Stevia rebaudiana germplasm characterization using microsatellite markers and steviol glycosides quantification by HPLC.

Stevia rebaudiana Bertoni, Asteraceae, is an herbaceous perennial plant native to Paraguay. This species is considered since ancient times a medicinal plant with important bioactive compounds and pharmacologic and food properties, namely diterpenes glycosides. The high natural sweetener potential stevioside and rebaudioside A produced by S. rebaudiana plants are suitable sucrose substitutes, and their obtention is influenced by environmental, phytosociological, and genetic factors. The plants' genetic profile and sweet potential depiction are needed for suitable plant selection for improvement and deployment. Thirty-one S. rebaudiana accessions grown in the same plot where leaves samples were collected in early 2019, were genotyped using six microsatellite markers, including two steviol glycosides biosynthesis functionally involved markers. Additionally, an aqueous extract of each sample was obtained in a water bath and purified by SPE for stevioside and rebaudioside A quantification by normal phase HPLC. Stevioside and rebaudioside A contents varied between 0.53-7.36% (w w-1) and 0.37-3.60% (w w-1), respectively. Two genotypes displayed interesting ratios of rebaudioside A/stevioside (number 3 and 33). The level of genetic similarity between genotypes was tested through a pairwise similarity coefficient, and two groups of individuals had the same fingerprinting. Strong relatedness was found within genotypes, possibly due to cloning, thus, influx of new germplasm ought to be made to prevent mating between relatives, and for further selection and genetic improvement.

Mentha aquatica L. aerial parts: in vitro anti-proliferative evaluation on human tumour and non-tumour cell lines.

Bearing in mind the several medicinal properties of Mentha genus, this work aimed to evaluate the anti-proliferative potential of the ethanolic extract (EE) and fractions from M. aquatica L aerial parts. Using the anti-proliferative protocol developed by the NCI/USA, four fractions (F2 - F4 and F6) obtained from EE showed promising anti-proliferative profile against a panel of human tumor and non-tumor cell lines. After 24-h exposure, F2 (0.25 µg/mL) showed potent and irreversible anti-proliferative effect without inducing cell cycle arrest in both NCI-H460 and MCF-7 cells, without (anti) estrogenic activity. These effects were lost after storage of F2 diluted in dimethyl sulfoxide at -80 °C during 2 weeks. Analysis by gas chromatography coupled to mass detection evidenced some chemical changes induced by F2 storage in solution. The present study demonstrated the anti-proliferative effect of M. aquatica. Further studies are necessary to determine better storage conditions to enhance F2 stability.

A set of microsatellite markers for Arrabidaea chica (Bignoniaceae), a medicinal liana from the Neotropics.

PREMISE OF THE STUDY: Microsatellite markers were developed, optimized, and characterized for Arrabidaea chica (Humb. & Bonpl.) Verl. (Bignoniaceae), a Neotropical liana extensively used in folk medicine. The aim of this study was to develop molecular tools to investigate the genetic structure and diversity of natural populations and germplasm collections of this species. • METHODS AND RESULTS: Eight highly polymorphic microsatellite markers revealed a multibanded pattern, suggesting that the species is polyploid. The total number of bands per locus ranged from 9 to 17, revealing high levels of polymorphism. • CONCLUSIONS: The high level of polymorphism detected with these markers indicates their utility in devising conservation strategies and rational exploitation of A. chica.