Temporal changes of phenolics, flavonoids, carotenoids and mineral constituents in the leaf of a medicinal plant Justicia wynaadensis

Abstract

Aim: The present study was conducted to investigate the temporal changes in the level of phenolics, flavonoids, carotenoids, and mineral constituents in the leaf extract of medical plant J. wynaadensis (Aati soppu) during monsoon, pre-and post-monsoon season. Methodology: Leaf samples of J. wynaadensis were collected in different seasons (i) first sampling (AS-I) during the onset of monsoon, i.e., first week of July; (ii) second (AS-II) during mid-monsoon (First week of August); and (iii) third sampling (AS-III) during post monsoon (First week of September). The collected samples were analyzed for total carotenoids and chlorophyll, phenolics, flavonoids antioxidant potential, and mineral contents. Individual phenolic acids were identified and quantified using UPLC-H class coupled with TQD-MS/MS. Results: Biochemical constituents significantly varied between the samples of J. wynaadensis collected in different seasons. The samples collected during monsoon season (AS-II) had significantly high amount of phenolics (388.2 mg GAE 100 g-1), flavonoids (287 mg CE 100 g-1), carotenoids (2.40 μg β-CE 100 g-1) when compared with samples collected during pre-and post-monsoon seasons. Among the phenolic acids quantified, Salicylic acid was found to be maximum (2455-4747 μg g-1f.wt.) followed by caffeic acid (350 μg g-1f.wt.). Among the minerals studied potassium was found maximum (240 to 278 mg 100g-1) followed by calcium (263 to 442 mg 100g-1). Leaf samples contained high amount of iron (2.37 to 3.313 mg 100g-1), Except for zinc, most of the micro minerals significantly reduced from onset of monsoon to fag end of monsoon. Interpretation: J. wynaadensis collected at stage AS-II contained significantly high amount of phenolics and flavonoids, which offers numerous health benefits. Increase in content of bioactive phytochemicals such as salicylic acid can be presumed to be responsible for the curative properties of Aati soppu collected during AS-II.