Antimicrobial, antioxidant properties and chemical composition of seaweeds collected from Saudi Arabia (Red Sea and Arabian Gulf)

Abstract

The present study demonstrates the antibacterial activity of selected brown and green marine algae collected from Saudi Arabia Red Sea and Arabian Gulf. The methanolic and acetone extracts were tested against gram positive, gram negative bacteria and in an attempt to be used as an alternative to commonly used antibiotics. Both brown seaweed species and methanolic extracts were found to be active against gram positive than gram negative; however, acetone extract gave the highest inhibitory activity against sp. On the other hand, organic extract demonstrated higher antibacterial activity than the fresh extract but both extracts revealed decreased activity compared to extracts. methanolic extract showed an obvious effect on methicillin resistant (MRSA). The present work shows a comparable therapeutic potency of the tested seaweed members and extracts in treating human microbial pathogens to synthetic chemical antibiotics. A remarkable higher antioxidant DPPH free radical scavenging effect was recorded with sp. compared to sp. FTIR Infrared Spectrometer analysis together with the high performance liquid chromatography provided a detailed description of the possible functional constituents and the major chemical components present in marine macroalgae particularly in brown seaweeds to be mainly of phenolic nature to which the potent antimicrobial activity is being attributed.

In vitro bioactivity and phytochemical analysis of two marine macro-algae

“…Binding of flavonoids to the red blood cell membranes significantly inhibits lipid peroxidation, protects them from free radical mediated oxidative hemolysis and enhances their integrity against lysis [20]. In the present study, inhibition of H 2 O 2 mediated hemolysis by the extracts of both the seaweeds indicates the presence of radical scavenging phytochemicals especially, flavonols, flavonoids and tannins.…”

“…The isolated strains were identified based on their morphological and biochemical characteristics as prescribed in Bergey's Manual of Determinative Bacteriology [19]. Antibacterial assay was performed by well diffusion method [20]. Following spread plate technique, a bacterial lawn was generated in Mueller-Hinton agar plates with 24 h broth culture of bacteria.…”

Antioxidant Activity and Proximate Analysis of Dry Powder from Brown Seaweed Sargassum hystrix

“…Its content was increased when absorbance-concentration were increasing. That value was equal to % RSA from crude extract of fucoidan S. glaucescens, with the value of 65% at the same concentration (Chun-Yung et al, 2016), but lower than % RSA from crude extract of S. latifolium was about 66% at concentration 0.15 mg/ml and S. platycarpum was about 60% at concentration 0.15 mg/ml (Moubayed et al, 2016). Meanwhile, that value was higher than radical scavenging activity (% RSA) of S. boveanum extract at concentration 3 mg/ml was about 94% (Zahra et al, 2007), sulfated polysaccharides extract of S. vulgare was about 22.2% at concentration 2.5 mg/ml (Dore et al, 2013), crude polysaccharides extract of S. pallidum was about 19.1% at concentration 3.8 mg/ml (Hong et al, 2008), polyphenol extract of S. polycystum was about 38.60% at concentration 1 mg/ml (Cahyaningrum et al, 2016), it also higher than DPPH scavenging activity of Ethyl Acetate fraction from S. marginatum was about 23.16%, Petroleum Ether fraction of Turbinaria conoides was about 19.55%, Petroleum Ether fraction of Padina tetrastomatica was about 17.79%, methanolic extract of T. conoides was about 17.35%, methanolic extract of P. tetrastomatica was about 14.78%, and methanolic extract of S. marginatum was about 11.00% at concentration 1000 ppm (Chandini et al, 2008).…”

“…As a consequence of an increasing demand for biodiversity in seeking therapeutic drugs from natural products, there is now a greater interest in marine organisms, especially algae. Seaweeds or marine algae are primitive nonflowering plants without true root stem and leaves (Moubayed et al, 2016). They are kinds of sea vegetables which have a potential of antioxidant sources.…”

“…Seaweed is strongly associated with longer life expectancy, reduced risk of developing some chronic diseases, and various types of cancer (Yan & Asmah, 2010;Moubayed et al, 2016). Seaweeds are known to contain a wide variety of bioactive compounds as such offering a rich source of new drugs with potentially lower toxicity.…”