Nanqun Zhu

Identification of reaction products of (−)-epigallocatechin, (−)-epigallocatechin gallate and pyrogallol with 2,2-diphenyl-1-picrylhydrazyl radical

Abstract Catechins, the major constituents of tea, have been shown to have powerful antioxidant and antitumor activity. In this study, the radical scavenging behavior of catechins on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) was studied. Three reaction products of (−)-epigallocatechin, (−)-epigallocatechin gallate and pyrogallol with DPPH radical were purified and identified. This study provides some insight into the specific mechanism of the antioxidant reaction of catechins. A possible mechanism for the formation of reaction products is suggested.

Bioactive constituents from gum guggul (Commiphora wightii)

Bioactivity-directed fractionation and purification afforded cytotoxic components of Commiphora wightii. The exudates of C. wightii were extracted with EtOAc and the extract was subjected to repeated column chromatography. A fraction showing cytotoxic activity was characterized as a mixture of two ferulates with an unusual skeleton by spectral and chemical methods, including by NMR, GC-MS and chemical derivatization. This fraction also showed moderate scavenging effect against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals.

New unusual iridoids from the leaves of noni (Morinda citrifolia L.) show inhibitory effect on ultraviolet B-induced transcriptional activator protein-1 (AP-1) activity.

A novel iridoid dimer in whose structure the two iridoid units are connected by a rare ether group, together with two new unusual iridoids showing significant inhibition of UVB-induced Activator Protein-1 (AP-1) activity in cell cultures, have been isolated from the leaves of noni (Morinda citrifolia L.). Their structures were determined on the basis of detailed high-field 1D and 2D spectral analysis. Their inhibitory effect on UVB-induced transcriptional Activator Protein-1 (AP-1) activity are also discussed.

Citrifolinin A, a new unusual iridoid with inhibition of Activator Protein-1 (AP-1) from the leaves of noni (Morinda citrifolia L.)

Abstract A new unusual iridoid, named citrifolinin A , showing significant inhibition of UVB-induced Activator Protein-1 (AP-1) activity in cell cultures, has been isolated from the leaves of Morinda citrifolia. Its structure was elucidated based on a detailed high-field 1D and 2D spectral analysis.

Two C21-steroidal glycosides isolated from Cynanchum stauntoi.

Studies on the roots of Cynanchum stauntoi led to the isolation of two C21-steroidal glycosides, formally named stauntosides A and B. Their structures were elucidated on the basis of spectroscopic evidence, especially that from analysis of 2D-NMR spectra. They were found to possess an unusual skeleton and were identified as stauntogenin 3-O-alpha-L-diginopyranosyl-(1-4)-beta-L-cymaropyranosyl-(1- 4)-beta-D- digitoxopyranosyl-(1-4)-beta-D-thevetopyranoside and stauntogenin 3-O-alpha-L-cymaropyranosyl-(1-4)-beta-D-digitoxopyranosyl-( 1-4)-beta-D-3- demethyl-2-deoxy-thevetopyranoside.

Process‐induced health‐promoting substances in foods

Abstract Food processing not only provides an organoleptic quality to food, but also generates health‐promoting substances. Some of these substances, derived from popular food items like garlic, soybean, tea, and dairy products have been found to be beneficial in prevention and treatment of various ailments and diseases ranging from bites, headache and wounds, to heart problems, cancer, and oxidative stress. This review article summarizes the chemistry and health benefits of some processing derived food components.