Seasonal Variation in Phenolics and Antioxidant Activity of Acorus calamus Linn.: An Important Medicinal Plant of Himalaya

Total phenolics and antioxidant activity varied significantly (p < 0.05) throughout the year, and phenolic content was found to be 1.5 to 2.0 fold higher in the preparation of senescence stage than the vegetative stage, while antioxidant activity was 1.5 to 3.0 fold higher in flowering and fruiting stage than the shoot bud bursting stage. The biochemical attributes such as phenolics (9.11 mg GAE/g), tannins (26.0 mg TAE/g) and FRAP antioxidant activity (5.86 mM AAE/100 g) were exhibited maximum in October. However, radical scavenging activity (ABTS 27.51; DPPH 6.66 mM AAE/100 g) was found higher in July. The climatic variables, like temperature showed positive (p < 0.01) relationship with DPPH activity (r = 0.523) and rainfall with ABTS activity (r = 0.534). Total phenolic content showed a significant (p < 0.01) relationship with antioxidant activity (ABTS r = 0.307; DPPH r = 0.304). The study concluded that October month was suitable for harnessing maximum natural bioactive constituents.