Proper chromatographic methods may reduce the challenges inherent in analyzing natural product extracts, especially when utilizing hyphenated detection techniques involving mass spectrometry. As there are many variations one can introduce during chromatographic method development, this can become a daunting and time-consuming task. To reduce the number of runs and time needed, the use of instrumental automatization and commercial software to apply Quality by Design and statistical analysis automatically can be a valuable approach to investigate complex matrices. To evaluate this strategy in the natural products workflow, a mixture of nine species from the family Malpighiaceae was investigated. By this approach, the entire data collection and method development procedure (comprising screening, optimization, and robustness simulation) was accomplished in only 4 days, resulting in very low limits of detection and quantification. The analysis of the individual extracts also proved the efficiency of the use of a mixture of extracts for this workflow. Molecular networking and library searches were used to annotate a total of 61 compounds, including O-glycosylated flavonoids, C-glycosylated flavonoids, quinic/shikimic acid derivatives, sterols, and other phenols, which were efficiently separated by the method developed. These results support the potential of statistical tools for chromatographic method optimization as an efficient approach to reduce time and maximize resources, such as solvents, to get proper chromatographic conditions.

OBJECTIVE: Most Neotropical species of Malpighiaceae produce floral fatty oils in calyx glands to attract pollinating oil-collecting bees, which depend on this resource for reproduction. This specialized type of pollination system tends to be lost in members of the family that occur outside the geographic distribution (e.g. Africa) of Neotropical oil-collecting bees. This study focused on the pollination ecology, chemical ecology and reproductive biology of an oil flower species, Pterandra pyroidea (Malpighiaceae) from the Brazilian Cerrado. Populations of this species consist of plants with oil-secreting (glandular) flowers, plants with non-oil-secreting flowers (eglandular) or a mix of both plant types. This study specifically aims to clarify the role of eglandular morphs in this species.
METHODS: Data on pollinators were recorded by in situ observations. Breeding system experiments were conducted by isolating inflorescences and by enzymatic reactions. Floral resources, pollen and floral oils offered by this species were analysed by staining and a combination of various spectroscopic methods.
RESULTS: Eglandular flowers of P. pyroidea do not act as mimics of their oil-producing conspecifics to attract pollinators. Instead, both oil-producing and oil-free flowers depend on pollen-collecting bees for reproduction, and their main pollinators are bumble-bees. Floral oils produced by glandular flowers are less complex than those described in closely related genera.
CONCLUSIONS: Eglandular flowers represent a shift in the pollination system in which oil is being lost and pollen is becoming the main reward of P. pyroidea flowers. Pollination shifts of this kind have hitherto not been demonstrated empirically within Neotropical Malpighiaceae and this species exhibits an unusual transition from a specialized towards a generalized pollination system in an area considered the hotspot of oil-collecting bee diversity in the Neotropics. Transitions of this type provide an opportunity to study ongoing evolutionary mechanisms that promote the persistence of species previously involved in specialized mutualistic relationships.