Citrus aurantium dulcis peel oil is an oil obtained with a chemical process from the orange peel, it is a sesquiterpene with antioxidant properties.

It is used as aroma in food, beverages, in cosmetics and in body cleansers with a function:

• Tonic
  
• Astringent
  
• Revitalizing
  

Extraction and antioxidant activity

The current method used in most countries for the production of cold-pressed orange oil is the simultaneous extraction of an emulsion of juice and oil from the whole fruit. Cold pressed orange oil contains waxes, pesticide residues and carotenoids (1). The current method used in most countries for manufacturing cold-pressed orange oil is simultaneous extraction of a juice and oil emulsion from the whole fruit. Cold-Pressed orange oil contains waxes, pesticide residues and carotenoids. For this reason it would be appropriate to adopt a molecular distillation method to remove them as this oil can be used in the clinical treatment of patients with malignant brain tumors (2), to inhibit angiogenesis, metastasis and cell death in human colon cancer cells (3).

In this study, the orange peel of 12 cultivars of Citrus sinensis from central-eastern Sicily was employed to obtain essential oils and extracts. The ones were extracted through steam distillation, the others through extraction in hexane. Chemical constituents were evaluated in terms of qualitative and quantitative analyses by gas chromatography/mass spectrometry. Fifty-four components were identified in the steam essential oils and 44 in the extracts. In all the cultivars, the main component is d-limonene (73.9-97%); discrete percentages of linalool, geraniol and nerol were also found. Cluster analysis based on essential oils composition showed a certain degree of affinity between cultivars of the same type. The antimicrobial activity was investigated against three micro-organisms (Staphylococcus aureus, Listeria monocytogens and Pseudomonas aeruginosa). 'Sanguinello' and 'Solarino Moro' essential oils are significantly active against L. monocytogenes, while 'Valencia' hexanic extract against all the tested micro-organisms(4).

Acute otitis media (AOM) animal model was built and diet containing orange peel essential oil microcapsules were administrated to AOM animals. Pharmacological test showed that orange peel essential oil treatment could decrease serum and cochlea malondialdehyde (MDA), immunoglobulins A (IgA), immunoglobulins G (IgG), immunoglobulins M (IgM) levels and increase antioxidant enzymes activities. It can be concluded that orange peel essential oil treatment could decrease oxidative injury in acute otitis media rats.

Typical chemical composition of an orange essential oil

Twenty four compounds, accounting for 97.9% of the total oil, were identified based on their mass spectra. The main components were terpenic molecules, and the oil was composed of 97.3% monoterpenes (which include 19.0% oxygenated monoterpenes) and 0.5% sesquiterpenes. The main constituents were limonene (74.6%), limonene 1,2-epoxide (3.5%), cis-p-mentha-2,8-dien-1-ol (3.2%) and (E)-carveol (2.4%) (6). 

Cosmetics

Tonic, astringent, revitalising function. Orange essential oil is also attributed moisturising, nourishing and firming properties. Cosmetic industries, which are continually bringing new products onto the market, are trying to meet the ever-increasing demands of consumers for natural products.

References______________________________

(1) Antioxidant and Anticancer Activities of Essential Oil from Gannan Navel Orange Peel.
Yang C, Chen H, Chen H, Zhong B, Luo X, Chun J.
Molecules. 2017 Aug 22;22(8). pii: E1391. doi: 10.3390/molecules22081391.

(2) Preclinical development and clinical use of perillyl alcohol for chemoprevention and cancer therapy.
Chen TC, Fonseca CO, Schönthal AH
Am J Cancer Res. 2015; 5(5):1580-93.

(3) D-limonene rich volatile oil from blood oranges inhibits angiogenesis, metastasis and cell death in human colon cancer cells.
Chidambara Murthy KN, Jayaprakasha GK, Patil BS
Life Sci. 2012 Oct 5; 91(11-12):429-439.

(4) Essential oil components of orange peels and antimicrobial activity.
Geraci A, Di Stefano V, Di Martino E, Schillaci D, Schicchi R.
Nat Prod Res. 2017 Mar;31(6):653-659. doi: 10.1080/14786419.2016.1219860. 

(5) Effect of orange peel essential oil on oxidative stress in AOM animals.
Lv YX, Zhao SP, Zhang JY, Zhang H, Xie ZH, Cai GM, Jiang WH.
Int J Biol Macromol. 2012 May 1;50(4):1144-50. doi: 10.1016/j.ijbiomac.2012.02.002. 

(6) Antioxidant and Anticancer Activities of Essential Oil from Gannan Navel Orange Peel.
Yang C, Chen H, Chen H, Zhong B, Luo X, Chun J.
Molecules. 2017 Aug 22;22(8). pii: E1391. doi: 10.3390/molecules22081391.