K.W. ABEYWARDHANA¹, D.C. ABEYSINGHE¹, R.M. DHARMADASA^2,, A.M.L ATHTHANAYAKE¹

Ocimum sanctum L. (Lamiaceae) is therapeutically important medicinal plant used in traditional systems of medicine. Present study was undertaken to determine the optimum growth stage in terms of total phenolic content (TPC), total flavonoid content (TFC) and antioxidant capacity (TAC) of leaf and bark extracts of hydroponically and field grown plants of O. sanctum in three different maturity stages. Alkaloids, flavonoids, saponins, tannins and steroid glycosides were qualitatively screened through established protocols. TPC, TFC and TAC were determined by colorimetric Folin-Ciocalteu method, aluminum nitrate method and Ferric Reducing Antioxidant Power (FRAP) assay respectively. Leaf and bark extracts of O. sanctum grown under both field and hydroponic conditions, at all three maturity stages exhibited the presence of all phytochemicals tested. TPC, TFC and TAC were increased with the maturity. Significantly higher TPC (8.34 ± 0.14 mg GAE /g DW), TFC (132.29 ± 1.45 mg RE /g DW) and TAC (120.02 ± 4.06 mg TE /g DW) were observed in leaf extracts taken from field grown plants at fully maturity stage. The order of increase was just before flowering< just after flowering< fully maturity stage. Presence of higher content of TPC, TFC and TAC in O. sanctum leaves at fully maturity stage, scientifically validate the traditional claims of harvesting of O. sanctum leaves at fully maturity stage for better therapeutic value. Moreover, presence of all tested phytochemicals in hydroponically grown plants is positive sign of use of hydroponic system as an alternative growing system for O. sanctum.

antioxidant capacity, growing systems, Ocimum sanctum, maturity stages, secondary metabolites