Pelargonium graveolens and Pelargonium zonale as Valuable Sources of Antioxidants to Be Applied in Cosmetic Preparations

Pelargonium graveolens and Pelargonium zonale are promising sources of natural antioxidants and other bioactive compounds that may find future use in topical cosmetic preparations. The aim of our study was to investigate the antioxidant properties and chemical composition of extracts obtained from various aerial parts of both plant species using ultrasound-assisted extraction (UAE) and Soxhlet extraction. Their suitability as active ingredients in cosmetic emulsions and hydrogel patches was also evaluated. The plant material was extracted with aqueous ethanol solutions of various concentrations under various extraction conditions. The antioxidant activity of the extracts was tested using the DPPH, ABTS, and Folin–Ciocalteu methods, whereas their chemical composition was characterized by gas chromatography–mass spectrometry (GC–MS). Selected extracts were incorporated into cosmetic formulations, which were then assessed for antioxidant activity, cytocompatibility, and antimicrobial properties. The antioxidant activity of the extracts depended on the Pelargonium species, plant organ, extraction method, and the composition of the aqueous ethanol solutions used for extraction. Among the extracts obtained by UAE, those prepared from dried P. graveolens leaves in 40% (v/v) EtOH after 30 min, fresh P. zonale leaves in 96% (v/v) EtOH for 60 min and fresh P. zonale flowers in 96% (v/v) EtOH for 60 min exhibited the highest antioxidant potential. GC–MS analysis revealed the presence of a large number of compounds with antioxidant properties reported in the scientific literature, including geraniol, citronellol, linalool, phytol, ethyl gallate, and 1,2,3-benzenetriol. These findings confirm that both plant species are rich in biologically active compounds. The developed cosmetic emulsions retained considerable antioxidant activity and showed high in vitro cytocompatibility toward human fibroblasts, although a modest concentration-dependent reduction in metabolic activity was observed at the highest concentration tested. Selected hydrogel discs containing Pelargonium extracts produced measurable control-corrected antibacterial responses against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. Among the four Soxhlet extracts evaluated, measurable minimum inhibitory concentration (MIC) values ranged from 5% to 28%. The lowest MIC value against S. aureus (5 ± 2%) was observed for the fresh-flower extract of P. zonale, whereas no MIC endpoint was observed for the dried-leaf extract of P. graveolens against E. coli within the tested concentration range. No measurable inhibition zone was observed for the cream formulations under the applied paper-disc diffusion conditions. The obtained results indicate that P. graveolens and P. zonale are valuable natural sources of bioactive compounds with antioxidant potential and that selected hydrogel formulations show preliminary antibacterial activity under the tested in vitro conditions.