Citral chemotypes Cinnamomum camphora (C. camphora) and Cinnamomum bodinieri (C. bodinieri) are promising industrial plants that contain abundant citral. For a more in-depth study, their significant biological effect, the chemical composition and antioxidant capacity of essential oils of citral-rich chemotype C. camphora and C. bodinieri (EOCC) were determined in the present study. The EOCC yield, obtained by hydro-distillation and analyzed by gas chromatography–mass spectrometry (GC-MS), ranged from 1.45–2.64%. Forty components more than 0.1% were identified and represented, mainly by a high content of neral (28.6–39.2%), geranial (31.8–54.1%), Z-isocitral (1.8–3.2%), E-isocitral (3.2–4.7%), geraniol (1.3–2.6%) and caryophyllene (0.6–2.4%). The antioxidant properties of EOCC were estimated by DPPH, ABTS and FRAP methods. As our results indicated, the antioxidant activity was significantly correlated to oxygenated monoterpenes. The variety of C. bodinieri (N7) presented the best antioxidant profile, given its highest inhibition of DPPH radical (IC₅₀ = 6.887 ± 0.151 mg/mL) and ABTS radical scavenging activity (IC₅₀ = 19.08 ± 0.02 mg/mL). To the best of our knowledge, more than 88% citral of C. bodinieri was investigated and the antioxidant properties described for the first time. Considering high essential oil yield, rich citral content and high antioxidant activity, the N7 variety will be a good candidate for pharmaceutical and cosmetic development of an improved variety.

To explore the patterns of essential oil synthesis and the optimal harvesting period of citral-type Camphora officinarum Nees ex Wall (C. officinarum) at different growth stages, three varieties (C1, C2, C3) from the citral-type C. officinarum coppice were taken as research objects. During the leaf growth cycle from February 2022 to January 2023 (12 periods in total), their morphological indicators, biomass, essential oil yield, chemical components, and output were determined. As a natural monoterpenoid widely used in the food additive, pharmaceutical intermediate, and flavor/fragrance industries, citral-related research is of great significance for improving the breeding value of citral-type C. officinarum germplasm resources. The results showed that: (1) The leaf area, total biomass, and leaf-branch ratio of the three varieties all reached the maximum in Period I (late August, full fruit stage), among which the leaf biomass and total biomass of C1 were significantly higher than those of C2 and C3. (2) The essential oil yield based on dry weight of leaves (0.53–2.79%) was significantly higher than that of branches (0.48–0.7%). Citral (geranial and neral) was the main component of the essential oil; the citral contents in C1 and C2 were the highest in Period G (late June, early fruit stage) (78.38% and 71.78%, respectively), while that in C3 peaked in Period F (late May, late flowering stage) (70.46%). (3) The total essential oil yield reached the peak in Period I, with C1 being significantly higher at 20.19 ± 1.88 g/plant than C2 (13.8 ± 0.61 g/plant) and C3 (16.47 ± 0.87 g/plant). Comprehensive analysis indicated that C1 was identified as the top-performing cultivar among citral-type C. officinarum, and July–August was the optimal harvest period. During this period, both essential oil yield and citral content could be balanced to maximize economic benefits.