Influence of seasonality on the chemical composition and antioxidant activity of essential oils from the leaves of Croton heliotropiifolius Kunth and Croton jacobinensis Baill. (Euphorbiaceae)

Croton heliotropiifolius and Croton jacobinensis are species native to Brazil, commonly found in the Caatinga phytogeographic domain. Although some previous studies have reported the effects of seasonal factors on the chemical composition of the essential oils of these plants, information on variation in antioxidant activity across seasons remains scarce in the literature. In this context, the present study evaluated the influence of seasonality on the chemical composition and antioxidant activity of essential oils from C. heliotropiifolius (EOCH) and C. jacobinensis (EOCJ) collected during the year 2024. Yields ranged from 0.05 to 0.16% for EOCH and from 0.07 to 0.11% for EOCJ. Based on gas chromatography-mass spectrometry (GC/MS) analysis, 27 compounds in EOCH and 22 compounds in EOCJ were tentatively identified. E- caryophyllene (20.25 – 33.23%) was the most abundant compound in EOCH, whereas bicyclogermacrene (30.33 – 47.77%) stood out as the main compound in EOCJ across all seasons. Moderate results were obtained using the DPPH method, with EOCH and EOCJ showing higher antioxidant activity in summer (IC 50 = 6.38 mg/mL) and spring (IC 50 = 4.49 mg/mL), respectively. The results obtained clearly indicate the influence of seasonal variations on the chemical composition and antioxidant activity of EOCH and EOCJ.