International Journal of Community Medicine and Public Health Dada TE et al. Int J Community Med Public Health. 2021 May;8(5):2564-2571 http://www.ijcmph.com pISSN 2394-6032 | eISSN 2394-6040 DOI: https://dx.doi.org/10.18203/2394-6040.ijcmph20211789 Review Article Nutritional and medicinal values of common green leafy vegetables consumed in Delta State, Nigeria: a review 1 2 3 1 1 Taiwo Esther Dada *, Kekere Otitoloju , Randy Adjonu , Judith Crockett , Ezekiel Uba Nwose 1School of Community Health, Charles Sturt University, Orange, Australia 2Department of Agronomy, Faculty of Agriculture, Adekunle Ajasin University, Akungba-Akoko, Ondo State, Nigeria 3School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, Australia Received: 04 January 2021 Revised: 30 March 2021 Accepted: 01 April 2021 *Correspondence: Taiwo Esther Dada, E-mail: [email protected] Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Green leafy vegetables (GLVs) play an important role in human nutrition. In sub-Saharan African countries, GLVs are a vital source of essential micronutrients, and their consumption has long been a part of the cultural heritage of African households. In Nigeria, GLVs are either cooked as a stew or consumed raw and used as a main or a supporting dish. These GLVs have great nutritional and medicinal value. It is hypothesized that providing knowledge about the botanical description, nutritional and medicinal benefits to consumers could improve consumption, but much of existing knowledge is poorly documented and inaccessible. This paper aims to address this gap by collating information on some consumed in Delta State, Nigeria: African jointfir (Gnetum africanum, locally known as Ukazi), jute mallow, (Corchorus olitorius, locally known as Malafiya), and cassava (Manihot esculenta, Crantz), giant yellow mulberry (Myrianthus arboreus), okra (Abelmoschus esculentus), clove (Syzygium aromaticum) and bush buck, (Gongronema latifolium, locally known as Utazi) leaves. Keywords: Nutritional value, Medicinal value, Green leafy vegetables, Indigenous foods, Malnutrition, Nigeria INTRODUCTION may be bitter, aromatic, or bland to taste tasteless.4 The consumption of GLVs has been a part of the cultural The global strategy on diet recommends at least 400 g of heritage among rural African households during meal fruit and vegetables daily to support consistent nutrition times, and are considered an essential part of their diet.5 and human health. Sub-Saharan Africans are known to Despite the medicinal, nutritional, and economic benefits consume green leafy vegetables (GLVs) as part of their of these vegetables, they are still underutilized by the diets.1 These GLVs are rich in macro-and micronutrients, population. This limitation may be due to the lack of which significantly impacts people’s nutritional status- awareness regarding the nutrition and health benefits of including vitamins such as A, C, K, and carotene (provit these GLVs. A).2 They are also sources of essential minerals such as iron, potassium, zinc, iodine, and calcium.3 It is argued that the provision of the necessary information about the nutritional and medicinal benefits Commonly consumed GLVs in Nigeria include waterleaf of GLVs that are commonly consumed may encourage (Talinum fruticosum), fluted pumpkin (Telifaira low-income populations in rural Nigeria to cultivate and occidentalis), bitter leaf (Vernonia amygdalina), jute consume more of these GLVs. The consumption GLVs as mallow (Corchorus olitorius), and clove (Syzygium part of a balanced diet can contribute to the prevention of aromaticum). GLVs display varied sensory attributes and nutrient deficiencies and the consequent malnutrition International Journal of Community Medicine and Public Health | May 2021 | Vol 8 | Issue 5 Page 2564 Dada TE et al. Int J Community Med Public Health. 2021 May;8(5):2564-2571 among these vulnerable population groups.6 There has Medicinal value been limited research and documentation on the medicinal and nutritional values of GLVs consumed by Locally, G. africanum has been used as remedy for sore the indigenous people of this Delta State, Nigeria. This throats, nausea, and pain management among women paper reviews the nutritional and medicinal values of during childbirth.10 G. africanum leaves contain selected GLVs, including African jointfir (Gnetum phytochemical properties like anti-carcinogenic, anti- africanum), jute mallow (Corchorus olitorius), cassava inflammatory, and antioxidant.8,10 (Manihot esculenta), giant yellow mulberry (Myrianthus arboreus), okra (Abelmoschus esculentus), clove Jute mallow (Corchorus olitorius L.) leaves (Syzygium aromaticum) and bushbuck (Gongronema latifolium). Botanical description NUTRITIONAL AND MEDICINAL VALUE OF Corchorus olitorious L. is an annual, much-branched with SELECTED GLVS CONSUMED IN DELTA STATE, young, tender with green leaves, belonging to the family NIGERIA belonging to Tiliaceae and genus Corchorus. It is commonly called jute mallow, bush okra, or West African African jointfir (Gnetum africanum-Welw) leaves sorrel.11 In Nigeria, it has many local names- ‘ewedu’ in Yoruba, ‘malafiya’ in Igbo, and ‘rama’ in Hausa.12 Botanical description The plant thrives in warm conditions and grows naturally in abandoned fields, grass, and fallow lands. It is 13 African Jointfir (Gnetum africanum) is an evergreen, cultivated in Asia, Latin America, Australia, and Africa. shade-tolerant vine, perennial with woody stems found in humid tropical forests, belonging to the family of C. olitorious in the Africa continent includes Nigeria, Gnetaceae and genus Gnetum L. jointfir. It has different Kenya, Uganda, Cameroon, Sudan, and Zimbabwe.14 The local names in different parts of the world. In Nigeria, leaves have alternate, ovate, lanceolate, and dentate common names are “wild spinach” (English name), shapes, flowers occur as single or two to three flower “Afang leaves” (Ibibio), “Okazi/Ukazi” (Igbo) and cymes in the leaf axil opposite to the leaf, and their fruit “Nkani” (Northern cross Riverians).7,8 It is also cultivated are usually brown, gray, or green (Figure 2).12 in central Africa, South America, and tropical and subtropical part of Asia. During the dry season, G. africanum continues to grow new shoots and develop, especially when the side shoots or stem has been cut removed (Figure 1). A Figure 1: Leaves of Gnetum africanum.9 Nutritional value B Figure 2: Leaves and flowers of jute mallow. The fruit, leaves, root sap, and seed are the edible parts of the plant. The leaves of G. africanum can be consumed as Nutritional value a vegetable and cooked to prepare Afang and okazi soup.7 They are also widely used as an ingredient in stews due to C. olitorius leaves are source of carbohydrates, proteins, their nutritional and therapeutic properties.10 The leaves essential amino acids, vitamin B, C, E, and β-carotene of the plant are a rich source of protein, iron, calcium, and (vitamin A).15 The young fresh leaves of this plant are iodine, with the presence of fibre mitigates iron also high in fibre and minerals (e.g., calcium and iron) bioavailability and calcium, creating an essential needed for good health.16,17 The leaves and tender shoots nutritional property.7 International Journal of Community Medicine and Public Health | May 2021 | Vol 8 | Issue 5 Page 2565 Dada TE et al. Int J Community Med Public Health. 2021 May;8(5):2564-2571 are the edible parts of the crop. The leaves either being locally called “Ganyen rogo” in Hausa, “Akwukwo ji eaten raw or be used to make a sticky sauce, which can akpu” or Mpoto, ipoto in Igbo, “Ewe ege” in Yoruba, be cooked in a stew/soup that accompanies the main “Nfang iwa” in Ibibio, and “Ikong iwa” in Efik. It is a dishes.18 The consumption of jute mallow provides well-known leafy vegetable widely grown in tropical and excellent sources of antioxidants. subtropical countries such as Asia, Africa, and Latin- America.24 Leaves are used for both culinary purposes Medicinal value and in folk medicines. Cassava is one of the most edible root vegetables in some Sub-Saharan Africa countries, The leaves, roots, and seeds part of the plant are also with the cassava tuber most commonly consumed. used for folk remedies and herbal medicines, to treat Cassava leaves are also consumed in Tanzania, Nigeria, various disease conditions such as gonorrhoea, aches and Sierra Leone, Liberia, and Zaire, where they are readily pains, dysentery, fever, piles, tumours, and chronic available throughout the year.24 They are used for both cystitis and to act as a purgative (Figure 3).18.19 culinary purposes and in folk medicines (Figure 4).25,26 Moreover, the leaves' cold infusion is said to restore appetite and strength in humans.20 Anae mia Treat Waist infertility pain in women Malari Herbal Diarrh a/ medicinal oea Fever uses Help Stomach with problems milk for &Piles Figure 4: Cassava leaves. nursing mothers Asthma Nutritional value Cassava leaves' nutritional value contains vitamins like B1, B2, C, and carotenoids, minerals, and protein.27 As a Figure 3: Herbal medicinal uses of jute mallow. result, the consumption of cassava leaves can be used to combat malnutrition. For example, In Brazil, the cassava leaf powder is used as a food supplement named The leaves of jute are well known as a diuretic and Multimistura to combat malnutrition among children and emollient. The decoction made from these leaves is used pregnant women.26 as a tonic to support human health.21,22 Figure 3 illustrates various ways the plant can be used for curing illness, such as the leaves used as herbal pharmacopeia to Medicinal value prevent typhoid fever or malaria. The root scraping from C. olitorous is used for the treatment of toothache.18 The The micronutrients found in cassava leaves have several leaf part of jute mallow is consumed at cultural events medicinal values in human health.