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Studies were carried out to determine the effects of heating on the vitamin A and C content of a green leafy vegetable known as Pterocapus Mildbraedii. The samples of Pterocapus Mildbraedii  leaves were boiled at different intervals (5 mins, 10 mins and 15 mins) guided and its extract was sequeezed. The vitamin C content was measured through titrimetric methods. The vitamin C levels of Pterocarpus Milbraedii  was found to be 73.92 ± 0.2mg/100g, while Vitamin A content was measured through the spectrophotometic method (with us-vis spectrophotometer). The vitamin A levels of Pterocarpus mildbraedii  was found to be 1.89 ± 0.04mg/100g. The vitamin C content of Pterocarpus mildbraedii reduced drastically after each time period during heating while vitamin A had little effect during the heating periods of the leaves. This is because vitamin C is water soluble so it dissolves into the water and is lost via evaporation, while vitamin A being immiscible water, is not easily lost during heating.



Title page





Table of content


  • Introduction
    • Literature review
    • Pterocarpus mildbraedii
    • Common names
    • Classification
    • Description/Features
    • Cultivation
    • Propagation
    • Distribution
    • Nutritional value
    • Edible uses
    • Medicinal uses
    • Other uses
    • Storage
    • Side effects
    • Life span
    • Vitamin A
    • Beta-carotene
    • Importance/Effectiveness of Beta-carotene
    • Mode of actions
    • Interactions with medications
    • Interactions with food
    • Vitamin C
    • Biological significance
    • Absorption, Transportation and Excretion
    • Deficiency
    • Role in mammals
    • Role in plants
    • Testing for ascorbate levels in the body
    • Adverse effects
    • Heating/cooking effects in vitamin c
    • Other nutrients contained in Pterocarpus mildbraedii


2.0  Materials and methods

2.1 Experimental materials and equipment

2.2  Experimental chemicals

2.3  Sample collection

  • Principle of test

2.5. Sampling preparation

2.6  Preparation of specific molarities of the reagents needed.

2.6.1 Iodine solution

2.6.2 Starch indicator solution

2.7  Titration

2.8  Spectrophotometric determination of vitamin A

2.8.1 Procedure



3.0  Results


4.0  Discussion and Conclusion







Vegetables form an integral part of meals of people all over Nigeria and across. Invariably, vegetables present a rich source of vitamins, minerals, fibre and protein. The selection of a particular vegetable for inclusion in the diet depends on the a number of factors such as nutrient composition, texture and price (Eyo Es et al., 1983). There are some less commonly used and inexpensive leafy vegetables whose nutritive potentials have not yet been adequately studied. One of such is the leaf of Pterocarpus mildbraedii.

Pterocarpus mildbraedii (local names: Ora, Igbo; Mkpa or mkpafere, Efik/Ibibio) thrives mainly in forest environment (Olorode O, 1984) the mature plant can attain a height of about twenty four meters. The leaves possess a glabrous common stalk, 10-20cm long, usually with five to nine leaflets in alternate but sometimes opposite arrangement. The upper leaflets are rather elongated abruptly acuminate and round at the base whereas the lower leaflets are more ovate (Keay RWJ et al, 1964). The leaves are light green in colour when young but becomes deep green upon maturity.

In some parts of Eastern Nigeria, the young and tender leaves of this plant are traditionally used as vegetable in the preparation of soups. Despite the rising cost of highly cherished food items, caused by the general inflationary trend in the country, the market price of some less popular food such as the edible leaves of Pterocarpus mildraedii have remained fairly stable and within the reach of a large segment of the population.

Vitamin A can be found in two principal forms on foods:

Retinol, the form of vitamin A absorbed when eating animal food sources, is a yellow, fat-soluble substance. Since the pure alcohol form is unstable, the vitamin is found in tissues in a form of retinyl ester, it is also commercially produced retinyl acetate or palmitate (Meschino health, 2012).

The second form is the carotene, alpha-carotene, beta-carotene, gamma carotene; and the xanthophyll beta cryptoxanthin (all of which contain beta-ionone rings), but no other carotenoids, function and provitamin A in herbivores and omnivore animals, which possess the enzyme beta carotene 15, 15-dioxygenase which cleaves  beta-carotene in the intestinal mucosa and converts it to retinal. (Deman, John 1999).

Vitamin C or L-ascorbic acid, or simply ascorbate (the anion of ascorbic acid) is an essential nutrient for humans and certain other animal species. Vitamin C refers to a number of vitamers that have vitamin C activity in animals, including ascorbic acid and its salts and some oxidized forms of the molecule like dehydroascorbic acid. Ascorbate and ascorbic acid are both naturally present in the body when either of these is introduced into cells, since the forms interconvert according to PH. Deficiency of this vitamin causes the disease scurry in humans (Higdon J, 2006).






Pterocarpus mildbraedii is a nutritious green leafy vegetable. It is grown/occurs in lowland rain forest, dry evergreen forest and riverine forest, upto 1250m attitude. Pterocarpus mildbraedii leaves are collected from the wild, but frequently marketed. Attempts to domesticate it are being made. Propagation can be done by seed, budding or cuttings. The leaves of Pterocarpus mildbraedii contain per 100g edible portion: water 85g, energy 237kj (57kcal) protein 3.8g, fat 0.8g, carbohydrate 8.2g, crude fibre 1.13g, calcium 72mg, magnesium 28mg, iron 4.7mg and zinc 3.1mg (Akpanyung et al 1995). Hydrogen cyanide and oxalate levels are high but not such that they pose a health danger for consumers. Pterocarpus mildbraedii  is found in sierra leone, Liberia, cote d’ivoire, Ghana, Benin, Nigeria, Cameroun, Equatortal Guines, Gabon and the Usambara and Udzungwe mountains (Tanzania).

The leaves of Pterocarpus mildbraedii are used as cooling vegetables on Nigeria. In Ghana, the trees have been planted or retained in cocoa. Plantations to provide shade. Pterocarpus mildbraedii is rarely exploited for its timber e.g. in Tanzania, and the wood is used to make mortars.


Pterocarpus milldbraedii have common/local names it is identified with all over Nigeria and across the Globe. Listed below are the common names it is known as;

English –African rose wood

Ivorycoast – Aguaya

Edo (Nigeria) – Urube

Hausa, Nigeria – Madoobiyaa

Igbo, Nigeria – Oha Ojii/ora

Efik/Ibibio, Nigeria – Mkpa or Mkpafere

Kisambaa, Tanzania – Mkulo

Other names: Pterocarpus mildbraedii Harms


Kingdom: Plantae

Phylum: Tracheophyta

Class: Magnoliopsida

Order: Fabales

Family: Leguminosae


Pterocarpus is a large tree, 15-36m tall, with long clean bole and small rounded crown; bark smooth, grey or pale brown; slash pale, exuding red gum. Branch lets brownish pubescent to tomentellous, usually soon glabrescent. Leaves up to 18-36cm. long; stipules oblong-lanceolate, up to 1cm long, caducous; lateral leaflets 3-5 on either side, elliptic-oblong to elliptic ovate or ovate, 6-14cm long, 2.8-7cm wide, the lower ones relatively shorter and broader, rather abruptly contracted to the narrow mucronate generally pronounced acumen, broadly rounded to cuneate at base, subglabrous, usually minutely glandular beneath, with 6-10 well spaced fine curved ascending primary lateral nerves looped near the margin and laxly reticulate prominulous venation racemes or little-branched panides axillary, but sometimes aggregated terminally or on short lateral branches into pseudopanides, 5-15cm. long; axes thinly pubescent to tomentellous bracts linear to oblong-lanceolate, acuminate, 3-12mm long, evanescent; bracteoles near top of the 3-6mm. long pedical, elliptic to oblong-lanceolate, 3-8mm. long, caduceus. Calyx 5-8mm long, mostly subglabnous but densely covered with short hairs near lobe-margins outside and on the lobes inside. Corolla 10-16mm long, golden-yellow; standard ovate-elliptic to suborbicular, usually emarginated; wings not much longer than the keel and nearly as long as the standard. Fruit obovate orbicular, 10-12cm. long, with a 0.6-1.2cm. long stipe and avery broad membranous glabnous wing bearing the style to one side, not much thickened over the see cavity, laxly venose but prominently so only over the seed cavity and towards the style base (J.B. Gillett et al., 1971).


  • The plant is tolerant of acid soils
  • The tree grows fast and coppices well
  • The root system is superficial most roots are in the top 30cm of the soil
  • The plant has an intermittent pattern of leaf flushes; flushes often appear in the dry season when other leafy vegetables are scarce
  • This species have a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plants growing nearby (National germ plasm resources laboratory, 2011).


Seed- it has a hand seed coat and may benefit from scarification before sowing in order to speed up and improve germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them) and then soaking them for 12-24 hours in warm water. By this time they should have imbibed moisture and swollen – if they have not, then carefully make a nick in the seed coat (eing careful not to damage the embryo) and soak for a further 12 hours before sowing.(Gillett J.B et al., 1971)


Pterocarpus mildbraedii is found in sierra leone, Liberia, cote d’ivoire, Ghana, Benin, Nigeria, Cameroon, Equatorial Guinea, Gabon and the Usambara and Udzungwe Mountains (Tanzania) it is distributed in two continents, Africa and madagascar.


The leaves of Pterocarpus mildbraedii contain per 100g edible portion:


Energy – 237 kj (57kcal)

Protein – 3.8g

Fat – 0.8g

Carbohydrate – 8.2g

Crude fibre – 1.13g

Calcium -72mg

Magnesium -28mg

Iron – 4.7mg

Zinc – 3.1mg

1.10            EDIBLE USES

Leaves-cooked and eaten as vegetable hydrogen cyanide and oxalate levels in the leaves are high, but not such that they pose a health danger for consumers.(Okafor J.C, 1991)


The bark and root are used for the treatment of rashes, eczema, diabetes, abdominal pains; it can also be used as an antipyretic and purgative.(Burkill H.M, 1995)



1.12       OTHER USES

In Ghana, the trees have been planted or retained in cocoa plantations to provide shade.

The tree is rarely exploited for its timber, although in Tanzania it  is used to make morters the red wood of the subspecies usambarensis polhill (as found in east Africa) is hand and heavy. It is used for timber, building poles, pestles and carving.

The wood is used for fuel and to make charcoal. The bark exudations produce gums and resins(Burkill H.M, 1995)

1.13              STORAGE

It can be air dried at room temperature. It can be grounded into coarse powder with an electric blender and kept in an air tight container(Anonymous, 2008)


1.14              SIDE EFFECTS

The leaves of Pterocarpus mildbraedii is high in calcium, Excessive high levels of calcium in the blood known as hyper calcemia can cause renal insufficiency, vascular and soft tissue calcification, hypercalciurra (high levels of calcium in the urine) and kidney stones. It can also cause constipation

1.15              LIFESPAN

It is perennial (i.e. it lives for more than two years (the Garden helper, 2008).


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