Folate content of cultivated and wild traditional leafy vegetables found in Nigeria
Authors: Ejoh Shirley Isibhakhomen , DUFIE WIREKO‐MANU Faustina , PAGE David , RENARD Catherine M.G.C. 
Published: November 2023

Folate is an important micronutrient in the prevention of neural tube defects and cardiovascular disease. Given its importance, it is necessary to establish accurately the folate content of food that could contribute significantly to dietary intake. The aim of the study was to quantify the folate content in raw and cooked traditional leafy and non‐leafy vegetables because there is a dearth of information on the folate content leafy vegetables found in Nigeria. The vegetables included: Corchorus olitorius, Adansonia digitata, Abelmoscus esculentus (fruit), Abelmoscus esculentus (leaves), Amaranthus hybridus, Launaea taraxacifolia, Solanum macrocarpon, and Crassocephalum crepidioides. They were further cooked in boiling water, until assessed as cooked according to Nigerian eating habits.

Folate is found in foods mainly as polyglutamate. The analysis of folate in the raw and cooked vegetable samples followed the process of extraction, deconjugation (using chicken pancreas deconjugase), derivatisation (a series of chemical reactions to convert all folate present in the deconjugated sample extracts, to 5‐methyltetrahydrofolic acid (THF‐5CH3) monosodium glutamate and / or diglutamate), purification by affinity chromatography with Folate Binding Protein and quantification by HPLC equipped with fluorimetric detection.

Folate content in the raw samples ranged from 183.4 μg/100g (FW) in Corchorus olitorius to 21.5 μg/100g (FW) in Solanum macrocarpon leaves; and in the boiled samples from 48.6 μg/100g (FW) in Launaea taraxacifolia to 8.5 μg/100g (FW) in Solanum macrocarpon. Loss of folate in the boiled vegetables varied from 46.6% in Launaea taraxacifolia to 88.4% in Adansonia digitata.

Traditional green leafy vegetables are good sources of folate. However cooking of the vegetables caused a considerable decrease in the folate content of the vegetables. Considering that most leafy vegetables are consumed in their cooked form in Nigeria, preparation methods of traditional leafy vegetables that would allow for optimal retention of folate are necessary.

Support or Funding Information

This work was supported by an Agropolis Foundation grant for the internship of SIE and FWMD at Institut National de la Recherch Agronomique (INRA), Avignon, France. AWARD Fellowship provided the platform and opportunity of a 6‐month research attachment/ Advanced science training in INRA to conduct this research; University of Ibadan granted the permission to participate in the Advanced Science training during which this study was carried out. Labex Agro also supported this work.

Uncultivated/wild and cultivated traditional green leafy vegetables studied

Scientific name
Family
English name
Local/common name
Status

Amaranthus hybridus L.
Amaranthaceae
Pig weed
Efo tete/ green
Cultivated

Abelmoscus manihot (L.) Medikus (leaves and tender shoots)
Malvaceae
Okro leaves
Ilasa

Adansonia digitatad
Malvaceae
Baobab leaves
Luru / kuka
Uncultivated

Corchorus olitorius L.
Malvaceae
Jute mallow
Ewedu
Cultivated

Crassocephalum crepidioides (Benth.) S. Moore
Asteraceae

Ebolo
Uncultivated

Launaea taraxacifolia (Wild.) Amin, ex C. Jeffrey
Asteraceae
African lettuce/wild lettuce
Yanrin
Uncultivated

Solanum macrocarpon L.
Solanaceae

Efo igbagba
Cultivated/wild

Folate content of vegetables: RESULTS – Folate content of traditional green leafy vegetables

Vegetable
Condition
Moisture
Folic acid
Loss

Local/common name
Scientific name

%
μg/100g
%

Ewedu
Corchorus olitorius
Fresh
82.59
183.36±12.9
74.2

Boiled
95.13
47.31 ±3.7

Luru / kuka
Adansonia digitata
Dried
‐
149.64±13.9
88.4

Boiled
90.11
17.36±2.1

Okro/ ila
Abelmoscus esculentus fruit
Fresh
87.09
106.00±15.6
66.3

Boiled
95.77
35.69±8.49

Ilasa
Abelmoscus manihot
Fresh
77.05
46.75±9.49
n/a

Efo tete/ green
Amaranthus hybridus
Fresh
84.34
62.15±13.7
48.2

Boiled
91.58
32.19±4.9

Yanrin
Launaea taraxacifolia
Fresh
88.12
91.13±11.2
46.6

Boiled
92.16
48.63±8.4

Efo igbagba
Solanum macrocarpon
Fresh
84.82
21.54±3.1
60.6

Boiled
89.55
8.48±1.2

Ebolo
Crassocephalum crepidioides
Fresh
89.07
70.98±4.9
75.8

Boiled
94.1
17.18±1.7