Experimental and Clinical Evaluation of Nootropic Activity of Bacopa monniera Linn. (Brahmi).

Bacopa monniera Linn. (Brahmi) is an annual creeper belonging to family Scrophulariaceae and growing all over the Indian sub-continent in marshy areas. It is a major Medhya Rasayana used in Ayurveda for treatment of memory disorders. Large number of saponins and glycosides has been isolated from the plant. Most of the experimental and clinical studies have been done with crude extracts or standardized preparation of the two active saponins Bacosides A and B. Extracts or saponin mixture facilitate learning, improve consolidation of learned behavior and delay extinction in several models of learnt behavior in normal rats and mice as well as in chemically induced or transgenic models of Alzheimer's disease. They also prevent or reverse amnesia produced by drugs, stress or ischemic hypoxia. Other CNS effects include anti-anxiety, anti-convulsant and analgesic activity. Several mechanisms have been proposed to explain the mechanism of these CNS effects. Extracts as well as the bacoside preparation have been found safe and well tolerated in healthy volunteers in single dose or chronic administration for several weeks in a number of double blind placebo controlled studies in India and abroad. Chronic administration significantly improved information processing, learning and memory consolidation. It was found more effective than caffeine in a comparative study. Double blind placebo controlled studies with bacoside preparation have demonstrated beneficial effects and safety in elderly patients with Age Related Memory Impairment and in children with Attention Deficit Memory Disorder. It has also been found useful in anxiety neurosis, epilepsy and sleep disturbances in post menopausal women. The standardized preparation is marketed as a prescription drug after having obtained the necessary regulatory approval in India, Australia, New Zealand and South Africa and as an OTC product in several other south east Asian and African countries.

Picroliv prevents oxidation in serum lipoprotein lipids of Mastomys coucha infected with Plasmodium berghei.

Picroliv, an iridoid glycoside mixture from the root and rhizome of Picrorhiza kurrooa, at the dose of 6 mg/kg p.o. for two weeks provided significant protection against the generation of lipid peroxidation products in serum beta-lipoproteins of P. berghei infected M. coucha. Incubation of normal rat hepatocytes with very low density lipoprotein or low density lipoprotein isolated from infected animals caused significant generation of lipid peroxides followed by a decrease in the viability of these cells, however these effects were partially reversed with the lipoproteins from infected and picroliv treated groups. High density lipoprotein from infected animals was not toxic to hepatocytes in vitro.

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.

Quantification of behaviour in social colonies of rhesus monkey.

It is necessary to use experimental animals with behavioural, physiological and disease susceptibility pattern similar to man so that the results have a clinical predictive value. For such studies the non-human primate is the animal of choice. Rhesus monkey is a good choice for this purpose but information about its behaviour is fragmentary. In order to obtain a quantitative baseline data for psychopharmacological studies, a protocol has been developed to score various social and solitary behaviours in adult male and female rhesus monkeys. The study was conducted on rhesus monkeys in a social colony of one male and seven female living in a semi-restricted environment. The behavioural patterns were quantitated so as to compare effect on various components of behaviour. Aggressiveness and vigilance were prominent in the male while social affiliative behaviour was dominant in the female. Other behavioural responses were of similar magnitude in both sexes. It is however necessary to have data with some standard CNS active agents on these behavioural protocol. Therefore, initially the behavioural effects of amphetamine and haloperidol were studied. Significant effects observed following d-amphetamine (1-4 mg/kg, im); it induced dose dependent suppression of social behaviour (approach, contact, grooming), feeding, hypervigilance, stereotypy and oral hyperkinesia. On the other hand haloperidol (0.01-0.04 mg/kg, im) produced decrease in social and solitary behaviour and marked cataleptic posture. It is possible to quantitate drug effects on various aspects of behaviour of the rhesus monkey and to develop neuropsychitric models with the help of this protocol for use in study of drug effects on behaviour.

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.

Picroliv affects gamma-glutamyl cycle in liver and brain of Mastomys natalensis infected with Plasmodium berghei.

Picroliv, the standardized preparation of iridoid glycosides from Picrorhiza kurrooa, at the dose of 6 mg/kg, po for two weeks provided significant protection against depletion of reduced glutathione levels in liver and brain of Plasmodium berghei infected Mastomys natalensis. The activation of gamma-glutamyl transpeptidase enzyme and decreased levels of cysteine, sulphydryl groups as well as glutathione synthesis in both tissues due to P. berghei infection were reversed by picroliv. Enzymatic and non enzymatic lipid peroxidation in microsomes in vitro was significantly reduced by picroliv along with the recovery of reduced glutathione.

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.

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.

Effect of picroliv on glutathione metabolism in liver and brain of Mastomys natalensis infected with Plasmodium berghei.

Administration of picroliv, the active principle from Picrorhiza kurrooa, at a dose of 6 mg/kg, po for two weeks showed significant protection against changes in liver and brain glutathione metabolism of Plasmodium berghei infected Mastomys natalensis. The depletion of reduced glutathione level and inhibition of glutathione-S-transferase, glutathione reductase and glutathione peroxidase activities due to P. berghei infection were markedly recovered by picroliv. The increased levels of lipid peroxidation products in damaged tissues were also reduced along with the recovery of glutathione metabolism.

Bioactivity of marine organisms: Part VI--Screening of some marine flora from Indian coasts.

Alcoholic extracts of 50 botanically identified species of marine flora have been screened for a wide range of biological activities. Of these, 2 extracts exhibited anti-amoebic and antiviral activity each, 3 of them had anti-implantation activity; 9 had hypoglycaemic activity while hypotensive activity was associated with 11 extracts; 14 extracts were found to be diuretic and 1 of them had anti-inflammatory activity. Further, 10 of these extracts exhibited 2 types of activities while a combination of 3 and 4 types of activities was observed in one extract each. Follow-up studies have been carried out in some plants with confirmed activity. The active principles and results of these studies are reported.

Effect of picroliv on protein and nucleic acid synthesis.

Oral administration of picroliv, a standardised fraction of roots and rhizomes of Picrorhiza kurroa, showed stimulation of nucleic acid and protein synthesis in rat liver. Results are comparable with a standard hepatoprotective agent, silymarin.

Involvement of adrenergic & cholinergic mechanisms in analgesia electrically induced from pretectal nucleus of rat.

Analgesia induced by pretectal stimulation in rat was analysed using suitable antagonists. Mild electrical stimulation of sites in the pretectal nucleus (PTN) caused analgesia of long duration, without signs of aversion and unassociated with motor deficit. Pretreatment of animals with ip atropine sulphate (1 mg/kg), phenoxybenzamine (5 mg/kg), sotalol (2 mg/kg) and haloperidol (1 mg/kg) but not with saline, markedly reduced the antinociceptive response to PTN stimulation. Mild PTN stimulation thus seems to induce potent and long lasting analgesia in rats probably involving multisynaptic antinociceptive pathway(s).

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.

Effect of monoamine antagonists on pretectal evoked analgesia in rat.

Mild and brief electrical stimulation of sites in the pretectal nucleus of rat produced analgesia (SPA) of long duration without significant aversion. Intracerebroventricular (icv) administration of 5-HT receptor antagonists methysergide (50 micrograms) and ketanserin (50 micrograms) and the dopaminergic antagonist haloperidol (50 micrograms) had no significant effect on pretectal SPA, but alpha and beta adrenoceptor antagonists phenoxybenzamine (50 micrograms) and sotalol (50 micrograms) on icv injection significantly antagonised the pretectal SPA. The results suggest that pretectal SPA involves activation of central adrenoceptors.

Histamine H2 receptor mediated relaxation of hamster (Mesocricetus auratus) uterus.

Histamine and 4-methyl histamine produced relaxation of KCl depolarized hamster uterus in vitro. The relaxation was selectively antagonized by histamine H2 receptor antagonist cimetidine which failed to antagonize the isoprenaline induced relaxation. The histamine induced relaxation was, further, not mediated through catecholamine release. The study indicated that, as in the albino rat, histamine produces relaxation of the hamster uterus mediated via the H2 receptors.

Hepatoprotective activity of picroliv against carbon tetrachloride-induced liver damage in rats.

Administration of carbon tetrachloride to normal rats increased activities of hepatic 5(1)-nucleotidase, acid phosphatase, acid ribonuclease while the activities of succinate dehydrogenase, glucose 6-phosphatase, superoxide dismutase and cytochrome P450 were decreased. Levels of lipid peroxides, total lipids and cholesterol of liver were also increased. The activities of serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and alkaline phosphatase were increased. Other serum parameters showing changes after carbon tetrachloride were: bilirubin, proteins, cholesterol, triglycerides and lipoprotein-X. Picroliv (from the plant Picrorhiza kurroa) in doses of 6 and 12 mg/kg provided a significant protection against most of the biochemical alterations produced by carbon tetrachloride. The degree of protection afforded by picroliv, when administered simultaneously or as a pretreatment was almost equal.

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.

Evaluation of hepatoprotective activity of picroliv (from Picrorhiza kurroa) in Mastomys natalensis infected with Plasmodium berghei.

Administration of picroliv, a standardized fraction of alcoholic extent of Picrorhiza kurroa (3-12 mg/kg/day for two weeks) simultaneously with P. berghei infection showed significant protection against hepatic damage in Mastomys natalensis. The increased levels of serum glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), alkaline phosphatase, lipoprotein-X (LP-X) and bilirubin in the infected animals were marked reduced by different doses of picroliv. In the liver, picroliv decreased the levels of lipid peroxides and hydroperoxides and facilitated the recovery of superoxide dismutase and glycogen. Picroliv had no effect on the degree of parasitaemia.

Hepatoprotective activity of silymarin against hepatic damage in Mastomys natalensis infected with Plasmodium berghei.

Silymarin, a flavolignan from the seeds of Silybum marianum, showed significant hepatoprotective activity in P. berghei-induced hepatic damage in M. natalensis, as assessed by changes in several serum and liver biochemical parameters. Changes in lipoprotein-X, GOT, GPT, alkaline phosphatase and bilirubin were found to be protected by silymarin at different doses. Maximum activity was observed at a dose of 5 mg/kg bw, po. Silymarin had no effect on parasitaemia.