ABSTRACT

This study determined the effect of organic fertilizer on the proximate, vitamins, mineral, essential oil and antimicrobial activities on the leaves of Ocimum gratissimum. The seeds of O. gratissimum used were raised into seedlings in nursery boxes before they were transplanted into planting buckets. Cultivation of the plants were carried out using 24 plastic buckets of 7L each containing 8 kg ofsoil. Organic fertilizer treatments were carried out in four replicates. O. gratissimum was treated with 5 g, 10 g, 15 g, 20 g and 25 g of organic fertilizer while zero plants served as the control. Treatment commenced two months after germination. The leafwas used for the analysis, since it is the most eaten part. The harvested leaves were dried at room temperature for 14 days and ground to reduce the surface area. Organic fertilizer treatment significantly (< 0.05) increased the moisture content (9.43 %), ash (5.54 %), crude protein (13.14 %), crude fibre (8.48 %), crude fat (3.27 %), potassium (340 mg/lOOg), phosphorus (210 mg/lOOg), ascorbic acid (0.040 mg/lOOg), in (7.65 mg/lOOg), niacin (4.27 mg/lOOg) contents of O. gratissimum. There was no significant increase in the retinol (1402 IU/100g), calcium (21.60 mg/lOOg), magnesium (22.00 mg/lOOg) and thiamine (23.60 mg/lOOg) contents on the leaves of O. gratissimum treated with organic fertilizer. Organic fertilizer treatment significantly (<0.05) decreased the carbohydrate (60.05 %) and Sodium (38.73 mg/lOOg) content of the leaves of O. gratissimum. The antimicrobial activities of the leaves of O. gratissimum on Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, Salmonella typhi, Pseudomonas areuginosa were significantly (<0.05) increased by organic fertilizer treatment. The inhibition zone increased with increase in the level of fertilizer treatment. Ethanol and methanol were used as extracts for the antimicrobial activity and Minimum Inhibitory Concentration (MIC). The concentration of the extracts affected their ability to inhibit the growth of microorganism. The ethanol leaf extracts had a higher effect against Klebsiella pneumonia (1.97 mg/ml), Escherichia coli (2.91 mg/ml), Staphylococcus auretis (1.32 mg/ml), Salmonella typhi (1.92 mg/ml), and Pseudomonas areuginosa (1.43 mg/ml). This research has revealed that organic fertilizer increased the quality of the chemical constituents of the leaves of O. gratissimum which enhanced its efficacy and medicinal value. Appropriate use of this treatment would increase the amount of these bioactive substances that are of medicinal importance, hence boosting their medicinal and nutritional value. Results data were analyzed using Analysis ofVariance (ANOVA) and LSD. Results were expressed as means with standard deviation