Flourensia fiebrigii S.F. blake: A medicinal plant from the Argentinean highlands with potential use as anti-rheumatic and anti-inflammatory

ETHNOPHARMACOLOGICAL RELEVANCE

Flourensia fiebrigii is a plant used in traditional medicine in the Argentine Calchaquí Valley as purgative, expectorant, anti-rheumatic and anti-inflammatory.

AIM OF THE STUDY

The aim of this study was to analyze the macroscopic and microscopic characteristics of F. fiebrigii leaf and stem, the phytochemical composition of leaves ethanolic extracts and to validate its traditional use as anti-rheumatic and anti-inflammatory.

MATERIALS AND METHODS

The macroscopic and microscopic description of F. fiebrigii leaf and stem was carried out. Two extracts (immersions and tinctures) from leaves were obtained. The phytochemical analysis and UHPLC-OT-MS metabolome fingerprinting of both extracts were performed. The anti-rheumatic and anti-inflammatory activities of both extracts were determined using enzymatic inhibition assays of xanthine-oxidase (XOD), secretory phospholipase A2 (sPLA2) and lipoxygenase (LOX).

RESULTS

The macroscopic and micrographic characters of F. fiebrigii were described to allow the botanical characterization of the plant species. The leaves extracts showed a high level of phenolic compounds with similar chromatographic patterns. Forty-five compounds were identified based on UHPLC-OT-MS including several sesquiterpenes, chalcones, flavonoids, isoflavonoids, a lignan and phenylpropanoids phenolic acids that have been identified for the first time in this plant species. F. fiebrigii extracts were able to inhibit the XOD activity and, consequently, the formation of uric acid and reactive oxygen species, primary cause of diseases, such as gouty arthritis (IC₅₀ values of 1.10-2.12 μg/mL). Pro-inflammatory enzymes like sPLA2 and LOX were also inhibited by F. fiebrigii extracts (IC₅₀ values of 22.00-2.20 μg/mL) decreasing the production of inflammation mediators.

CONCLUSIONS

The present work validates the traditional medicinal use of F. fiebrigii as anti-rheumatic and anti-inflammatory through the use of enzymatic assays. The presence of several chemical compounds with demonstrated anti-rheumatic and anti-inflammatory properties also supports the bioactivity of the F. fiebrigii.

Microscopic anatomy and ultrastructure of the resin ducts of Ferula ferulaeoides (Steud.) Korov. in Xinjiang

Ferula ferulaeoides (Steud.) Korov. is a perennial herb that belongs to Umbelliferae (Apiaceae). Its resin and roots have extensive commercial and medicinal value in the Xinjiang region. However, the resin-secreting resin ducts (RDs) of F. ferulaeoides have not been studied in detail. This study used optical and transmission electron microscopy to explore the anatomical features, including the distribution, size, and structure, of the RDs among different organs of F. ferulaeoides. The microstructure data revealed that the RDs consisted of a round lumen, a layer of secretory cells, and multiple layers of sheath cells. Notably, the RDs in stem were arranged alternatively in a multilayered ring with vascular bundles of three distinct sizes. The ultrastructural analysis revealed that organelles in the secretory cells potentially play important roles in resin secretion. Those data may be of great significance to understanding the anatomy of the RDs in Ferula L. and Umbelliferae.

Microstructural and histochemical analysis of aboveground organs of Centaurea cyanus used in herbal medicine

Centaurea cyanus L. is a valuable source of many different bioactive substances. It is used in herbal medicine, but the structure of its organs used as raw material and secretory tissues has been insufficiently examined. The aim of this paper was to investigate the microstructure of C. cyanus flowers, bracts, stems and leaves with particular emphasis on secretory structures. Moreover, the main classes of secondary metabolites present in the secretion were identified and the taxonomic value of some micromorphological and anatomical features was analysed. Histochemical, micromorphological and ultrastructural analyses of aboveground organs of C. cyanus were carried out using light, fluorescence, scanning and transmission electron microscopy. The analyses revealed the presence of petal papillae and a characteristic cuticular pattern on the petals, stamens and stylar hairs. There were four types of non-glandular trichomes on the bracts, leaves and stem surfaces. The epidermal cells of the bracts contained prismatic calcium oxalate crystals. Two kinds of secretory structures, i.e. glandular trichomes and ducts, were observed in the C. cyanus organs. The glandular trichomes were located on the bract and stem surfaces, and the ducts were detected in the leaves and stems. Ultrastructural analyses of the epithelium of the ducts showed the presence of strongly osmiophilic insoluble phenolic material in vacuoles as well as moderately osmiophilic insoluble lipidic material in elaioplasts and vesicles. The results of histochemical assays showed a heterogeneous nature of the duct secretion, which contained essential oil, lipids, flavonoids, tannins and terpenes containing steroids.

Leaf blade structure of Verbesina macrophylla (Cass.) F. S. Blake (Asteraceae): ontogeny, duct secretion mechanism and essential oil composition

Secretory structures are common in Asteraceae, where they exhibit a high degree of morphological diversity. The species Verbesina macrophylla, popularly known as assa-peixe, is native to Brazil where it is widely used for medicinal purposes. Despite its potential medical importance, there have been no studies of the anatomy of this species, especially its secretory structures and secreted compounds. This study examined leaves of V. macrophylla with emphasis on secretory structures and secreted secondary metabolites. Development of secretory ducts and the mechanism of secretion production are described for V. macrophylla using ultrastructure, yield and chemical composition of its essential oils. Verbesina macrophylla has a hypostomatic leaf blade with dorsiventral mesophyll and secretory ducts associated with vascular bundles of schizogenous origin. Histochemistry identified the presence of lipids, terpenes, alkaloids and mucopolysaccharides. Ultrastructure suggests that the secretion released into the duct lumen is produced in plastids of transfer cells, parenchymal sheath cells and stored in vacuoles in these cells and duct epithelial cells. The essential oil content was 0.8%, and its major components were germacrene D, germacrene D-4-ol, β-caryophyllene, bicyclogermacrene and α-cadinol. Secretory ducts of V. macrophylla are squizogenous. Substances identified in tissues suggest that both secretions stored in the ducts and in adjacent parenchyma cells are involved in chemical defence. The essential oil is rich in sesquiterpenes, with germacrene D and its derivatives being notable components.

Volatiles and Nonvolatiles in Flourensia campestris Griseb. (Asteraceae), How Much Do Capitate Glandular Trichomes Matter?

The distribution and ultrastructure of capitate glandular trichomes (GTs) in Flourensia species (Asteraceae) have been recently elucidated, but their metabolic activity and potential biological function remain unexplored. Selective nonvolatile metabolites from isolated GTs were strikingly similar to those found on leaf surfaces. The phytotoxic allelochemical sesquiterpene (-)-hamanasic acid A ((-)-HAA) was the major constituent (ca. 40%) in GTs. Although GTs are quaternary ammonium compounds (QACs)-accumulating species, glycine betaine was not found in GTs; it was only present in the leaf mesophyll. Two (-)-HAA accompanying surface secreted products: compounds 4-hydroxyacetophenone (piceol; 1) and 2-hydroxy-5-methoxyacetophenone (2), which were isolated and fully characterized (GC/MS, NMR), were present in the volatiles found in GTs. The essential oils of fresh leaves revealed ca. 33% monoterpenes, 26% hydrocarbon- and 30% oxygenated sesquiterpenes, most of them related to cadinene and bisabolene derivatives. Present results suggest a main role of GTs in determining the volatile and nonvolatile composition of F. campestris leaves. Based on the known activities of the compounds identified, it can be suggested that GTs in F. campestris would play key ecological functions in plant-pathogen and plant-plant interactions. In addition, the strikingly high contribution of compounds derived from cadinene and bisabolene pathways, highlights the potential of this species as a source of high-valued bioproducts.