Antioxidant, Anti-Tyrosinase, Antiglycation and Safety of Longan Leaf Extract for Cosmeceutical Application

Abstract Many potential bioactive phytoconstituents in longan (Dimocarpus longan Lour.) leaf have been reported. Most chemical compounds belong to either phenolics or flavonoids, known as potent antioxidants. This research explores the multifunctional potential as a bioactive cosmetic ingredient used in skin care for adding value to longan leaves. The dried powder of longan leaves was extracted with 50%(v/v) ethanol in de-ionized water, then quantified for total phenolic and flavonoid contents. The hydroethanolic extract was investigated for various antioxidant methods including DPPH, nitric oxide (NO) scavenging and lipid peroxidation inhibition assays. The anti-tyrosinase activity was also evaluated for skin-whitening properties. Furthermore, Anti-aging activity in term of antiglycation was also conducted. The high number of polyphenols within the extract possessed a high antioxidant potential with IC50 0.023 ± 0.002, 0.478 ± 0.033 and 1.495 ± 0.153 mg/ml for DPPH scavenging, NO scavenging and lipid peroxidation inhibition, respectively. The extract could inhibit the tyrosinase enzyme with IC50 4.90 ± 0.50 and 6.60 ± 0.18 mg/ml for L-tyrosine and L-DOPA as substrates. The extract also exhibited a potent antiglycation activity with IC50 0.023 ± 0.003 mg/ml. Moreover, it showed no irritation effect on the chorioallantoic membranes (CAMs) within 5 min using the Hen’s Egg Test-Chorioallantoic Membranes (HET-CAMs). In conclusion, the polyphenolic-rich longan leaf extract displayed a good antioxidant, anti-tyrosinase and excellent antiglycation potential with safety that could constitute a promising multifunctional bioactive ingredient for skin care cosmeceutical products. Keywords: Longan leaf extract, Antioxidants, Anti-tyrosinase, Antiglycation, Irritation, HET-CAMs, Cosmeceutical