Optimization of Microwave-Assisted Extraction of Phlorotannin From Sargassum swartzii (Turn.) C. Ag. With Ethanol/Water

Sargassum is a genus of brown macroalgae in the class Phaeophyta, distributed widely in all oceans, including those of Vietnam. Species of this genus have been proven to possess diverse biological activities, such as antioxidant, anti-fungal, and anti-inflammatory, along with many benefits and applications for human health, including anti-diabetic, obesity, and thrombosis. These benefits arise from a diverse chemical composition, with compounds such as fucoidan, mannitol, and especially phlorotannin—a group of phenolic derivatives found predominantly in brown algae. In this study, we evaluated and optimized the factors that affected the extraction process of phlorotannins from Sargassum swartzii (Turn.) C. Ag., a common species of brown macroalgae in Vietnam. The process utilized ethanol and water as the solvent system, and the extraction process was assisted with the use of microwaves. To carry out optimization studies, Response Surface Methodology (RSM) was adopted according to a Central Composite Desisgn (CCD), taking four processing factors into consideration, ethanol concentration (%, v/v), extraction time (minutes), solvent/material ratio (v/w), and microwave output power (W) as independent variables. Phlorotannin concentration (mgPhE/g) and extract mass (mg) were regarded as optimization outcomes. Experimental conditions that produced the highest phlorotannin yield from 10 g of S. swartzii are as follows: Extraction time of 65 minutes, ethanol concentration of 52%, microwave output power of 613 W, and solvent/material ratio of 33/1 (v/w). These conditions corresponded to a phlorotannin concentration of 5.59 ± 0.11 mg PhE/g, and a total extract content of 27.88 ± 0.13 mg/g.

Anti-Inflammatory Effects of Sulfated Polysaccharide from Sargassum swartzii in Macrophages via Blocking TLR/NF-Κb Signal Transduction

This study involves enzymatic extraction of fucoidan from Sargassum swartzii and further purification via ion-exchange chromatography. The chemical and molecular characteristics of isolated fucoidan is evaluated concerning its anti-inflammatory potential in RAW 264.7 macrophages under LPS induced conditions. Structural properties of fucoidan were assessed via FTIR and NMR spectroscopy. NO production stimulated by LPS was significantly declined by fucoidan. This was witnessed to be achieved via fucoidan acting on mediators such as iNOS and COX-2 including pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), with dose dependent down-regulation. Further, the effect is exhibited by the suppression of TLR mediated MyD88, IKK complex, ultimately hindering NF-κB and MAPK activation, proposing its therapeutic applications in inflammation related disorders. The research findings provide an insight in relation to the sustainable utilization of fucoidan from marine brown algae S. swartzii as a potent anti-inflammatory agent in the nutritional, pharmaceutical, and cosmeceutical sectors.

Distribution patterns and biogeography of Sargassum (Fucales, Phaeophyceae) along the coast of Vietnam

Sargassum species form large beds that play an important role in coastal ecosystems. The beds are abundant and Sargassum is often used as food and in Asian medicine in Vietnam. As a base for future use and conservation, we surveyed 14 species of Sargassum at eight locations during April-May of 2018 and 2019. Sargassum species from Vietnam were divisible into northern and southern groups; the northern group comprised Sargassum graminifolium, Sargassum herklotsii, and Sargassum cotoense, which occur in the North and North Central zones. The southern group comprised Sargassum bicorne, Sargassum feldmannii, Sargassum ilicifolium, Sargassum swartzii, and two endemic species, Sargassum phamhoangii and Sargassum quinhonense, which occur in the Central to South West zones. Three species, Sargassum aquifolium, Sargassum oligocystum, and Sargassum polycystum, were widespread along the long coast of Vietnam. This is the first report on distribution patterns of Sargassum species along the long coast of Vietnam. Our study provides baseline data for evaluating ecological disturbance and risks of Sargassum-associated ecosystems.

Synergistic Effect of Trisodium citrate (TSC) on the Inhibition Efficiency of Sargassum swartzii (SS) -Zn2+ System on Mild Steel in Aqueous Environment

The aquatic plant kingdom is a treasure of potential bioactive compounds. Aquatic plants contain some organic compounds that provide definite physiological actions on the human body. In the present study deals with the synergistic effect of Trisodium citrate (TSC)on the inhibition efficiency of methanolic extract of Sargassum swartzii (SS) and Zn2+ system on mild steel in aqueous environment. The corrosion monitoring techniques adopted in the study were weight-loss methods, electrochemical measurements, FT-IR and surface morphological techniques namely SEM and EDX. It has proved the formulation consisting of 100 ppm of Zn2+, 120 ppm of SS and 100 ppm of TSC has 95.77% IE. The high performance of SS - Zn 2+- TSC system could be due to synergistic effect that covers a wide surface coverage area on the metal surface and thus retarding the corrosion. Polarization study reveals that this formulation functions as a mixed inhibitor. AC impedance spectra suggest the presence of protective film on the metal surface. FT-IR spectra reveals that the protective film consists of Fe2+-SS complex, Fe2+-TSC complex and Zn (OH)2. SEM and EDX provide a pictorial representation on the nature of surface film in the absence and presence of inhibitors. Thus, it concluded that Sargassum swartzii - Zn 2+- TSC inhibitor system acted as a good inhibitor in aqueous medium.