Seagrass as a potential source of natural antioxidant and anti-inflammatory agents

Abstract

Context: Halophila spp. is a strong medicine against malaria and skin diseases and is found to be very effective in early stages of leprosy. Seagrasses are nutraceutical in nature and therefore of importance as food supplements.

Objective: The antibacterial, antioxidant, and anti-inflammatory activities of Halophila ovalis R. Br. Hooke (Hydrocharitaceae) methanol extract were investigated and the chemical constituents of purified fractions were analyzed.

Materials and methods: Plant materials were collected from Pondicherry coastal line, and antimicrobial screening of crude extract, and purified fractions was carried out by the disc diffusion method and the minimum inhibitory concentration (MICs) of the purified fractions and reference antibiotics were determined by microdilution method. Antioxidant and anti-inflammatory activities were investigated in vitro. Chemical constituents of purified fractions V and VI were analyzed by gas chromatography–mass spectrometry (GC–MS), and the phytochemicals were quantitatively determined.

Results: Methanol extract inhibited the growth of Bacillus cereus at a minimum inhibitory concentration of 50 µg/mL and other Gram-negative pathogens at 75 µg/ml, except Vibrio vulnificus. Reducing power and total antioxidant level increased with increasing extract concentration. H. ovalis exhibited strong scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals at IC₅₀ of 0.13 and 0.65 mg/mL, respectively. Methanol extract of H. ovalis showed noticeable anti-inflammatory activity at IC₅₀ of 78.72 µg/mL. The GC–MS analysis of H. ovalis revealed the presence of triacylglycerols as major components in purified fractions. Quantitative analysis of phytochemicals revealed that phenols are rich in seagrass H. ovalis.

Discussion and conclusion: These findings demonstrated that the methanol extract of H. ovalis exhibited appreciable antibacterial, noticeable antioxidant, and anti-inflammatory activities, and thus could be use as a potential source for natural health products.

Keywords::

• Antibacterial
• GC–MS
• Halophila ovalis
• MIC
• triacylglycerols

Acknowledgments

The authors thank Prof. N. Parthasarathy, Salim Ali School of Ecology, Pondicherry University, Pondicherry for the identification of seagrasses. We also thank Dr. Babu Rajendar, Dept. of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli for providing the GC–MS facility.

Declaration of interest

This work was supported by a grant from Department of Biotechnology (DBT), New Delhi, India. The authors declare that there are no other conflicts of interest.