Rhodiola imbricata (Crasullaceae) is a perennial herb growing at high altitude (4000-5000m) in the western Himalayas.The aim and objectives of the present study was to investigate anti-stress and adaptogenic activity of Rhodiola imbricata aqueous root extract using a cold (5 o C)-hypoxia (428 mmHg)restraint (C-H-R) animal model and its safety evaluation.The effects of Rhodiola imbricata aqueous root extract were examined in rats for its adaptogenic activity and toxicity.Dose dependent adaptogenic activity evaluation of extract was carried out at different doses administered orally, 30 min prior to C-H-R exposure.After sub-acute toxicity studies on 10 and 20 times doses of normal effective dose administered for 14 days (single oral dose/day), biochemical and hematological variables were evaluated.The maximal effective adaptogenic dose of the extract was 100 mg/kg body weight.No significant changes were observed in organ weight/body weight ratios, of any vital organ studied and biochemical and hematological parameters of the sub-acute extract treated animals in comparison to control rats.The LD 50 of the extract was observed to be >10g/kg when given orally.The results indicate that Rhodiola imbricata root aqueous extract possess potent adaptogenic activity with no toxicity even after sub-acute administration of maximal effective extract dose.

In the present study, oral supplementation of l-arginine in rats was evaluated for its anti-stress and adaptogenic activity using the cold (5°C)–hypoxia (428 mmHg)–restraint (C-H-R) animal model. A dose-dependent study of l-arginine was carried out at doses of 12.5, 25.0, 50.0, 100.0, 200.0 and 500.0 mg/kg body weight, administered orally 30 min prior to C-H-R exposure. The time taken by the rat to attain a rectal temperature of 23°C (Trec 23°C) during C-H-R exposure and its recovery to Trec 37°C at normal atmospheric pressure and 32 ± 1°C were used as biomarkers of anti-stress and adaptogenic activity. Biochemical parameters related to lipid peroxidation, anti-oxidants, cell membrane permeability, nitric oxide and stress, with and without administration of the least effective l-arginine dose, were measured in rats on attaining Trec 23°C and Trec 37°C. The least effective adaptogenic dose of l-arginine was 100.0 mg/kg body weight. The C-H-R exposure of control rats, on attaining Trec 23°C, resulted in a significant increase in plasma malondialdehyde (MDA), blood lactate dehydrogenase (LDH) and a decrease in blood catalase (CAT) and plasma testosterone levels. On recovery (Trec 37°C) of control rats, there was a further decrease in CAT and plasma testosterone, and an increase in LDH. l-Arginine supplementation resulted in a significant decrease in plasma MDA, an increase in blood superoxide dismutase (SOD), CAT levels maintained at control values and a lower increase in LDH compared with controls (45.3 versus 58.5% and 21.5 versus 105.2%) on attaining Trec 23°C during C-H-R exposure and on recovery to Trec 37°C. The results suggested that l-arginine possesses potent anti-stress activity during C-H-R exposure and recovery from C-H-R-induced hypothermia.

Objective: Investigation of lecithin administration in rats for its antistress and adaptogenic activity. Design: Lecithin was administered orally (1 mg/g body weight) to rats 0.5 hour, 1.5 hours, 3.0 hours, and 6.0 hours prior to cold (5 degreesC)-hypoxia (428 mm Hg)-restraint (C-H-R) exposure and serum choline estimation. The rectal temperature (T-rec) of the rats was monitored during the exposure and the recovery periods. The time for decrease of T-rec to 23 degreesC and its recovery to 37 degreesC were used as indices of antistress and adaptogenic activity. Results: Lecithin administration 3-6 hours prior to C-H-R exposure was found to have significant adaptogenic activity that correlated with increased serum choline levels. Lecithin administration prior to C-H-R exposure increased the stress tolerance of the rats by delaying the time for decrease of T-rec to 23 degreesC during C-H-R exposure. It also helped shorten poststress recovery as observed by decreased time to attain T-rec of 37 degreesC from C-H-R-induced hypothermia (T-rec, 23 degreesC) Conclusions: The results suggested that lecithin supplementation acted as an antistress and adaptogenic functional food. It improved resistance during C-H-R exposure and enhanced recovery from hypothermia.

OBJECTIVEIsolation of biologically active fractions and compounds from the roots of Withania somnifera, a plant used extensively as a constituent of rasayana, in Ayurveda and to test their adaptogenic activity on stress indices using the cold-hypoxia-restraint (C-H-R) model.DESIGNBioactivity-guided fractionation of an aqueous extract of the roots of Withania somnifera led to the isolation of a new species of withanolide 1-oxo-5beta, 6beta-epoxy-witha-2-ene-27-ethoxy-olide. Structure elucidation, was carried out using proton nuclear magnetic resonance, infrared (IR), ultraviolet (UV), and mass spectroscopic analysis. Stress-related indices were evaluated, namely serum creatine phosphokinase (CPK) activity, serum lactate dehydrogenase (LDH) activity, serum corticosterone levels, and serum lipid peroxidation (LPO) levels.RESULTSThere was a significant decrease in a serum CPK, LDH, and LPO levels in animals pretreated with (1) fraction-I (20 mg/kg body weight), (2) 1-oxo-5beta, 6beta-epoxy-witha-2-ene-27-ethoxy-olide (2.5 mg/kg body weight) in comparison to control when subjected to C-H-R stress.CONCLUSIONSThe results show that the a new species of withanolide, 1-oxo-5beta, 6beta-epoxy-witha-2-ene-27-ethoxy-olide (compound-1) could prove to be an effective agent to counteract C-H-R stress.

OBJECTIVE Investigation of lecithin administration in rats for its antistress and adaptogenic activity. DESIGN Lecithin was administered orally (1 mg/g body weight) to rats 0.5 hour, 1.5 hours, 3.0 hours, and 6.0 hours prior to cold (5 degrees C)-hypoxia (428 mm Hg)-restraint (C-H-R) exposure and serum choline estimation. The rectal temperature (T(rec)) of the rats was monitored during the exposure and the recovery periods. The time for decrease of T(rec) to 23 degrees C and its recovery to 37 degrees C were used as indices of antistress and adaptogenic activity. RESULTS Lecithin administration 3-6 hours prior to C-H-R exposure was found to have significant adaptogenic activity that correlated with increased serum choline levels. Lecithin administration prior to C-H-R exposure increased the stress tolerance of the rats by delaying the time for decrease of T(rec) to 23 degrees C during C-H-R exposure. It also helped shorten poststress recovery as observed by decreased time to attain T(rec) of 37 degrees C from C-H-R-induced hypothermia (T(rec), 23 degrees C). CONCLUSIONS The results suggested that lecithin supplementation acted as an antistress and adaptogenic functional food. It improved resistance during C-H-R exposure and enhanced recovery from hypothermia.

OBJECTIVE Investigation of the mechanism of increased tolerance to stress induced hypothermia after the administration of composite Indian herbal preparation II (CIHP II), a combination of several plant ingredients and minerals. DESIGN The effect of oral CIHP II administration (1 mg/g of body weight), prior to cold (5 degrees C)-hypoxia (428 mm Hg)-restraint (C-H-R) exposure in rats on cardiac and skeletal muscle oxidation was studied in vitro by estimating conversion of glucose-U-14C and Palmitate-1-(14)C to 14CO2. In vitro adipose tissue lipolysis and incorporation of glucose-U-14C into skeletal muscle glycogen was also studied. RESULTS A single dose of CIHP II-enhanced resistance to hypothermia (rectal temperature [T(rec)] 23 degrees C) during C-H-R exposure as evidenced by increased glucose turnover rate in heart and skeletal muscle tissue. The blood glucose and skeletal muscle glycogen were conserved. Cardiac free fatty acid oxidation was also increased. During recovery from hypothermia (T(rec) 37 degrees C) blood glucose and muscle glycogen levels were conserved. Five doses of CIHP II increased resistance to cold by increased adipose fat mobilization and cardiac oxidation. Glucose oxidation was spared. During recovery from hypothermia, the glucose turnover and oxidation in skeletal muscle was increased as was fat mobilization from adipose tissue and its oxidation by heart muscle. CONCLUSIONS CIHP II intake prior to C-H-R exposure resulted in increased glucose turnover rate and fat utilization. This perhaps helped increase the resistance to C-H-R-induced hypothermia and speeded recovery.

OBJECTIVE:A composite Indian herbal preparation-I (CIHP-I) containing ingredients derived from 7 different plants and asphalt was tested for its adaptogenic activity and its mechanism of action was investigated.DESIGN:CIHP-I was tested using the cold-hypoxia-restraint (C-H-R) animal model in which the restrained rats were exposed to 5 degrees C at 428 mm Hg atmospheric pressure. Rectal temperature (Trec) of the rats was continuously monitored during the exposure and the recovery periods. The time for fall of Trec to 23 degrees C and its recovery to 37 degrees C were used as indices of endurance and the adaptogenic activity. Carbohydrate and lipid parameters were investigated to find out the nature of fuel being used during thermogenesis.RESULTS:After 12 weeks of administration of an oral dose of 7.5 mg/kg(-1)/day(-1), CIHP-I was found to possess significant adaptogenic activity. CIHP-I helped improve resistance to C-H-R induced hypothermia (Trec 23 degrees C) in animals by increased mobilization of free fatty acids (FFA) from adipose tissue. Blood glucose and muscle glycogen levels were maintained. CIHP-I treatment restricted the release of creatine phosphokinase (CPK) into the circulation during C-H-R exposure.CONCLUSIONS:The results suggested that CIHP-I is a strong adaptogen. It improved cold resistance during C-H-R exposure and enhanced recovery from hypothermia. The energy-dependent cell membrane permeability was maintained. Stored lipids were mobilised and possibly used for thermogenesis in preference to carbohydrates.

Substances which enhance endurance for physical and mental work and increase non-specific resistance to stress during a prolonged stay in physiologically adverse habitats are called 'adaptogens'. Panax ginseng is well known for its anti-stress and adaptogenic properties. In the present study, adaptogenic activity by the intake of a herbo-vitamin-mineral preparation (HVMP) containing P. ginseng and multivitamin-mineral preparation (MVMP) was evaluated using the cold-hypoxia-restrained (C-H-R) animal model. The aim was to determine whether the cold tolerance and recovery from acute hypothermia mediated by P. ginseng was modified by simultaneous intake of additional vitamins and minerals. Results suggest that the adaptogenic effect of HVMP was more or less the sum total of its two components P. ginseng and MVMP. In HVMP, P. ginseng was found to be effective for developing resistance to cooling and MVMP helped in stimulating faster recovery from acute hypothermia.

CIHP II, an Ayurvedic combination of several plant ingredients and minerals, was tested for its adaptogenic action. CIHP II had a strong adaptogenic action in single, multiple, and prolonged dose schedules. It had a cumulative adaptogenic property. CIHP II intake resulted in an improved maintenance of blood glucose levels at the end of exhaustive swimming exercises with little difference in blood lactic acid as compared with control rats without CIHP II intake. This suggested conservation of glucose utilisation. CIHP II,vas found to potentiate the oxygen delivery system by increasing red cell 2,3 Diphosphoglyceric acid (2,3-DPG) levels on exposure to hypobaric hypoxia. It improved cellular membrane permeability, as the release of creatine phosphokinase in circulation during hypobaric hypoxia was restricted on CIHP II intake. However, several tissue metabolite concentrations were not altered during the resting state. The CIHP II appeared to induce a state of non-specific increased resistance (SNIR) during stress.

A new animal model for evaluating improvement in physical work performance and endurance in an adverse environment is described. In this model, rats in restraint were exposed to 5°C at 480 mmHg atmospheric pressure. Results were compared to an animal forced to swim in water at 23°C. In both the models, colonie temperature (Tr) of the rats was continually monitored during exposure to adverse environment and during recovery at 32°C and normal atmospheric pressure. The time and pattern for Tr fall to 23°C and its recovery to 37°C were used as measures of endurance. The cold-hypoxia-restraint model was found to provide more precise results compared with the cold-swimming model. Panax ginseng root and Ginkgo biloba leaf extracts were compared for their positive endurance-promoting properties using both models.

Studies were carried out in 29 healthy young adults in the Indian Army stationed in the plains and posted at an elevation of 3500 m for more than 6 months. After exposure to a low elevation in Delhi (260 m) for 3 weeks they were reinduced to a height of 3500 m. The subjects were divided into three groups, each of which was treated with either placebo or acetazolamide or spironolactone. The drug treatment was started immediately after their landing at high altitude and continued for 2 days only. Total body water, extracellular fluid, intracellular fluid, plasma volume, blood pH, PaO2, PaCO2 and blood viscosity were determined on exposure at Delhi and on re-induction to high altitude. Plasma volume was increased after the descent from high altitude and remained high for up to 21 day's study. This increased plasma volume may have some significance in the pathogenesis of pulmonary oedema. Total body water and intracellular fluid content were increased at 260 m elevation, while extracellular fluid decreased. On re-induction there was a decrease in total body water with no change in the extracellular fluid content.

Haematologic studies were carried out in 20 high altitude natives during two months stay at plains (200 m) and on their return to an altitude of 3,500 m. Haemoglobin, erythrocyte count, haematocrit and reticulocyte count decreased rapidly on arrival to plains and attained minimum level by the end of fourth week. All these parameters increased rapidly on return to high altitude and were found to attain maximum values by 23rd day on return to high altitude. Mean cell volume and mean cell haemoglobin showed significant increase at altitude. Blood volume and red cell mass increased significantly at altitude. It is concluded that the high altitude natives of Ladakh were well adapted to hypoxic environment due to normocythaemic hypervolemia.

In the present communication, effect of low doses of phosphate supplementation on short-term high altitude adaptation has been examined. Studies were carried out in 36 healthy, male, sea-level residents divided in a double blind fashion into drug and placebo treated groups. 3.2 mmol of phosphate were given orally to each subject of the drug treated group once a day for 4 days on arrival at an altitude of 3,500 m. Sequential studies were done in the subjects in both groups on the 3rd, 7th, 14th and 21st day of their altitude stay. Haemoglobin, haematocrit, erythrocyte and reticulocyte counts increased to the similar extent in both groups. Blood pH, pO2 and adenosine tri-phosphate (ATP) did not differ between the two groups. On 3rd day of the altitude stay, inorganic phosphate and 2,3-diphosphoglycerate (2,3 DPG) levels in the drug treated group increased significantly as compared to the placebo group. No significant difference in inorganic phosphate and 2,3 DPG was observed later on in the two groups. Psychological and clinical tests also indicated that the drug treated subjects felt better as compared to the placebo treated subjects. The present study suggests that low doses of phosphate increases circulating 2,3-DPG concentration which in turn brings about beneficial effect towards short term high altitude adaptation.

Studies were conducted on 29 male healthy subjects having no previous experience of living at high altitude. These subjects were divided into three groups, i.e., subjects treated with placebo, acetazolamide and spironolactone. These subjects were first studied in Delhi. The drug schedule was started 24 hour prior to the airlift of these subjects to an altitude of 3,500 m and was continued for 48 hour after arrival at high altitude. Total body water, extra cellular water, plasma volume, blood electrolytes, pH, pO2, pCO2 and blood viscosity were determined on 3rd and 12th day of their stay at high altitude. Total body water, extra cellular water intracellular water and plasma volume decreased on high altitude exposure. There was a further slight decrease in these compartments with acetazolamide and spironolactone. It was also observed that spironolactone drives out more water from the extracellular compartment. Loss of plasma water was also confirmed by increased plasma osmolality. Increase in arterial blood pH was noticed on hypoxic exposure but the increase was found less in acetazolamide and spironolactone cases. This decrease in pH is expected to result in better oxygen delivery to the tissues at the low oxygen tension. It was also confirmed because blood pO2 increased in both the groups. No significant change in plasma electrolytes was observed in subjects of various groups. Blood viscosity slightly increased on exposure to high altitude. The degree of rise was found less in the group treated with spironolactone. This study suggests that both the drugs are likely to be beneficial in ameliorating/prevention of AMS syndrome.

Regional blood distribution was studied in rats, which were divided into four groups viz., (i) control, (ii) exposed to acute hypobaric hypoxia, (iii) exposed to acute hypobaric hypoxia after oral treatment with 25mg acetazolamide, and (iv) exposed to acute hypobaric hypoxia after oral treatment with 6mg spironolactone. The regional blood distribution was measured using radio-iodinated serum albumin (R131ISA). The acute hypoxic exposure results in major readjustment in the blood flow to the various organs mainly from the renal and splanchic vascular beds to the heart and brain. Treatment with acetazolamide and spironolactone results only in a slight decrease in blood contents of the heart, brain and lung as compared to thehypoxia alone exposed group.

Rats were exposed to acute hypobaric hypoxia corresponding to an altitude of 6,100 m for 5 hours and 24 hours and were studied for organ fluid changes. Total water and extracellular water content of various organs, i.e. lung, liver, spleen, heart, kidney, muscle, brain testis and subcutaneous tissue were determined by the difference of dry and wet weights and using radiobromide-82 respectively. Lung and liver were found to be significantly hydrated with lower water contents in subcutaneous tissue, spleen and muscle on prolonged exposure. The data indicated a shift of fluids from extracellular to intracellular compartment.