Chemical characterization (GC-MS and NMR fingerprinting) and bioactivities of South-African Pelargonium capitatum (L.) L’Herit. (Geraniaceae) essential oil

Chemical fingerprinting of commercial Pelargonium capitatum (Geraniaceae) essential oil samples of south African origin was performed by GC, GC/MS, and 13C- and 1H-NMR. Thirty-seven compounds were identified, among which citronellol (32.71%) and geraniol (19.58%) were the most abundant. NMR Spectra of characteristic chemicals were provided. Broad-spectrum bioactivity properties of the oil were evaluated and compared with those of commercial Thymus vulgaris essential oil with the aim to obtain a functional profile in terms of efficacy and safety. P. capitatum essential oil provides a good performance as antimicrobial, with particular efficacy against Candida albicans strains. Antifungal activity performed against dermatophyte and phytopathogen strains revealed the latter as more sensitive, while antibacterial activity was not remarkable against both Gram-positive and Gram-negative bacteria. P. capitatum oil provided a lower antioxidant activity (IC50) than that expressed by thyme essential oil, both in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching tests. Results in photochemiluminescence (PCL) assay were negligible. To test the safety aspects of P. capitatum essential oil, mutagenic and toxicity properties were assayed by Ames test, with and without metabolic activation. Possible efficacy of P. capitatum essential oil as mutagenic protective agent against NaN3, 2-nitrofluorene, and 2-aminoanthracene was also assayed, providing interesting and significant antigenotoxic properties.