Fast method for the simultaneous quantification of toxic polyphenols applied to the selection of genotypes of yam bean (Pachyrhizus sp.) seeds.

The purpose of the research was to develop and validate a rapid quantification method able to screen many samples of yam bean seeds to determine the content of two toxic polyphenols, namely pachyrrhizine and rotenone. The analytical procedure described is based on the use of an internal standard (dihydrorotenone) and is divided in three steps: microwave assisted extraction, purification by solid phase extraction and assay by ultra high performance liquid chromatography (UHPLC). Each step was included in the validation protocol and the accuracy profiles methodology was used to fully validate the method. The method was fully validated between 0.25 mg and 5 mg pachyrrhizin per gram of seeds and between 0.58 mg/g and 4 mg/g for rotenone. More than one hundred samples from different accessions, locations of growth and harvest dates were screened. Pachyrrhizine concentrations ranged from 3.29 mg/g to lower than 0.25 mg/g while rotenone concentrations ranged from 3.53 mg/g to lower than 0.58 mg/g. This screening along with principal component analysis (PCA) and discriminant analysis (DA) analyses allowed the selection of the more interesting genotypes in terms of low concentrations of these two toxic polyphenols.

Selection methodology with scoring system: application to Mexican plants producing podophyllotoxin related lignans.

As most anticancer drugs are derived from natural sources, the screening of local medicinal flora should be considered a primary step in the search for new sources for antineoplastic agents. In Mexico, more than 6000 medicinal plant species are used for the treatment of various diseases, including cancer. A multifactorial plant selection method, employing various criteria was designed and applied in order to select alternative sources of podophyllotoxin lignan analogues. For each criterion (chemotaxonomy, traditional medical uses and published scientific data), an arbitrary score system was ascribed to the species and the sum of these enabled us to compare potential candidates. The resulting selected plants were tested for cytotoxic activity and the compounds responsible for this activity were evaluated by liquid chromatography-mass spectroscopy (LC-MS). Around 50 species from the Mexican flora were initially considered. From these, six species were selected by referring to the results from the scoring system and these were then collected. Three extracts were evaluated as being highly cytotoxic against three different cancer cell lines. Finally, podophyllotoxin-like lignans could be identified by observing the fragmentation pattern on mass spectra, obtained from the LC-MS in two species: Linum scabrellum and Hyptis suaveolens.