In the 1970s, Eucommia leaf
tea, known as Tochu-cha in Japanese, was developed from roasted Eucommia leaves in Japan and is considered as a healthy
tea. The
antihypertensive,
diuretic, anti-stress,
insulin resistance improving, and anti-
obesity effects of Eucommia leaf extract have been reported. However, the identification and properties of the active components as well as the underlying mechanism of action are largely unknown. In this review, we summarize studies involving the
oral administration of
geniposidic acid, a major
iridoid component of Eucommia leaf extract which increases plasma
atrial natriuretic peptide (
ANP) on the atria of spontaneously hypertensive rats (SHR) by activating the
glucagon-like peptide-1 receptor (GLP-1R). To achieve the
antihypertensive effects of the Eucommia leaf extract through
ANP secretion in humans, combining a potent cyclic
adenosine monophosphate phosphodiesterase (cAMP-PDE) inhibitor, such as
pinoresinol di-β-d-
glucoside, with
geniposidic acid may be necessary. Changes in the gut microbiota are an important aspect involved in the efficacy of
asperuloside, another component of the Eucommia leaf extract, which improves
obesity and related sequelae, such as
insulin resistance and
glucose intolerance. There are species differences of mechanisms associated with the
antihypertensive and anti-
obesity effects between rodents and humans, and not all animal test results are consistent with that of human studies. This review is focused on the mechanisms in
antihypertensive and anti-
obesity effects of the Eucommia leaf extract and summarizes the differences of mechanisms in their effects on rodents and humans based on our studies and those of others.