Nomenclatural and taxonomic notes on Mediterranean narrow-leaved plantains (Plantago section Maritima, Plantaginaceae)

Ecology as a Tool to Assist Conservation of a Rare and Endemic Mediterranean Plantago Species

Reviewing the ecological studies on the endangered endemic Plantago almogravensis Franco, an Al-hyperaccumulator plant, and combining these with morphological, physiological, biochemical, and molecular data, significant knowledge on the limiting factors that cause its narrow geographical distribution and rarity status is achieved, which can contribute to suited conservation guidelines. Emphasis was given on (i) the major factors limiting P. almogravensis’ ecological niche (biotic and abiotic); (ii) phases of the life cycle and population dynamics; and (iii) and the phylogenetically close taxa (Plantago subulata aggregate) in order to fill the knowledge gaps in the uniqueness of P. almogravensis ecology, its phylogeny, and conservation status. The identification of relevant ecological data and using plant functional (morphological and physiological) traits, as well as genetic attributes, substantiate into a powerful tool to guide protection and conservation measures, usable toward this and other endangered hyperaccumulator plant species. Knowledge of the limitations of this strongly narrowly distributed plant allows for better design of conservation measures and to guide value and investment strategies in order to secure the species’ current area (habitat conservation and reclamation), direct the expansion of the existing population (assisting in populational densification and colonization), and/or grant ex situ conservation (genetic resources conservation).

Plantago subulata as indicator of potentially toxic elements in the substrate

Plantago subulata is a facultative serpentinophyte, with predominantly ultramafic distribution in Serbia and Montenegro. The plant samples were collected from ultramafic and non-ultramafic substrate, including two abandoned mining sites, with the aim to assess the accumulation potential of this species. The samples were collected from 10 sites in Serbia and Montenegro and element concentrations in plants and soils were determined. Particularly high concentrations of Fe, Cu, Mn, Zn, and Cd were found in the soil and plant samples from an abandoned iron mining site, Mt. Kopaonik, Suvo Rudište. The concentrations of Ni, Cr, Fe, Co, and Cd were statistically different between soil and plant samples from ultramafic and non-ultramafic bedrock. Considering the fact that concentrations of Zn, Ni, and Cr in roots and shoots were positively correlated with their respective contents in the soil, i.e., the chemical composition of the plant and soil samples reflected the characteristics of the substrate, and for most of the elements analyzed, P. subulata acted as indicator species. For Cd and Pb, only the root concentrations were positively correlated with soil content, indicating exclusion and root sequestration as the main tolerance strategies for these elements. Although below the hyperaccumulation threshold, a strong accumulation capacity of P. subulata was found for Ni and Cu.

Enzyme inhibitory assessment of the isolated constituents from Plantago holosteum Scop

Plants of the Plantago genus are widely used in Turkish folk medicine especially for the treatment of wound, abscess, and inflammation. The aqueous extract and five phenylethanoid glycosides acteoside (1), arenarioside (2), echinacoside (3), isoacteoside (4), and leucosceptoside A (5) isolated from the aerial parts and roots of Plantago holosteum Scop. (Plantaginaceae) were tested for their possible inhibitory activity against hyaluronidase, elastase, and collagenase, related to wound pathogenesis. Even though the aqueous extract prepared from the aerial parts (36.26%) and roots (47.01%) and the isolated compounds acteoside (29.13%), echinacoside (28.73%), and isoacteoside (31.69%) exerted a notable inhibition, arenarioside and leucosceptoside A were found inactive in the hyaluronidase enzyme inhibition test. Similar results were obtained from the collagenase enzyme inhibition test. The aqueous extract prepared from the aerial parts (31.09%) and roots (35.17%), echinacoside (25.13%), and isoacteoside (23.85%) exerted a notable inhibition in this test. However, none of the extracts and isolated compounds displayed elastase enzyme inhibitory activity. The experimental data demonstrated that P. holosteum displayed a remarkable enzyme inhibitory activity against hyaluronidase and collagenase. This paper is the first report regarding the in vitro enzyme inhibitory activity of P. holosteum.