Aim: The aim of the study was to carry out a comparative analysis of the phytochemical composition of the leaves of four selected tropical medicinal plants namely: Ocimum gratissimum, Piper guineense, Gongronema latifolium and Vernonia amygdalina. Methodology: The phytochemicals in the plant leaves were extracted by cold maceration in ethanol and subjected to both qualitative and quantitative analysis of the phytochemicals. Results: The qualitative and quantitative analysis revealed the presence of the bioactive compounds alkaloids, Saponins, flavonoids, steroids, glycosides, terpenoids, polyphenols, specific cardiac glycosides, tannins, phytates and reducing compound in the leaves of each plant at varying quantities. Resins were only detected in O. gratissimum. From the quantitative analysis, Gongronema latifolium had the highest percentage content of alkaloids, glycosides, saponins, tannins and reducing sugars. Ocimum gratissimum had the highest flavonoid content. Conclusion: Taken together, G. latifolium on balance had a higher phytochemical content than the other three plants and thus should be more versatile in the treatment of a whole range of diseases. This was followed by V. amygdalina, O. gratissimum and P. guineense in that order. The fact that most of these phytochemicals have antioxidant activity may be responsible for their antidiabetic activities and use in treatment of other free radical prone diseases.

Aim: The aim of the study was to carry out a comparative analysis of the proximate, vitamin and mineral composition of the leaves of four selected tropical vegetable plants namely: Ocimum gratissimum, Piper guineense, Gongronema latifolium and Vernonia amygdalina. Methodology: Fresh leaves of each vegetable were washed and air dried at room temperature for two weeks. The dried leaves were pulverized using a mechanical grinder. Measured amounts were subjected to quantitative proximate, vitamin and mineral analysis. Results: For all four plants, carbohydrates was the major macronutrient constituents (range 49.61-64.09% dry wt.) followed by fats (15.06-29.43%), Protein (7.28-12.53%), ash (1.81-14.82%) and fiber (2.92-7.53%) in that order. G. latifolium had the highest carbohydrate (64.09±0.09% dry weight) and protein (12.53±0.10%) composition while V. amygdalina had the highest fat (29.43±0.03%) composition. Results of Ash analysis of the four leaves showed P. guineense to have the highest total mineral content (14.82±0.12% dry wt.) followed by V. amygdalina (10.75±0.01%), O. gratissimum (4.60±0.04%) and G. latifolium (1.81±0.01%) in that order. O. gratissimum and P. guineense had the highest composition of fiber (7.53±0.02% and 7.22±0.02% respectively) closely followed by G. latifolium (6.03±0.02%) and V. amygdalina (2.92±0.02%). Vitamin analysis revealed that leaves of the four vegetable plants contained high levels of vitamin C (range 18.1-43.4 mg/100 g) and appreciable quantities of vitamins A (0.3-1.2 mg/100 g) and E (0.67-0.9 mg/100 g). V. amygdalina leaf contained the highest concentration of vitamin C (43.4±0.01 mg/100 g) and A (1.2±0.9 mg/100 g) while O. gratissimum had the highest vitamin E content (0.9 mg/100 g). The mineral assay indicated that the leaves of the plants contain high levels of Magnesium (Mg)(3.6-24.8 mg/100 g), Phosphorus (P) (2.8-34.3 mg/100 g), Calcium (Ca) (12.1-19.0 mg/100 g) and copper (Cu) (5.8-18.5 mg/100 g) relative to their Zinc (Zn) (1.1-2.1 mg/100 g), Potassium (K) (2.1-6.9 mg/100 g)  and Sodium (Na) (4.3-8.1 mg/100 g) contents. Conclusion: In conclusion, these plants were shown to be rich in carbohydrates, proteins and fats, vitamins and minerals justifying their use in diets. That the plants were particularly rich in vitamins and mineral with antioxidant properties could explain the therapeutic uses of the various preparations of these leafy vegetables, in traditional medicine, for the treatment and management of diseases that have their etiology and pathophysiology in free radical generation and oxidative stress.

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