Enhancing Respiratory Health Through Marula

Introduction

Defining respiratory health

The human body is composed of cells that require oxygen to survive. This need is fulfilled by breathing oxygen and other gases found in the air. The respiratory system's role is to circulate oxygen into the body and to remove waste gases. Once oxygen is inhaled into the lungs and carried into the bloodstream, it moves throughout the body. Each cell in the body exchanges oxygen for a waste gas known as carbon dioxide. The bloodstream then transports the carbon dioxide back to the lungs, where it is removed from the body through exhalation. This process is known as gas exchange, an automatic respiratory response for the lungs to perform its vital role in the human body. Additionally, the respiratory system also performs other roles that are crucial for breathing. For example, ensuring the oxygen is aligned with core body temperature and the right humidity level. The lungs also protect the body from inhaling and ingesting harmful substances by coughing, sneezing, filtering or swallowing them.¹

The Importance of maintaining respiratory health

The maximum amount of oxygen the lungs can hold is approximately six litres. The lungs are known to mature by the age of 25 years and after the age of 35, it is usual for lung function to decrease in performance as an individual ages. This can make breathing difficult and it is advised to consult a doctor immediately. It is important to maintain respiratory health as this could be a sign of lung disease, rather than the usual process of ageing. As the body goes through ageing natural body changes occur that are the cause of decreased lung capacity. Muscles, such as the diaphragm, become weaker and lung tissue loses elasticity that keeps the airways open, resulting in constricted airways and less room for the diaphragm to expand during exhalation.¹

Although a decline in lung function is a normal part of ageing, there are steps to strengthen the lungs to maintain respiratory health. These include staying active, avoiding tobacco and ensuring vaccinations are up to date. Lung capacity is commonly measured by a diagnostic test known as ‘Spirometry’, which provides an assessment of lung capacity. Spirometry results are used to evaluate the effectiveness of treatment for lung conditions, such as chronic obstructive pulmonary disorder (COPD) and asthma.¹

Introduction to Marula and its potential benefits for respiratory health

Treating diseases with the use of medicinal plants is a common trend and is seen in many developing countries. This practice is highly common in remote regions due to inadequate healthcare infrastructure. Marula, a plant grown in Africa has shown a wide sociological and economic importance in the southern parts of the African continent. 

The fruits are consumed as food and alcoholic beverages. In other parts of Africa, the bark of the marula plant is traditionally used to treat a variety of conditions such as gastrointestinal and infectious diseases. These include gastritis, ulcers, stomach cancer as well as sexually transmitted diseases. Kokwaro, also known as marula, has shown vital antioxidant properties. Sarkar and colleagues reported the plant to consist of antimicrobial, antifungal and anti-inflammatory activities that are crucial for potentially beneficial treatment of diseases.²

Recently, a global health concern has risen due to respiratory diseases. Coronavirus 2019 (COVID-19), a respiratory-based disease, was affiliated to more than 523 million cases worldwide. In Zimbabwe respiratory diseases are mainly managed by herbal medicines. This is due to low costs and accessibility.³

Understanding Marula

Nyagumbo and colleagues have discussed how traditional plant-based remedies can provide a therapeutic outcome in suppressing symptoms that consist of sneezing, coughing and swollen glands. Which in turn can provide relief in chest and nasal congestion and soothe irritated airways. Herbal remedies have portrayed antihistamine and antioxidant properties that are crucial in easing respiratory conditions.³ Marula, a well-known indigenous plant grown in southern Africa shown to portray this. 

Marula fruits can be consumed in fresh form or squeezed to make juice, jam or jelly. The kernels are also edible and can be extracted as an oil. Furthermore, the bark, roots, seeds and leaves are also utilised in traditional medicine. The marula tree is one of the most valuable cultural and economic resources in the country. The Forest Acts of Botswana and Namibia 1968 protects marula as an indigenous fruit tree. 

Marula is a medium-sized tree that can reach heights of 17 metres and bears fruits from January to March. In the wild, fruiting occurs around 7-10 years but the yield of fruit can increase to over 100 years. Marula is oval, flesh-coloured plum-like fruits, around 3.5 cm in diameter.⁴ 

Literature has highlighted that sweet fruit usually contain 2-3 edible kernels, but do vary per fruit. Kernels consist of high protein as well as minerals of phosphorus, magnesium, zinc, iron and copper. Extracts from the bark and leaf of the marula plant contain antioxidant properties.⁴

Summary of relevant scientific findings 

Kamanula et al investigated the nutritional and phytochemical variation from extracts taken from the marula tree in Malawi. The following results were obtained Vitamin C (81 mg/100 g), iron (1.4 to 3.3 mg/100 g), zinc (0.3 to 0.8 mg/100 g), calcium (1.8 to 5.3 mg/100 g) in the fruit pulp, fat (51.6 to 57.7%) and fibre (4.1 to 6.9%) in the seed kernel. The research was correlated with nine other provenances in Africa, similar findings were obtained. Phytochemical scores showed that all samples contained a weak concentration of alkaloids. Generally, the amount of vitamin C was predominantly higher in the research.⁵ Research has discussed vitamin C and its importance in marula in treating diseases. It is suggested that further studies should be carried out to determine the environmental interaction and the genotype of vitamin C; to assess its prevalence in the marula plant.⁵

Practical applications of consuming marula for respiratory health 

Consuming marula has led to practical applications for respiratory health. Research has suggested the roots, leaves and bark are the main parts of the plant used for the treatment of respiratory conditions in Zimbabwe. Although this is the least environmentally sustainable solution, it is the most preferred source of medicine. Nyagumbo et al discussed in some instances the whole fruit, twig, stem or another plant part may be utilised. This implies that the roots have the most effectual antimicrobial and bioactive characteristics.³

Due to the high cost of pharmaceuticals demand has increased in identifying new targets for developing novel, cost-effective alternative medications. Drawbacks have included where there has been a limited plantation of tree nurseries and processing facilities. There is a lack of biodiversity studies and insufficient information about the nutritional and therapeutic values of the marula plant.³

Additionally, research on marula has become prevalent and can be used as a guide in regions where it has not been established. Collaboration is needed between regions, such as to identify superior trees, develop vegetation propagation as well and improve germplasms in the farming system. Mokgolodi et al have highlighted farming techniques that could be developed for the ex-situ conservation of marula trees. This could assist in cloning the initial planting to avoid long juvenile periods from seeds.⁴

FAQ’s

Why are lungs important?

The lungs play a part in circulating oxygen into the body and removing waste gases, a vital role in the human body. The lungs also protect the body from inhaling and/or ingesting harmful substances by coughing, sneezing, filtering or swallowing them.¹

What is the medicinal use of marula?

Marula has been identified as a potential medicinal plant that can be used to manage and treat respiratory infections, asthma, chronic obstructive pulmonary disease, tuberculosis and lung cancer.³

What vitamins are in marula?

Marula has high nutritional value and consists of a rich composition of vitamins and phytochemical variation and these are even included with vitamin C, iron, zinc, calcium, fat and fibre.⁵

Summary

Respiratory diseases are the top ten causes of mortality and morbidity conditions worldwide. Zimbabwe is largely affected by respiratory infections, asthma, chronic obstructive pulmonary disease, tuberculosis as well as lung cancer. Marula has been identified as a potential medicinal plant that can be used in future to manage and treat respiratory infections. A review by Nyagumbo et al has documented that marula has been traditionally utilised in Zimbabwe over the past four years to treat respiratory conditions.³

Researchers have observed a variation in the nutritional and phytochemical composition in marula fruits. Which could be due to the genetic composition and the origin of the plants. Kamanula et al suggested attentive selection of the origin of the plants. Further studies could investigate vegetative propagation, selecting traits that are rich in nutritional and phytochemical value before seed propagation.⁵

Unfortunately, there is limited indigenous knowledge about medicinal plants; due to the unavailability of scientific studies to validate traditional beliefs and the limited scale of domestication and documentation. However, there has been a gradual increase in scientific research on the plants to treat respiratory ailments in Zimbabwe.³