The Antimicrobial Activity, Mosquito Larvicidal Activity, Antioxidant Property and Tyrosinase Inhibition of Piper betle

The essential oil and methanolic and aqueous extracts of Piper belle L. were assayed for their antimicrobial activity, mosquito larvicidal activity, antioxidant property and mushroom tyrosinase inhibition. The methanolic and aquaous extracts showed strong activity against the yeasts: C. albicans, and M. pachydermatis. The crude essential oil exhibited a broad-spectrum strong antimicrobial activity against all test organisms. The strongest activity was observed against C. albicans, followed by S. aureus and M. pachydermatis. The chemical composition of the essential oil and its fractions was analyzed by GC/MS analysis. Eugenol (36.2%), chavibetol acetate (16.9%), 4-allylphenyl acetate (9.4%) and 4-allylphenol (7.2%) were the main components, comprising 69.7% of the oil. The fractionation of the essential oil gave two fractions. Fraction I was rich in eugenol (71.3%) and fraction II in eugenol (46.4%), chavibetol acetate (19.4%) and 4-allylphenyl acetate (11.8%). The essential oil exhibited the mosquito larvicidal activity with 2 h and 24 h LD50 value of 86 and 48 ppm, respectively. The methanolic extract of P belle showed larvicidal activity with 2 h and 24 h LD50 value of 153 and 125 ppm, respectively, whereas the aqueous extract showed slight active. The individual antioxidant assays such as DPPH scavenging activity, chelating effect of ferrous ions and reducing power have been used. P belle showed remarkable antioxidant activity in DPPH and reducing power assays. The activity observed can be attributed to the presence of the phenolic compounds. The essential oil exhibited concentration-dependent inhibition of mushroom tyrosinase, giving an IC50 value of 126 ppm. The fraction I showed a strong inhibition of tyrosinase activity, giving an IC50 value of 115 ppm. The presence of 4-allylphenolic components in the essential oil may play an important role in the inhibition of tyrosinase. In conclusion, the results presented here show that Piper belle essential oil could be considered as a natural antimicrobial, mosquito larvicidal, antioxidant and tyrosinase inhibition source.