Total Phenolic Compounds Extraction in Leaves of Ocimum gratissimum L. and Their Potential Activity against Some Agricultural Contaminants

Abstract

Aims: Phenolic compounds are secondary metabolites that are important in the plant due to their role in plant defense and their antioxidant activity with other biological properties such as antipyretic, analgesic and antimicrobial activities. This study focused on the biological potential activity of total phenolic compounds extracted by soxhlet method from Ocimum gratissimum leaves (Lamiaceae), a popular medicinal plant harvested at Daloa (Côte d’Ivoire). Study Design: Activities were directed on the in vitro antifungal and antioxidant activities combined to phenolic compounds analysis. Place and Duration of Study: The study was carried out at the Department of Environment and Plant Protection, and Laboratory of Chemistry and Biochemistry, University of Agricultural Sciences and Veterinary Medicine (USAMV) between March to July 2014, Laboratory of Biochemistry and Microbiology (Bioactives Natural Substances Unit), Jean Lorougnon Guédé University between September 2014 to January 2015. Methodology: The extract obtained named TPCOG was tested against Fusarium species for its antifungal activity by applying agar slant double dilution method and for its antioxidant activity by DPPH radical scavenging assay. Qualitative and quantitative evaluation of phenolic compounds were carried out by HPLC analysis method with sigma chemical standards. Results: Tests showed that TPCOG was a powerful antifungal extract with MIC and MFC ranging between 3.125 µg/mL to 12.5 µg/mL. This extract was fungicidal and its antioxidant activity reached F= 541.25± .25 mM Trolox/mL (I= 70 ±1.85%) with a total phenolic content equal 195.70±1.33 mg GAE/g. Radical scavenge and antifungal activities correlated very well with total phenolic compounds. Phenolic content analysis showed presence of phenolic acids and flavonoids with a higher concentration for Quercetin (393.475 mg/100 g sample). Conclusion: All this results demonstrated the biological potential activity of total phenolic compounds extracted from leaves of O. gratissimum and the possibility to use it in replace to essential oil for the formulation of biofungicides and nutraceuticals by industries.