Spatial and seasonal variation in density,reproductive status,length and phenolic content of the invasive brown macroalga Sargassum muticum (Yendo) Fensholt along the coast of Western Brittany (France)

The introduced macroalga Sargassum muticum (Yendo) Fensholt is currently observed along the coasts of Brittany. From February 2003 till June 2004, variations in density, reproductive status, length and phenolic content were assessed at three sites. Seasonal variability of the density was pronounced at two exposed sites (Fort Bloqué and Pointe du Diable), but absent at the sheltered site (Callot), where the macroalga was observed year-round. Thalli were generally longer in Summer (up to 73.2 ± 2.7 cm at Fort Bloqué), and had reproductive receptacles from May to September at Pointe du Diable, though only from June to September in the other stations (Callot and Fort Bloqué). Phenolic content was maximal during the reproductive period, which could be interpreted as chemical protection of the receptacles. Finally the collected data were used to explain the persistence of S. muticum and its proliferation in Brittany.     

胁迫条件对一土生青霉菌总酚积累及其清除自由基能力的影响

旨在阐明胁迫条件对一土生青霉菌总酚积累及其抗氧化活性的影响。采用固体培养基培养青霉菌,以紫外线辐射、添加H2O2水溶液和降低培养基营养物质含量作为胁迫手段,检测受到胁迫后,菌体总酚的积累及酚类清除自由基的能力。菌丝体总酚含量以Folin-Ciocalteu法测定,自由基清除率以分光光度法测定。结果表明,在胁迫条件下,各实验组菌丝体的总酚含量较对照组均有显著提高,添加H2O2组的总酚含量最高达63.86mg/g,紫外线辐射组的总酚含量最高达58.4mg/g,营养胁迫组的总酚含量最高达43.19mg/g。各实验组酚类提取物对羟自由基的清除率最高,其中添加1mmol/LH2O2组为35.28%,紫外线辐射40s组为69.97%,75%营养胁迫组为50.83%。因此,胁迫条件可增加该青霉合成酚类化合物及提高其抵抗胁迫的能力。     

Harvested locations influence the total phenolic content,antioxidant levels,cytotoxic, and anti-inflammatory activities of stingless bee honey

Kelulut honey (KH) is a natural product-derived food produced by stingless bees of Trigona or Meliponine species. Several studies have shown that the geographical origin of honey significantly affects its pharmacological properties. Thus, this study aims to characterise the pharmacological properties of KH harvested from different geographical locations. The total phenolic content (TPC), antioxidant levels, cytotoxic, and anti-inflammatory activities of pure KH harvested from three different locations (Sarawak, Pahang and Selangor) were compared. Among the samples, KH harvested from Selangor exhibited the highest TPC, antioxidant levels, and cytotoxic activity against MDA-MB-231 and MCF-7 cells, followed by KH harvested from Sarawak and Pahang. The IC₅₀ of MCF-7 cells treated with KH harvested from Selangor was at least 2-fold lower than the IC₅₀ of MDA-MB-231 cells, suggesting that KH is more cytotoxic to oestrogen receptor (ER)- and progesterone receptor (PR)-positive (MCF-7) compared to triple-negative (MDA-MB-231) breast cancer cells. Two non-cytotoxic concentrations (1% and 0.5%; v/v) were selected for the anti-inflammatory assay using lipopolysaccharide (LPS)-induced RAW 264.7 cells. KH harvested from Selangor and Pahang (at a concentration of 1%; v/v) significantly inhibited nitric oxide (NO) production in LPS-induced RAW 264.7 cells compared to control cells. These findings provide evidence that the geographical origin of KH may indeed influence its pharmacological properties. Our data suggest that KH harvested from Selangor has a better quality compared to KH harvested from Pahang and Sarawak based on its high TPC, antioxidant levels and anti-inflammatory activity. Furthermore, it exhibits in vitro anticancer potential in breast cancer cell lines.     

Alginate,mannitol, phenolic compounds and biological activities of two range-extending brown algae, <Emphasis Type="Italic">Sargassum mangarevense</Emphasis> and <Emphasis Type="Italic">Turbinaria ornata</Emphasis> (Phaeophyta: Fucales), from Tahiti (French Polynesia)

This study deals with two range-extending brown algae from Tahitian coral reefs, Sargassum mangarevense and Turbinaria ornata; their alginate properties, mannitol and phenolic contents, antioxidant and antimicrobial activities were determined. Turbinaria ornata showed the richest alginate content with the highest extraction yield (19.2 ± 1.3% dw). Their alginates also exhibited the highest viscosity (50 ± 18 mPa.s), but the M:G ratios (mannuronic acid to glucuronic acid) of alginates (1.25–1.42) were similar in both species. Alginate yield displayed spatial variations, but no significant seasonal changes. The highest mannitol content was found in S. mangarevense (12.2 ± 2.1% dw) during the austral winter. With respect to other tropical Fucales, both algae exhibited also a high phenolic content (2.45–2.85% dw) with significant spatio-temporal variations. Furthermore, high antioxidant activity and activity against Staphylococcus aureus were also detected in extracts. According to these preliminary results, these two range-extending algae are of key interest in numerous industrial areas.