The saying that the most important things in life are free might not be entirely true. Some of the basic things that humans need for survival are naturally around us. While they might not be totally free to obtain, they are largely cheap.
I have always loved rural life where natural products such as fresh fruits, herbs, and food products can be obtained with ease and at very cheap prices, if not free. Unlike in the city where getting fresh natural products are difficult to come by and when they do, they are usually at cut-throat prices and not fresh in the real sense of it.
I happen to be one of the few lucky ones that live in a semi-urban area where I can get easy access to fresh natural products as well as the ease that comes with urban life.
A few days ago, I was driving around town to get some groceries when I saw boiled African walnut fruits being hawked just by the road. Each time I see this fruit and how ignorant people are about its potentials, especially when it comes to human health. Hence, I decided to dedicate this little write-up to the fruit.
Meet the plant: African Walnut
African walnut is a common name for a plant that is botanically nomenclatured as Tetracarpidium conophorum or Plukenetia conophora. Other common names given to the plant include conophor or conophor nut, while in some quarters, it is simply referred to as Nigerian walnut.
Locally here in Nigeria, the plant is known with a wide variety of names depending on the tribe. Here in the Southwest, among the Yoruba speaking people, it is popularly known as awusa or asala and the fruit is commonly seen being hawked in traffic during the fruiting season between February and September every year.
African walnut belongs to a family of flowering plants known as Euphorbiaceae. It grows as a woody climber of 3-15 m long and produces numerous branches/leaves on the crown of their supporting trees. At maturity, the plant flowers and produces pod-esque fruits that are initially green in colour but turn black as they ripen.
The fruit are not themselves edible, but the seeds inside them. The seeds are protected by a relatively thick and hard seed coat that requires 'cracking' before the endosperm can be accessed. The number of seeds per pod varies from one to six depending on the side of the pod. Most of the time, the fruits show their maturity by falling off the plant.
African walnut plant is largely propagated from its seeds, although there have been reports of vegetative propagation from stems. It is a usual practice by local farmers to crack the seed coats a little before planting them in the soil. This method has been found to quickens the germination period compared to the uncracked seeds.
The endosperm absorbs water and expands, eventually cracking the seed coats which allows for the emergence of the plumule and the radicle. While the latter grows downward into the soil to become the root, the former grows upward, emerges from the soil, and then develops to become the woody climber.
The plant is widely cultivated in Nigeria where it is often grown in association with cocoa and kola-nut. Its distribution, however, transcends the country to other African countries like Cameroon, Gabon, Niger, etc.
One of the most interesting things about the African walnut is its wide ethnobotanical and health benefits. Virtually all the tissues in the various parts of the plant have found their uses for man, but, the seeds have found the most uses.
The barks of the stem have been reported for laxative properties while the leaves extracts have been used to regulate menstrual disorders and boost fertility in women. Apart from its edibility, the seeds are known to be applicable in the treatment of fibroids in women and low sperm counts in men. The iodine-rich oil from the seeds is useful has been found to be useful for the production of paints.
The seeds of African walnut is usually boiled or roasted before consumption. It has been found to be a good source of antioxidants, vitamins, proteins, fats, fiber, and nutrients like magnesium, copper, zinc, and manganese.
Several scientific inquiries have been made into the pharmacological properties of the extracts from different parts of the African walnut plant. Nwachoko and Jack reported the anti-diarrhea activities of the hot aqueous extract of the seeds in 2015. The sperm boosting activities of the seed's extract have also been investigated and found to be true by several researchers.
Other pharmacological activities of the extracts of the plant confirmed by researchers include anti-diabetic, anti-chelating, anti-lipidemic, antioxidant, anti-ulcer, antimicrobial, antimalarial, anticancer, and antidepressant.
The seeds of the African walnut plant, even though edible, do not belong to the category of fruits people can actually label as sweet. Even though cheap and has several medicinal benefits, people do not appreciate its value of the seeds due to this unconventional taste. Considering the scientifically proven immense medicinal, culinary, and ethnobotanical benefits, I am of the opinion that the plant is massively underrated.
What do you think?
- Physical properties of the African walnut (Tetracarpidium conophorum) from Nigeria.
- Tetracarpidium conophorum
- Tetracarpidium conophorum (African walnut) Hutch. & Dalziel: Ethnomedicinal uses and its therapeutic activities
- Phytochemical and Proximate Compositions of Tetracarpidium
Conophorum [African Walnut] Seeds
- Nwachoko, N. & Jack, I.R., 2015, ‘Phytochemical screening and anti-diarrhea activities of Tetracarpidium conophorum induced in albino rats’, Sky Journal of Biochemistry Research 4(4), 21–24.