Biopharmaceutical potential, chemical profile and in silico study of the seagrass – Syringodium isoetifolium (Asch.) Dandy

Syringodium isoetifolium (Asch.) Dandy (Family: Cymodoceaceae) is a seagrass growing in the oceans across the globe except in cold waters. This study investigated into the polyphenolic content, antioxidant [2,2-diphenyl-1-picrylhydrazyl(DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), metal chelating, phosphomolybdenum)]and enzymatic properties [α-amylase, α-glucosidase, tyrosinase, acetylcholinesterase (AChE), butylcholinesterase (BChE)] of S. isoetifolium. Detailed phytochemical profiling was also conducted using Ultra Performance High-Pressure Liquid Chromatography (UHPLC) technique. The methanolic extract was found to possess greater amount of phenolic than flavonoid compounds. Antioxidant results showed that the extract was a better ABTS radical scavenger (9.56 ± 0.40 mg TE/g) compared to DPPH (5.39 ± 0.09 mg TE/g and exhibited good reducing potential with CUPRAC assay (18.66 ± 0.46 mg TE/g). In terms of enzymatic inhibition, strong activities were noted against tyrosinase (25.92 ± 0.11 mg KAE/g) in contrast to α-amylase, α-glucosidase and cholinesterase. Phytochemical data revealed the presence of 14 compounds with chicoric acid and caftaric acid among them. Docking the identified compounds, namely, caftaric acid, loliolide and Iso-loliolide at the active site of the tyrosinase enzyme has elucidated the binding affinity of these inhibitors and their interactions with the active site. Based on our findings, S. isoetifolium may be considered as a good natural antioxidant and clinical enzyme inhibitors that can be exploited in pharmaceutical/or cosmeceutical industries.