Abstract
Seaweeds are now recognized as a treasure of bioactive compounds. However, the bioactivity of seaweed originating in Bangladesh is still unexplored. So, this study was designed to explore the secondary metabolites and antioxidant activities of solvent extracts of Padina tetrastromatica and Gracilaria tenuistipitata. Phytochemical screening and FTIR spectra confirm the diverse type of bioactive compounds. Antioxidant activity of extracts were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power (RP), phosphomolybdenum, hydrogen peroxide and nitric oxide (NO) scavenging assays. Here, methanolic extract of P. tetrastromatica showed highest amount of total phenolic content (85.61 mg of GA/g), total flavonoid content (41.77 mg of quercetin/g), DPPH (77.07%), ABTS (77.65%), RP (53.24 mg AAE/g), phosphomolybdenum (31.58 mg AAE/g), hydrogen peroxide (67.89%) and NO (70.64%) assays compared to its methanolic extracts of G. tenuistipitata. This study concluded that methanol as a solvent extract of brown seaweed (P. tetrastromatica) exhibited bioactivity and antioxidant potentiality which will be useful for pharmacological as well as in functional food application.
Highlights
Free radicals are chemical species that are incredibly reactive, usually contain unpaired electrons, and can be produced in living cells from endogenous or exogenous s ources[1]
It was observed that every extract contained varying amounts of active secondary metabolites such as saponin, terpenoid, cardiac glycoside, phlobatannin, phenolic and flavonoid (Table 1)
The physiological and mechanical capabilities of marine living beings that permit them to endure in multifaceted living forms give an extraordinary impending generation of secondary metabolites, which are not observed in earthborn circumstances
Summary
Free radicals are chemical species (atoms, molecules, or ions) that are incredibly reactive, usually contain unpaired electrons, and can be produced in living cells from endogenous or exogenous s ources[1]. The presence of free radicals will result in several damages like denaturing of enzymes and cellular proteins, lipid peroxidation in tissue membranes, nucleic acid disruption, and cellular function distraction[3,4]. These damages by free radicals are termed oxidative stress, which is reported to be responsible for various diseases such as A DHD5, autism6, cancer[7], Alzheimer’s d isease[8], Parkinson’s d isease[9], and aging[10]. In this case, natural sources of antioxidants such as ascorbic acid, chlorophyll derivatives, polyphenols, amines, amino acids, and flavonoids might be more efficient than synthetic antioxidants. In the current study, we used a variety of qualitative and quantitative tests (Phytochemical analysis and FTIR) to screen and measure for functionally bioactive compounds and determine antioxidant activities using various in vitro spectroscopic assays, as well as their correlation among different assays of various crude extracts of P. tetrastromatica and G. tenuistipitata
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