Effects of Thanaka (Hesperethusa crenulata) Stem Bark Extract on Collagen Activation and Anti-Melanogenesis for Cosmetic Applications

Thanaka (Hesperethusa crenulata) stem bark has been utilized as natural cosmetics, particularly in Myanmar since a thousand years ago. However, information on bioactive compounds is still limited. This research aimed to quantify the marmesin levels in the extracts of Thanaka stem bark using High-Performance Liquid Chromatography (HPLC). Thanaka stem bark samples were obtained from diverse markets in Myaing Township, Magway Region (S1), Monywa Township (S2), and Shwebo Township (S3) from Sagaing Region. Moreover, antioxidant activity, cytotoxicity, collagen production, and anti-melanogenic effects were investigated. The marmesin content in Thanaka stem bark extracts derived from S1, S2, and S3 were 12.86 ± 0.48, 1.38 ± 0.09, and 7.61 ± 0.68 mg/g dry extract, respectively. The results of Pearson’s correlation coefficient revealed a significant relationship between antioxidant activity and total phenolic content. S1 exhibited the most favorable IC50 values for DPPH and ABTS which were 56.43 ± 1.49 µg/mL, and 14.04 ± 0.05 µg/mL, respectively. Additionally, it demonstrated a corresponding FRAP value of 337.62 ± 11.00 mM in terms of Ferrous sulfate equivalent per gram dry extract. Cell assays revealed no toxicity in immortalized human epidermal keratinocytes (HaCaT cells) treated with extracts at concentrations below 1000 µg/mL. Moreover, human foreskin fibroblasts (HFF-1 cells) exhibited enhancement in collagen production without any observed toxicity. Furthermore, Thanaka stem bark extracts could reduce melanin content and provide moderate tyrosinase inhibition in murine melanoma (B16F10) cells without toxicity. In conclusion, Thanaka stem bark extract demonstrates promising biological activities for development as a multifunctional skin care product.