Aromatase inhibitors isolated from a flowering tea, snow Chrysanthemum (the capitula of Coreopsis tinctoria Nutt.)

• Published in: Journal of natural medicines 2023-03, Vol.77 (2), p.387-396
• Main Authors: Luo, Fenglin, Manse, Yoshiaki, Ishikawa, Satoshi, Nishi, Sakura, Chen, Anshin, Wang, Tao, Morikawa, Toshio
• Format: Article
• Language: English
• Subjects: Aromatase; Aromatase Inhibitors; aurones; Biomedical and Life Sciences; Biomedicine; chalcones; Chrysanthemum; Chrysanthemum - chemistry; chrysin; Complementary & Alternative Medicine; Coreopsis - chemistry; Coreopsis tinctoria; Enzymatic activity; enzyme activity; flavanols; flavanones; Flavonoids; Flavonols; Flowering; Medicinal Chemistry; methanol; moieties; Naringenin; Pharmacology/Toxicology; Pharmacy; Plant Extracts - chemistry; Plant Sciences; Resorcinol; Steroid 5α-reductase; Tea; Testosterone
• ISSN: 1340-3443; 1861-0293
• DOI: 10.1007/s11418-022-01678-3

Methanol extract from the capitula of Coreopsis tinctoria Nutt. (Asteraceae), which is also known as a flowering tea or blooming tea “Snow Chrysanthemum ,” was found to inhibit the enzymatic activity of aromatase. A total of 24 known isolates ( 1 – 24 ) were identified from the extract, including three chalcones ( 1 – 3 ), an aurone ( 4 ), five flavanones ( 5 – 9 ), four flavanols ( 10 – 13 ), a flavonol ( 14 ), and two biflavanones ( 15 , 16 ). Among them, okanin ( 1 , K i = 1.6 μM), (2 S )-naringenin ( 5 , 0.90 μM), isookanin ( 6 , 0.81 μM), (2 S )-7,3',5'-trihydroxyflavaone ( 7 , 0.13 μM), and (2 S )-5,7,3',5'-tetrahydroxyflavanone ( 8 , 0.32 μM) exhibited relatively potent competitive inhibition. Specifically, the isolates 7 and 8 , having a common 3',5'-resorcinol moiety at the B ring in their flavanone skeleton, exhibited potent inhibitory activities compared to those of a clinically applied aminoglutethimide (0.84 μM) and naturally occurring flavone, chrysin (0.23 μM), which is a common non-steroidal aromatase inhibitor. Importantly, the active flavonoid constituents ( 1 and 5 – 8 ) did not inhibit the activity of 5 α -reductase enzyme, which normally reacts with the same substrate “testosterone,” thus, these compounds were suggested to be specific to aromatase.