Nigella sativa seeds (black seed or black cumin seed) grows in the Middle East and holds a place of honor in the medicine of that region. Benefits have been seen in diabetes and hypertension from treatment with black seed oil. Its active ingredient, thymoquinone, reduces blood levels of cholesterol, triglyceride, and glucose, and decreases gastric acid secretion. Black seed has been used traditionally to treat respiratory diseases and asthma.

The purpose of this article by Keyhanmanesh, R., et al, was to review the medical literature for articles written about the smooth* muscle relaxant effects of black seed have been studied in the past. The seeds have been found to be rich in tocopherols and polyphenols and even have been shown to reduce blood levels of prolactin.

Water soluble extracts of plants are mainly responsible for the relaxant effects on smooth muscle fibers. Studies have consistently shown that thymoquinone has a relaxant effect on smooth muscle of the trachea, the vascular smooth muscle such as of the aorta and pulmonary artery, and the smooth muscle of the small intestine. Black seed oil also inhibited spontaneous contractions of the smooth muscle of the uterus.

The method by which N. sativa oil relaxes smooth muscle is not known, but various methods have been suggested, such as blocking of calcium and potassium channels in cell walls and the production of nitric oxide (NO). NO has been shown to relax smooth muscles of airway origin. This could make black seed oil useful for treatment of asthma and chronic obstructive pulmonary disease (COPD).

Hypertensive patients may have lower diastolic and systolic blood pressures with the use of black seed oil, as well as a reduction of total cholesterol and LDL-cholesterol levels. The relaxant effect of thymoquinone on gastrointestinal smooth muscle explain the success of the traditional use of black seed in diarrhea and colitis.

CONCLUSION: Oil of N. sativa has been well studied for the relaxant effect on smooth muscle in airways, blood vessels, gastrointestinal hollow organs and tissues of urogenital origin. The success of the oils in relaxing smooth muscle makes it likely that the oils will have many clinical uses.

NOTE: *Smooth muscle includes the muscles that line our blood vessels allowing them to dilate and constrict and muscles that line our hollow internal organs, such as trachea and intestines.

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PMID: 25859297.

Summary #736.