Pouteria campechiana pulp ethanol-water extract as a bioactive ingredient for topical delivery of oil-in-water nanoemulsion

Abstract

The aging process is an inevitable natural course of each human, affecting the entire body, notably the skin's surface. Numerous over-the-counter nanoformulations are available, but none has considered Pouteria campechiana (Pc) extract as a source of the active ingredient in the formulation. In this study, the hydrophilic fraction of the Pc fruit extract was used as an O/W formula for topical application to the human skin. Fatty acid analysis showed that over 18 types of fatty acids were present in the Pc pulp, with the Pc oil showing an acid value of 6.451. The proximate analysis gave an 8.4% moisture content, 1.7% ash, 4.0% protein, 1.0% fat, 84.9% carbohydrates, with a total energy value of 364.60 Kcal/100g. Next, ultrasonic-assisted extraction (UAE) used in this study facilitated satisfactory extraction of phenolic compounds from the Pc pulp. Under optimized UAE conditions (extraction time = 30 min, extraction temperature = 25 °C, ratio of ethanol:water = 60%, v/v), the experimental response surface methodology-assisted optimization, a maximum total phenolic content (TPC) of 1162.80 mg GAE/100 g (DW) was obtained. In the screening process, compositions of jojoba oil (JO), grapeseed oil (GSO), Tween 80, and glycerol (GLY) at 6–12%, 20–26%, 5–7%, and 25–27% gave good particle sizes and PdI between 280–420 nm and 0.18–0.44, respectively. The resultant Pc extract showed a percentage 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition at 82.91%, IC50 of 2.344 mg/mL, ferric reducing antioxidant power (FRAP) value of 836.30±30.60 μmol/100 g DW, and total flavonoid content (TFC) of 813.29 mg QE/100 g. In the D-optimal Mixture Experimental Design experiment, the optimized Pouteria campechiana extract nanoemulsion (OPT-PcE-Ne) formulation comprised JO amount (6.25%), GSO amount (34.38%), T80 (14.06%), and GLY (45.31%) at fixed 0.5% phenoxyethanol, 5% PcE, 2% xanthan gum (XG), and 0.5% perfume oil. The OPT-PcE-Ne yielded the lowest particle size at 222±0.61 nm and PdI of 0.16. The OPT-PcE-Ne gave good organoleptic and stability profiles by remaining creamy white, without any color change for up to 90 days, with a zeta potential of –32.6±0.5 mV and an acceptable pH (4.81±0.02). The OPT-PcE-Ne droplets were averagely sized at 93.46−183.13 nm in the transmission electron microscopy (TEM) micrograph and gave conductivity of 0.22 μS/cm. The OPT-PcE-Ne rheology followed a Bingham plastic behavior, suggesting that the cream must be applied to the skin in successive layers. In the accelerated tests, phase separation in the OPT-PcE-Ne was absent in the ultracentrifugation and freeze-thaw cycle studies. Next, samples stored for 6 weeks showed mean particle size and PdI between 155–315 nm and 0.16−0.28 for 4±2 °C, 415–150 nm and 0.16−0.26 for 28±2 °C and 125–295 nm and 0.14−0.45 for storage at 50±2 °C. The general non-linearity for the OPT-PcE-Ne stored at 4±2 °C, 28±2 °C proved the system was not destabilized by coalescence but more so by Ostwald ripening when stored for long durations at 28±2 °C (R2=0.7753). The OPT-PcE-Ne exhibited a release of ~0.18% of PcE in the 0–6 h duration, with a maximal level of 5.17% after 24 h. Pertinently, the OPT-PcE-Ne was also free from microorganisms- and heavy metal contamination. In the sensory evaluation study, the OPT-PcE-Ne exhibited the highest color and texture scores compared to other commercial lotions scoring 7.3 and 6.6, respectively. However, the scent was the lowest-rated factor at a collective scale of 6.1. The study findings supported the use of the PcE as a natural-based ingredient in cosmeceuticals and the OPT-PcE-Ne as a topical lotion on human skin.