Introduction

Marula oil is otherwise known as birrea oil. Its tree is native to Southern Africa. Historical records show that the Marula tree has been used for multiple purposes for centuries, as long as 10,000 years. The documented uses range from food purposes, alcoholic drinks and cosmetic purposes.¹

The multipurpose benefits of Marula make it one of the most critical economic trees in Africa. The fruits can be eaten and fermented into alcoholic beverages like beer. The oil extract is used in skincare and food preservation, especially meat products.

Its benefits in traditional medicine include treating diarrhoea, hypertension, and diabetes and its antioxidant and antimicrobial benefits. Marula (Family: Anacardiaceae) is also regarded as the ‘Tree of Life’ in many cultures. The taxonomic nomenclature of Marula is Sclerocarya birrea (A.Rich) Hochst; this was coined from the Greek words skelros and karyon, which means complex and walnut, respectively. Birrea, conversely, is derived from a Senegalese word for tree- birr.

The tree is a massive part of the African culture and is a protected tree in South Africa. The Marula tree is widely distributed across African countries, including Zimbabwe, Mozambique, Namibia, Zambia and South Africa. It can grow as tall as 17 metres. The fruit is white with a sweet, sour flesh. Kernels contained in its nuts are the source of the oil extract.²

The fruits are yellow and oblong-shaped; they can be eaten fresh. Typically, the tree is without leaves for many months in a year. It begins to flower between September and November. Fruit-bearing starts between January and March.

Traditional uses of marula oil in skincare

Marula oil extracts have been found to provide multiple benefits and are used for many purposes. In some parts of South Africa, such as the Limpopo region, the oil is used as a moisturiser for the whole body. Baby’s bodies are also massaged using the oil. It has been used for years in these indigenous populations as a preventative measure to protect the skin against dryness and cracked skin and as a shampoo for dry and fragile hair and scalp.

The oil has been famous as a base in soap formulations and nose drops for newborns. Additionally, it is used in leather treatment, and it is highly considered to be of high value economically, culturally and ethnomedicinally.^3,4

Marula oil is popular in the cosmetic industry. It has shown significant potency in hydration of the skin and improvement of skin smoothness, as well as reduction of transepidermal water loss.⁵

Biochemical composition of marula oil

The Marula tree fruit contains a high concentration of vitamin C, and the fruit juice also contains sesquiterpene hydrocarbons (copaene, humulene, and caryophyllene). The kernels of the fruits contain high amounts of oils and proteins, and the oil is rich in fatty acids, oleic acids, and stearic and myristic amino acids. Other sources include glutamic and arginine acids.

Additionally, the seeds of Sclerocarya birrea are rich in potassium, iron, magnesium, phosphorus, and copper. The edible portion of the seeds is significantly rich in proteins. However, essential amino acids such as lysine, threonine, and phenylalanine-tyrosine are in low concentrations compared to the World Health Organisation (WHO) standard protein requirement.

The fruits of this tree are a significant source of vitamin C. Moreover, the juice extracted is made up of thirty-three sesquiterpene hydrocarbons. The gum derived from the tree contains gum and has been popularly used as an alternative to ink.⁴

Uses of marula in tradomedicine

Marula has a wide range of uses in traditional medicine. These have been verified by many scientific studies, which assessed its chemical composition and medicinal uses. Some of the known benefits of Marula include its antioxidant, antimalarial, antidiabetic, and antagonistic effects.

High phenolic compounds in the juice, roots, bark, and kernel oil cake have been found to provide antioxidant benefits. These can scavenge free radicals, hinder linoleic acid oxidation, and prevent beta-carotene bleaching. Hence, antioxidants are a desirable component of healthy diets because they help prevent many chronic diseases and even fortify bodily antioxidant defence systems.

Marula is also well-known in traditional medicine for its anti-diabetic properties. Studies show that they are capable of showing hypoglycemic properties, which makes them popular as an adjunct treatment in diabetes management. They have also been found to regulate blood pressure readings in rats.

Folk medicines also use Sclerocarya birrea to manage inflammatory conditions and pain. Many studies have also found extensive use as an antimicrobial agent, particularly in the treatment of trypanosomiasis and dysentery. Some studies have attributed these to the ethanol, methanol, and water content.

In many African communities, dried seeds and nuts are a part of their staple diets, and the tree's different parts are used to treat many health conditions ranging from infertility to gastrointestinal problems.⁴

Summary

The Marula tree is native to Southern Africa. Its use dates back as much as 10,000 years. It is popular for its versatility, with benefits ranging from food purposes to traditional medicine to cosmetics and alcoholic beverages. The tree is also known as Sclerocarya birrea, and it holds a cultural significance, hence why it is also known as the ‘Tree of Life’.

Marula oil is extracted from the kernels of tree fruits and is popular in the cosmetic industry for its benefits to the skin. For decades, many African communities have used Marula oil to hydrate skin and prevent transepidermal water loss for both adults and newborns. It has been shown to prevent skin cracking and dryness. Therefore, it is used in many formulations of soap and skin oil.

Marula oil comprises vitamin C, sesquiterpene hydrocarbons, and fatty acids. The seeds are also rich in iron, potassium, magnesium, phosphorus, and copper. Therefore, marula oil has high ethnocultural and economic significance. 

Conclusion

Marula oil is a multipurpose resource deeply rooted in Southern African culture. It offers benefits not only in skincare and cosmetics but in traditional medicine, highlighting its value as an economically, culturally, and ethnomedicinally significant tree in the region.