Antioxidant activity, phenolic-flavonoid content and high-performance liquid chromatography profiling of three different variants of Syzygium cumini seeds: A comparative study

Abstract

Background: The medicinally important phytochemicals present in Syzygium cumini seeds probably accounts for its wide use in traditional systems of medicines in India, like Ayurveda, Unani, and Siddha.

Aim: The aim of the study was to determine the antioxidant potential of three different geographical variants of S. cumini seeds and to compare the phenolic profiling to know the effect of geographical variation in phenolic composition.

Materials and methods: Total phenolic and flavonoid content of S. cumini seeds were analyzed. Antioxidant activities in terms of 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), nitric oxide and superoxide radical scavenging assays were performed. The most active fractions were subjected to high-performance liquid chromatography (HPLC) profiling to identify the phenolic composition.

Results: Among all the fractions, 70% methanol fraction of S. cumini seed showed significant antioxidant potential. There existed a linear correlation between phenolic content and antioxidant activity. HPLC profiling of 70% methanol (ME) fractions of all the variants revealed the presence of phenolic compounds with high concentrations of ellagic acid and gallic acid. The differences in phenolic concentration due to geographical changes might be the reason for higher antioxidant potential showed by 70% ME of Trivandrum variant.

Conclusion: 70% methanolic fraction of S. cumini can act as a novel source of natural antioxidant.

Keywords: Antioxidant activity; Syzygium cumini; high-performance liquid chromatography; total flavonoid content; total phenolic content.

Figure 1

Graph showing percentage yield in different fractions of three different variants of Syzygium cumini seeds. TVM: Trivandrum variant, TCH: Trichy variant, MPA: Malampuzha variant

Figure 2

(a) Total phenolic content (mg GA equivalents/g dry wt.) (b) total flavonoid content (mg QE/g dry wt.) in different fractions of three different variants of Syzygium cumini seeds. Values are the means ± standard deviation of three replicated samples. Duncan’s multiple range test was conducted and data in the same column with different letters/symbols indicate statistically significant differences among groups at P < 0.05. TVM: Trivandrum variant, TCH: Trichy variant, MPA: Malampuzha variant

Figure 3

(a) 2,2-diphenyl-1-picrylhydrazyl (b) nitric oxide (c) super oxide (d) 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activities of EA, ME, 70% ME and WEs of different variants of Syzygium cumini. EA: EA fraction, ME: ME fraction, 70% ME: 70% methanol fraction, WE: Water fraction, TVM; Trivandrum variant, TCH: Trichy variant, MPA: Malampuzha variant. Each value represents mean ± standard deviation (SD) from triplicate measurements. Values are means ± SD; n = 3; *Represents groups differ significantly from control group (P ≤ 0.05)

Figure 4

Representative high-performance liquid chromatography-diode array detector chromatograms of mixed standards and 70% methanol fractions of Trivandrum variant, Trichy variant and Malampuzha variant recorded at 280 nm. Standards are (1) gallic acid, (2) catechol, (3) chlorogenic acid, (4) caffeic acid, (5) syringic acid, (6) coumaric acid, (7) ferulic acid, (8) ellagic acid, (9) myricetin, (10) cinnamic acid, (11) quercetin, (12) kaempferol, (13) apigenin

Figure 5

Prominent phenolic compounds (mg/g dry wt.) 70% methanol fractions of Syzygium cumini seeds quantified by high-performance liquid chromatography-diode array detector. Values are the means ± standard deviation of three replicated samples. GA: Gallic acid, ClA: Chlorogenic acid, FA: Ferulic acid, EA: Elagic acid. TVM: Trivandrum variant, TCH: Trichy variant, MPA: Malampuzha variant