S. cervi adults were implanted intra-peritoneally, increased the blood mf count by 1.5-fold after the first phase of treatment for 10 days. Following the third phase of treatment and thereafter, the mf density was reduced by more than 80%. No toxic effect of the saponins was observed in rats. The rise in mf count indicated that the drug induced a very high physiological stress on the adult worms which increased the rate of discharge of the mf before impending death. The treated rats on autopsy did not show any adult worms.

Photoperiodism in Japanese quail (Coturnix coturnix japonica) with special reference to relative refractoriness.

Abstract: Cloacal gland (an androgen dependent sex accessory) of Japanese quail exhibits full breeding condition as long as these were maintained under long days (LD 16:8). When shifted to short daylength (LD 6:18), scotosensitivity (cloacal gland regression) was observed up to 5 weeks, followed by scotorefractoriness (cloacal gland development). There was a regression in cloacal gland volume of the birds when shifted to intermediate daylength (LD 13.5:10.5 and 13:11) after 12 weeks of exposure to long days (relative refractoriness) but no regression when shifted to relatively short days (< 14 hr) after 3 weeks of exposure to long daylength. Birds maintained under constant short photoperiod (LD 6:18) exhibited cyclicity. Shift experiments (quail reared and maintained under continuous light; LL, were shifted to LD 16:8, 13:11 and 8:16, similarly quail maintained under LD 16:8 were shifted to rest three photoperiods and so on) made to compare the cloacal gland responses indicated that if the difference between two photoperiods (previous and shifted one) was more the percentage of difference in cloacal gland response was also high. Short daylength (LD 8:16) was always gonadoinhibitory for the quail previously exposed to any daylength (13L, 16L or 24L) and 16L and 24L were always stimulatory for the quail previously exposed to other daylength (8L, 13L, 16L). But, when the birds were shifted to 13L, photoresponses cannot be generalized and it depends on the photoperiod to which quail were exposed previously (i.e. photoperiodic history).

Role of lipid peroxides, glutathione and antiperoxidative enzymes in alcohol and drug toxicity.

Abstract: Ethanol administration to rats for 30 days and 90 days followed by paracetamol administration resulted in liver injury indicated by the significant increase in the serum GOT and GPT levels. The ethanol treatment to rats and the administration of paracetamol to the normal and alcoholic rats also caused a significant increase in the activity of serum acid and alkaline phosphatase. The hepatotoxicity of ethanol and paracetamol were indicated by the histological alterations in this study. The content of lipid peroxidation products-malondialdehyde, hydroperoxides and conjugated dienes were increased in the liver, heart, kidney and brain of the acute and chronic ethanol treated and paracetamol treated rats. The activities of the antiperoxidative enzymes-SOD and catalase decreased in the ethanol and paracetamol treated rats. The changes in the activities of the antiperoxidative enzymes in alcoholism and drug toxicity suggests increased peroxidation, increased synthesis of ecosonoids and increased damage to the tissues. The glutathione levels were decreased in the rats administered ethanol for 30 days, while the glutathione levels increased in the 90 days ethanol treated rats. The paracetamol treatment caused a decrease in the glutathione levels in the normals and the ethanol treated rats.

Inhibition of lipid peroxidation by piperine during experimental inflammation in rats.

Abstract: Carrageenin induced rat paw oedema shows a direct co-relationship with liver lipid peroxidation and not with kidney or brain. Pretreatment with piperine or oxyphenylbutazone reduced the liver lipid peroxidation, acid phosphatase and oedema induced by carrageenin. However, no such co-relationship was observed with treatment of these anti-inflammatory agents in control animals. It is, therefore, suggested that the inhibition of these liver enzymes is non specific in nature.

Additive effect of alcohol and nicotine on lipid metabolism in rats.

Abstract: Administration of alcohol along with nicotine in rats showed an increase in the concentration of cholesterol, triglycerides, phospholipids and free fatty acids in serum and various tissues compared to that of alcohol fed rats. The increased cholesterogenesis was evidenced by the increased activity of HMG CoA reductase, increased incorporation of labelled acetate in to cholesterol and decreased hepatic degradation of cholesterol to bile acids. The concentration of cholesterol in HDL lipoprotein fraction decreased, while in LDL + VLDL fraction increased. Administration of nicotine along with alcohol is found to enhance the lipogenic tendency of alcohol in rats.

Effect of piracetam on electroshock induced amnesia and decrease in brain acetylcholine in rats.

Abstract: Piracetam, a prototype of a new class of psychotropic agents, the nootropic agents, which improve learning ability and memory retention, was found to induce a dose-related prevention of disruption of acquisition of a passive avoidance response produced by electroshock application. The amnesia attenuating effect of piracetam was accompanied by prevention of the decrease in acetylcholine concentrations of rat brain induced by electroshock. The study indicates that the cognition enhancing effect of piracetam may be due to a facilitatory effect on cholinergic transmission.

Aluminum ingestion alters behaviour and some neurochemicals in rats.

Abstract: Effect of aluminum (Al) has been investigated on the brain of rats exposed to this metal (500 mg Al/liter in drinking water) daily for 180 days. A significant reduction in the spontaneous locomotor activity was noticed after 90 and 180 days of Al exposure to the rats, the magnitude of the change being almost identical at both the time intervals. Aluminum exposure also produced significant deficits in acquisition and retention of learned response in active avoidance situation, these changes being time dependent. A significant retardation of the extinction of the learned task was noted in Al exposed rats especially at 180 days. There was significant increase in the lipid peroxidation and decrease in the activity of Mg(2+)-ATPase and Na+,K(+)-ATPase in the brain of rats at 180 days after Al exposure. The increase in the contents of the metal was maximum in rest of the brain region (87% of control) followed by hippocampus and cerebral cortex (59% of controls), cerebellum and corpus striatum (43% and 44% of controls, respectively) after 180 days. Whether Al is responsible to initiate neurotoxic effects by producing changes in the structure and function of the plasma membrane needs further investigations.

Histomorphological changes in lung of rats following exposure to wood smoke.

Abstract: Rats were exposed to repeated, intermittent exposure to smoke generated from combustion of 1g wood/15 min, total period for 75 min daily under dynamic exposure conditions, over a period of 15, 30 and 45 days. First 15 days exposure caused mild bronchiolitis, hyperplasia and hypertrophy of bronchiolar epithelial lining cells, some necrosed lining cells desquamated into lumens, congestion of parenchymatous blood vessels, oedema, hyperplasia of lymphoid follicles, peribronchiolar and perivascular infiltration of polymorphonuclear cells, and mild emphysema. These lesions progressed further during 30 and 45 days of exposure, though emphysematous changes remain constant. By 30 days and 45 days, hyperplastic and hypertrophic changes of bronchioles become quite marked, with mononuclear cells infiltration and alveolar septa thickening. Hematological studies show marginal alterations in hemoglobin levels, ESR, PCV and TLCS during 15 days, where as significant changes in eosinophil were observed during 30 and 45 days, and ESR during 45 days only. The results indicate progressive pathomorphological pulmonary lesions with subsequent exposure to wood smoke in controlled conditions.

Restoration of tissue antioxidants and prevention of renal stone deposition in vitamin B6 deficient rats fed with vitamin E or methionine.

Abstract: Observed loss in body weight gain, increased lipid peroxidation reaction, decreased concentrations of antioxidants, ascorbic acid, alpha-tocopherol and reduced glutathione and antioxidant enzymes, glutathione peroxidase and catalase and increased concentration of hydroperoxides and hydroxyl radicals in vitamin B6 deficient rat liver [J Nutri Biochem, 2 (1991) 245] and kidney [Biochem International, 21 (1991) 599] were nearly normalized on feeding with vitamin E or methionine. Accumulation of oxalate and calcium during vitamin B6 deficiency was abolished by feeding vitamin E or methionine. Calcium oxalate deposition observed in vitamin B6 deficient kidney was completely prevented when fed along with vitamin E or methionine. However the hyperoxaluria and hypercalciuria persisted even after feeding with vitamin E or methionine.

Purification of two azoreductases from Escherichia coli K12.

Abstract: Two azoreductases (I and II) were purified to homogeneity from extracts of E. coli K12. Azoreductase I was a dimer of two identical subunits of molecular weight 28000 whereas azoreductase II was a monomer of 12,000 molecular weight. Both NADH and NADPH functioned as electron donors for the azoreductases. Azoreductase I and II used Ponceau SX, Tartrazine, Amaranth and Orange II as substrates. Ponceau SX was the best substrate for both the enzymes. However, azoreductase II utilized tartrazine, amaranth and orange II less efficiently than azoreductase I.

Evaluation of vanillic acid analogues as a new class of antifilarial agents

Abstract: A number of vanillic acid analogues (1-14) have been synthesised and evaluated against experimental filarial infections using cotton rats (Sigmodon hispidus) infected with Litomosoides carinii, a primary screening model, at a dose of 30 mg/kg, ip for 5 days. Of the 8 compounds tested, 4 (5,7, 11 and 12) exhibited high micro- and macro-filaricidal activity with sterilization of surviving female worms. Compounds 5, 7, 12 showed remarkable adulticidal action (> 80%). Sterilization of the female worms by compounds 11 and 12 was highly significant (80-100%).

Protective effect of BR-16A (Mentat), a herbal preparation on alcohol abstinence-induced anxiety and convulsions

Abstract: Chronic administration of ethanol (2-5 g/kg, po) on days 1 to 6 and its withdrawal produced anxiogenic reaction in mice and rats as assessed on the elevated plus-maze. Daily administration of BR-16A (100 mg/kg) prior to ethanol intoxication for 6 days prevented withdrawal induced anxiety in both rats and mice. However, acute administration of a single dose of BR-16A, to animals withdrawn from ethanol, i.e. on the 7th day, showed significant anxiogenic response. Ethanol withdrawal also sensitized the convulsogenic reaction to pentylenetetrazole (PTZ). A non-convulsive dose (40 or 60 mg/kg) of PTZ produced full blown convulsions and increased mortality in ethanol withdrawn rats and mice, respectively. Both acute and chronic administration of BR-16A (100 mg/kg) exhibited significant protection against ethanol withdrawal-induced reduction in PTZ threshold in rats and mice. The results suggest the usefulness of this safe herbal psychotropic preparation in the management of ethanol withdrawal reactions.

Antifertility activity of Ailanthus excelsa Linn. in female albino rats.

Abstract: Alcoholic extract of leaf and stem bark of A. excelsa at a dose of 250 mg equivalent of plant material/kg body weight, exhibited remarkably high anti-implantation and early abortifacient activities. The results are in agreement with the traditional use of this plant as a abortifacient by the Irula women of the Nilgiri district.

Anti-platelet activating factor property of Rubia cordifolia Linn.

Abstract: Rubia cordifolia is clinically used for the purification of blood by the physicians of the Indian System of Medicine. For the first time, the effect of the partially purified fraction of this whole plant has been studied on rabbit platelets. It inhibits the platelet aggregation induced by PAF (platelet activating factor) but not thrombin. It also inhibits the binding of 3H-PAF to the platelets in the dose-dependent manner. Thus it appears that R. cordifolia inhibits action of PAF at its receptor level either by it's blocking or by desensitization.

Effect of biotic and abiotic factors on pupation height in four species of Drosophila.

Abstract: Effect of different biotic and abiotic factors such as sex, density, larval development time, moisture, temperature and light on pupation height were tested in Drosophila ananassae, D. bipectinata, D. malerkotliana and D. biarmipes which are commonly distributed in India. In the four species there are no sex differences in pupation height. Density of larvae and moisture content of food medium strongly influence pupation height. Larval development time, light and temperature also affect pupation height but there are intra- and interspecific variations in response to these factors for pupation site preference. Thus pupation site preference in these Indian species of Drosophila is influenced by various biotic and abiotic factors. The comparison of the present results with those found in other species clearly indicates that different species may vary in their response to different factors.

(+/-)Baclofen sensitive scopolamine-induced short-term memory deficits in mice.

Abstract: Possible involvement of GABA receptor systems in scopolamine-induced short-term memory deficits was investigated using latency of mice to reach shock-free zone (SFZ) and number of mistakes (descents) the animal made in 15 min as parameters for acquisition and retention of memory in passive avoidance paradigm. Atropine (1-5 mg/kg), scopolamine (0.1-0.5 mg/kg) but not pirenzepine (5-20 mg/kg) caused disruption of memory. GABA (50, 75 and 100 mg/kg) showed retention enhancing effects in scopolamine-treated and untreated animals but GABA agonist progabide (5-20 mg/kg) did not affect any of the parameter significantly. GABAA agonist, muscimol (0.05 and 0.1 mg/kg) and GABAB agonist, (+/-)baclofen (0.25, 0.5 and 1 mg/kg) and (-)baclofen (0.25 and 0.5 mg/kg) also displayed memory enhancing action. Whereas, GABAA antagonist, bicuculline produced hind limb rigidity, GABAB antagonist, CGP 35348 did not show any effect per se, but reversed the (+/-)baclofen-induced delay in latency, without affecting retention enhancing action of (+/-)baclofen. Combined administration of subeffective dose of GABA (50 mg/kg) and (+/-)baclofen (0.25 mg/kg), showed a significant improvement in acquisition and retention. However, the effect of GABA (100 mg/kg) on acquisition was reversed by bicuculline (2 mg/kg) and by CGP 35348 (100 mg/kg) while improving retention. The present study extends support to the cholinergic concept in cognitive performance and provide an evidence for the influence of GABAergic (particularly GABAB) modulation in scopolamine-induced learning and memory deficits in mice.