| Summary: | <i>Helichrysum</i> species are prominent South African medicinal plants. From the essential oils (EOs) of three <i>Helichrysum</i> species, <i>H</i>. <i>petiolare</i>, <i>H</i>. <i>odoratissimum</i>, and <i>H</i>. <i>cymosum</i>, sixty-three constituent components were identified, with hydrocarbons and oxygenated monoterpenes and sesquiterpenes as major components. The compounds were analyzed by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy. In <i>H</i>. <i>petiolare</i> EO, the major components were faurinone (20.66%) and (E)-β-ocimene (17.21%). Faurinone was isolated from this EO for the first time. In <i>H</i>. <i>odoratissimum</i>, 1,8-cineole (17.44%) and α-pinene, and γ-curcumene (15.76%) were the major components whereas, in <i>H</i>. <i>cymosum</i>, α-pinene (29.82%) and (<i>E</i>)-caryophyllene (19.20%) were the major components. In the antibacterial activity study, the EOs were tested against <i>Staphylococcus aureus</i>, <i>Escherichia coli</i>, and <i>Pseudomonas aeruginosa</i>. The EOs were found to possess low antibacterial, anti-tyrosinase, and photoprotection activities and moderate antioxidant capacities, thus establishing these <i>Helichrysum</i> EOs as valuable antioxidant agents.
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