Biomonitored UHPLC-ESI-QTOF-MS 2 and HPLC-UV thermostability study of the aerial parts of Sphagneticola trilobata (L.) Pruski, Asteraceae

Quality Control of Herbal Medicines: From Traditional Techniques to State-of-the-art Approaches

Herbal medicines are important options for the treatment of several illnesses. Although their therapeutic applicability has been demonstrated throughout history, several concerns about their safety and efficacy are raised regularly. Quality control of articles of botanical origin, including plant materials, plant extracts, and herbal medicines, remains a challenge. Traditionally, qualitative (e.g., identification and chromatographic profile) and quantitative (e.g., content analyses) markers are applied for this purpose. The compound-oriented approach may stand alone in some cases (e.g., atropine in Atropa belladonna). However, for most plant materials, plant extracts, and herbal medicines, it is not possible to assure quality based only on the content or presence/absence of one (sometimes randomly selected) compound. In this sense, pattern-oriented approaches have been extensively studied, introducing the use of multivariate data analysis on chromatographic/spectroscopic fingerprints. The use of genetic methods for plant material/plant extract authentication has also been proposed. In this study, traditional approaches are reviewed, although the focus is on the applicability of fingerprints for quality control, highlighting the most used approaches, as well as demonstrating their usefulness. The literature review shows that a pattern-oriented approach may be successfully applied to the quality assessment of articles of botanical origin, while also providing directions for a compound-oriented approach and a rational marker selection. These observations indicate that it may be worth considering to include fingerprints and their data analysis in the regulatory framework for herbal medicines concerning quality control since this is the foundation of the holistic view that these complex products demand.

Metabolomic analysis among ten traditional "Arnica" (Asteraceae) from Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of several Asteraceae species in Brazil are popularly used as anti-inflammatory. Some of these species are popularly recognizes as "arnica" because of the morphological and sensorial analogy with the traditional European Arnica montana. These used species in Brazil were identified as Calea uniflora Less, Chaptalia nutans (L.) Polák, Lychnophora ericoides Mart. Lychnophora pinaster Mart. Lychnophora salicifolia Mart. Porophyllum ruderale (Jacq.) Cass, Pseudobrickellia brasiliensis (Spreng.) R. M. King & H. Rob. Sphagneticola trilobata (L.) Pruski and Solidago chilensis Meyen. However, the comparative chemical profile of these so-called "arnicas" has never been reported in the literature.

AIM OF THE STUDY

This work aimed to compare the main plants recognized as "arnica" in Brazil by using metabolomic analysis, based on UPLC-ESI-QTof-MS² data and multivariate statistical analysis.

MATERIALS AND METHODS

The metabolites profiling of 10 "arnica" species were established by UPLC-ESI-QTof-MS². Three tinctures of each species (dry leaves) were produced and one aliquot of each tincture was injected and analyzed three times by UPLC-ESI-QTof-MS². Data were acquired both in negative and positive modes and processed by MassLynx®, MarkerLynx® and Matlab® softwares. Principal component analysis (PCA) was used to reduce dimensionality and data redundancy; hierarchical trees helped to identify and eliminate contaminated or misplaced injections/samples. To achieve the objectives both hierarchical and k-means clustering techniques were employed to group similar samples or species.

RESULTS

Diagnostic analysis of MS data allowed the identification of 54 metabolites. The identification was supported with the use of an external standard, fragmentation pattern and data from the literature. The main classes of identified compounds included phenolic acids, coumarin, flavonoids, heterosides, terpenoids and nitrogen compounds. Cluster analysis revealed that Sphagneticola trilobata, Solidago chilensis and Lychnophora pinaster have some chemical features similar to those of Arnica montana. In contrast, the same statistical analysis also showed that Pseudobrickellia brasiliensis, Porophyllum ruderale and Chaptalia nutans are chemically diverse from Arnica montana. The variability of the samples relied principally on nitrogenated compounds (confidence level 4) found in P. brasiliensis and P. ruderale, three phenolic compounds (level 2) detected in P. brasiliensis and in C. nutans and triterpenes (level 3) found in L. salicifolia and L. pinaster.

CONCLUSIONS

In summary, the mass spectrometry technique in conjunction with multivariate statistical analysis proved to be an excellent tool to identify correlated compounds, as well as to verify the chemical similarity among evaluated species. This methodology was successfully used to establish important correlations in medicinal preparations of so-called "arnicas" used in Brazil.

Asteraceae family: a review of its allelopathic potential and the case of Acmella oleracea and Sphagneticola trilobata

Abstract Asteraceae family is as an interesting target for researching natural alternatives for crop protection. Many species from this family grow as weeds, and some of them can influence the development of other species by the allelopathy phenomenon. This paper aimed to review the literature for the main genera and species of the Asteraceae family with allelopathic or phytotoxic potential, as well as the classes of secondary metabolites present in this family and responsible for such activity. Artemisia, Ambrosia, Bellis, Bidens, Helianthus and Tagetes were identified as the main genera with phytotoxic or allelopathic activity. Among the secondary metabolites from this family, terpenes, polyacetylenes, saponins, sesquiterpene lactones, phenolic acids and flavonoids were described as responsible for inhibiting the development of other species. In addition, the phytotoxic potential of Acmella oleracea and Sphagneticola trilobata against the weeds Calopogonium mucunoides. and Ipomoea purpurea was described for the first time. At 0.2 mg/mL, crude extract and fractions of A. oleracea inhibited above 60% of C. mucunoides root growth. Hydroalcoholic extract and fractions of S. trilobata, except hexane, significantly affected I. purpurea root growth, ranging from 38 ± 14% to 59 ± 8% of inhibitory effect at different concentrations (0.19 mg/mL to 1.13 mg/mL).

Bioprospecting for Antibacterial Drugs: a Multidisciplinary Perspective on Natural Product Source Material, Bioassay Selection and Avoidable Pitfalls

Bioprospecting is the exploration, extraction and screening of biological material and sometimes indigenous knowledge to discover and develop new drugs and other products. Most antibiotics in current clinical use (eg. β-lactams, aminoglycosides, tetracyclines, macrolides) were discovered using this approach, and there are strong arguments to reprioritize bioprospecting over other strategies in the search for new antibacterial drugs. Academic institutions should be well positioned to lead the early stages of these efforts given their many thousands of locations globally and because they are not constrained by the same commercial considerations as industry. University groups can lack the full complement of knowledge and skills needed though (eg. how to tailor screening strategy to biological source material). In this article, we review three key aspects of the bioprospecting literature (source material and in vitro antibacterial and toxicity testing) and present an integrated multidisciplinary perspective on (a) source material selection, (b) legal, taxonomic and other issues related to source material, (c) cultivation methods, (d) bioassay selection, (e) technical standards available, (f) extract/compound dissolution, (g) use of minimum inhibitory concentration and selectivity index values to identify progressible extracts and compounds, and (h) avoidable pitfalls. The review closes with recommendations for future study design and information on subsequent steps in the bioprospecting process.