Biological activities of microorganisms from hot springs for “green” cosmetics higher in nature, find researchers

22 May 2023 --- Italian researchers have evaluated the biochemical composition of natural and cultivated microbial communities growing around hot springs known as bioglea to reveal “interesting” antimicrobial and radical scavenging activities.

Comparing the composition and biological activities of microorganism communities collected in different spas with isolated strains grown under laboratory conditions, the researchers found higher activities for extracts from on-site communities than for isolated strains. 

This was particularly true for lipophilic extracts’ antimicrobial and radical scavenging activity. At the same time, the general biochemical composition did not significantly differ in bioglea and isolated strains, except for the bioglea sampled at the bottom of the pool in Saturnia, which showed a lower carbohydrate content.

“Microalgae and cyanobacteria have received increasing attention for their application in cosmetic products,” the study states.

Thermal spring waters display beneficial effects on the skin due to their physicochemical composition.Thermal microorganisms
The research further details that the beneficial effects of thermal muds are partly due to physical properties (e.g., heat) and chemical components (e.g., minerals). Meanwhile, additional functions (e.g., antioxidant and anti-inflammatory) may originate from the maturation process carried out in the presence of microorganisms, which usually include an important phototrophic component.

The researchers highlight that several of these microorganisms have the characteristics to become cosmetic ingredients. Polysaccharides may be used as thickeners and moisturizing agents, endowed with antioxidant, anti-inflammatory and anti-aging activity. Pigments have a dual nature of colorants and antioxidant compounds. Other molecules of interest are phenolics, fatty acids, sunscreens such as scytonemin and mycosporine-like amino acids, and biologically active peptides.

“Microbial communities growing around hot springs (bioglea), of which cyanobacteria are the main components, contribute to beneficial properties of thermal muds and often enter cosmetic treatment products,” say the authors.

“Bioglea is obtainable via alternative approaches to harvesting from nature: direct cultivation of whole communities and isolation and cultivation of the isolated strains. Cultivation represents a step toward industrial production, guaranteeing higher availability, quality and safety.”

The researchers highlight that further investigations should elucidate isolates’ full potential by combining them into synthetic communities to simplify production and standardization. “At present, the increasing request for natural products is accompanied by the need to meet stringent quality and safety standards. In this respect, the analysis carried out in this work can provide some indications useful to improve the exploitation of microbial resources from hot springs,” they suggest.

Thermal water rejuvenation
A previous study examined 12 thermal spring waters to demonstrate beneficial effects on the skin due to their physicochemical composition highlighting their potential to be used as an active ingredient in cosmetic products.

Avène, La Roche-Posay and Vichy, among others, were analyzed. Clinical trials revealed cosmetic thermal waters reduced skin discomfort through their soothing and exhibited moisturizing and anti-irritant properties.

Moreover, last December, a Portugal-based study championed cyanobacteria strains for cosmetic purposes and sustainability. The researchers evaluated extracts from the genera Cyanobium and Leptothoe and strains within Synechococcales and Oscillatoriales orders, showing antioxidant activity, photoprotective compounds and carotenoids, which have anti-aging and skin protective properties.

“Overall, the results obtained drive the studies on cyanobacteria toward the cosmetic industry as a promising source of natural extracts with potential in cosmetic formulations,” noted the study authors from the University of Porto and Polytechnic Institute of Porto, Portugal.

Edited by Radhika Sikaria