Chiy-Rong Chen

Screening and profiling stilbene-type natural products with angiotensin-converting enzyme inhibitory activity from Ampelopsis brevipedunculata var. hancei (Planch.) Rehder

In this study, we screened 10 resveratrol derivatives isolated from Ampelopsis brevipedunculata var. hancei (Planch.) Rehder (ABH) for angiotensin I converting enzyme (ACE) inhibitory (ACEI) activity. Among these compounds, (+)-hopeaphenol and (+)-vitisin A showed the lowest IC50 values (∼ 1.5 μM) toward ACE. In addition, the compounds abundances and distributions in ABH were profiled using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Interestingly, trimers and tetramers of resveratrol were mainly obtained from the bark of ABH when 90% ethanol was used for extraction. This result implies that the antihypertension effect of ABH extract may be mainly contributed by (+)-hopeaphenol (F1) and (+)-vitisin A (F2) in the ABH bark due to their remarkable ACE inhibitions. Moreover, the sizes and structures of these compounds were further correlated to their affinities toward ACE using molecular docking calculations. The results showed that resveratrol tetramers interact with ACE more favorably than other smaller oligomers.

Chemical Constituents from the Stems of Diospyros maritima

A new phenolic, bis(6-hydroxy-2,3,4-trimethoxylphen-1-yl)methane (1) and a new butanedioate, butylmethyl succinate (2), along with twenty-nine known compounds including one naphthoquinone derivative, two chromanones, eight benzenoids, one lignan, one tocopherol, and sixteen triterpenoids were isolated from the stems of Diospyros maritima. epi-Isoshinanolone (3) was isolated in pure form for the first time. In addition, 5,7-dihydroxy-2-methylchomanone (4) was isolated from a natural source for the first time. Their structures were established on the basis of spectroscopic data as well as direct comparison with authentic samples.

Ficuschlorins A – D, Lactone Chlorins from the Leaves of Ficus microcarpa

Four new lactone chlorins, ficuschlorins Au2009–u2009D (1–4, resp.), and six known pheophytins were isolated from the leaves of Ficus microcarpa. The structures of these compounds were determined by 1D‐ and 2D‐NMR spectroscopy, and other techniques. New natural pheophytins were rarely obtained. In the past ten years, only three new pheophytins were isolated from natural sources.

Qualitative and quantitative analysis of seven signature components in the fruiting body of Antrodia cinnamomea by HPLC—ESI—MS/MS

An accurate and rapid liquid chromatography–electrospray ionizaion– tandem mass spectrometry (LC—ESI—MS/MS) analytical method was developed and validated for the simultaneous determination of antcins A, B, C, H, and K, dehydroeburicoic acid, and 4,7-dimethoxy-5-methyl-1,3-benzodioxole in the extract and capsule of Antrodia cinnamomea (AC) fruiting body. These seven signature compounds were ionized using an electrospray ion source and analyzed by a triple-quadrupole mass analyzer under a multiple reaction monitoring (MRM) mode. The MRM transitions of m/z 453/409 (antcin A), m/z 467/408 (antcin B), m/z 469/425 (antcin C), m/z 485/413 (antcin H), m/z 487/407 (antcin K), m/z 467/337 (dehydroeburicoic acid), and m/z 197/139 (4,7-dimethoxy-5-methyl-1,3-benzodioxole) were used to quantify these seven components, respectively. Their calibration curves presented good linear regressions (R2 > 0.997) within the tested concentration range. The intra- and inter-day precisions were less than 1.97% and 2.53%, respective...