"In Vitro Bioactivity and Phytochemical Profiling of Leaf Extracts from the Mangrove Plant Excoecaria agallocha"

Abstract

The most prevailing microbial diseases and antibiotic resistance exhibited by many pathogens has prompted to discover new antimicrobials of plant origin owing to their minimal side effects. Recent widespread interest in mangrove ecosystem, reflects its validity regarding the potential medicinal application in various diseases. Considering the biomedical importance of mangroves, the present study evaluates the phytochemical screening, antimicrobial, antioxidant activities and  characterization using TLC and LC-MS of leaf fractionated extracts of Excoecaria agallocha  (Euphorbiaceae), a small milky mangrove extensively  studied  for  its  chemical  composition and many bioactivities. Initial crude extract preparation of leaves was carried out using four   dissimilar solvents viz., acetone, diethyl ether, petroleum ether and water to study the phytochemical constituents which revealed the bearing of saponins, flavonoids, glycosides, steroids, phytosterols and reducing sugars particularly with relatively high abundance in petroleum ether extract. The antimicrobial activity was evaluated by means of zone of inhibition using agar well diffusion assay. Among the tested bacterial and fungal species, the maximum zone of inhibition was recorded in fungal species ranging from 5 to 12 mm compared to bacterial species ranging from 0.2 to 0.7mm, indicating compounds to be better antifungal agents. Also the performed antioxidant activity of petroleum ether extracts using 2,2-diphenyl-1-picrylhydrazyl (DPPH) recorded total free radical scavenging capacity with IC₅₀ value of 247.92 μg/ml and with ferric reducing antioxidant potential (FRAP) method showed higher activity of 47.66 ug/ml. Further partial characterization of the petroleum ether extracts was carried out by thin layer chromatography and LC-MS analysis indicated the presence of bioactive compounds in the extracts of the Excoecaria agallocha  species.