Spasmolytic activity of Toddalia asiatica Var. floribunda.

The spasmolytic activity of the aerial parts of Toddalia asiatica var. floribunda (family Rutaceae) was evaluated. The ethanol extract exhibited significant spasmolytic activity and was then partitioned into five fractions. The activity was found to be concentrated only in the hexane and chloroform fractions. This activity was shown not to be due to the coumarins, toddalolactone and toddanone, as was previously thought.

Ex vivo and in vivo investigations of picroliv from Picrorhiza kurroa in an alcohol intoxication model in rats.

Picroliv, the active constituent isolated from the plant Picrorhiza kurroa, was evaluated as a hepatoprotective agent against ethanol-induced hepatic injury in rats. Alcohol feeding (3.75 g/kg x45 days) produced 20-114% alteration in selected serum (AST, ALT and ALP) and liver markers (lipid, glycogen and protein). Further, it reduced the viability (44-48%) of isolated hepatocytes (ex vivo) as assessed by Trypan blue exclusion and rate of oxygen uptake. Its effect was also seen on specific alcohol-metabolizing enzymes (aldehyde dehydrogenase, 41%; acetaldehyde dehydrogenase, 52%) in rat hepatocytes. The levels of these enzymes were found to be reduced in the cells following alcohol intoxication. Ethyl alcohol also produced cholestasis (41-53%), as indicated by reduction in bile volume, bile salts and bile acids. Picroliv treatment (3-12 mg/kg p.o. x45 days) restored the altered parameters in a dose-dependent manner (36-100%).

Bioactivity of marine organisms: Part VIII--Screening of some marine flora of western coast of India.

Methanolic extracts of 31 botanically identified species of marine flora, collected from Gujarat Coast, have been screened for a wide range of biological activities. Of these, 3 extracts showed anti-implantation, 2 had antiviral, 2 showed hypotensive, 1 had anti-inflammatory while 12 extracts showed diuretic activities. The antiviral activity; against EMCV, was confirmed in one alga. The active principles and results of these studies are reported.

Evaluation of inhibitory effect of diphenhydramine on benzodiazepine dependence in rats.

Effect of diphenhydramine was investigated on withdrawal signs in lorazepam dependent rats. Physical dependence was produced by giving lorazepam admixed with the food in the following dose schedule: 10 x 4, 20 x 4, 40 x 4, 80 x 4 and 120 x 7 (mg/kg, daily x days). The parameters observed during the periods of administration of lorazepam and after its withdrawal were spontaneous locomotor activity (SLA), body temperature, reaction time to pain, foot shock aggression (FSA) and audiogenic seizures. Diphenhydramine was administered orally in the dose schedules of once daily (10, 20 and 40 mg/kg) and twice daily (5, 10 and 20 mg/kg) in separate groups during the withdrawal period. The withdrawal signs observed in control group (without diphenhydramine) were hyperkinesia, hyperthermia, hyperaggression and audiogenic seizures. Hyperkinesia and hyperthermia were blocked in all the groups of diphenhydramine-treated rats. FSA was inhibited only by diphenhydramine (10 and 20 mg/kg) given twice daily. Audiogenic seizures were completely blocked by once daily (20 and 40 mg/kg) as well as twice daily (20 mg/kg) doses of diphenhydramine. It may be concluded that diphenhydramine exerts a protective effects on benzodiazepine withdrawal syndrome.

Protective effect of picroliv, active constituent of Picrorhiza kurrooa, against oxytetracycline induced hepatic damage.

Picroliv, the active constituent of P. kurrooa, showed a dose dependent (1.5-12 mg/kg, po for 7 days) hepatoprotective activity against oxytetracycline induced hepatic damage in rat. It increased the number of viable hepatocytes (ex-vivo) significantly. Increase in bile volume and its contents in conscious rat suggests potent anticholestatic property. Picroliv also antagonised alterations in enzyme levels (GOT, GPT, and alkaline phosphatase) in isolated hepatocytes and serum, induced by oxytetracycline (200 mg/kg, i.p.) feeding. Picroliv was more potent than silymarin a known hepatoprotective drug.

Effect of calcium channel blockers on withdrawal syndrome of lorazepam in rats.

Effects of calcium channel blockers were investigated on withdrawal signs in lorazepam dependent rats. Physical dependence was produced by giving lorazepam admixed with the food in the following dose schedule: 10 x 4, 20 x 4, 40 x 4, 80 x 4 and 120 x 7 (mg/kg daily x days). Parameters such as body weight, food intake, spontaneous locomotor activity (SLA), body temperature, reaction time to pain, foot shock-aggression (FSA) and audiogenic seizures were observed during the period of administration of lorazepam and after its withdrawal. Calcium channel blockers viz. verapamil, nifedipine and nimodipine in different doses were administered orally twice daily in separate groups during the withdrawal period. The withdrawal signs observed in control group (without calcium channel blockers) were hyperkinesia, hyperthermia, hyper-aggression and audiogenic seizures. The administration of verapamil (5-20 mg/kg), nifedipine (1.75-7 mg/kg) and nimodipine (5-20 mg/kg) during the withdrawal period of lorazepam showed dose dependent significant blockade of all the withdrawal signs. Audiogenic seizures were completely blocked by 20 mg/kg dose of verapamil and nimodipine while nifedipine was partially effective. It may be concluded that calcium channel blockers exert protective effects on benzodiazepine withdrawal syndrome.

Screening of Indian plants for biological activity: Part XV.

Alcoholics extracts of 266 botanically identified plant materials from 222 plant species have been tested for various biological activities including chemotherapeutic and pharmacological screenings. Biological activities have been observed in 89 extracts. Follow-up studies have been carried out in some plants with confirmed activity. The active principles and results of these studies are reported.

Activity of certain fractions of Tribulus terrestris fruits against experimentally induced urolithiasis in rats.

An ethanolic extract of the fruits of T. terrestris showed significant dose dependent protection against uroliths induced by glass bead implantation in albino rats. On subsequent fractionation of the ethanol extract, maximum activity was localised in the 10% aqueous methanol fraction. It provided significant protection against deposition of calculogenic material around the glass bead. It also protected leucocytosis and elevation in serum urea levels. Further, fractionation lead to decreased activity. This could be either due to loss of active compounds during fractionation, or the antiurolithiatic activity of T. terrestris being a combined effect of several constituents present in the methanolic fraction.

Andrographolide protects rat hepatocytes against paracetamol-induced damage.

Andrographolide, the active constituent isolated from the plant Andrographis paniculata, showed a significant dose dependent (0.75-12 mg/kg p.o. x 7) protective activity against paracetamol-induced toxicity on ex vivo preparation of isolated rat hepatocytes. It significantly increased the percent viability of the hepatocytes as tested by trypan blue exclusion and oxygen uptake tests. It completely antagonized the toxic effects of paracetamol on certain enzymes (GOT, GPT and alkaline phosphatase) in serum as well as in isolated hepatic cells. Andrographolide was found to be more potent than silymarin, a standard hepatoprotective agent.

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

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.

Prevention of galactosamine-induced hepatic damage by picroliv: study on bile flow and isolated hepatocytes (ex vivo).

Picroliv, a standardized extract from the plant Picrorhiza kurrooa containing active constituents, showed a significant dose dependent (3-12 mg/kg p.o. x 7) protective activity against galactosamine-induced hepatic damage in rat as evaluated on the isolated hepatocytes (ex vivo) preparation. It markedly increased the percentage of viability of hepatocytes. It also restored the galactosamine-induced changes in the levels of enzymes (GOT, GPT and alkaline phosphatase) both in isolated hepatic cells as well as in serum. In addition, picroliv possessed a marked anticholestatic effect. Picroliv was found to be more potent than silymarin, a standard hepatoprotective agent.

Effect of picroliv on low density lipoprotein receptor binding of rat hepatocytes in hepatic damage induced by paracetamol.

Picroliv from root and rhizome of Picrorhiza kurroa showed reversal of low density lipoprotein (LDL) binding to paracetamol-induced damaged hepatocytes of rats. Changes in levels of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, alkaline phosphatase, conjugated dienes and lipids of hepatocytes were significantly prevented by picroliv at different doses. The effect of picroliv on enzyme levels, LDL receptor binding and lipids in damaged hepatocytes was found to be comparable to silymarin, a known hepatoprotective agent.

Pharmacological screening of few new 2-(substituted acetyl) amino-5-alkyl-1,3,4-oxadiazoles.

Nine new 2-(substituted acetyl) amino-5-alkyl-1,3,4-oxadiazoles were synthesised and confirmed on the basis of IR and nitrogen analysis. These were screened for spasmolytic, anti-inflammatory and their effects on blood pressure after determining ALD50. Compounds GK-4 i.e. 2-(diethylaminoacetyl)- amino-5-methyl-1,3,4-oxadiazole and GK-8 i.e. 2-(din-propylamino acetyl)-amino-5-ethyl-1,3,4-oxadiazole were found to be spasmolytic. Compound GK-6 i.e. 2-(diethylaminoacetyl)-amino-5-n-propyl-1,3,4-oxadiazole was found to be a potent hypotensive agent with the effect lasting for more than two hours.

Neuropsychopharmacological study of 2,4-dihydro[1,2,4]triazolo[3,4-c][1,4]benzothiazine-1-one (IDPH-791).

The neuropsychopharmacological profile of a new centrally acting skeletal muscle relaxant, 2,4-dihydro[1,2,4]triazolo[3,4-c][1,4]benzothiazine-1-one (IDPH-791), an analogue of triazolobenzothiazine, has been described and compared to mephenesin, a well known centrally-acting muscle relaxant. IDPH-791 was found to be safer and of longer duration of action than mephenesin in all the tests conducted in this study. Both IDPH-791 and mephenesin caused ataxia, decrease in spontaneous activity and inhibition of pinnal reflex. IDPH-791 was 1.5 to 2.0 times more potent in exhibiting motor inco-ordination and anticonvulsant activity than mephenesin in mice and rats. IDPH-791 was twice as active in inhibiting various spinal polysynaptic reflexes, crossed extensor, flexor, and linguomandibular reflexes; however, both did not affect the typical monosynaptic reflex, patellar reflex. IDPH-791 and mephenesin did not have sedative activity. Although mephenesin exhibited haemolytic activity, IDPH-791 was devoid of this activity. It is concluded that IDPH-791 is a safe and effective centrally-acting muscle relaxant having a longer duration of action than mephenesin. IDPH-791 is also devoid of sedative and haemolytic activity.

Choleretic effect of andrographolide in rats and guinea pigs.

Andrographolide from the herb Andrographis paniculata (whole plant) per se produces a significant dose (1.5-12 mg/kg) dependent choleretic effect (4.8-73%) as evidenced by increase in bile flow, bile salt, and bile acids in conscious rats and anaesthetized guinea pigs. The paracetamol induced decrease in volume and contents of bile was prevented significantly by andrographolide pretreatment. It was found to be more potent than silymarin, a clinically used hepatoprotective agent.

Antihepatotoxic properties of picroliv: an active fraction from rhizomes of Picrorhiza kurrooa.

The hepatoprotective activity of picroliv, the irridoid glycoside mixture from Picrorhiza kurrooa, was determined in adult male albino rats. Pretreatment with picroliv prevented the hepatotoxic effects of paracetamol and galactosamine as evidenced by various biochemical and histopathological observations. Maximum hepatoprotective effect was observed with daily oral doses of 6 and 12 mg/kg for 7 or 8 days. The antihepatotoxic action of picroliv seems likely due to an alteration in the biotransformation of the toxic substances resulting in decreased formation of reactive metabolites.

In vitro effect of Phyllanthus amarus on hepatitis B virus.

To evaluate the effects of P. amarus on hepatitis B virus (HBV) antigens and HBV-DNA, initial ethanolic extract and subsequent fractions of the plants were prepared. The whole plant material was dried, powdered and extracted with alcohol and subsequently fractionated in hexane, chloroform, butanol and finally in water. All the material were tested for in vitro effects on HBsAg, HBeAg and HBV-DNA in serum samples positive for HBV antigens followed by the screening of respective antigens by Elisa. HBV-DNA was determined by molecular hybridization. The extracts were effective against HBV antigens, the butanol extract being the most potent. Further chromatographic fractions showed an enhanced activity. The active fractions inhibited the interaction between HBsAg/HBeAg and their corresponding antibodies suggesting anti-HBs, anti-HBe-like activity and also an effect on HBV-DNA.

Choleretic effect of picroliv, the hepatoprotective principle of Picrorhiza kurroa.

Picroliv, the hepatoprotective principle of the plant Picrorhiza kurroa, showed a dose-dependent (1.5-12 mg/kg x 7) choleretic effect in conscious rats and anaesthetised guinea pigs. It also possessed a marked anticholestatic effect against paracetamol- and ethynylestradiol-induced cholestasis. It antagonised the changes in bile volume as well as the contents (bile salts and bile acids). Silymarin, a known hepatoprotective agent, was tested simultaneously for comparison. Picroliv was found to be a more potent choleretic and anticholestatic agent than silymarin.

In vitro studies on the effect of certain natural products against hepatitis B virus.

Picroliv (active principle from Picrorrhiza kurroa), its major components picroside I, catalpol, kutkoside I, kutkoside, andrographolide (active constituent of Andrographis paniculata), silymarin and Phyllanthus niruri extract were tested for the presence of anti hepatitis B virus surface antigen (anti HBs) like activity. HBsAg positive serum samples obtained from hepatitis B virus (HBV) associated acute and chronic liver diseases and healthy HBsAg carriers were used to evaluate the anti-HBs like activity of compounds/extract. The latter were mixed with serum samples and incubated at 37 degrees C overnight followed by HBsAg screening in the Elisa system. A promising anti-HBsAg like activity was noted in picroliv (and its major components) catalpol, P. niruri which differed from the classical viral neutralization. Picroliv also inhibited purified HBV antigens (HBsAg and HBsAg) prepared from healthy HBsAg carriers. The in vitro testing system appears to be a suitable model to identify an agent active against HBV, prior to undertaking detailed studies.