Optimization of the microwave-assisted extraction of phlorotannins from Saccharina japonica Aresch and evaluation of the inhibitory effects of phlorotannin-containing extracts on HepG2 cancer cells

Anti-proliferative activity and chemical characterization by comprehensive two-dimensional liquid chromatography coupled to mass spectrometry of phlorotannins from the brown macroalga Sargassum muticum collected on North-Atlantic coasts

“…However, the parameter values obtained in the present study seem to be close to the antiproliferative concentration levels of brown seaweeds extracts published in various reports for other in vitro cell studies [11,29,30]. As an example, He et al [31] reported cell viability inhibition values of 36.9 and 60.5% for the brown seaweed Saccharina japonica extracts containing phlorotannins (2.19 and 1.28 mg g −1 , respectively) on hepatocellular carcinoma cells following a exposure time of 24 h at the concentration of 60 g mL −1 . Interestingly, data summarized in Table 4 also showed that N1 extract, which contained lower phlorotannin concentration than N2 extract (see Table 1 for the values of TPC and total phlorotannins for the purified N1, N2, P1 and P2 extracts), exerted slightly higher effect on cell proliferation than N2 extract, provided by the lower values obtained for the parameters at the different incubation times.…”

The Quest for Phenolic Compounds from Macroalgae: A Review of Extraction and Identification Methodologies

“…Other parameters, namely SLr (1:40), extraction time (40 min), irradiation power (200 w) and temperature (50 • C) were also optimized in this study. The SLr used in MAE varied from low values, such as 1:3 [111] or 1:4 [108], to considerable higher ratios, such as 1:50 [109]. In a previous study it was verified that the TPC of Caulerpa racemosa MAE extracts increased more than fivefold when the SLr increased from 1:10 to 1:20, after which the increasing trend remains almost insignificant [109].…”

“…Finally, MAE using ethanol or ethanol:water (50:50) were performed, yielding Sargassum muticum extracts with much lower TPC; however, no optimization of these approaches was performed. He et al verified that an ethanol concentration of 55% (from a studied range between 50% and 70%) maximized the TPC of Saccharina japonica extracts, while other parameters, such as SLr (1:8), temperature (60 • C), irradiation power (400 w) and time (25 min) were also optimized [108]. Table 3.…”

“…Table 4 summarizes the studies concerning the MAE extraction of phenolic compounds from macroalgae. Ethanol:water mixtures have been the most commonly used in MAE of phenolic compounds from macroalgae [108,109], although few authors have applied acetone:water mixtures [54], methanol:water [110], or just water [111]. Pérez et al studied and optimized the MAE of phenolic compounds from Sargassum muticum wet samples in two stages, with a solvent-free extraction followed by a water extraction, adding only the moisture content [112].…”

Phlorotannins

“…The use of a microwave-assisted extraction (MAE) method for the extraction of phlorotannins from Saccharina japonica Aresch has been evaluated with particular emphasis on the influential parameters, including the ethanol concentration, solid/liquid ratio, extraction time, extraction temperature, and microwave power (He et al, 2013). Biosynthesis of phlorotannins has also been explored (Bertoni, 2013).…”