Formulation of anti-tyrosinase face serum using combretum indicum leaf extract / Tanesha A/p Thanaseelan

Faculty of Chemical and Process Engineering Technology

Thesis (Master of Science) -- Universiti Malaysia Pahang – 2025

Includes bibliographical references

Tyrosinase, a key enzyme involved in melanin synthesis, plays a critical role in skin pigmentation. Overactivity of this enzyme can lead to hyperpigmentation disorders, making the inhibition of tyrosinase a target for cosmetic and therapeutic applications. While synthetic tyrosinase inhibitors are effective, they are often associated with side effects and regulatory restrictions, underscoring the need for safer, natural alternatives. This research aims to address this gap by investigating the potential of Combretum indicum (C. indicum) leaf extract as a natural tyrosinase inhibitor and its incorporation into a stable anti-tyrosinase face serum. The study began with the extraction of C. indicum leaves using the maceration method and water as a solvent, followed by phytochemical screening and total phenolic content (TPC) determination. The leaf extract demonstrated a TPC of 177.6 mg GAE/g and the presence of phenols, tannins, flavonoids, and terpenoids, which contribute to its potent anti-tyrosinase activity. The extract’s tyrosinase inhibition was evaluated using a mushroom tyrosinase inhibition assay with the extract concentrations ranging from 0.2 mg/mL to 1.2 mg/mL. The result showed a dose-dependent inhibition with a maximum activity of 68.96 ± 0.26% at 1.2 mg/mL. An anti-tyrosinase face serum was formulated using the C. indicum leaf extract and assessed for anti-tyrosinase activity, physicochemical properties, antimicrobial efficacy, and stability. The formulated serum exhibited a tyrosinase inhibition rate of 44.38 ± 0.27%, confirming the functionality of the extract in the product. It also demonstrated desirable physicochemical properties, including a pH of 5.26 and a viscosity of 12.28 cP, comparable to a benchmark commercial serum. Antimicrobial evaluation showed no bacterial or fungal growth (0 CFU/g), validating the preservative system's efficacy. The product remained stable over three months under varying storage conditions (5, 25, and 40 °C), with no phase separation or significant changes in pH and viscosity. In conclusion, this study highlights the potential of C. indicum leaf extract as a natural tyrosinase inhibitor and its successful incorporation into a stable face serum, addressing the need for natural alternatives in cosmeceutical formulations. The highlighted potential lays a foundation for future research and commercialisation.