Related Experiment Video
Updated: Feb 10, 2026

Flavonoid Content During the Growth and Floral Development of Calendula officinalis L.
Published on: June 27, 2025
[Flavonoids from root of Machilus wangchiana]
Abstract:
Twelve flavonoids were isolated from an ethanol extract of Machilus wangchiana by a combination of various chromatographic techniques including column chromatography over silica gel and Sephadex LH-20 and reversed-phase flash chromatography and HPLC. Their structures were identified by spectroscopic data analysis (IR, MS, and NMR) as (+)-catechin (1), (-)-epicatechin (2), 3'-O-methyl-(+)-catechin (3), 3'-O-methyl-(-)-epicatechin (4), 3, 5, 7, 2', 5'-pentahydroxy flavan (5), (-)-naringenin (6), (-)-eriodictyol (7), (-)-liquiritigenin (8), (2R,3R)-(+)-dihydrokaempferol (9), (2R,3S)-(-)-dihydro- kaempferol (10), (2R, 3R)-(+)-taxifolin (11), and quercetin (12). Compounds 1-10 are isolated from the genus Machilus for the first time.
Related Concept Videos
Primary and Secondary Growth in Roots and Shoots
Root Mean Square
For example, consider the velocity of gas molecules in a container. The gas molecules are moving in different directions, which might impart positive and negative...
Properties of the Root Locus
To determine if a point lies on the root locus, the criterion involves the sum of angles contributed by all poles and zeros to that point. Specifically, this sum must be an odd multiple of 180 degrees. The gain at any point on...
Root-Locus Method
This system can be represented by a block...
Construction of Root Locus
For positive gain values, the root locus exists on the real axis to the left of an odd number of finite open-loop poles or zeros. The root locus starts at the open-loop poles and traces the paths of the closed-loop poles as the gain...
Plotting and Calibrating the Root Locus
The maximum gain occurs at the breakaway points between open-loop poles on the real axis, while the minimum gain is...

