Lavandula dentata L.: Phytochemical Analysis, Antioxidant, Antifungal and Insecticidal Activities of Its Essential Oil

Abstract

Antioxidant, antifungal and insecticidal activities of essential oil (EO) extracted from the Moroccan lavender (<i>Lavandula dentata</i>) were investigated and their chemical constituents determined. Gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry analyses (GC-MS) were used to examine the phytochemical composition of EO. Antioxidant potential was examined in vitro by use of three tests: DPPH inhibition, reducing power (FRAP) and total antioxidant capacity (TAC). Antifungal activity was assessed by calculating inhibition of growth of <i>Alternaria alternata</i>, <i>Botrytis cinerea</i> and <i>Fusarium oxysporum</i>. Repellent potential and toxicity of EO by contact and inhalation were performed against <i>Callosobruchus maculatus</i>. Sixteen constituents were detected in the EO of <i>Lavandula dentata</i>. The major component was linalool (45.06%) followed by camphor (15.62%) and borneol (8.28%). EO exhibited a significant antioxidant activity, as measured by DPPH and FRAP assays, with IC₅₀ and EC₅₀ values of 12.95 ± 1.300 mg/mL and 11.88 ± 0.23 mg/mL, respectively. EO of lavender exhibited total antioxidant capacity of 81.28 ± 2.28 mg AAE/g EO. EO of lavender showed an inhibitory effect on mycelial growth against tested fungi and was 100% in the case of <i>B. cinerea</i>. EO caused total mortality of adult <i>C. maculatus</i> from 5 µL/L air with LC₅₀ value of 4.01 µL/L air. Significant reduction in numbers of eggs laid (99.2%) and emergence (100%) was observed in a dose-dependent manner up to maxima of 100% and 99.2%, respectively. EO of lavender also showed a moderate potency to repel insects with a mean of 34.44%. EO of Moroccan <i>Lavandula dentata</i> has potential to be an effective natural agent against free radical damage and could be an environmentally friendly alternative bio-fungicide and bio-insecticide.