Agriculture Reference
In-Depth Information
Constituents —
The nutrient value of
Solanum aethiopicum
fruits is comparable with that of
eggplant. A 100 g edible portion yields the following: water 90.6 g, energy 135 kJ (32 kcal), protein
1.5 g, fat 0.1 g, carbohydrate 7.2 g, fiber 2.0 g, Ca 28 mg, P 47 mg, Fe 1.5 mg, β-carotene 0.35 mg,
thiamin 0.07 mg, riboflavin 0.06 mg, niacin 0.8 mg, and ascorbic acid 8 mg. The composition of
fresh leaves per 100 g edible portion is water 82.1 g, energy 215 kJ (51 kcal), protein 4.8 g, fat 0.3 g,
carbohydrate 10.3 g, fiber 2.4 g, Ca 523 mg, P 94 mg, Fe 6.0 mg, β-carotene 6.40 mg, thiamin 0.23
mg, riboflavin 0.44 mg, niacin 1.8 mg, and ascorbic acid 67 mg. Other constituents of the fruits
include the phytosterols betulin and sterolin (sitosterol glucoside), flavonoids, and terpenes. The
characteristic bitter taste has been attributed to furostanol glycosides.
Several sesquiterpenoids, the antifungal agents lubimin and epilubimin, have been found in the
roots. The leaves contain oxalate and alkaloids (e.g., solasodine), which has glycocorticoid effects.
Their concentration is reduced by cooking.
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Pharmacological Studies —
Solanum aethiopicum
has been evaluated mainly for its nutri-
tional value. The bitter cultivars with steroidal alkaloids exhibit the pharmacological activity associ-
ated with that class of compounds. The anti-inflammatory activity of the fruits has been evaluated
using the egg albumin-induced rat paw edema model. Extracts of garden egg significantly (
p
< 0.05)
reduced the fresh egg albumin-induced rat paw edema and also significantly (
p
< 0.05) reduced the
granuloma tissue formation in the treated groups when compared to the control.
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In a comparative
study to determine the effect of African garden egg,
S. aethiopicum,
against gastric ulcer, a metha-
nol extract of the fruit was administered orally at dose levels of 100, 200, and 400 mg/kg and 100
mg/kg of ranitidine to rats with experimentally induced ulcers. For the indomethacin and aspirin
models, ulcerogenic agents (indomethacin 50 mg/kg and aspirin 200 mg/kg) were given 30 min
after extract treatments, and animals were sacrificed 8 h later. The acidified ethanol model (ethanol
60% + 0.1 mol/l HCl) was given 1 h after extract treatment, and animals were sacrificed 1 h later.
The ulcer index was checked and analyzed with appropriate statistical tools. The extract of
S. aethi-
opicum
showed a positive effect on all the models used. It produced higher ulcer inhibition than
ranitidine in the indomethacin and acid-ethanol models. All the antiulcer effects of the extract at
different doses were dose dependent, but only in the indomethacin model did it produce statistically
significant (
p
< 0.05) ulcer reduction in all doses compared to the control. Garden egg therefore has
a high potential as a cheap and available source for a natural antiulcer remedy.
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The plant has also been found to possess antifungal, antioxidant, and hepatoprotective activities.
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Toxicity —
Some members of the Solanaceae family contain steroidal alkaloids, and some of
them are known to be toxic. The rule of thumb is to avoid very bitter cultivars. The related
Solanum
macrocapon
has been shown to contain antinutrient principles (phytate and cyanide) in the leaves.
The aqueous infusion of the fresh leaves of
S. macrocapon
caused hemolysis of human erythrocytes
in vitro
. The blood type SS were more susceptible to hemolysis than either AA
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or AS.
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It was
therefore concluded that the various conventional food-processing techniques significantly reduce
the nutrient and antinutrient content of eggplant leaves without adversely affecting the estimated
Zn bioavailability to a critical level. Furthermore, the leaf infusion had high hemolytic effect on
genotype SS
in vitro
.
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Agriculture —
The African garden egg plants are cultivated extensively throughout tropical
Africa. It is an easily grown plant that thrives well in most soils. Nonetheless, it does best in soils
of high fertility, especially those high in nitrogen and phosphorus. Sandy loam to friable clay soils
with a pH range of 5.5 to 6.8 have been declared particularly suitable. It has been shown that simul-
taneous planting of cowpea and scarlet eggplant produced 90-99% the fruit yield of sole scarlet
eggplant, while planting cowpea 2 and 4 weeks ahead produced 65-80% and 58-60% of sole crop
yield, respectively. Competition between component crops, however, was most favorable for both
cultivars of cowpea when planted 2 weeks ahead of scarlet eggplant. Planting cowpea 2 weeks
ahead of the main crop also produced the highest land equivalent ratio (LER), most likely due to
more efficient utilization of sunlight, water, and soil nutrients. Simultaneously planting cowpea
