Comparative Study of Ethanolic and Propylene Glycol Extraction of Hemp Leaf Extracts: Phytochemical Analysis and Skincare Formulation Development

Abstract

This study investigated chemical profiles, bioactivity, and formulation potential of Cannabis sativa L. (hemp) leaf extracts for skincare applications. Hemp leaves were extracted using ethanol (EH) and propylene glycol (PGH), and the extracts were analyzed for phytochemical content, antioxidant activity, and astringent properties. Chemical analysis using liquid chromatography coupled with triple quadrupole mass spectrometry revealed that both extracts contained diverse phytochemicals, with cannabinoids as the predominant compounds. Ethanolic extraction demonstrated superior efficiency, yielding significantly higher concentrations of cannabidiol (CBD) at 224.90 ± 1.42 µg/mL higher than the propylene glycol extraction which has CBD at 0.83 ± 0.00 µg/mL. Bioactivity assays confirmed that EH exhibited robust antioxidant activity with IC50 values of 258.06 ± 34.38 µg/mL for H2O2 scavenging and 315.38 ± 50.10 µg/mL for DPPH scavenging, while PGH demonstrated mild astringent activity (7.11 ± 1.18%) suitable for sensitive skin applications. Despite lower phytochemical yields, PGH demonstrated superior integration into water-based skincare systems, maintaining optimal viscosity, pH compatibility, and homogeneity better than EH. Stability challenges were identified during heating–cooling cycle cycling, which triggered CBD degradation and color shifts, although the formulations maintained structural integrity without phase separation under heat-cool testing. These findings establish PGH offers superior practical advantages for cosmetic stability and formulation compatibility. Furthermore, the identification of mild astringent properties in PGH provides a novel functional justification for its use in specialized sensitive skincare, bridging the gap between raw phytochemical efficacy and industrial product viability.