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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Functional Foods Research » Research » Publications at this Location » Publication #302656
Title: Bioactive compounds from culinary herbs inhibit a molecular target for type 2 diabetes management, dipeptidyl peptidase IV

Author
item BOWER, ALLYSON - University Of Illinois
item HERNANDEZ, LUIS M - University Of Illinois
item Berhow, Mark
item DE MEJIA, ELVIRA GONZALEZ - University Of Illinois

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2014
Publication Date: 6/1/2014
Citation: Bower, A.M., Real Hernandez, L.M., Berhow, M.A., Gonzalez de Mejia, E. 2014. Bioactive compounds from culinary herbs inhibit a molecular target for type 2 diabetes management, dipeptidyl peptidase IV. Journal of Agricultural and Food Chemistry. 62(26):6147-6158.

Interpretive Summary: Greek oregano, marjoram, rosemary, and Mexican oregano are concentrated sources of bioactive compounds. The aims of this study were to characterize extracts from greenhouse grown or commercially purchased herbs for their ability to inhibit enzymes related to type 2 diabetes progression. Greenhouse herbs contained more polyphenols and flavonoids compared to the equivalent commercial herbs. Greenhouse rosemary and Mexican oregano were the best inhibitors of one key phase 2 diabetes enzyme, while commercial rosemary, Mexican oregano, and marjoram were the best inhibitors of the second marker enzyme. The phytochemicals hispidulin, cirsimaritin and carnosol were identified by mass spectrometric analysis as being present in greenhouse-grown Mexican oregano and rosemary. Naringenin and eriodictyol were only identified in Mexican oregano. Computational modeling indicated that hispidulin, carnosol and eriodictyol would have the best binding affinities to phase 2 diabetes marker enzyme 1. Biochemically, the best inhibitors were cirsimaritin, hispidulin, and naringenin. This study shows that these herbs contain a number of key chemical compounds that significantly inhibit the activities of two key enzymes involved in the profession of events that lead to phase 2 diabetes. These herbs are being further investigated regarding their potential in diabetes management.

Technical Abstract: Greek oregano (Origanum vulgare), marjoram (Origanum majorana), rosemary (Rosmarinus officinalis) and Mexican oregano (Lippia graveolens) are concentrated sources of bioactive compounds. The aims of this study were to characterize extracts from greenhouse grown or commercially purchased herbs for their ability to inhibit dipeptidyl peptidase-IV (DPP-IV) and protein tyrosine phosphatase 1B (PTP1B), enzymes related to type 2 diabetes progression. Greenhouse herbs contained more polyphenols (302.7 - 430.1 µg GAE/mg dry weight of extract, DWE) and flavonoids (370.1 - 661.4 µg RE/mg DWE) compared to the equivalent commercial herbs. Greenhouse rosemary and Mexican oregano were the best inhibitors of DPP-IV (IC50 : 16 µM and 31 µM, respectively). Commercial rosemary, Mexican oregano, and marjoram were the best inhibitors of PTP1B (32.4 – 40.9% at 500 µM). The phytochemicals hispidulin, cirsimaritin and carnosol were identified by LC-ESI-MS as being present in greenhouse-grown Mexican oregano and rosemary. Naringenin and eriodictyol were only identified in Mexican oregano. Computational modeling indicated that hispidulin, carnosol and eriodictyol would have the best binding affinities to DPP-IV. Biochemically, the best inhibitors were cirsimaritin (IC50 : 0.43 ± 0.08 µM), hispidulin (IC50: 0.51 ± 0.08 µM) and naringenin (IC50 = 2.84 ± 0.62 µM). Overall, herbs contain several flavonoids that inhibit DPP-IV and should be investigated further regarding their potential in diabetes management.