Currently, medicinal plants have had a great relevance due to their beneficial healthy properties [1]. Many studies reflect that these biological properties, such as antioxidant, anti-proliferative, and antimicrobial activities are related to different bioactive molecules, including phenolic compounds. Although some of their mechanisms of action are unknown, in many cases it has been shown that various natural phenolic compounds are related to numerous bioactive properties, which have aroused the interest of the scientific community [2]. On this basis, the study focused on the analysis of five medicinal plants, such as Achillea millefolium L., Arnica montana L., Calendula officinalis L., Chamaemelum nobile (L.) All., and Taraxacum officinale Wiggers, all belonging to the Asteraceae family. After an initial review, a heat-assisted extraction with ethanol/water (80:20, v/v) was carried out to obtain extracts rich in phenolic compounds. Afterword’s, these extracts were evaluated regarding there antioxidant, antimicrobial, anti-inflammatory, cytotoxic, and enzymatic properties, together with the identification of the phenolic composition. The antioxidant activity measured through the TBARS assay, indicated that A. millefolium extracts presented an outstanding activity (0.013 mg/mL), while C. officinalis extract presented the best antimicrobial and antifungal activities with MIC values ranging from 0.25 to 0.5 mg/mL of extract. Regarding, the anti-inflammatory and cytotoxic activities, C. nobile extracts showed the greatest effect compared to the other species, with a IC₅₀ values of 15.2 µg/mL for the anti-inflammatory activity, and GI₅₀ values between 54 and 10.3 µg/mL, in the case of cytotoxic activity. On the other hand, A. montana extracts showed the highest content of phenolic compounds (119 mg total phenolic compounds/g of extract), being 3-O-caffeolyquinic acid, 5-O-caffeolyquinic acid and caffeic acid the most representative compounds. Concerning the enzymatic assays, both C. nobile and C. officinalis extracts showed the greatest inhibitory effects on two enzymes related to Alzheimer's disease, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Overall, this study provides scientific evidence to the assessment of the potential of medicinal plant extracts for the development of new products.

References

[1] Garcia-Oliveira, P., Fraga-Corral, M., Pereira, A. G., Lourenço-Lopes, C., Jimenez-Lopez, C., Prieto, M. A., & Simal-Gandara, J. (2020). Scientific basis for the industrialization of traditionally used plants of the Rosaceae family. Food Chemistry, 330, 127197.

[2] Garcia-Oliveira, P., Barral, M., Carpena, M., Gullón, P., Fraga-Corral, M., Otero, P., Prieto, M. A. & Simal-Gandara, J. (2021). Traditional plants from Asteraceae family as potential candidates for functional food industry. Food & Function.

Acknowledgments

The research leading to these results was supported by MICINN supporting the Ramón y Cajal grant for M.A. Prieto (RYC-2017-22891); by Xunta de Galicia for supporting the program EXCELENCIA-ED431F 2020/12, the pre-doctoral grant of P. García-Oliveira (ED481A-2019/295) and the program Grupos de Referencia Competitiva that supports the work of M. Barral-Martínez (GRUPO AA1-GRC 2018); by EcoChestnut Project (Erasmus+ KA202) that supports the work of B. Nuñez-Estevez. The authors are grateful to Ibero-American Program on Science and Technology (CYTED—AQUA-CIBUS, P317RT0003) and to the Bio Based Industries Joint Undertaking (JU) under grant agreement No 888003 UP4HEALTH Project (H2020-BBI-JTI-2019). The JU receives support from the European Union’s Horizon 2020 research and innovation program and the Bio Based Industries Consortium. The project SYSTEMIC Knowledge hub on Nutrition and Food Security, has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI launched in 2019 under the ERA-NET ERA-HDHL (n° 696295). The authors would like to thank the EU and FCT for funding through the project PTDC/OCE-ETA/30240/2017- SilverBrain - From sea to brain: Green neuroprotective extracts for nanoencapsulation and functional food production (POCI-01-0145-FEDER-030240). The authors are also gratefull to FCT, Portugal for financial support through national funds FCT/MCTES to the CIMO (UIDB/00690/2020); and L. Barros and R. Calhelha thank the national funding by FCT, P.I., through the institutional and individual scientific employment program-contract for their contracts.