Mass spectrometry as a tool for the dereplication of saponins from Ampelozizyphus amazonicus Ducke bark and wood

Abstract

Introduction Mass spectrometry in natural products research has been used as a first step to identify possible chemical structures and to guide subsequent efforts to isolate novel compounds. Preparations of Ampelozizyphus amazonicus Ducke (AA) are known for their high content of saponins, especially dammarane‐type triterpenoid aglycones. In the Amazon, where it is known as “saracura‐mirá”, roots and bark are widely used for the treatment and prevention of malaria, while the wood is discarded. The extract prepared from the wood is also saponin‐rich, but its exact chemical composition has not been described. Objective This study provides information on the chemical profiling and tentative structural identification of the major compounds (saponins) present in aqueous and ethanol extracts of bark and wood of AA by mass spectrometry. Methods The strategy used to identify compounds present in all samples was ultra‐high‐performance liquid chromatography with an ultraviolet detector coupled to tandem mass spectrometry (UHPLC‐UV‐MS/MS) for the analysis of fragmentation patterns through product ion scan using MZmine 2 software. Also, direct sample injection and electrospray ionisation combined with high‐resolution mass spectrometry (DI‐ESI‐HRMS) measurements were performed. Results The extracts showed chemical similarity, and 95 saponins were tentatively identified in AA wood and bark, including 73 which are described for the first time as tentative structures for this plant species. Conclusion This research describes a useful method for the fast and simultaneous tentative identification of major saponins in AA, contributing to the study of the chemical properties of this genus and family. Furthermore, it demonstrates the importance of the qualitative dereplication process, allowing a straightforward way to propose the tentative identification of compounds.

Dereplication of phenolic derivatives of three Erythroxylum species using liquid chromatography coupled with ESI‐MSn and HRESIMS

“…Posteriorly, these samples were again injected into a high-performance liquid chromatograph using the same method as previously reported, but this time, the high-performance liquid chromatograph was coupled to a micrOTOF II mass spectrometer (Bruker Daltonics, Billerica, MA, USA) for HRESIMS analyses. The compounds were tentatively identified by the interpretation of the molecular formula (HRESIMS), their fragmentation patterns (MS 2 and MS 3 ) and correlations of their corresponding data with scientific literature, which could be confirmed by analyses of the isolated compounds.…”

“…Currently, the dereplication of natural products is generally obtained using high-performance liquid chromatography coupled to UV-Vis spectrophotometry and mass spectrometry. 2,3 Erythroxylum is represented by nearly 250 species and is considered the largest genus among the four genera of the Erythroxylaceae family. Erythroxylum species are widely distributed in the tropical regions of South America and Africa, where countries such as Brazil, Venezuela and Madagascar stand out for being endemic areas.…”

“…In both cases, the fragment m/z 301 was produced, which is equivalent to the quercetin aglycone 31,32. The fragments of quercetin aglycone (m/z 301) were also analyzed with an MS3 spectrum to confirm the quercetin aglycone skeleton. The main fragments generated by quercetin were m/z 271 ([M-30-H] − ), corresponding to CH 2 O loss, m/z 255 ([M-46-H] − ), produced from the loss of a CH 2 O 2 moiety, and m/z 179 ([M-122-H] − ), generated by RDA cleavage between O-C2 and C2-C3, promoting the loss of a C 7 H 6 O 2 molecule, and the last important fragment in this analysis was m/z 151 ([M-150-H] − ), which was also a result of RDA cleavage, but only this time, between O-C2 and C3-C4 followed by the loss of C 8 H 6 O 3 (Figure S14).…”

Saracura-Mirá, a Proposed Brazilian Amazonian Adaptogen from Ampelozizyphus amazonicus

“…The chemistry of A. amazonicus follows the trend of other Rhamnaceae representatives, such as the Ziziphus genus (Z. joazeiro, Z. jujuba, Z. spina-christi, etc. ), which is the production triterpenes and saponins, especially those of the dammarane skeleton [66][67][68]. The first works on the chemistry of this plant are from Brandão [55,69] who described in the 1990s the isolation and identification of three saponins with a dammarane-type aglycone from the roots of the plant.…”

“…More recently, the chemical profiling and tentative structural identification of the major saponins present in aqueous and ethanol extracts of bark and wood of the plant were accomplished by mass spectrometry [66]. In the traditional process of beverage preparation, the bark is removed, and the wood discarded.…”