Bitter Orange
Fructus aurantia
By Steven H. Horne
The fruit of the bitter orange has long been used as a medicine in China. Known as zhi shi, it is considered a valuable chi regulator. It has traditionally been used for aiding digestion, its bitter and acrid taste being used to remove stagnation in the digestive tract and relieve gas and intestinal bloating. It also directs chi downward, helping to open up the bowel.
More recently, the Chinese have started using bitter orange to treat shock, heart conditions and cardiac exhaustion. It is also used to resolve phlegm, i.e., to loosen phlegm in the body and get it to move. It is particularly helpful for sticky yellow phlegm.
Bitter orange peel contains a volatile oil, flavonoids, coumarins, triterenes and vitamin C. The flavonoids in bitter orange are known to have anti-inflammatory, antibacterial and antifungal properties.
Recent research has shown that the unripe peel contains neohesperidin and five amines with adrenergic action (synephrine, N-methyltyramine, hordenine, octopamine, and tyramine). Adrenergic receptors are receptor sites for the sympathetic hormones and neurotransmitters epinephrine and norepinephrine. This means bitter orange acts as a stimulant to the body.
Synephrine is one of the key components here because it has a similar chemical structure to ephedrine (from Chinese ephedra which has been taken off the market). This makes bitter orange a good substitute for ephedra in respiratory formulas.
Bitter orange is also being used in weight loss formulas. Synephrine has been shown to increase resting metabolic rate more than ephedrine did. However, synephrine doesn’t cross the blood-brain barrier to overstimulate the brain. Research also suggests that synephrine and the other amines in bitter orange only work on beta-3 receptor sites, which are primarily found in fat and liver tissue. Stimulation of these receptor sites increases breakdown of fat and raises metabolism. However, because these amines don’t stimulate other adrenergic receptors as much, bitter orange does not affect the heart and blood pressure the way ephedra does. This means it helps burn fat without overstimulating the heart. It can raise blood pressure slightly, but nowhere near as much as ephedra can.
Octopamine, another of these amines, appears to stop insects from eating the unripe peeling. In humans, octopamine causes the pituitary to secrete growth hormone, which contributes to tissue repair and muscle growth. Whether the effect is strong enough with the herb to have a significant effect or not has yet to be determined.
However, while scientists are still researching these isolated chemicals from bitter orange, we still have the benefits of the whole plant in many NSP formulas. Four of NSP’s respiratory formulas make use of bitter orange as a key ingredient. They are: Sinus Support EF, Seasonal Defense, Chinese Lung Support and SnoreEase. All of these formulas help to decongest the respiratory tract.
However, since bitter orange has traditionally been used as a digestive remedy, it is probably helping reduce respiratory congestion at its source, since most respiratory congestion starts with digestive and colon problems. It’s also the reason bitter orange is an ingredient in both Spleen Activator and Chinese Anti-Gas formula, combinations designed to aid the digestive system.
Trigger Immune, a general immune and energy tonic, also contains bitter orange as does MetaboMax EF, a weight loss formula. The flowers of bitter orange are the source of the essential oil neroli, which is used as a relaxant for stress, depression, headaches and heart palpitations.
Selected References
The Encyclopedia of Medicinal Plants by Andrew Chevallier.
The Comprehensive Guide to Nature’s Sunshine Products by Tree of Light Publishing
Chinese Herbal Medicine Materia Medica compiled and translated by Dan Bensky and Andrew Gamble
Complete Guide to Medicinal Herbs by Penelope Ody
