The topical efficacy and safety of Citrullus lanatus seed oil: A short-term clinical assessment

The oil obtained from the seeds of Citrullus lanatus (Thunb.) Matsum. & Nakai (Kalahari melon) is highly sought after in the cosmetic industry as a prized ingredient to maintain healthy skin. Seed oils contain a range of fatty acids that may be beneficial upon topical application to the skin. The quantification of the fatty acids was done using two dimensional gas chromatography coupled to mass spectrometry (GC × GC–MS). The safety (irritancy potential test) and efficacy (transepidermal water loss (TEWL), hydration and occlusivity tests) of topically applied Kalahari melon seed oil on healthy Caucasian adult female volunteers (n = 20) was determined. Skin irritation and dryness were determined by visual scoring using a 2 × magnifying lamp while Chromameter®, Aquaflux® and Corneometer® instruments were used to quantify the irritancy level, TEWL and hydrating properties of Kalahari melon oil, respectively. The occlusive effect of the oil was assessed using Aquaflux® and Corneometer® instruments. Four major fatty acids, linoleic acid (51.4%), oleic acid (36.7%), stearic acid (6.3%) and palmitic acid (5.6%), were quantified using comprehensive GC × GC–MS analysis. Kalahari melon seed oil was non-irritant to the skin when topically applied (observed at 24, 48, 72 and 96 h). Aquaflux® and Corneometer® results showed that the application of Kalahari melon seed oil resulted in reduced TEWL and increased moisture retention. The non-irritant, hydrating and moisturising effects of Kalahari melon seed oil observed in this study justifies its incorporation into cosmetic products.