Pyrrolizidine alkaloids in Pulmonaria obscura

Biological Activities and Phytochemicals of Lungworts (Genus Pulmonaria) Focusing on Pulmonaria officinalis

Lungworts (members of genus Pulmonaria), especially Pulmonaria officinalis, have been used as medicinal plants in folk and traditional medicine. The potential biological activities of lungworts, such as antioxidant, anti-inflammatory, anti-neurodegenerative, skin whitening, anticoagulant, antibacterial, anti-anemic, anticonvulsant, and wound-healing properties, have been observed in different studies. More than 90 phytochemicals belonging to pharmacologically active phytochemical classes have been reported for lungworts, which can be considered as one of the important contributors to the biological properties along with micronutrients. However, safety studies and clinical trials are missing for lungworts to establish most of their potential biological properties. Similarly, in vivo studies are lacking for anti-inflammatory and anti-neurodegenerative disorders and more in vivo studies are required to strengthen the knowledge of their antioxidant, anticoagulant, and anti-convulsant properties. A comprehensive compilation of the phytochemicals and biological properties of lungworts is also lacking in the literature, which can provide future direction for further pharmacological research. Hence, an attempt has been made in this study to compile the phytochemicals and biological properties to not only provide the resources for the design of further research to develop the pharmacological application of lungworts, but also to highlight the gaps and provide suggestions for future development.

Ontogeny of Defensive Chemistry in Longitarsus Flea Beetles (Coleoptera, Chrysomelidae): More Protection for the Vulnerable Stages?

Several species of the flea beetles genus Longitarsus sequester pyrrolizidine alkaloids (PAs) from their host plants. Previous data demonstrated that PAs may be transferred from root-feeding larvae into the adult beetles. Here we compared the patterns and concentrations found in larvae and pupae of L. anchusae and L. echii with those of the roots of their respective hosts, Symphytum officinale and Echium vulgare (Boraginaceae). PA patterns and concentrations in the roots were complex and variable, whereas those in the larvae and pupae were simpler and more constant. In L. anchusae, intermedine and lycopsamine were the dominant PAs even if they could not be detected in the roots. In L. echii simpler, hydrolized PAs prevailed. Overall, the concentrations of total PAs of larvae and pupae were significantly higher than those of the roots the larvae had been feeding on. Larvae and pupae of both species also had considerably higher PA concentrations than determined previously for field collected beetles. Possibly the rather immobile juvenile stages enjoy a better protection by higher PA concentrations. On the other hand, we could not detect PAs in eggs of either species, indicating that transmission of appreciable amounts of PAs from mother to offspring does not occur.

Yunnaneic Acid B, a Component of Pulmonaria officinalis Extract, Prevents Peroxynitrite-Induced Oxidative Stress in Vitro

Our work reveals that the aerial parts of Pulmonaria officinalis L. are a new source of yunnaneic acid B. We studied antioxidant activity and cytotoxicity of this compound (1-50 μg/mL) and its contents in various plant extracts. This is the first study confirming the presence of yunnaneic acid B in P. officinalis L. and Pulmonaria obscura Dumort and hence in the Boraginaceae family. Determination of 1,1-diphenyl-2-picrylhydrazyl radical reduction and peroxynitrite-scavenging efficacy in inorganic experimental systems provided EC₅₀ values of 7.14 and 50.45 μg/mL, respectively. Then we examined the antioxidant action of yunnaneic acid B in blood plasma under peroxynitrite-induced oxidative stress in vitro. Yunnaneic acid B effectively diminished oxidative damage to blood plasma proteins and lipids. Furthermore, it was able to prevent the peroxynitrite-induced decrease in nonenzymatic antioxidant capacity of blood plasma. Additionally, cytotoxicity of yunnaneic acid B (at concentrations ≤50 μg/mL) toward peripheral blood mononuclear cells was excluded.

Diversity of Pyrrolizidine Alkaloids in the Boraginaceae Structures, Distribution, and Biological Properties

Among the diversity of secondary metabolites which are produced by plants as means of defence against herbivores and microbes, pyrrolizidine alkaloids (PAs) are common in Boraginaceae, Asteraceae and some other plant families. Pyrrolizidine alkaloids are infamous as toxic compounds which can alkylate DNA und thus cause mutations and even cancer in herbivores and humans. Almost all genera of the family Boraginaceae synthesize and store this type of alkaloids. This review reports the available information on the present status (literature up to early 2014) of the pyrrolizidine alkaloids in the Boraginaceae and summarizes the topics structure, distribution, chemistry, chemotaxonomic significance, and biological properties.