Formulation and evaluation of herbal antioxidant cream from selected plantscollected from the Nepalese Himalayan region

Due to the strong tyrosinase inhibition and antioxidant effects, green tea and licorice are valuable herbal sources in the cosmetic industry for their beneficial effects on the skin. However, data on the addition of essential oils, green tea and licorice, to cream formulations to examine antioxidant activities is limited. Herbal antioxidants fight against radicals, UV rays, and unstable oxygen molecules that affect skin cells and produce wrinkles. The purpose of this study was to develop and assess herbal creams' antioxidant and tyrosinase-inhibitory characteristics using crude aqueous extracts of green tea and licorice loaded with essential oils. To load the best concentration on cream formulations, plant aqueous extracts were designed, evaluated, and correlated in terms of total phenolic content (TPC), total flavonoid content (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Moreover, Ocimum tenuiflorum and O. basilicum essential oils were extracted and added to a cream formulation. The spreadability profile, water washability, centrifugation test, and organoleptic characteristics of the formulated oil-in-water cream were all satisfactory. The cream exhibited a non-Newtonian rheological profile and a pH range of 6.353±0.065 to 6.467±0.050 over successive 0, 1, 2, and 3 months at normal room temperature. The 50% inhibition concentrations shown by the herbal cream were 13.764±0.153 µg/mL, 301.445±1.709 µg/mL and 8.082±0.055 µg/mL respectively, for 2,2 -diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric (Fe3+) reducing antioxidant power (FRAP) and 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity, and that of standard ascorbic acid were 6.716±0.077 µg/mL, 171.604±1.551 µg/mL and 5.645±0.034 µg/mL, which showed the formulated cream had strong antioxidant characteristics. The formulated herbal cream with a 50% tyrosinase inhibition concentration of 22.254±0.369 µg/mL compared to standard Kojic acid 12.535±0.098 µg/mL demonstrated a satisfactory tyrosinase inhibition profile for skin whitening properties. Herbal cream was reportedly stable in physical and chemical parameters for successive 0, 1, 2, and 3 months at both real and accelerated time study zones, according to the results of the stability study. The results provided evidence that formulated creams using plant-based natural ingredients are antioxidant-enriched products for skin protection.