Showing papers in "Indian Journal of Experimental Biology in 2000"

Cellular and clinical implications of glutathione.

Abstract: abundant intracellular thiol compound present in virtually all mammalian tissues -• Functions of GSH in reductive processes are essential for the synthesis and also degradation of proteins, formation of the deoxyribonucleotid precursors of deoxyribonucleic acid (DNA), regulation of enzymes, and protection of the cells against reactive oxygen species and free radicals produced even in normal metabolism•. By its multifunctional properties GSH attracts the interest of researchers in various subjects such as enzyme mechanisms, biosynthesis of macromolecules, intermediary metabolism, drug metabolism, radiation, cancer, oxygen toxicity, transport, immunology, endocrinology, environmental toxins, aging and exercise·-. Most of the new information about GSH biochemistry is produced with selective inhibitors of the enzymes involved in GSH turnover. Selective modulation of GSH metabolism also makes new therapeutic approaches possible• Glutathione metabolism still looks promising to scientists in cell biology and exercise physiology thanks to its central role in the antioxidant defense and modulation by specific inhibitors for experimental purposes. In addition, glutathione may have clinical importance since enzyme deficiencies of the glutathione metabolism may cause haemolytic anemia and neurologic symptoms in children· ' 11 and

Hypoglycemic, diuretic and hypocholesterolemic effect of Winter cherry (Withania somnifera, Dunal) root

Abstract: Hypoglycemic, diuretic and hypocholesterolemic effects of roots of W. somnifera (ashvagandha) were assessed on human subjects. Six mild NIDDM subjects and six mild hypercholesterolemic subjects were treated with the powder of roots of W. somnifera for 30 days. Suitable parameters were studied in the blood and urine samples of the subjects along with dietary pattern before and at the end of treatment period. Decrease in blood glucose was comparable to that of an oral hypoglycemic drug. Significant increase in urine sodium, urine volume, significant decrease in serum cholesterol, triglycerides, LDL (low density lipoproteins) and VLDL (very low density lipoproteins) cholesterol were observed indicating that root of W. somnifera is a potential source of hypoglycemic, diuretic and hypocholesterolemic agents. Clinical observations revealed no adverse effects.

Influence of dietary ginger (Zingiber officinales Rosc) on antioxidant defense system in rat: comparison with ascorbic acid.

Abstract: Ginger (Z. officinale; 1% w/w) significantly lowered lipid peroxidation by maintaining the activities of the antioxidant enzymes--superoxide dismutase, catalase and glutathione peroxidase in rats. The blood glutathione content was significantly increased in ginger fed rats. Similar effects were also observed after natural antioxidant ascorbic acid (100 mg/kg, body wt) treatment. The results indicate that ginger is comparatively as effective as ascorbic acid as an antioxidant.

Antioxidant activity of tannoid principles of Emblica officinalis (amla) in chronic stress induced changes in rat brain.

Abstract: Effect of tannoid principles emblicanin A, emblicanin B, punigluconin, and pedunculagin of E. officinalis was assessed on chronic unpredictable footshock-induced stress-induced perturbations in oxidative free radical scavanging enzymes in rat brain frontal cortex and striatum. Chronic stress, administered over a period of 21 days, induced significant increase in rat brain frontal cortical and striatal superoxide dismutase (SOD) activity, concomitant with significant reduction in catalase (CAT) and glutathione peroxidase (GPX) activity. The changes in the enzyme activities was accompanied by an increase in lipid peroxidation, in terms of augmented thiobarbituric acid-reactive products. Administration of Emblica tannoids (10 and 20 mg, po) for 21 days, concomitant with the stress procedure, induced a dose-related alteration in the stress effects. Thus, a tendency towards normalization of the activities of SOD, CAT and GPX was noted in both the brain areas, together, with reduction in lipid peroxidation. The results indicate that the reported antistress rasayana activity of E. officinalis may be, at least partly due to its tendency to normalize stress-induced perturbations in oxidative free radical scavenging activity, in view of the postulate that several stress-induced diseases, including the process of aging, may be related to accumulation of oxidative free radicals in different tissues.

Adaptogenic activity of Siotone, a polyherbal formulation of Ayurvedic rasayanas

Abstract: Siotone (ST) is a herbal formulation comprising of Withania somnifera, Ocimum sanctum, Asparagus racemosus, Tribulus terristris and shilajit, all of which are classified in Ayurveda as rasayanas which are reputed to promote physical and mental health, improve defence mechanisms of the body and enhance longevity. These attributes are similar to the modern concept of adaptogenic agents, which are, known to afford protection of the human physiological system against diverse stressors. The present study was undertaken to investigate the adaptogenic activity of ST against chronic unpredictable, but mild, footshock stress induced perturbations in behaviour (depression), glucose metabolism, suppressed male sexual behaviour, immunosuppression and cognitive dysfunction in CF strain albino rats. Gastric ulceration, adrenal gland and spleen weights, ascorbic acid and corticosterone concentrations of adrenal cortex, and plasma corticosterone levels, were used as the stress indices. Panax ginseng (PG) was used as the standard adaptogenic agent for comparison. Additionally, rat brain levels of tribulin, an endogenous endocoid postulated to be involved in stress, were also assessed in terms of endogenous monoamine oxidase (MAO) A and MAOB inhibitory activity. Chronic unpredictable footshock induced marked gastric ulceration, significant increase in adrenal gland weight and plasma corticosterone levels, with concomitant decreases in spleen weight, and concentrations of adrenal gland ascorbic acid and corticosterone. These effects were attenuated by ST (50 and 100 mg/kg, p.o.) and PG (100 mg/kg, p.o.), administered once daily over a period of 14 days, the period of stress induction. Chronic stress also induced glucose intolerance, suppressed male sexual behaviour, induced behavioural depression (Porsolt's swim despair test and learned helplessness test) and cognitive dysfunction (attenuated retention of learning in active and passive avoidance tests), and immunosuppression (leucocyte migration inhibition and sheep RBC challenged increase in paw oedema in sensitized rats). All these chronic stress-induced perturbations were attenuated, dose-dependently by ST (50 and 100 mg/kg, p.o.) and PG (100 mg/kg, p.o.). Chronic stress-induced increase in rat brain tribulin activity was also reversed by these doses of ST and by PG. The results indicate that ST has significant adaptogenic activity, qualitatively comparable to PG, against a variety of behavioural, biochemical and physiological perturbations induced by unpredictable stress, which has been proposed to be a better indicator of clinical stress than acute stress parameters. The likely contribution of the individual constituents of ST in the observed adaptogenic action of the polyherbal formulation, have been discussed.

Mechanism of plant growth promotion by rhizobacteria.

Abstract: Plant growth results from interaction of roots and shoots with the environment. The environment for roots is the soil or planting medium which provide structural support as well as water and nutrients to the plant. Roots also support the growth and functions of a complex of microorganisms that can have a profound effect on the growth anti survival of plants. These microorganisms constitute rhizosphere microflora and can be categorized as deleterious, beneficial, or neutral with respect to root/plant health. Beneficial interactions between roots and microbes do occur in rhizosphere and can be enhanced. Increased plant growth and crop yield can be obtained upon inoculating seeds or roots with certain specific root-colonizing bacteria- 'plant growth promoting rhizobacteria'. In this review, we discuss the mechanisms by which plant growth promoting rhizobacteria may stimulate plant growth.

Protective antioxidant effect of vitamins C and E in streptozotocin induced diabetic rats.

Abstract: We have investigated the protective effect of vitamin C and E together supplementation on oxidative stress and antioxidant enzyme activities in the liver of streptozotocin-induced diabetic rats, unsupplemented diabetic and control rats. We also determined the levels of both the vitamins and oxidative stress in plasma. Vitamin supplementation in diabetic rats lowered plasma and liver lipid peroxidation, normalised plasma vitamin C levels and raised vitamin E above normal levels. In liver, the activity of glutathione peroxidase was raised significantly and that of glutathione-S-transferase was normalised by vitamin supplementation in diabetic rats. The levels of lipid peroxidation products in plasma and liver of vitamin-supplemented diabetic rats and activities of antioxidant enzymes in liver suggest that these vitamins reduce lipid peroxidation by quenching free radicals.

Hypoglycemic effect of aqueous extract of Enicostemma littorale Blume (chhota chirayata) on alloxan induced diabetes mellitus in rats.

Abstract: The whole plant aqueous extract of E. littorale was tested for its hypoglycemic activity on normoglycemic, hypergly­ cemic and alloxan induced diabetic rats. Blood sugar lowering activity was not observed in normoglycemic and glucose loaded hyperglycemic rats in the short time experiment. But in case of diabetic rats, the fall of blood sugar after 30 days treatment with the aqueous extract was found to be significant (P

Semecarpus anacardium Linn. nuts--a boon in alternative medicine.

Abstract: In alternative medicine, medicinal plant preparations have found widespread use particularly in the case of diseases not amenable to treatment by modern methods. Chemical and phytochemical analyses of Semecarpus anacardium nut reveal the presence of biflavonoids, phenolic compounds, bhilawanols, minerals, vitamins and amino acids. A variety of nut extract preparations from this source are effective against many diseases, viz. arthritis, tumours, infections etc. and non-toxic even at high dose of 2000 mg/kg. However understanding of the mechanism of the pharmacological action of S. anacardium nut can be greatly aided by the isolation of its active principle from the nut and determination of the structure-function relationship. Also, the potent curative effect of S. anacardium nut extract against human ailments need to be verified by controlled clinical studies.

Study on cephalopod's ink for anti-retroviral activity.

Abstract: Aqueous extracts of ink from four cephalopods, adult and young Sepiella inermis and Loligo duvaucelli were tested against Moloney murine leukaemia virus reverse transcriptase (MMLV RT). Ink from young cephalopods, S. intermis and L. duvaucelli showed strong inhibition of MMLV RT.

Effect of Piper longum Linn, Zingiber officianalis Linn and Ferula species on gastric ulceration and secretion in rats.

Abstract: Use of Dipaniya Mahakasaya, a group consisting of 10 herbal drugs, has been suggested in Charaka Samhita to improve digestion. Out of these 10 plants, three, viz. P. longum (water decoction), Z. officianalis (water decoction) and Ferula species (colloidal solution) were studied for their antiulcer and mechanism of antiulcer effects in rats. All the drugs in the dose of 50 mg/kg, p.o., 60 min prior to experiment, showed significant protection against gastric ulcers induced by 2 hr cold restraint stress, aspirin (200 mg/kg, 4 hr) and 4 hr pylorus ligation. The antiulcerogenic effect seemed to be due to the augmentation of mucin secretion and decreased cell shedding rather than offensive acid and pepsin secretion which however, were found to be increased by them.

Radiosensitization of a mouse melanoma by withaferin A: in vivo studies.

Abstract: The radiosensitizing effect of a plant withanolide, withaferin A, on the B16F1 mouse melanoma was studied in vivo. Treatment of 100 mm3 tumours with 10 to 60 mg/kg withaferin A intraperitoneally produced a dose dependent increase in growth delay and volume doubling time. Injection of 30-50 mg/kg withaferin A, followed by 30 Gy local gamma irradiation, significantly enhanced the tumour response. No systemic or local adverse reactions were noted in these groups. The drug was most effective when injected intraperitoneally 1 h before irradiation. However, neither the individual agents nor their combination could produce any complete response (tumour cure). Melanoma is a relatively radioresistant tumour. The present results indicate that the radiation response of this tumour can be significantly enhanced by pretreatment with withaferin A.

Growth inhibitory and antifeedant activity of extracts from Melia dubia to Spodoptera litura and Helicoverpa armigera larvae.

Abstract: The growth inhibitory activity and deterrency of Melia dubia (Meliaceae) extracts to Spodoptera lilllra and Heficovl'11J(/ armigera were investigated Artiticial diet bioassays using neonate larvae of both S litura and H armigera indicated that dichloroethane (DCE) and methanol (Me) extracts of M dubia inhibited growth in a dose dependent manner DCE and Me-SII fractions also resulted in SO% deterrency at concentrations of 22S and 168 Ilglcm2 respectively against S lilura larvae in a leaf disc-choice test The DCE-S fraction was found to be more toxic to larvae (LC~o of 06S %) than the Me-SII (LCso of 08%), 72hr after topical application Both fractions lack contact toxicity, but the deterrent effect persisted for at least 60hr under laboratory conditions Although salannin was isolated from the DCE fraction to show antifeedant activity, the physico-chemical characteristics of the active fractions DCE-S and Me-SII were not identical with either salannin or azadirachtin Interest in the possible application of natural products in integrated pest management (IPM) remains high; during the last decade ample emphasis has been placed on the reduced use of synthetic pesticides and the use of biopesticides less disruptive to the environment Melia dubia plant has been used in Indian folk medicine to control insect pests, however, its taxonomic placement has remained controversial Some authors consider M dubia synonymous with M composital,2 and others synonymous to M azedarach 3 4 although quite a few features remain different in this species and chemical profiles of these taxa differ Accordingly we have prefered to retain the name M dubia for the species The bioactivity is apparently similar to that observed in related species like the neem tree, Azadirachta indica, the chinaberry tree, Melia azedarach and Melia volkensii Several studies have already shown the potential of A indica for insect controI 5 6 M azedarach 7 - IO and M volkensii also possess insect growth inhibitory properties " · '2 but their bioactive compounds are not identical with azadirachtin, the principal bioactive compound in neem Toosendanin, a limonoid occurring in the bark of Melia toosendan and M azedarach, also possesses insect growth inhibitory activity mainly against lepidopteran pests lJ , but it is far less active than azadirachtin As little information exists on the bioactivity of M dubia, we separated and tested the most active fractions against two species of lepidopterous pests in order to establish the possibility of developing a biopesticidal material from this source Materials and Methods Plant material-Leaves and twigs of Melia dubia were collected from the Ganga Lake area of Arunachal Pradesh in the Eastern part of India during May and June Months for 3 subsequent years The plant material was shade-dried and subsequently pulverised to a fine powder The powder (223 kg) was extracted with petroleum ether (PE; bp 60°80°C) followed by dichloroethane (DeE) and methanol (Me) extractions respectively Extract yields ' were 2% (PE), 11% (DeE) and 53% (Me) Each extract was subjected to bioassay directed fractionation using column chromatography over silica gel following the scheme Fig I As the PE extract was the least active, it was not subjected to further fractionation Salannin was isolated from one of the DeE extract fractions by the method described earlier2

Hepatic and renal oxidative stress in acute toxicity of N-nitrosodiethylamine in rats.

Abstract: Nitrosoamines such as N-nitrosodiethylamine (NDEA) produce oxidative stress due to generation of reactive oxygen species and may alter antioxidant defence system in the tissues. NDEA was administered ip as a single dose to rats in LD50 or in lower amounts and the animals were sacrificed after 0-48 hr of treatment. The results showed that lipid peroxidation in liver increased, however no significant increase in kidney LPO was observed after NDEA administration. Superoxide dismutase (SOD) and glutathione reductase (GSH-R) activity increased in liver, however, catalase (CAT) activity in liver was inhibited in NDEA treated rats. Kidney showed an increase in SOD activity after an initial decrease along with increase in GSH-R activity in NDEA treated rats. However, kidney CAT activity was not significantly altered in NDEA intoxicated rats. Serum transaminases, serum alkaline phosphatase blood urea nitrogen, serum creatinine and scrum proteins were elevated in NDEA treated rats. The results indicate NDEA-induced oxidative stress and alteration in antioxidant enzymes in liver and kidney to neutralise oxidative stress.

Immunostimulatory effect of azadirachtin in Oreochromis mossambicus (Peters).

Abstract: The effect of azadirachtin, a trit erpenoid derived from Azadirachta indica on th e immune response was studi ed in the freshwater teleost, 0. 111ossambicus . Bovine serum albumin (BSA) and sheep erythrocytes (SRBC) were used as anti gens to evoke immune response. The immune responses in fish were measured by quantifying antibodi es prod uced and counting the peripheral blood leucocytes in control and experimen tal fish. In general, azad irachtin s ignificantly e nh anced the antibody re­ sponse and leucocyte count in a dose dependant manner. An inverse relationship was observed between the dose of azadi­ rachtin and th e degree of immunostimulation. Timing of azadirachtin ad ministrati on in relation to immunization revealed that the maximum enhancement o f antibody response was observed when the stimul ant was given two days prior to immuni­ zation. The observed immunostimulatory property of azadirachtin has an implication in the maintenance of finfish health in freshwater intensive aquaculture practices.

Anxiolytic activity of Indian Hypericum perforatum Linn: an experimental study.

Abstract: The putative anxiolytic activity of 50% ethanolic extract of Indian Hypericum perforatum (IHp) was investigated in rats using various experimental paradigms of anxiety viz. open field exploratory behaviour (OFB), elevated plus maze (EPM), elevated zero maze (EZM), novelty induced suppressed feeding latency (FL) and social interaction (SI) tests. Pilot studies indicated that single dose administration of IHp had little to no acute behavioural effects, hence the extract of IHp was administered orally at different dose levels once daily for three consecutive days, while lorazepam (LR) (0.5 mg/kg, i.p.) was administered acutely. IHp extract (100 and 200 mg/kg, p.o.) showed significant anxiolytic effects on all the paradigms of anxiety. The results indicate that IHp and LR induced a significant increase in open field ambulation and slight increase in rearings and activity in centre, whereas grooming and fecal droppings remain unchanged. In EPM, significant augmentation of open arm entries, open arm/closed arm entries ratio and time spent on open arms was noted in IHp treated rats. In EZM test, significant increase in time spent on open arms and entries in open arms were observed, whereas slight increase in head dips and stretched attend postures were also observed. IHp and LR significantly attenuated the novelty induced increase in feeding latency. IHp treated rats also showed significant increase in social interaction in the novel environment. The IHp extracts showed consistent and significant anxiolytic activity in all the tests. The effects induced by 50% ethanolic extract of IHp were less marked than those of lorazepam were.

In vitro multiplication of Peganum harmala--an important medicinal plant.

Abstract: The frequency of shoot regeneration and multiplication of P. harmala was influenced by the type of explant and kind and concentration of hormones. Of the various seedling explants, cotyledonary node exhibited maximum shoot regeneration frequency from axillary region on MS medium supplemented with 5 microM BAP. Addition of 0.1 microM NAA enhanced the efficacy of BAP for multiple shoot regeneration as well as improved the growth of shoots. BAP (5 microM) in combination with NAA (0.1 microM) was found to be the optimal for inducing an average of 4-5 shoots per explant in 75% of the cultures within 5 weeks. Replacement of BAP with other cytokinins at equimolar concentration of BAP i.e. 5 microM was not effective in inducing multiple shoots. Regenerated shoots were rooted on MS medium containing IBA (8 microM) with 80% efficiency. The plantlets were successfully established in soil where 80% of them developed into morphological normal plants.

Iron chelation and related properties of Podophyllum hexandrum, a possible role in radioprotection.

Abstract: Aqueous extract of Podophyllum species has been reported to render significant protection against radiation induced mortality, cytogenetic damage and cell death. In view of this, present study was undertaken to investigate its antioxidant properties. Chelation, oxidation and reduction of Fe2+ and Fe3+ were measured using chelating agents 2-2' bipiridyl and potassium thiocyanate respectively. Podophyllum extract, in a dose dependent manner, chelated Fe2+ more efficiently than Fe3+ and also modulated Fe2+/Fe3+ ratio. Homogenate of mouse liver was used to measure TBARS for estimating lipid peroxidation. Podophyllum extract also inhibited lipid peroxidation in a dose dependent manner and maximum inhibition (92%) was achieved at 1000 micrograms/ml concentration. These results demonstrates that Podophyllum exhibits antioxidant properties as seen through chelation and modulation of redox state of iron ions and these may primarily contribute towards its radioprotective manifestation.

Stress induced neuron degeneration and protective effects of Semecarpus anacardium Linn. and Withania somnifera Dunn. in hippocampus of albino rats: an ultrastructural study.

Abstract: Effects of herbal formulations were studied on hippocampal neuron cell bodies. Study was carried out in adult Swiss albino rats . Experimental rats (E) were divided into three groups. Group EI rats were given immobilization stress for 14 hr/day for 30 days. Rats in E2 and E3 group were given daily single dose (40 mglkglbody wt.) of alcoholic extract of S. anacardiunl and W. somnifera. After 1 hr giving the plant extract, the rats were subjected to stress. Treatment continued for 14 hr for 30 days. Control rats were kept in complete nonstress condition. Ultrastructural characteristics of neuron cell bodies in hippocampal sublayer (CAI-CA4 and Dg) was studied in rats of EI, E2 and E3 groups and compared with control. Results of the present study demonstrated, that both CA2 and Dg, 85% of neuron cell bodies exhibited degenerating characteristics , (which includes karyorrhexis, membrane blebbing, chromatin condensation, chromatin fragmentation and intracellular spacing). Interestingly, after the treatment with S. ancardium cells demonstrating degenerating characteristics was significantly reduced (80%) as compared to treatment with W. somnifera. Study suggests that probably both the herbal drugs have cytoprotective properties.

Polyamines and plant alkaloids

Abstract: Naturally occurring alkaloids are nitrogenous compounds that constitute the pharmacogenically active basic principles of flowering plants. Alkaloids are classified into several biogenically related groups. Tobacco alkaloids are metabolised from polyamines and diamines putrescine and cadaverine. N-methyl transferase is the first enzyme in alkaloid biosynthetic pathway which drives the flow of nitrogen away from polyamine biosynthesis to alkaloid biosynthesis. Arginine decarboxylase has been suggested to be primarily responsible for providing putrescine for nicotine synthesis. Tryptophan is the precursor of indole alkaloids. However, the biosynthetic pathway of tropane and isoquinoline alkaloids are not clear. Genes for several key biosynthetic enzymes like arginine decarboxylase, ornithine decarboxylase, putrescine N-methyl transferase and spermidine synthase, hyoscyamine 6 beta hydroxylase,tryptophan decarboxylase etc have been cloned from different plant species. These genes are regulated by plant hormones, light, different kinds of stress and elicitors like jasmonates and their strong expression is primarily in the cultured roots. In view of this, the axenic hairy root cultures induced by Agrobacterium rhizogenes have been utilised to synthesise secondary metabolites. The current development in the knowledge of alkaloid biosynthesis, particularly molecular analysis, has been discussed in this review that may help to open up new avenues of investigation for the researchers.

Antinociceptive pattern of flavone and its mechanism as tested by formalin assay.

Abstract: Flavone, dextrose and long swim stress exhibited antinociception. Degree of antinociception was greater with long swim stress as compared to flavone or dextrose. Combination of these treatments resulted in potentiation of antinociception. Naloxone (opioid antagonist; 5 mg/kg i.p.) antagonised flavone or long stress induced antinociception showing opioid medicated mechanism, however, failed to reverse the potentiated antinociceptive component recorded in long stressed animals which received flavone and dextrose. Antinociceptive activity of flavone, dextrose and long swim stress which was documented by acetic acid assay has been confirmed in the present study. Role for opioid system in this action has been demonstrated. Therefore, formalin test can also be considered as an useful assay procedure for testing flavonoids. However, like acetic acid assay this assay procedure also has the limitation that it is unable to detect minor changes in the degree of antinociception produced by physiological interventions such as long swim and dextrose.

Ageing, gerontogenes, and hormesis.

Abstract: Evolutionary theories of ageing and longevity argue against the existence of specific genes that cause ageing. However, genes whose altered activity influences ageing and longevity, may be termed gerontogenes. Several putative gerontogenes have been identified in various ageing systems, including the Drosophila, budding yeast, nematodes and cells in culture. Since ageing is characterized by a progressive failure of maintenance and repair, it is reasoned that genes involved in homeodynamic repair pathways are the most likely candidate gerontogenes. A promising approach for the identification of critical gerontogenic processes is hormesis-like positive effects of stress. Stimulation of various repair pathways by mild stress has significant effects on delaying the onset of various age-associated alterations in cells, tissues and organisms.

Teratogenic effects of sinusoidal extremely low frequency electromagnetic fields on morphology of 24 hr chick embryos.

Abstract: To examine the potential teratogenicity of electromagnetic fields (EMF; sinusoidal and rectangular) on development of chick embryos (white leghorn), 221 freshly fertilized chicken eggs (55-65g) were exposed during first 24hr of postlaying in­ cubation (38° ± 0.5°C) to 24 different EMFs, with 50Hz repetition rate and 8.007-10.143 mT flux density. Following expo­ sure, the exposed fertilized chicken eggs (n=8-l 0) and sham-exposed fertilized chicken eggs (n= 15) were incubated simulta­ neously for 8 more days and unexposed control fertilized chicken eggs (n=20) for 9 days in absence of EMFs.The embryos were removed from egg shells and studied blind. All 24 EMF exposed-groups (inside the coil with exposure) showed an in­ crease in the percentage of developmental anomalies compared to sham - exposed (inside the coil with no exposure) and control groups (outside the coil). Further, egg's weight was evaluated on day 9. This variable did not show significant dif­ ference between control and exposed-groups. The investigation also covered the measurement of body weight, length of crown to rump, length of tip of the beak to occipital bone, heart and liver weight. Statistical comparison between sham­ exposed and control values did not show significant differences, but comparison between 8.007, 8.453 and 8.713 mT ex­ posed- groups and control groups showed significant differences; in other exposed-groups, the changes were not significant. These results revealed that 50Hz electromagnetic fields can induce irreversible developmental alterations in 24hr chick em­ bryos and confirm that its strength could be a determinant factor for the embryonic response to extremely low frequen cy electromagnetic fields (window effects). Very weak low frequency pulse magnetic fields (PMFs) can induce significant effect on the development of chick embryos, exposed at first 48hr of incubation .These effects are dependent on the frequency, intensity and wave form' - 5 . In other series of experiments, effects of PMFs were found to be dependent on the stage of development. First 24hr of incubation was reported to be crucial and could have some effects on the orientation of embryo in relation to the direction of the field 6 • 4 ; but others did not find any differences between exposed and control unexposed chicken eggs 7 9

Anticonvulsant and behavioral actions of triterpene isolated from Rubia cordifolia Linn.

Abstract: Effect of a triterpene isolated from the acetone solubl e part of petroleum ether ex tract of R cordifolia was studi ed on convul sions induced by maximum electro shock (MES), electrical kindling and various chemoconvulsants in rats and mice The effect of triterpene was also investigated on behavior and gamma-aminobutyric acid (GABA) and serotonin (5 -HT) content in mouse brain Triterpene inhibited seizures induced by MES, electrical kindling, pentylenetetrazol (PTZ), and lithium-pilocarpine However, seizures induced by strychnine were not inhibited Triterpene reduced locomotion as well as rearing Pentobarbi tone induced sleep was potentiated and amphetamine induced stereotypy was inhibited The triterpene was found to possess anxiogeni c activity Brain GABA and 5-HT cont ent s were raised by th e compound The st ud y suggests th at th e triterpene isolated from Rcordifolia bear a potential fo r further study Rubia cordifolia Linn (Family: Rubiaceace) is a climbing plant growing in north-west Himalaya, and other hilly district s of India The methanolic extract of roots has anticancer activity' Dried roots are used as astringent and diuretic They are used in folklore medicine for treatment of dropsy, paralysi s, jaundice amenorrhoea, and visceral obstructions 2 Ethanolic extract of the aerial parts of the plant shows hypoglycemic activity in albino rat s' Tripathi and her associates have reported the lipoxygenase activity of ethanolic extract of roots and ethyl acetate fraction of this extract is th e most active lipoxygenase inhibitor 4

Stress responses in two genotypes of mulberry (Morus alba L.) under NaCl salinity.

Abstract: Changes in biomass yield rates, cell membrane stability (CMS), malondialdehyde (MDA) content and in the levels of physiological stress markers such as proline and glycine betaine in two high yielding genotypes (S1 and ATP, salt tolerant and salt sensitive, respectively) of mulberry under NaCl salinity were studied. Biomass yield rates and CMS were significantly decreased in both the genotypes under stress conditions. Per cent of decrease in biomass yield rate and CMS was relatively less in S1 than in ATP. Salt stress results a significant increase in the accumulation of proline, by 6-fold in S1 and 4-fold in ATP. Glycine betaine content was also increased significantly in stressed plants. However, the per cent increase was more in S1 than in ATP. The level of lipid peroxidation as indicated by MDA formation was greater in ATP than in S1. These results clearly support the better salt tolerant nature of S1 compared to ATP genotype.

Somatic embryogenesis in Vigna radiata (L.) Wilczek.

Abstract: Somatic embryogenesis was achieved from immature cotyledon derived callus of mungbean, Vradiata (L) Wilczek in MS liquid medium Embryogenic callus was induced on MS medium with NAA (5 mg/L) Differentiation of somatic embryos was observed when embryogenic callus was transferred to MS liquid medium containing 2,4-D (15 mg/L) and L-proline (50 mg/L) The torpedo shaped embryos were transferred to MS liquid medium with BAP and ABA (1 mg/L each) for maturation and germination Fifty per cent of torpedo shaped embryos were converted into tiny plants (8-9 plants out of 17) after one week of culture The germinated embryos were isolated and transferred to MS half strength basal (solid) medium for further development

Comparison of skin permeability of drugs in mice and human cadaver skin.

Abstract: In vitro percutaneous absorption of four antihypertensive drugs were carried out across the mice and human cavader skin in order to compare their skin permeability. An interesting trend was noticed in these experiments. Poorly water soluble drug prazosin hydrochloride showed 13 times enhanced flux in the mice skin whereas the steady-state flux of the water soluble drug propranolol hydrochloride was almost same in both human cadaver and mice skin. The permeation rate of prazosin hydrochloride and propranolol hydrochloride through the human cadaver skin fluctuated widely over time, but in mice skin, distinct trends were noticed. The study indicates that the overall permeation rate in mice skin is higher than that in the cadaver skin and the meeting of the target-flux in mice skin does not guarantee its good permeability in human skin.

Nitric oxide: a molecule of the millennium.

Abstract: Recognition of Nitric oxide (NO) as the chemical entity of endothelium-derived relaxing factor (EDRF) has renewed the interest of the scientific community in the last decade. The outcome of research the world over is that the dreaded environmental pollutant is found to be a fundamental physiological mediator and effector. NO is synthesized endogenously by enzymes nitric oxide synthase (NOS) in specialized tissues from its precursor L-arginine. The L-arginine-NO biosynthetic pathway is involved in physiological processes such as vasodilation, memory, neuroprotection, peristalsis, penile erection, immune defense, various endocrine and exocrine secretions in various systems such as cardiovascular, CNS, reproductive and immune system. Small quantities of NO produced by constitutive enzymes mediate these physiological effects. The expression of inducible enzyme or overstimulation of constitutive enzymes leading to production of large quantities of NO is implicated in the cytotoxic effects observed in various disorders like AIDS, cancer, Alzheimer's, arthritis etc. In conclusion, NO is a 'double edged sword' and the challenge before the scientific community is to develop strategies for using it to our advantage.

Methemoglobinemia in aluminium phosphide poisoning in rats.

Abstract: Aluminium phosphide (AlP) a grain fumigant is the leading cause of intentional poisoning in North India. The mechanisms involved in toxicity are not known and there is no antidote till date. The present study was carried out to investigate the oxygen free radical generation, methemoglobinemia and effect of methylene blue treatment on survival time in rat model of AlP poisoning. AlP (50 mg/kg, intragastric) was administered in one group and the other group received AlP + Methylene Blue (MB) (0.1%, 1 mg/kg/5 min, i.v.). Malonyldialdehyde (MDA) and methemoglobin (MeHb) levels were measured at 10 and 30 min intervals. Blood MDA levels increased at 10 and 30 min after AlP exposure with simultaneous rise in MeHb levels suggesting methemoglobinemia could be due to increased oxygen free radical generation. Methylene blue caused a significant fall in both the parameters with prolongation of survival time. It is concluded that AlP causes methemoglobinemia responding to methylene blue treatment.

Fungal metabolites from Aspergillus niger AN27 related to plant growth promotion.

Abstract: Two metabolites have been isolated from Aspergillus niger AN27, a biocontrol agent, and identified as 2-carboxymethyl 3-n-hexyl maleic acid (compound 1) and 2-methylene-3-hexylbutanedioic acid (compound 2). Their biological activities related to crop growth promotion have been assayed. Both the compounds increased germination and improved crop vigour. Compound 1 was more effective for increase in germination and shoot length, whereas compound 2 had relatively greater role in increasing the root length and biomass of cauliflower seedlings.