Haplophyllum tuberculatum (Forssk.) A. Juss Essential Oils: Seasonal Contents Variation, Bioactivity of the Traditionally-favored, High-yield and Frequent-use Summer Season Oil.

Haplophyllum tuberculatum (Forssk.) A.Juss. volatile oils were obtained by distillation of the aerial parts of the plant growing in Libya during the summer and spring seasons. A yield and componential analysis revealed that the summer season oil, which is frequently used in traditional medicaments by North African communities, was high in yield (0.858%) compared to the spring season oil (0.47%), and distinguished by the presence of major and various diverse constituents, some of which are considered chemical markers. Owing to the traditional and high incidence of use of the summer-produced essential oil for the treatment of several disorders, including hepatic diseases, and fatigue, the oil was pharmacologically investigated for its varied bioactivities of anti-microbial, in vivo anti-oxidant, and in vitro anti-cancer properties. Thirty-three compounds were identified and represented 96.2% of the peaks in the GCchromatogram of the summer oil, in which the major volatile constituents were δ-3-carene (21.5%), bornyl acetate (16.9%), and limonene aldehyde (15.2%). The summer-based essential oil of the plant demonstrated moderate anti-bacterial activity against Gram-positive bacteria and a relatively strong antibacterial effect against Gram-negative bacteria as compared to the positive antibacterial controls, ampicillin and gentamicin, respectively. Also, antifungal activity against Aspergillus sp. was observed. The summerproduced oil also exhibited in vivo antioxidant and in vitro anti-cancer activities.