The Essential Properties of theBitter Orange
by the Doctor Matteo Politi
Pharmacological activity
It is known that essential oils obtained from bitter orange show marked pharmacological effects4; among these we find in particular the anxiolytic, antimicrobial one, to alleviate gastrointestinal and premenstrual symptoms.
Anxiolytic activity
Bitter orange essential oil (obtained from the peel) and Neroli have both been found to be effective as sedatives and in reducing anxiety associated with various clinical conditions. In a systematic review of the scientific literature5, the aromatherapeutic use (through inhalation or oral administration) of both essential oils is described; this has reduced the level of anxiety in most of the stress conditions studied such as those in subjects affected by chronic myeloid leukemia6, preoperative patients7 and with acute coronary syndrome.8,9
Antimicrobial activity
Bitter orange essential oil has a strong antimicrobial activity against a variety of microorganisms including various Gram-positive and Gram-negative bacteria, as well as an antifungal, antioxidant and flavouring agent.1; can be used for storing food and food products.
Gastrointestinal symptoms
The traditional uses of bitter orange essential oils to relieve certain gastrointestinal disorders are well known.10 Some scientific evidence, especially at pre-clinical level, indicates in particular its efficacy as a gastroprotector11, in cases of ulcers and gastritis12,13 and in those of intestinal dysbiosis.14
Premenstrual symptoms
A couple of double-blind clinical studies conducted on female college students indicate the effectiveness of Neroli with respect to PMS, especially by virtue of the psychological effects associated with this syndrome.15,16
Phytochemical profile
The most important essential oils obtained from the bitter orange tree (Citrus aurantium L.), from an industrial/production point of view, are the one obtained by pressing the peels (bitter orange essential oil), Neroli (obtained by hydrodistillation of the flowers) and Petitgrain (obtained by hydrodistillation of the leaves).1
The following are the results of a study carried out on essential oils obtained from plant material collected in Greece and analysed by GC-MS2:
Hydrodistillation of peels, flowers, young and old leaves gave yields of 1.67%, 0.12%, 0.27% and 0.45% (ml/100 g of fresh plant material), respectively. Twenty compounds constituted 99.87% of the essential oil obtained from the peels, among which the main ones were: limonene (94.67%), myrcene (2.00%), linalool (0.76%), β-pinene (0.62%) and α-pinene (0.53%). In Neroli, twenty-six compounds constituted 99.44% of this essential oil, among which the main ones were: linalool (29.14%), β-pinene (19.08%), limonene (12.04%), trans-β-ocimene (6.06%) and E-farnesol (5.14%). The composition of both Petitgrains (obtained from young and old leaves) was found to be similar. Sixteen compounds were in common, among which the main ones were: linalool (58.21% – 36.03%), α-terpineol (7.11% – 12.89%), geranyl acetate (4.49% – 8.70%), neryl acetate (2.18% – 4.46%) and trans-β-ocimene (4.08% – 3.11%). α-Pinene, α-humulene and (E)-β-farnesene (cumulative equal to 0.42%) were detected only in young leaves, while terpinyl acetate and nerolidol E (cumulative equal to 0.21%) were detected only in old leaves.2
In a similar study where the plant material comes from Tunisia, the main constituent of the peel was found to be limonene (90.6%). Neroli was found to contain mostly linalool (34.4%), linalyl acetate (11.3%) and limonene (10.9%). In Petitgrain the main components were linalool (36.8%), linalyl acetate (22.1%) and α-terpineol (11.7%).3
Citrus × aurantium THE.
- Angiosperms
- Rutaceae
- Citrus
Source of botanical nomenclature
Bibliography
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10. Dosoky NS, Setzer WN. Biological activities and safety of citrus spp. Essential oils. Int J Mol Sci. 2018;19:1966. doi:10.3390/ijms19071966
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14. Hawrelak JA, Cattley T, Myers SR. Essential oils in the treatment of intestinal dysbiosis: A preliminary in vitro study. Altern Med Rev. 2009;14(4):380-384.
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