Elvira de Mejia, a professor in the Department of Food Science and Human Nutrition at the University of Illinois at Urbana-Champaign, and colleagues report their findings in the Journal of Agricultural and Food Chemistry.
The authors point out, in view of the fact type 2 diabetes affects over 8% of Americans and costs the nation around $175 billion a year, there is a need for as many ways to tackle the disease as possible.
While some people can manage the disease with changes to diet and increasing physical activity, and others do so with medication to keep blood glucose in check, not everyone can stick to changes in lifestyle or afford the prescription drugs, they add.
Herbs may offer an alternative way to keep glucose in check
The researchers note that recent studies have shown herbs may provide an alternative, natural way to keep glucose in check, so they decided to take a closer look.
In their paper, they describe how they investigated the properties of Greek oregano (Origanum vulgare), marjoram (Origanum majorana), rosemary (Rosmarinus officinalis), and Mexican oregano (Lippia graveolens).
They prepared extracts of these plants obtained from greenhouse-grown and commercially purchased dried forms and examined their ability to inhibit two enzymes – one called DPP-IV (also calld DPP-4) that plays a role in insulin secretion, and another called PTP1B that is involved in insulin signaling.
These enzymes have been identified as targets of drugs for managing diabetes. For example, the drugs sitagliptin and metformin are medications in the DPP-4 inhibitor family. However, searching for inhibitors of PTP1B is proving more challenging.
Prof. de Mejia and colleagues found that the greenhouse-grown herbs contained more polyphenols and flavonoids than the commercial, dried versions.
Compounds in rosemary, oregano, and marjoram showed ability to inhibit enzymes
They also found that extracts of greenhouse-grown rosemary, Mexican oregano, and marjoram were the best inhibitors of DPP-IV, while extracts from the commercial, dried versions were the best inhibitors of PTP1B.
Further analysis revealed a number of individual compounds contributed to these inhibitory effects.
The team calls for more studies to understand the role of these compounds in reducing the risk of type 2 diabetes in humans.
In January 2014, Medical News Today reported a clinical trial that found traditional Chinese herbal medicines may halt progress of type 2 diabetes. The researchers said the results show Chinese herbal medicines hold promise for slowing the progression from prediabetes to an official diabetes diagnosis.