Determination of Suitable Agro Climatic Region and Optimum Harvesting Stage by Means of Total Phenolic Content, Total Flavonoid Content and Total Antioxidant Capacity of Ocimum tenuiflorum L. (Lamiaceae) Grown in Sri Lanka

Abstract

Ocimum tenuiflorum L. (Lamiaceae) is a industrial important medicinal plant,cultivated for its therapeutic values in many Asian countries. Even though the therapeutic properties of O. tenuiflorum is mainly depend on its secondary metabolites, presently required plant materials for Ayurveda and traditional systems of medicine are collected from the wild without considering its age and therapeutic properties. Therefore, the present study is undertaken tp compare the important phytochemicals (total .phenolic content (TPC), total flavonoid content (TFC)) and total antioxidant capacity (TAC), of different parts of Ocimum tenuiflorum.which were harvested at three consecutive pruning stages from two agro climatic regions in Sri Lanka. TPC, TFC and TAC were performed using colorimetric Folin-Ciocalteu method, aluminum nitrate method and Ferric Reducing Antioxidant Power (FRAP) assay respectively. Data were analyzed using the general linear model (GLM) procedure of Minitab statistical package followed by Duncan’s Multiple Range Test (DMRT) for mean separation. Total antioxidant capacity of leaf, bark, flower and seed extracts were significantly (p=0.05) increased from first pruning to third pruning irrespective of agro climatic regions. Antioxidant capacity and Total flavonoid content of different parts of O. tenuiflorum cultivated in low country intermediate-Zone (IL1a) and low country dry zone (DL1b) was varied as leaf> bark> flower> seeds. Even though the TPC was significantly varied among different parts as well as pruning stages, remarkable relationship was observed neither agro climatic region nor pruning intervals. Results of the present study are vital important for the determination of suitable agroclimatic region, optimum harvesting stage for higher phytochemical, bioactivity and optimum therapeutic properties of O. tenuiflorum.