Anti-bacterial, and Anti–Tyrosinase Activities of Secondary Metabolites of Lichen Roccella Montagnei
Lichens are fascinating organisms believed to have appeared over 300 million years ago. They are a combination of fungi and algae or cyanobacteria. Roccella montagnei, a lichen species found in mangroves in Sri Lanka, produces a variety of unique chemical compounds not found in other higher plants or organisms. These lichens, growing in bright and exposed environments, contain many colorful compounds.
In this project, secondary metabolites were extracted from Roccella montagnei using
sequential extraction and column chromatography. Pure components were isolated from the non-polar extract through
preparative thin-layer chromatography (TLC).
The isolated metabolites were then tested for antibacterial and anti-tyrosinase activities.
The antibacterial properties were evaluated using the agar well diffusion method against four non-pathogenic
bacteria: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Staphylococcus epidermidis.
Tyrosinase is a key enzyme involved in melanin production, catalyzing the oxidation of tyrosine to melanin pigments responsible for skin, hair, and eye color.
High levels of tyrosinase activity can lead to hyperpigmentation, especially in brown skin affected by sun exposure,
which drives the need for safe inhibitors to manage skin hyperpigmentation. In this study, anti-tyrosinase activity was measured using UV-Vis spectroscopy,
comparing isolated metabolites from Roccella montagnei with Kojic acid, a commercial standard known for its skin-lightening effects but often
associated with side effects like irritation and dermatitis. This research aimed to identify natural, safer alternatives for pigmentation control,
providing fundamental insights in potential cosmetic applications. The findings were presented at the 2018 TradMed International Conference in Colombo, Sri Lanka.