LAUSR

Abstract The Myrtaceae represents a plant family with several species having important medicinal virtues. In view of these properties four Syzygium species namely S. latifolium, S. commersonii, S. coriaceum, S. petrinense and two Eugenia species namely E. pollicina and E. pyxidata were studied. Phytochemical analysis showed that the methanol extracts had higher content of total phenolics and total flavonoids than the hexane extracts. The in vitro antioxidant activity evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing antioxidant potential (FRAP) assays was significant. The antibacterial activity of the extracts against Staphylococcus epidermidis, Staphylococcus aureus, Propionibacterium acnes and Escherichia coli was also promising. Species studied displayed significant tyrosinase inhibitory activity with S. petrinense having the highest activity. Interestingly, when the expression analysis of the tyrosinase cDNA in mouse melanocyte cells was studied it was observed that the methanolic Syzygium extracts inhibited melanogenesis by upregulating or downregulating the tyrosinase gene. Phylogenetic analysis of the ribosomal DNA sequences showed the genetic uniqueness of each plant species reflecting in their unique biological activity. Bioprospecting of endemic Mauritian Eugenia and Syzygium could be envisaged against acne vulgaris, skin hyperpigmentation and possible exploitation as phytotherapeutics.