The grapefruit, Citrus paradisi (Fam: Rutaceae), is yellow-orange skinned and generally oblate spheroid in shape. The flesh is segmented, varying in colour, from white, pink, to red pulps of varying sweetness. Common varieties are yellow and pink pulp colours. Grapefruit, like other citrus fruits, grows on trees. It tends to grow in more tropical climates, as the trees grow better in sandy soil. It is called mkpuru osisi greepu in Igbo and eso girepufurutu in Yoruba.
Raw grapefruit contains water, carbohydrates, protein and negligible fat. Grapefruit juice contains organic acids (mainly citric acid), fibre, sugars (mainly sucrose), calcium, iron, magnesium, phosphorus, potassium, zinc, copper, manganese and Vitamins A, E, B1, B2, and C. It also contains niacin, folate, panthotenic acid, lycopene, choline, monoterpenes and sesquiterpenes.
Grapefruit can be used as fresh fruit, dried fruit, juice, oil, peel or vapour. It may be eaten raw or cooked. It can be used to make jam, jellies, marmalade and syrups, and is an ingredient in desserts and salads.
Pharmacological actions and medicinal uses
The water-soluble nutrients in grapefruit are useful in body protein metabolism, wound healing, nerve communication for body movements and reducing signs of premature ageing. Research shows that including grapefruit in diet can help in weight reduction. In theory, this may be due to an ingredient in grapefruit called nootkatone, which is thought to activate certain proteins that aid obesity treatment.
Besides, its fibre content helps to promote fullness and reduce calorie intake by suppressing appetite. Grapefruit may also help prevent insulin resistance, thus lowering the risk of developing type 2 diabetes.
The nutrients and antioxidants in grapefruit help to protect the heart by regulating blood pressure and cholesterol levels. Antioxidants like flavanones may help to prevent the development of some chronic conditions like heart disease and cancer. Formation of calcium oxalate crystals may be reduced by the citric acid found in grapefruit.
Some research shows that eating vitamin C-rich citrus fruits, including grapefruit, might improve lung function in people with asthma. It is also used for the common cold, flu (influenza), and swine flu. Grapefruit seed extract is taken by mouth for bacterial, viral, and fungal infections, including yeast infections. Grapefruit seed extract vapour has also been inhaled for the treatment of lung infections.
Some people inhale grapefruit vapours to help the body retain water, for headache, stress, and depression. Grapefruit flower extract is sometimes used for insomnia.
Grapefruit oil is applied to the skin for tired muscles, hair growth, toning the skin, and for acne and oily skin.
Grapefruit causes drug interactions by inhibiting drug metabolism or absorption in the intestine. The resultant effect is either toxicity from overdose in the bloodstream or reduced drug effect. Too much grapefruit can cause gastrointestinal reactions such as diarrhoea. In some instances, eating grapefruit may lead to tooth enamel erosion.
Economic uses and potentials
Global international trade in grapefruit was $924m in 2019.
Nigeria is one of the 50 largest consuming countries. Red grapefruit costs about N4,800 per kg of the big size in the Nigerian market.
Grapefruit is useful in the farming (primarily for pigs and cattle), food, pharmaceutical, cosmetics, furniture-making and building industries. In fact, grapefruit is a wealth creator.
Pharm., MSc (Clinical Pharmacy), MPH, FPCPharm (Nigeria Natural Medicine Development Agency)