Mastering nature: targeted metabolomic approach for the phytochemical authentication of Ophiopogon japonicus
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Presented by: Laurie Verzeaux
Introduction
Ophiopogon japonicus tubers are used in Traditional Chinese Medicine and are currently traded for the treatment of pathological skin conditions. Consumers are demanding natural based solutions and the dermo-cosmetic industry has high expectations of the mastery of nature. However, it is important that natural raw materials are sustainably sourced, their identity checked and they contain the active ingredient. The plant of interest is Ophiopogon japonicus and the tubers of this species are morphologically similar to other species including Liriope spicata, making them very difficult to discriminate by botanic and organoleptic analyses. Many advanced technologies are now available to enable us to differentiate between the species. These technologies can be used to spot adulterations thus ensuring good quality materials are used. To avoid falsifications, rigorous analytical authentication of these plants tubers is an essential step.
Aim of the study
The objective of this work was to develop an analytical approach to identify specific markers of Ophiopogon japonicus and Liriope spicata to avoid falsification and secure a supply of good quality tubers.
Methods
Phytochemical profiles of certified Ophiopogon japonicus and Liriope spicata specimens from referent collections was investigated by ultra-performance liquid chromatography coupled with tandem high resolution mass spectrometry (UPLC-MS/MS). A targeted metabolomic analysis based on literature was then performed on these referent specimens to determine their specific molecular signature. Finally, a comparative analytical study of various samples of Ophiopogon japonicus tubers in powder form, supplied from different regions and suppliers, was assessed to authenticate the natural raw materials.
Results
Chromatograms obtained from targeted metabolomic analysis of certified referent samples revealed 10 specific markers for Ophiopogon japonicus and 2 for Liriope spicata, A comparison of parent and fragment ions were used to identify a a range of homoisoflavonoids and alkaloids.
The data from the taxonomically certified samples of each species could then be compared from samples labelled as O. japonicus from the trade. The analysis of 4 different samples of natural powdered raw material demonstrated that one sample contained the markers present in Liriope spicata markers but none of the markers of Ophiopogon japonicus , revealing that this sample was falsified. The second sample contains alkaloids not present in the Asparagaceae family (i.e. the family that both Ophiopogon japonicus and Liriope spicata belong to), thus also suggesting falsification of this sample. The chromatograms obtained for the two othersamples, from different regions and suppliers, displayed the specific markers of authentic Ophiopogon japonicus.
Discussion
The analytical characterization of certified samples of Ophiopogon japonicus and Liriope spicata identified a specific molecular signature for these two similar species. The comparative and targeted metabolomic analysis of 4 natural powdered raw materials from different regions and suppliers allowed us to rigorously identify those from Ophiopogon japonicus and to discard non-conforming samples. This approach makes it possible to go beyond the organoleptic, microscopic and macroscopic analyses to discriminate non-differentiable powders. It allows the authentication of raw materials that cannot be discriminated using classical botanically and organoleptically techniques. This reliable methodology will permit a strict quality control of our future supplies of this starting raw material.
Conclusion
This study demonstrated the use of metabolomics to establish the molecular signature of raw materials that are difficult to discriminate botanically and organoleptically and thus to authenticate them rigorously. This is a prerequisite for the development of cosmetic and dermo-cosmetic products.
Ophiopogon japonicus tubers are used in Traditional Chinese Medicine and are currently traded for the treatment of pathological skin conditions. Consumers are demanding natural based solutions and the dermo-cosmetic industry has high expectations of the mastery of nature. However, it is important that natural raw materials are sustainably sourced, their identity checked and they contain the active ingredient. The plant of interest is Ophiopogon japonicus and the tubers of this species are morphologically similar to other species including Liriope spicata, making them very difficult to discriminate by botanic and organoleptic analyses. Many advanced technologies are now available to enable us to differentiate between the species. These technologies can be used to spot adulterations thus ensuring good quality materials are used. To avoid falsifications, rigorous analytical authentication of these plants tubers is an essential step.
Aim of the study
The objective of this work was to develop an analytical approach to identify specific markers of Ophiopogon japonicus and Liriope spicata to avoid falsification and secure a supply of good quality tubers.
Methods
Phytochemical profiles of certified Ophiopogon japonicus and Liriope spicata specimens from referent collections was investigated by ultra-performance liquid chromatography coupled with tandem high resolution mass spectrometry (UPLC-MS/MS). A targeted metabolomic analysis based on literature was then performed on these referent specimens to determine their specific molecular signature. Finally, a comparative analytical study of various samples of Ophiopogon japonicus tubers in powder form, supplied from different regions and suppliers, was assessed to authenticate the natural raw materials.
Results
Chromatograms obtained from targeted metabolomic analysis of certified referent samples revealed 10 specific markers for Ophiopogon japonicus and 2 for Liriope spicata, A comparison of parent and fragment ions were used to identify a a range of homoisoflavonoids and alkaloids.
The data from the taxonomically certified samples of each species could then be compared from samples labelled as O. japonicus from the trade. The analysis of 4 different samples of natural powdered raw material demonstrated that one sample contained the markers present in Liriope spicata markers but none of the markers of Ophiopogon japonicus , revealing that this sample was falsified. The second sample contains alkaloids not present in the Asparagaceae family (i.e. the family that both Ophiopogon japonicus and Liriope spicata belong to), thus also suggesting falsification of this sample. The chromatograms obtained for the two othersamples, from different regions and suppliers, displayed the specific markers of authentic Ophiopogon japonicus.
Discussion
The analytical characterization of certified samples of Ophiopogon japonicus and Liriope spicata identified a specific molecular signature for these two similar species. The comparative and targeted metabolomic analysis of 4 natural powdered raw materials from different regions and suppliers allowed us to rigorously identify those from Ophiopogon japonicus and to discard non-conforming samples. This approach makes it possible to go beyond the organoleptic, microscopic and macroscopic analyses to discriminate non-differentiable powders. It allows the authentication of raw materials that cannot be discriminated using classical botanically and organoleptically techniques. This reliable methodology will permit a strict quality control of our future supplies of this starting raw material.
Conclusion
This study demonstrated the use of metabolomics to establish the molecular signature of raw materials that are difficult to discriminate botanically and organoleptically and thus to authenticate them rigorously. This is a prerequisite for the development of cosmetic and dermo-cosmetic products.