Mediation of Endogenous β-Endorphin in the Plasma Glucose-Lowering Action of Herbal Products Observed in Type 1-Like Diabetic Rats

Table 1

Herbal products exert plasma glucose-lowering action via β-endorphin secretion or activation of peripheral MOR in type 1-like diabetic animals

Herbal products	Chemical names	Insulin-independent plasma glucose-lowering mechanisms
Caffeic acid	3,4-Dihydroxycinnamic acid [83–85]	Activation of α1-ARs on adrenal glands to increase β-endorphin secretion; the released β-endorphin then stimulates peripheral MOR leading to enhance glucose uptake and attenuate hepatic gluconeogenesis
Isoferulic acid	3-Hydroxy-4-methoxycinnamic acid [86–89]
Puerarin	4′,7-Dihydroxy-8-C-glucosylisoflavone [90–92]
Andrographolide	2.4.5.7-Trihydroxyflavone [93–95]
Myricetin	3,3′,4′,5,5′,7-Hexahydroxyflavone [96, 97]	The insulin-independent plasma glucose-lowering action of these compounds was induced by activation of peripheral MOR via released β-endorphin, while the receptor mediated on the enhancement of adrenal β-endorphin secretion is still unclear.
Ginsenoside Rh2	Proto-panaxadiol-3-o-β-D-glucopyranoside [98]
Syringin	4-(3-hydroxy-1-propenyl)-2,6-dimethoxyphenyl [99, 100]