Iodine value: 70 - 80 g/100g

Saponification value - 193-200

SAP Value NaOH: 0.140

SAP Value KOH: 0.197

INCI name (PCPC) : Sclerocarya birrea

CAS No: 68956-68-3

Family: Anacardiaceae

Appearance/form:  clear, pale, yellowish-brown colour 

Introduction 

Marula oil is obtained from the kernels or nuts found inside the fruits of the marula tree. The seeds are usually boiled or pressed to extract the oil. The tree is indigenous to sub-Saharan tropical Africa, providing food and commercial goods and treasured for its historical and cultural relevance. The marula tree is also known as the "marriage tree" and is a symbol of purity.  In Zulu culture, it is believed that those who marry beneath its branches will be blessed with fertility.  The fruit is often called the "food of kings" because of its high Vitamin C content. It is also used to make Amarula cream, a liqueur with unique flavours used in many desserts, cocktails and cuisines locally, but is also enjoyed as a delicacy worldwide (1).

Marula oil is a popular ingredient in cosmetic products like skin lotions, lipsticks and foundations. The demand for this rich African oil increased due to its benefits and varied uses. In 2018, it was estimated that over US$ 20 million was spent on cosmetic product manufacturing using marula oil (2). 

Physical and Chemical Characteristics 

The marula tree sheds its leaves during the winter months and flowers from September to November. Its yellow, oblong-shaped fruits are found from January to March every year. When harvested, they have plain, tough skin with juicy flesh. The seed contains 2–3 soft white edible kernels.  

The oil extracted from the seeds and kernels, through cold pressing techniques, is medium rich, lightweight and silky to the touch, with its clear, light yellow colour and nutty aroma. Its 'slip factor' makes it ideal to use as a massage oil (3).

Health Benefits of Internal Use 

Marula oil is considered a delicacy and is used as a cooking oil in traditional and modern recipes by the indigenous tribes in Africa. In some regions, it is used to preserve meats that can then last for about a year. It is rich in monounsaturated fatty acids and is relatively stable, which makes it ideal for treating leather as well (2).

Skin and Hair Care Benefits 

Marula oil has been used as a body oil or as an ingredient in body lotions, used to massage new-born babies' delicate skin. It is a good emollient that works with it all skin types. The fatty acids present in the oil are very similar to those present in the skin's epidermis and are therefore considered biomimetic. Due to high concentrations of vitamins C and E ( tocopherols), it may also be used for acne-prone skin and reduce redness and inflammation in conditions like psoriasis or eczema (2). 

Marula oil has been shown to improve skin hydration while decreasing trans epidermal water loss. Known for its occlusive properties, it creates a light layer on top of the skin to seal in moisture. The high concentration of oleic acid enables it to easily penetrate and nourish the layers of the skin without leaving a greasy residue. It is therefore used as an active ingredient in cosmetic formulations for skincare (4).

Marula oil is known for its antioxidative properties, which combats the action of free radicals formed after exposure to harmful UV rays from the sun and pollution. These are known to cause age spots and changes in skin texture (5). 

The oil inhibits the enzymes that break down both collagen and elastin, the proteins that keep the skin supple, smooth and elastic. It is rich in amino acids like L-arginine and glutamic acid, which have anti-ageing properties and are believed to ward off fine lines and wrinkles. It helps with skin repair and regeneration and is used in formulations that prevent the formation of scars, hyperpigmentation or stretch marks after pregnancy (6).

Marula oil is used on hair and nails as well. It keeps the scalp healthy and boosts healthy hair growth. It is used to nourish hair from root to tip without making it greasy. It is added to shampoos and conditioners for dry, damaged, frizzy, or brittle hair and nails and chapped lips (7). 

The oil is often used as a base oil for soap due to its abundant source of natural oleic acid, which makes it ideal for producing cocoa butter equivalents that are extensively used in the food and cosmeceutical industries (8).

Conclusion 

Marula oil is an active ingredient in cosmetology products due to its ability to hydrate, smoothen, and moisturize the skin, hair, and nails.  

References 

1.Ref: https://www.southafrica.net/gl/en/travel/article/amarula-marula-tree-magic2. 2.

2. Komane B, Vermaak I, Summers B, Viljoen A. Safety and efficacy of Sclerocarya birrea (A.Rich.) Hochst (Marula) oil: A clinical perspective. J Ethnopharmacol. 2015;176:327-335. doi:10.1016/j.jep.2015.10.037

3.Mariod, A., Matthäus, B. And Eichner, K. (2004), Fatty Acid, Tocopherol And Sterol Composition As Well As Oxidative Stability Of Three Unusual Sudanese Oils. Journal of Food Lipids, 11: 179-189. https://doi.org/10.1111/j.1745-4522.2004.01131.x 

4.Houghton, C. "New natural oils and their properties." Anglia Oils Ltd., Bulk Speciality Division (1999). 

5. Gruenwald, Joerg. "Anti-ageing nutraceuticals-Joerg Gruenwald considers existing and new botanicals used in anti-ageing products." Food Science Technology-Information Quarterly of the Institute of Food Science and Techn 20.3 (2006): 50-51. 

6. Shoko T, Maharaj VJ, Naidoo D, et al. Anti-aging potential of extracts from Sclerocarya birrea (A. Rich.) hochst and its chemical profiling by UPLC-Q-TOF-MS. BMC Complement Altern Med. 2018;18(1):54. doi:10.1186/s12906-018-2112-1 

7. Abdalbasit Adam Mariod & Siddig Ibrahim Abdelwahab (2012) Sclerocarya birrea (Marula), An African Tree of Nutritional and Medicinal Uses: A Review, Food Reviews International, 28:4, 375-388, DOI: 10.1080/87559129.2012.660716 

8. Hore, D. (2004). Formulation of cosmetic skin lotions using Adansonia digitata and Sclerocarya birrea oil from Zimbabwe. University of Zimbabwe, Harare. https://www.sciencedirect.com/science/article/pii/S0254629911001074