Serum melatonin and serotonin levels in long-term skilled meditators.

INTRODUCTION: Melatonin and its precursor serotonin are neurochemicals that play an important role in the physiological regulation of mood, sleep, and behavior. Studies have suggested the possibility of changes in the levels of melatonin and serotonin following meditation. However, the outcome of Buddhist meditation on both these two neurochemicals collectively have not been studied yet. OBJECTIVE: To assess the effect of Vipassana meditation on serum melatonin and serotonin levels in long-term meditators and to compare them with an age, gender, and education level matched, non-meditating control group. METHODS: The serum melatonin and serotonin levels of long-term meditators (n=30), recruited using a validated interview, and age, gender and educational level matched control subjects (n=30) who had never practiced meditation, were determined using commercial ELISA kits (LDN, Nordhorn, Germany). RESULTS: The median concentration of melatonin (18.3 pg/ml) and serotonin (149.0 ng/ml) in the meditator group, were significantly higher compared to the control group; melatonin (15.6 pg/ml; p = 0.006), serotonin (118.1 ng/ml; p < 0.001). The levels had no significant correlation with demographic factors but positively correlated with meditation factors in those who had meditated for <=10years (n=26, p < 0.05). CONCLUSION: The findings indicate elevated melatonin and serotonin levels in the long-term meditators with potential beneficial effects in decreasing stress and improving relaxation in individuals.

Antiinflammatory Activity of Hot Water Infusion of Nyctanthes arbo-tristis Flowers.

In Sri Lankan ethnomedicate it is claimed the flowers of Nyctanthes arbo-tristis is effective in the treatment of inflammatory conditions but this has not been scientifically validated. This experiment was carried to investigate the antinflammatory potential of hot water infusion of Nyctanthes arbo-tristis flowers. Oral antiinflammatory activity of hot water infusion of Nyctanthes arbo-tristis flowers (concentrations: 3.75, 7.5, 12.5 and 18.75 mg/kg) was assessed in rats using both acute (carrageenan-induced paw oedema assay) and chronic (formaldehyde induced-paw oedema and cotton pellet-granuloma tests) inflammatory models. In an attempt to investigate its mode of action, antihistamine activity (by wheal test), inhibition of prostaglandin synthesis (by enteropooling test), inhibition of Tumor necrosis factorα secretion (using human mononuclear cells), and suppression of vascular permeability (acetic acid-induced vascular permeability test) and cytotoxicity (Evans blue test) were assessed. In the carrageenan-induced paw oedema test, hot water infusion simultaneously suppressed both initial and late stages of inflammation in an inversely dose related manner. Hot water infusion also inhibited paw oedema in formalin and cotton pellet granuloma tests. In addition, this infusion exhibited marked anti histamine activity, prostaglandin synthesis inhibition and suppression of vascular permeability. These findings scientifically support the traditional use of Nyctanthes arbo-tristis flowers in treatment of inflammatory conditions.

Anti-inflammatory activity of dried flower extracts of Aegle marmelos in Wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Almost all part of the plant Aegle marmelos (Bael tree) has been used in the traditional medicine systems of Asian countries to treat various diseases over many centuries. The water extract of the dried flowers of Aegle marmelos is a commonly used beverage among Sri Lankan population in rural areas. Although extensive investigations done on many parts of the plant there are no experimental data available on the extracts of flowers. Anti-inflammatory effect of the water extract of dried flowers of Aegle marmelos (WEAM) was evaluated in the present study. MATERIALS AND METHODS: The anti-inflammatory effect of the WEAM was evaluated by inhibition of the rat paw oedema, induced by carrageenan. The mechanism of the anti-inflammatory effect was assessed by the inhibition of production of nitric oxide (NO) by rat peritoneal cells, infiltration of rat peritoneal cells, anti-histamine effect, membrane stabilization activity, the antioxidant capacity and inhibition of lipid peroxidation by the WEAM. RESULTS: The maximum percentage inhibition of paw oedema was exhibited by the dose of 200 mg/kg at 2 h. The WEAM showed a significant increment of rat peritoneal cell infiltration, inhibition of NO production by rat peritoneal cells and inhibition of wheal formation on the skin of the rat after injection of histamine. The WEAM protected the erythrocyte membrane from heat-induced lysis in a dose-dependent manner and showed a significant anti-oxidant effect and lipid peroxidation inhibition activity. CONCLUSION: The WEAM possesses significant anti-inflammatory effect by multiple mechanisms in Wistar rats.