An investigation on the influence of yogic methods on heart rate variability.

BACKGROUND: The role of underlying mechanisms of yogic strategies which exert beneficiary effects on cardiac autonomic control is poorly understood. We have performed heart rate variability (HRV) analysis on subjects performing yogic methods and control subjects who mimic them through paced breathing and focused attention tasks using external cues. METHODS: Heart rate (HR) time series is generated from electrocardiogram measured from subjects of yogic group (YG); performing yogic practices (n = 15), paced breathing group (PBG); involved in breathing exercises cued at breathing rates (BR) from 3 to 15 cycles per minute (cpm) (n = 23), normal breathing group (NBG) under regular breathing (n = 15), and subjects performing three different cognitive tasks designated as focused attention group (FAG), (n = 24). HRV is analyzed using coherence plots, spectrograms, HRV parameters, and instantaneous frequency recurrence plots (IFRP). RESULTS: HRV is similar among YG and PBG (at BR <12 cpm) and significantly different for YG vs. NBG (p < 0.001) and PBG vs. NBG (p < 0.001). Regularity of breathing oscillations observed in HR is quantified using IFRP and is identical among FAG, PBG, and YG and significantly different for YG vs. NBG (p < 0.01), PBG vs. NBG (p < 0.01), and FAG vs. NBG (p < 0.05). CONCLUSIONS: Low-frequency breathing (BR <12 cpm) plays a primary role in eliciting physiologically significant changes in HRV. By identifying a similarity in breathing oscillations of HR of FAG, YG, and PBG, the results recognize the coexistence of attention and breathing strategies and postulate their joint role in sustaining autonomic benefits, while effects induced by breathing alone on HRV could be attained even intermittently.

Anticonvulsant activity of Aloe vera leaf extract in acute and chronic models of epilepsy in mice.

OBJECTIVES: The effect of Aloe vera in epilepsy has not yet been explored. This study was done to explore the effect of aqueous extract of Aloe vera leaf powder on three acute and one chronic model of epilepsy. METHODS: In acute study, aqueous extract of Aloe vera leaf (extract) powder was administered in doses 100, 200 and 400 mg/kg p.o. Dose of 400 mg/kg of Aloe vera leaf extract was chosen for chronic administration. Oxidative stress parameters viz. malondialdehyde (MDA) and reduced glutathione (GSH) were also estimated in brain of kindled animals. KEY FINDINGS: In acute study, Aloe vera leaf (extract) powder in a dose-dependent manner significantly decreased duration of tonic hind limb extension in maximal electroshock seizure model, increased seizure threshold current in increasing current electroshock seizure model, and increased latency to onset and decreased duration of clonic convulsion in pentylenetetrazole (PTZ) model as compared with control group. In chronic study, Aloe vera leaf (extract) powder prevented progression of kindling in PTZ-kindled mice. Aloe vera leaf (extract) powder 400 mg/kg p.o. also reduced brain levels of MDA and increased GSH levels as compared to the PTZ-kindled non-treated group. CONCLUSIONS: The results of study showed that Aloe vera leaf (extract) powder possessed significant anticonvulsant and anti-oxidant activity.

The effect of the essential oil of Eugenia caryophyllata in animal models of depression and locomotor activity.

OBJECTIVE: The essential oil of Eugenia caryophyllata (clove oil; Family: Myrtaceae) is used in dental care as an antiseptic and analgesic. The present study investigates the effect of clove oil on animal models of depression and locomotion. METHODS: Clove oil was administered in doses of 0.025, 0.05, and 0.1 ml/kg/day, intraperitoneally (i.p.) for 3 weeks. The forced swim test (FST) and the tail suspension test (TST) were used to assess depression. To evaluate locomotor activity, the rota rod test and the photoactometer procedure were performed. RESULTS: In the FST, it was observed that the duration of immobility was significantly decreased (P < 0.01) in animals treated with clove oil (0.05 and 0.1 ml/kg); however, the clove oil dose of 0.025 ml/kg showed an insignificant increase in the immobile period. The TST demonstrated that pretreatment with clove oil decreases (P < 0.01) the immobile period significantly at all the three administered doses. Similarly, the photoactometer procedure showed increased locomotor activity at all the three doses, although significant (P < 0.05) only at 0.1 ml/kg. In addition, the rota rod test showed that animals treated with clove oil (0.1 ml/kg) enhanced muscle coordination as demonstrated by a significant increase (P < 0.05) in the latency to fall from the rota rod as compared to the control. However, the lowest administered dose (0.025 ml/kg, i.p.) decreased the latency to fall from the rota rod significantly (P < 0.05) compared to the control. Clove oil (0.05 ml/kg) also showed a decrease in the latency to fall from the rota rod although the result was not statistically significant. DISCUSSION: Thus, it can be concluded that pretreatment with clove oil decreases depression and enhances locomotor activity similar to that exhibited by psychostimulants.

Acute effect of Aloe vera gel extract on experimental models of pain.

The present study was performed to explore the effect of aqueous extract of Aloe vera on behavioural parameters of pain. Pain assessment was performed by the tail-flick and formalin tests. A. vera (100 mg/kg, per oral (p.o.)) produced an insignificant decrease in the pain response in the tail-flick and formalin tests. Moreover, A. vera (200 and 400 mg/kg, p.o.) did not have significant effect on the tail-flick test. However, A. vera (200 and 400 mg/kg, p.o.) significantly decreased the second phase of the formalin-induced pain. Thus, these findings suggest that A. vera exerts its effect by a peripheral mechanism of action rather than central.

Acute effect of essential oil of Eugenia caryophyllata on cognition and pain in mice.

The essential oil of Eugenia caryophyllata (clove oil; Family: Myrtaceae) is used in dental care as an antiseptic and analgesic. The study aims to evaluate the effect of clove oil on experimental models of pain and cognition in mice. To observe the acute effects of clove oil at different doses, the elevated plus maze was used for the assessment of cognition, and the tail flick and formalin tests were used for the study of pain. The formalin test showed that clove oil (0.1 ml/kg, i.p.) demonstrated significantly reduced pain response in both the phases. The lower doses (0.025 and 0.05 ml/kg, i.p.) reduced the formalin-induced pain response significantly in the second phase only. The tail-flick test showed variable response. The dose 0.1 ml/kg, clove oil, significantly decreased the tail-flick latency at 30 min and this effect was reversed by naloxone (1 mg/kg). On the contrary, the dose 0.025 ml/kg of clove oil, at 30 and 60 min increased the mean tail-flick latency compared to control group, but this effect was not statistically significant. Yet naloxone significantly (p < 0.05) reversed the effect of clove oil 0.025 ml/kg at 30 min. Clove oil (0.025 and 0.05 ml/kg, i.p.) significantly reversed the scopolamine-induced retention memory deficit induced by scopolamine, but clove oil (0.1 ml/kg, i.p.) significantly reversed both acquisition as well as retention deficits in elevated plus maze induced by the scopolamine. Clove oil exhibits reduced pain response by a predominantly peripheral action as evidenced by formalin test and the tail flick test showed the involvement of opioid receptors. Clove oil also significantly improved scopolamine-induced retention memory deficit at all doses.

Essential oil of clove (Eugenia caryophyllata) augments the humoral immune response but decreases cell mediated immunity.

The present study was undertaken to explore the effect of the essential oil isolated from the buds of Eugenia caryophyllata on some immunological parameters. Humoral immunity was assessed by measuring the hemagglutination titre to sheep red blood cells and delayed type hypersensitivity was assessed by measuring foot pad thickness. Clove oil administration produced a significant increase in the primary as well as secondary humoral immune response. In addition, it also produced a significant decrease in foot pad thickness compared with the control group. Thus, these results suggest that clove oil can modulate the immune response by augmenting humoral immunity and decreasing cell mediated immunity.

Modulation of pentylenetetrazole-induced kindling and oxidative stress by curcumin in mice.

Epilepsy is a chronic neurological disorder affecting 1% population worldwide. A number of experimental studies have reported anticonvulsant, neuroprotective and antioxidant activity of certain natural products like curcumin, an active ingredient of turmeric. The present study was designed to explore the effect of acute administration of curcumin at doses 50, 100 and 200 mg/kg, orally (p.o.) pentylenetetrazole-induced kindling in mice. Further two oxidative stress markers viz., malondialdehyde (MDA) and glutathione were estimated in brain tissues of rodents. Curcumin (50, 100 and 200 mg/kg, p.o.) dose dependently suppressed the progression of kindling in mice. In addition, the increased levels of MDA and glutathione were also reduced by curcumin in kindled animals. These results suggest that curcumin appears to possess protective activity against kindling in mice.

Lipotab, a polyherbal formulation, attenuates isoprenaline-induced left ventricular remodeling and heart failure in rats.

The present study was designed to evaluate the effect of Lipotab, a polyherbal formulation on isoprenaline (ISO)-induced left ventricular (LV) remodeling and heart failure (HF). HF in Wistar albino rats was produced by two consecutive injections of ISO (150 mg/kg, s.c.) at an interval of 24 h. After 15 days of 2nd ISO injection, HF was indicated by rise in left ventricular end-diastolic pressure (LVEDP), lowering of maximal rate of rise of LV pressure divided by LV systolic pressure (LVdP/dtmax/P; cardiac contractility) and maximal rate of fall of LV pressure (LVdP/dtmin), fall in cardiac output (CO), cardiac hypertrophy (heart to body weight ratio) and histopathological changes in heart. HF rats showed a significant increase in serum malondialdehyde (MDA), reduction in serum reduced glutathione (GSH) content and a significant rise in tumor necrosis factor-α (TNF-α) level. Prior treatment with Lipotab (275 mg/kg/day, p.o.) was significantly able to preserve LV functions. Post treatment with Lipotab (275 mg/kg/day, p.o.) also improved LV functions but did not prevent the fall in LVdP/ dtmin, CO and cardiac hypertrophy. Lipotab significantly prevented fall in GSH levels, rise in level of MDA and TNF-α in serum of HF rats. Histopathological examination confirmed hemodynamic and biochemical findings. Results of the present study indicate that Lipotab prevents ISO-induced LV remodeling and consequent HF in rats through its antioxidant and anti-inflammatory activity.

Anti-inflammatory, immunomodulatory and antinociceptive activity of Terminalia arjuna Roxb bark powder in mice and rats.

Terminalia arjuna back powder (400 mg/kg, po) significantly reduced formalin-indued paw oedema at 24 h but not carrageenan-induced paw oedema. It significantly increased the anti-SRBC antibody titre in the secondary phase of immune response. The same dose significantly reduced the duration of licks and bites in both phases of formalin-induced pain response and showed significant increase in tail flick latency at higher dose (800 mg/kg, po). These effects of T. arjuna were antagonised by pretreatment with naloxone (1 mg/kg, ip). In another series of experiments, mice pretreated with morphine for three days in increasing doses (10, 15, 20 mg/kg, ip; twice daily) showed a decreased response in antinociceptive activity of morphine (5 mg/kg, ip). Further, cross tolerance was observed with T. arjuna (800 mg/kg, po) in morphine tolerant animals. These findings support the hypothesis that T. arjuna has anti-inflammatory potential against some phlogistic agents along with some immunomodulatory activity and also has antinococeptive action probably mediated via central opioid receptors.

Curcumin has anticonvulsant activity on increasing current electroshock seizures in mice.

Epilepsy is one of the most common serious disorders of the brain. Several experimental studies have reported neuroprotective and antioxidant activity of certain natural products like curcumin, an active ingredient of turmeric. The present study was designed to explore the effect of acute administration of curcumin at doses 50, 100 and 200 mg/kg, orally (p.o.) and its chronic (x 21 days) administration in 100 mg/kg, p.o. on increasing current electroshock (ICES) test, elevated plus maze and actophotometer in mice. Curcumin in a dose of 100 mg/kg significantly increased the seizure threshold in ICES test on both acute and chronic administration. The same dose of 100 mg/kg on acute administration showed anxiogenic effect on elevated plus maze and actophotometer test. However, this anxiogenic effect of curcumin disappeared on chronic administration. These results suggest that curcumin appears to possess anticonvulsant activity in mice.

Attenuation of the effect of lindane on immune responses and oxidative stress by Ocimum sanctum seed oil (OSSO) in rats.

Present study was done to evaluate the effect of Ocimum sanctum seed oil (OSSO) on the immunotoxicity and oxidative activity of lindane in rats. Rats were divided into four groups (n = 8) and were treated with lindane (10 mg/kg, po) and/or OSSO (1 mg/kg, po) during the study period. Humoral immunity was assessed by measuring haemagglutination titre to sheep red blood cells (SRBC) and delayed type hypersensitivity (DTH) was assessed by measuring foot pad thickness. Lindane showed significant decrease in anti-SRBC antibody titre and also decreased percentage change in foot pad thickness in DTH response as compared to control group. OSSO per se produced significant increase in anti-SRBC antibody titre, but did not produce significant change in the foot pad thickness as compared to control group. However, it significantly antagonized the effect of lindane on the anti-SRBC antibody titre and foot pad thickness parameters. Lindane produced oxidative stress as indicated by increase in the levels of MDA and decrease in GSH levels. Treatment with OSSO per se showed antioxidant activity and also reversed the oxidative stress produced by lindane. The results suggest that OSSO can attenuate the immunotoxicity and oxidative stress produced by lindane.