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The chemical composition of three rockrose Cistus species, Cistus monspeliensis, Cistus libanotis and Cistus villosus, collected in Tunisia, was studied by HPTLC, focusing on the terpenes and phenols constituents. Diterpenes of Cistus are important as the main constituents of the leaf sticky aromatic resin, known as labdanum, which are highly appreciated in perfumery. Polyphenols in the methanolic extracts of each species were identified, quantified as total and as flavonoids and tannins, and tested for antioxidant activity. Diterpenes were evident in C. libanotis and C. monspeliensis, whereas they were practically absent in C. villosus; C. libanotis had higher phenolic amount, whereas antioxidant activities were important, but different according to the following tests: DPPH radical scavenging, conversion of the Fe(3+/)ferricyanide complex and inhibition of β-carotene bleaching. The reported data confirm the validity of utilisation of Cistus sp. in marketed herbal products, as well as the relevant presence of diterpenes in species actually not used for labdanum production.

In continuation of our ongoing study on Mediterranean Flora, we focused the attention on Cistus genus. These plants possess interesting secondary metabolites and are used in many fields, principally in perfumery and more recently as raw material for food supplements (botanicals). n this article, we report the phytochemical analysis of Cistus libanotis L. from Tunisia. Among the diterpenes, labdane compounds resulted absent, in favour of two clerodanes, one of that never reported in Cistus sp. The main representative compounds were found to be several flavonoids with various grades of O-methylation. Other interesting components were two cinnamic esters of borneol, reported here for the first time in Cistus. The identified compounds confirm in part the reported biological properties and add chemotaxonomic data to this complicated genus.