Evaluation of antioxidant properties of Tabernaemontana heyneana Wall. leaves

The leaf extract of Tabernaemontana heyneana Wall. from different solvents was investigated for in vitro antioxidant activities. The antioxidant stability of the extracts under preserved condition (one month stored at 4oC) was also analyzed. The fresh extracts were found to contain appreciable total polyphenolic content (11.4 ± 0.17 mg/g tissue), total flavonoids (4.3 ± 0.17 mg rutin equivalents/g tissue) and ascorbic acid (5.0 ± 0.01 mg/ g tissue). The methanolic leaf extract of T. heyneana Wall. (METH-L) possesses remarkable reducing power [ferrous, cupric and cerium (IV) ions]. The metal ions were chelated at IC50 = 549 μg/ml and hydroxyl, ABTS and DPPH radicals were inhibited at IC50= 577 μg/ml, 537 μg/ml and 507 μg/ml, respectively. A noteworthy superoxide (69.07% ± 11.88) and nitric oxide (74.73 % ± 10.12) radical scavenging activities were observed in METH-L. Similarly, the preserved leaf extracts have proved to possess a stable antioxidant activity compared to fresh extracts (FRAP=1.25% decrease, CUPRAC = 3.88% decrease, metal chelation =3.36% decrease and DPPH = 2.05% decrease). The overall scientific documentation indicated that the METH-L possess significant antioxidant activity than the other solvent extracts.