Citral, Myrcene and Limonene
As measured by the open-field test in mice, citral, myrcene, and limonene (100 and 200 mg/kg body wt., i.p.), constituents of essential oils, decreased not only the number of crossings but also numbers for rearing and grooming. Although only the highest doses of citral (200 mg/kg body wt.) and myrcene (100 and 200 mg/kg body wt.) were seen for muscle relaxation, this effect was observed even at the lowest dose of limonene (50 mg/kg body wt.). Citral and myrcene (100 and 200 mg/kg body wt.) improved sleeping time for the barbiturate relative to placebo. Also, limonene was effective at the highest dose, and although citral did not increase the onset of sleep, it increased the duration of sleep. Citral (100 and 200 mg/kg body wt.) raised the barbiturate sleep time in mice by 2.3 and 3.5 times. Related effects were observed at the maximum dose (200 mg/kg body wt.) for myrcene and limonene, which decreased the sleep time by about 2.6 times. No impact was observed in the elevated-plus labyrinth with citral up to 25 mg/kg body wt, although at a high dose, the number of entries in the open arms decreased by 46 percent. Limonene was found to have a lower but significant impact (5 mg/kg body wt.). Although myrcene (10 mg/kg body wt.) decreased the number of entries only by 22 percent, this parameter decreased by 48 percent at the maximum dose. Our study showed that both citral, limonene, and myrcene had a sedative and relaxing effect on the motor. Researchers also developed a potentiation of the pentobarbital-induced sleeping period in mice, which was more severe in the presence of citral, but only at the maximum dose. Moreover, none of them displayed an anxiolytic reaction, but rather a mild anxiogenic form of response at the higher doses.
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