EFFECT OF UV-B PRETREATMENT ON ESSENTIAL OIL COMPONENTS, HEALTH SENSORY SECONDARY METABOLITES AND ANTIOXIDANT POTENTIAL OF COLEUS AROMATICUS
Effect of Ultraviolet-B radiation on secondary metabolism relates to mechanism involves in triggering of defense related gene expression, activation in enzyme activity, results to induced synthesis and/or accumulation of health sensory phyto-metabolites. In present study, we investigates on different level UV-B treatment response on comparative change in some medicinal bioactive metabolites, e.g. volatile oil, phenolic compounds, flavonoids, alkaloids, vitamins, saponin, tannins as well as at antioxidants level in a medicinally important aromatic plants Coleus aromaticus. In present experiment, plants were exposed to different level UV-B radiation exposure with an intensity of 3 J/s at low dose supplemental UV-B (UV1; 2h), high supplemental UV-B (UV2; 3h), and ambient level UV-B. A control group excluded UV-B radiation treatment. Various biochemical experiments conducted on field grown and growth chamber condition plants and analyzed the level of various phyto-constituents in Coleus leaf extracts i.e. total phenolics, alkaloids, total triterpenes, saponin, alkaloids, flavonoids and others. Plants grown under controlled growth chamber exposed with different dose UV-B treatment. In ambient UV-B condition (FC grown plants), total phenolic content was observed to be higher accumulated with respect to growth chamber plants. After UV-B treatment, various bioactive compounds were quantified and results ensures that UV-B supplementation induces the changes in concentration of volatile oil constituents, terpenes, alkaloids, ascorbic acid content at lower dose UV-B enhancement whereas at high intensity it may induces the inhibitory effects (hormesis effect)