Bioglea as a Source of Bioactive Ingredients: Chemical and Biological Evaluation

Abstract

This study focused on bioglea in thermal material sampled at Saturnia spa (Tuscany, Italy). Bioglea is the term used to define the thermal plankton consisting of biogenic substances that have been investigated little from the chemical and biological points of view. Bioglea is mainly formed of cyanobacteria, particularly from the Oscillatoriales subsection, and it seems to have an important role in the maturation of thermal mud for the development of organic matter. This cyanobacteria-dominated community develops in a large outdoor pool at the spa, where the spring water is collected, over the sediments, with matter floating at the surface. Throughout the year, the cyanobacterial species of bioglea were the same, but their relative abundance changed significantly. For chemical characterization an extractive method and several analytical techniques (HPLC, GC-MS, SPME) were used. We also studied the radical scavenging activity using in vitro tests (DPPH, ORAC, ABTS). We found various groups of compounds: saturated and unsaturated fatty acids, hydroxyl acids, alcohols, phenols, amino acids. Many of the compounds have already been identified in the mud, particularly the lipid component. SPME indicated several hydrocarbons (C11–C17) and long-chain alcohols (C12–C16). The qualitative composition of volatile substances identified in bioglea was very similar to that of the mud previously analysed. These results contribute to our knowledge on thermal photosynthetic community and its possible exploitation.

Microalgal Peloids for Cosmetic and Wellness Uses

“…Centini et al [40] recently analyzed the composition and antioxidant capacity of biogleas present in the Satunia Terme mud and confirmed earlier findings on the increased lipid profile during the maturation process and analyzed the hydrophilic fraction. Studies on antioxidant power revealed that bottom mud extracts are more active than surface extracts and that hydrophilic extracts are more active than lipid extracts.…”

Hot Springs Cyanobacteria Endowed with Biological Activities for Cosmetic Applications: Evaluation of On-Site Collected Communities and Isolated Strains

“…Finally, in Saturnia, but also in Petriolo, microbial communities develop in pools open to the surrounding environment in which people bathe, so exogenous active substances may be absorbed/adsorbed in the microbial biofilms and mats, contributing to their antimicrobial activity. In the case of Saturnia bioglea, Centini et al [51] actually found some contaminant cosmetics preservatives (e.g., sorbic acid, 4-hydroxy benzoic acid, phenoxyethanol) in the chloroform extracts (including those from the same samples analysed in this work), besides plant-derived molecules with known antimicrobial activity (abietic and dehydroabietic acids) [52] and several phenolics (e.g., methoxy cinnamic acid), which origin is not known but might also have antimicrobial activity [53]. The hydrophilic extracts contained mainly hydrophilic pigments (phycobiliproteins) and other protein-derived compounds (e.g., some free amino acids).…”

“…Chlorophyll and its derivatives might also have contributed to radical scavenging activity, as they are known as radical scavengers [69]. In Saturnia bioglea extracts, several lipophilic compounds with antioxidant activity were detected in chloroform extracts, such as the chlorophyll-derived alcohol phytol, the carotenoid lycopersene and some cinnamic acid derivatives [51], which might have contributed to the radical scavenging activity observed. Determination of phenolics content and profile in the isolated strains will help to understand whether this component may be responsible for the observed radical scavenging activity.…”

“…Phospholipid derivatives, such as diacylglycerols might also contribute. Furthermore, exogenous contaminants due to people bathing in the pool can also be responsible for part of the observed radical scavenging activity in Saturnia bioglea, as antioxidant chemicals deriving from cosmetic products, such as BHT and squalene, were found in the extracts [51]. Hydrophilic extracts contained phycobiliproteins, which are well-known antioxidant and anti-inflammatory molecules [70].…”