Kenaf (Hibiscus cannabinus L.) seed oil: Application as cosmetic product ingredients

The effectiveness and efficiency of a cosmetic product depends not only on the active ingredients, but also on the stability of formulation devoted in improving the bio-functionality. Thus, improving the stability of topical applications with vitamin E is important. The study aimed to optimise kenaf seed oil percentage on gel-cream formulations supplemented with palm-based α-tocopherol and determine their physicochemical properties, antioxidant activities, and α-tocopherol content. The samples were produced by high shear homogenisation and subjected to optimisation to obtain the best formulation with good physical stability and antioxidant activities. The antioxidant activities were determined by radical scavenging assays and α-tocopherol content was quantified by ultra-high performance chromatography. Vitamin E gel-cream formulated from 9% kenaf seed oil (S3) was selected based on its stability in viscosity and antioxidant activities. S3, with pH 6.02 showed viscosity value at 6106.3 cP was physically stable. Also, the α-tocopherol obtained for S3 was 9.34 mg/g sample that indicated 3.63 mg TE/g sample and 10.42 mg TE/g sample for diphenyl-1-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzot-hiazoline-6-sulphonic acid) radical scavenging activities, respectively. For 12 weeks storage stability study at 25 ± 2 °C and 40 ± 2 °C, S3 showed good microbial stability but with mild depletion of tocopherol content. Overall, the results herein gathered are very promising towards the development of new cosmetic formulations using kenaf seed oil and palm-based α-tocopherol.