Chiang Mai Journal of Science

 The objectives of this study were to examine the biological activities of petal extract (PE) and stamen extract (SE) from Nymphaea rubra Roxb. ex Andrews, develop the extracts into a cosmeceutical product and evaluate the skin irritation as well as test the performance of the emulsion containing N. rubra extract. The petal and stamen extracts of N. rubra were conducted with 95% ethanol. The antioxidant activity, tyrosinase activities and total phenolic and flavonoid content of the extracts were determined. The anti-aging capability of the extracts were also tested by the inhibition of MMP-2, MMP-9 and hyaluronidase activities. The PE showed the highest antioxidant activity on lipid peroxidation inhibition and inhibition of tyrosinase activity together with the highest amount of total phenolic and flavonoid contents. Both the PE and SE showed high ability as antioxidants tested by DPPH and ABTS assays, which are comparable to ascorbic acid and trolox. Furthermore, they strongly inhibited MMP-2 and MMP-9, while the PE showed the highest in vitro hyaluronidase inhibition. The PE was then selected for incorporation into O/W emulsion, and the PE emulsion was stable under various tested conditions. According to the clinical evaluation, the PE emulsion was effective on skin wrinkle reduction and skin whitening with no irritation in 30 healthy volunteers after 60 days of twice daily application. Thus, the petal extract and PE emulsion possess potential anti-free radical, skin lightening and anti-aging properties.