Phytochemical constituents, antioxidant properties and p-coumaric acid analysis in some seagrasses

Seagrasses have a long history of being used for a variety of remedial purposes, such as treatment of fever, skin diseases, muscle pains, wounds and stomach problems. Hence it is essential to study their bioactive metabolites and medicinal properties when considering their food applications. In the present study, the leaves of six seagrasses Enhalus acoroides, Thalassia hemprichii, Halodule pinifolia, Syringodium isoetifolium, Cymodocea serrulata and Cymodocea rotundata were extracted with aqueous methanol and tested for their antioxidant capacity. Among them, H. pinifolia recorded high phenolic (21.64 mg g−1), tannin (17.12 mg g−1) and vitamin E (34.49 mg g−1) content. Flavonoid level was high in C. serrulata (5.12 mg g−1) and vitamin C in C. rotundata (28.43 mg g−1). Higher total antioxidant activity of 15.75, 8.37 and 6.65 mg ascorbic acid equivalent/g was observed respectively in H. pinifolia, E. acoroides and C. rotundata; while C. rotundata (70.30%) was found to be the most potent DPPH radical scavenger. The inhibition was more than 53.74% in C. rotundata and 51.05% in H. pinifolia for scavenging OH radicals to prevent oxidative degradation of deoxyribose substance. The HPTLC analysis confirmed the presence of p-coumaric acid in the aqueous methanolic extracts of H. pinifolia and C. rotundata and these findings suggest the possible pharmacological application of these seagrasses. ► Phytochemical constituents and antioxidant activity of seagrasses were evaluated. ► H. pinifolia and C. rotundata exhibited predominant antioxidant activity. ► HPTLC analysis confirmed the antioxidant compound p-coumaric acid. ► Seagrasses could be effectively used as natural antioxidants.