Tithonia diversifolia Powder and Compost Ameliorate Plant Growth Parameters, Essential Oils, Phenols and Flavonoids Content and Anticandida Activity of Ocimum gratissimum L.

Aims: Ocimum gratissimum is an aromatic and medicinal plant, well known for its medicinal values such as antifungal properties. This study aimed at evaluating the effect of T. diversifolia powder and compost use as biofertilizer on the growth parameters, essential oil (EO), total phenolic and flavonoid content and anticandida activity of O. gratissimum.

Study Design: O. gratissimum plants were cultivated for 8 months in an experimental farm designed as a split plot into 4 blocks. Each block was amended (main factor) either with T. diversifolia compost (150 g/plant), powder (40 g/plant) or the synthetic fertilizer NPK (10 g/plant), respectively, followed by sprayed (second factor) with same fertilizer at 20 g/L, 20 g/L and 2 g/L or water every two weeks after transplantation. The control block received no amendment and was sprayed with water or the previous fertilizer.

Place and Duration of Study: This work was carried out within August 2019 to October 2020 in Yaoundé-Cameroon.

Methodology: Plant growth parameters (fresh and dry leaves weight, florescent weight and plant height) were evaluated at four and eight months after transplantation. The harvested fresh leaves were hydrodistillated for EO and the hot aqueous extract. Both extracts were used for the evaluation of the anticandida activity while the latter was submitted to total flavonoids and phenolic analyses.

Results: At 4 and 8 months after transplantation, the synthetic fertilizer and T. diversifolia compost significantly increased plant growth parameters as compared to other treatments. The plants treated with T. diversifolia biofertilizer compost showed the highest total phenolic (53.16 µg GAE/µL), flavonoid (36.32 µg// GAE/µL) content, and EO yield (0.666%). The EO from O. gratissimum treated with T. diversifolia compost showed the best inhibitory activity on C. albicans NR-29451.

Conclusion: This study showed that T. diversifolia compost was a promising organic fertilizer in optimizing the growth, secondary metabolites and anticandida activity of O. gratissimum.