Assessment of phytochemicals from marine algae Ulva fasciata and Dictyota dichotoma with antioxidant and antimicrobial potential

The marine ecosystem is a rich source of novel secondary metabolites with significant biomedical applications. Seaweeds are considered as the treasury of secondary metabolites with various biological activities. This study aims to analyze antioxidant and antimicrobial potential in green seaweed Ulva fasciata and brown seaweed Dictyota dichotoma. Extracts from four different solvents such as petroleum ether, chloroform, ethyl acetate and methanol using Soxhlet apparatus were tested for the qualitative analysis of phytochemicals. Secondary metabolites were analyzed quantitatively to correlate with the antioxidant (DPPH assay) and antimicrobial potential of seaweeds. Results showed a better antioxidant activity of U. fasciata in its methanolic extract (89.29%) and D. dichotoma manifested a maximum antioxidant activity (70.1%) for its ethyl acetate extract. Structural characteristics of seaweed derived bioactive material were investigated by Fourier transform infrared spectroscopy (FTIR) and manifested the presence of alcohol and phenolic compounds. The inhibition zone formed around the crude extract reveals the antimicrobial nature of bioactive substances of seaweed extract against the pathogens. High inhibition and antioxidant activity indicate an effective drug’s evolution from seaweeds against human pathogens.