Fenchone and camphor: Main natural compounds from Lavandula stoechas L., expediting multiple in vitro biological activities

Lavandula stoechas, a Mediterranean plant, renowned in traditional medicine for its health benefits, is also arousing strong interest associated with its essential oils (EOs) with promising therapeutic properties. The aim of this study was to analyze the chemical composition of the plant, as well as to study its major activities, including antioxidant, anti-diabetic, dermatoprotective, anti-inflammatory, and antibacterial effects, focusing on its major molecules. Using the GC-MS method, the main compounds identified in L. stoechas EO (LSEO) were fenchone (31.81 %) and camphor (29.60 %), followed by terpineol (13.14 %) and menthone (8.96 %). To assess their antioxidant activity, three in vitro methods were used (DPPH, FRAP, and ABTS). The results revealed that LSEO exhibited the best antiradical property (54 ± 62 μg/mL) according to the DPPH test, while fenchone demonstrated the highest antioxidant capacity (87 ± 92 μg/mL) in the FRAP test, and camphor displayed the highest antioxidant capacity (96 ± 32 μg/mL) in the ABTS test. However, these results were lower than those obtained by Trolox used as a reference. In addition, study also explored the anti-diabetic potential of LSEO and its major compounds by evaluating their inhibitory activity towards two digestive enzymes, α-glucosidase and α-amylase. Camphor (76.92 ± 2.43 μg/mL) and fenchone (69.03 ± 2.31 μg/mL) exhibited the best inhibitory activities for α-amylase and α-glucosidase assays, respectively. Interestingly, all elements of the study exerted activities superior to those of acarbose, regardless of the test performed. In contrast, the evaluation of the dermatoprotective potential was carried out in vitro by targeting two enzymes involved in cutaneous processes, tyrosinase and elastase. In this light, fenchone (53.14 ± 3.06 μg/mL) and camphor (48.39 ± 1.92 μg/mL) were the most active against tyrosinase and elastase, respectively. It should be noted that the effect of both molecules, as well as that of LSEO, ranged between 53.14 ± 3.06 and 97.45 ± 5.22 μg/mL, which was significantly lower than the standard, quercetin (IC50 of 246.90 ± 2 0.54 μg/mL) against tyrosinase. Furthermore, the anti-inflammatory potential of these elements has been studied by evaluating their ability to inhibit lipooxygenase (LOX), a class of enzymes involved in the inflammatory process in the human body. As a result, the LSEO demonstrated a remarkable effect with an IC50 of 6.34 ± 1.29 μg/mL, which was almost comparable to the standard, quercetin (IC50 = 3.93 ± 0.45 μg/mL). Concerning the antibacterial potential, we carried out a quantitative analysis of the various products tested, revealing a bactericidal activity of the LSEO against the strain L. monocytogenes ATCC 13932 at a minimum effective concentration (MIC = CMB = 0.25). Overall, LSEOs offer significant potential as a source of natural antioxidants, and antidiabetic and anti-inflammatory agents, as well as dermatoprotective and antibacterial compounds. Its major molecules, fenchone and camphor, showed promising activity in these areas of study, making it a valuable candidate for future research and development in the field of natural medicine.