Effects of 1,8-cineole on hypertension induced by chronic exposure to nicotine in rats.

OBJECTIVES: The monoterpenic oxide 1,8-cineole is a major component of many essential oils. We investigated its effects on systolic blood pressure (SBP) and oxidative stress in rats chronically exposed to nicotine. METHODS: Male Sprague-Dawley rats (100-120 g) were intraperitoneally injected with 0.8 mg/kg/day nicotine for 21 days, followed by 3 mg/kg nicotine the next day. Rats were subsequently injected intraperitoneally with 0.01, 0.1 and 1 mg/kg 1,8-cineole, or 10 mg/kg nifedipine. SBP was measured using a tail cuff transducer, plasma nitrite concentration was measured colorimetrically, and plasma corticosterone concentration was measured by enzyme immunoassay. KEY FINDINGS: We found that 0.1 mg/kg 1,8-cineole significantly reduced SBP, and that 1.0 mg/kg 1,8-cineole significantly increased plasma nitrite concentrations, compared with rats chronically exposed to nicotine alone. Rats chronically exposed to nicotine showed a significant increase in lipid peroxidation levels, an elevation significantly antagonized by treatment with 0.01 mg/kg and 0.1 mg/kg 1,8-cineole. Chronic exposure to nicotine also significantly increased plasma corticosterone levels, but this effect was not diminished by treatment with 1,8-cineole. CONCLUSIONS: These results indicate that 1,8-cineole may lower blood pressure, and that this antihypertensive effect may be associated with the regulation of nitric oxide and oxidative stress in rats chronically exposed to nicotine.

Citrus bergamia Risso Elevates Intracellular Ca (2+) in Human Vascular Endothelial Cells due to Release of Ca (2+) from Primary Intracellular Stores.

The purpose of the present study is to examine the effects of essential oil of Citrus bergamia Risso (bergamot, BEO) on intracellular Ca(2+) in human umbilical vein endothelial cells. Fura-2 fluorescence was used to examine changes in intracellular Ca(2+) concentration [Ca(2+)]i . In the presence of extracellular Ca(2+), BEO increased [Ca(2+)]i , which was partially inhibited by a nonselective Ca(2+) channel blocker La(3+). In Ca(2+)-free extracellular solutions, BEO increased [Ca(2+)]i in a concentration-dependent manner, suggesting that BEO mobilizes intracellular Ca(2+). BEO-induced [Ca(2+)]i increase was partially inhibited by a Ca(2+)-induced Ca(2+) release inhibitor dantrolene, a phospholipase C inhibitor U73122, and an inositol 1,4,5-triphosphate (IP3)-gated Ca(2+) channel blocker, 2-aminoethoxydiphenyl borane (2-APB). BEO also increased [Ca(2+)]i in the presence of carbonyl cyanide m-chlorophenylhydrazone, an inhibitor of mitochondrial Ca(2+) uptake. In addition, store-operated Ca(2+) entry (SOC) was potentiated by BEO. These results suggest that BEO mobilizes Ca(2+) from primary intracellular stores via Ca(2+)-induced and IP3-mediated Ca(2+) release and affect promotion of Ca(2+) influx, likely via an SOC mechanism.

Antidepressant-like effect of Salvia sclarea is explained by modulation of dopamine activities in rats.

AIM OF THE STUDY: The purpose of the present study was to screen aromatic essential oils that have antidepressant effects to identify the regulatory mechanisms of selected essential oils. MATERIALS AND METHODS: The antidepressant effects of essential oils of Anthemis nobilis (chamomile), Salvia sclarea (clary sage; clary), Rosmarinus officinalis (rosemary), and Lavandula angustifolia (lavender) were assessed using a forced swim test (FST) in rats. Rats were treated with essential oils by intraperitoneal injection or inhalation. Serum levels of corticosterone were assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Among the essential oils tested, 5% (v/v) clary oil had the strongest anti-stressor effect in the FST. We further investigated the mechanism of clary oil antidepression by pretreatment with agonists or antagonists to serotonin (5-HT), dopamine (DA), adrenaline, and GABA receptors. The anti-stressor effect of clary oil was significantly blocked by pretreatment with buspirone (a 5-HT(1A) agonist), SCH-23390 (a D(1) receptor antagonist) and haloperidol (a D(2), D(3), and D(4) receptor antagonist). CONCLUSIONS: Our findings indicate that clary oil could be developed as a therapeutic agent for patients with depression and that the antidepressant-like effect of clary oil is closely associated with modulation of the DAnergic pathway.