New insights into the potential of the red seaweed Gelidium corneum in sustainable cosmetics
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Presented by: Susete Pinteus
INTRODUCTION: Cosmetic industry remains a major focus of economic development in the 21st century being actively interlocked with health-based concerns and environmental awareness. On the other hand, consumer´s demand for sustainability is driving the search of new active natural ingredients.
Marine environment is characterized by an incredible biodiversity as well as by the occurrence of multiple stress factors that have an impact on species´ survival. As a defence mechanism, those organisms, including seaweeds, need to activate secondary metabolic pathways to produce bioactive molecules with unique structural features that can be profited by the cosmetic, pharmaceutical and food sectors.
AIM: The aim of this work was to study the cosmetic potential of Gelidium corneum, a red seaweed commonly found in the Portuguese shore.
METHODS: Hydroalcoholic (70:30) extracts from the dried biomass were subjected to sequential liquid-liquid partitions, affording five fractions with different chemical profiles. The water insoluble (F2) and the aqueous (F5) fractions were selected for cosmetic potential studies through a set of in vitro assays concerning their i) cell viability in HaCaT cells, using the 3-(4,5-dimethythiazol-2-yl)- 2,5-diphenyl tetrazolium bromide (MTT) assay; ii) photoprotective effect, by measuring reactive oxygen species (ROS) levels after UVA-B exposure, iii) healing capacity (scratching assay) in HaCaT cells, and iv) antimicrobial activity and possible mechanisms of action against three bacteria of the skin microbiota, Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (DSM 1798), and Cutibacterium acnes (DSM 1897). As a proof-of-concept, O/W emulsions were prepared with the aqueous fraction, being emulsion´ stability assessed by optical microscopy, droplet size analysis, centrifugation test, and rheology analysis.
RESULTS: At subtoxic concentrations, the lipophilic fraction F2 has provided photoprotection (25%) against UV light-induced photooxidation in HaCaT cells, which can be attributed to the high content of lipid-soluble pigments. Additionally, this fraction together with the most hydrophilic one, F5, have shown a high potential in the healing assay, with 76.8 ± 10.0% and 61.83 ± 7.25% of healed area in 12 h, respectively.
Concerning the antimicrobial potential, fraction F2 was the most effective one, significantly reducing the growth of S. epidermidis and C. acnes, with an IC50 of 53.29 μg/mL and 16.10 μg/mL, respectively. The study of the mechanisms of action suggest that the antimicrobial effects seem to be related with cytoplasmatic membrane hyperpolarization of both microorganisms.
Since the best extraction yields were attained with the aqueous fraction, it was selected to prepare O/W emulsions containing 10% and 1% of extract.
All formulations were semi-solid. The control was white and glossy. In contrast, the emulsions containing the Gelidium corneum extracts (1 and 10%) presented a dark caramel tone. The particle size values are between 10 μm and 100 μm. At a higher extract concentration, this values slightly decreases. All samples showed shear-thinning and solid-like behaviour, with a storage modulus G′ higher than G′′ (loss modulus) in frequency sweep tests. Regarding the stability behaviour, the best performance was achieved with the 1% formulation. The polysaccharides presented in this fraction can be regarded as valuable natural ingredients due to their healing effect and water retention properties, together with their role on the bonding and consistency of formulations.
CONCLUSIONS: The results suggest that Gelidium corneum should be explored as a source of bioactive ingredients with multitarget properties for cutaneous use. The noticeable antimicrobial effect of the most lipophilic fraction over two microorganisms of skin microbiota is a basis for more detailed studies on this fraction aiming the development of a formulation able to control microbial growth without affecting skin homeostasis.
Marine environment is characterized by an incredible biodiversity as well as by the occurrence of multiple stress factors that have an impact on species´ survival. As a defence mechanism, those organisms, including seaweeds, need to activate secondary metabolic pathways to produce bioactive molecules with unique structural features that can be profited by the cosmetic, pharmaceutical and food sectors.
AIM: The aim of this work was to study the cosmetic potential of Gelidium corneum, a red seaweed commonly found in the Portuguese shore.
METHODS: Hydroalcoholic (70:30) extracts from the dried biomass were subjected to sequential liquid-liquid partitions, affording five fractions with different chemical profiles. The water insoluble (F2) and the aqueous (F5) fractions were selected for cosmetic potential studies through a set of in vitro assays concerning their i) cell viability in HaCaT cells, using the 3-(4,5-dimethythiazol-2-yl)- 2,5-diphenyl tetrazolium bromide (MTT) assay; ii) photoprotective effect, by measuring reactive oxygen species (ROS) levels after UVA-B exposure, iii) healing capacity (scratching assay) in HaCaT cells, and iv) antimicrobial activity and possible mechanisms of action against three bacteria of the skin microbiota, Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (DSM 1798), and Cutibacterium acnes (DSM 1897). As a proof-of-concept, O/W emulsions were prepared with the aqueous fraction, being emulsion´ stability assessed by optical microscopy, droplet size analysis, centrifugation test, and rheology analysis.
RESULTS: At subtoxic concentrations, the lipophilic fraction F2 has provided photoprotection (25%) against UV light-induced photooxidation in HaCaT cells, which can be attributed to the high content of lipid-soluble pigments. Additionally, this fraction together with the most hydrophilic one, F5, have shown a high potential in the healing assay, with 76.8 ± 10.0% and 61.83 ± 7.25% of healed area in 12 h, respectively.
Concerning the antimicrobial potential, fraction F2 was the most effective one, significantly reducing the growth of S. epidermidis and C. acnes, with an IC50 of 53.29 μg/mL and 16.10 μg/mL, respectively. The study of the mechanisms of action suggest that the antimicrobial effects seem to be related with cytoplasmatic membrane hyperpolarization of both microorganisms.
Since the best extraction yields were attained with the aqueous fraction, it was selected to prepare O/W emulsions containing 10% and 1% of extract.
All formulations were semi-solid. The control was white and glossy. In contrast, the emulsions containing the Gelidium corneum extracts (1 and 10%) presented a dark caramel tone. The particle size values are between 10 μm and 100 μm. At a higher extract concentration, this values slightly decreases. All samples showed shear-thinning and solid-like behaviour, with a storage modulus G′ higher than G′′ (loss modulus) in frequency sweep tests. Regarding the stability behaviour, the best performance was achieved with the 1% formulation. The polysaccharides presented in this fraction can be regarded as valuable natural ingredients due to their healing effect and water retention properties, together with their role on the bonding and consistency of formulations.
CONCLUSIONS: The results suggest that Gelidium corneum should be explored as a source of bioactive ingredients with multitarget properties for cutaneous use. The noticeable antimicrobial effect of the most lipophilic fraction over two microorganisms of skin microbiota is a basis for more detailed studies on this fraction aiming the development of a formulation able to control microbial growth without affecting skin homeostasis.