ABSTRACT
The genus Itea (Iteaceae) is recognised as a genus with about 21 extant species of shrubs and trees. Within the genus, most species have oblong to elliptical leaves. The lanceolate and obolanceolate leaves are only found in three species, vix Iteaamoena Chun, Iteariparia Collett & Hemsl. and Iteatenuinervia S. Y. Liu. The results of our examination of literature, specimens and living plants in the wild have shown that Iteatenuinervia is conspecific with Iteariparia and is here reduced to a synonym of the latter species. The morphological description, colour pictures, voucher specimens, distribution map of Iteariparia and its related Iteaamoena, together with the morphological comparisons between the two species, are provided in this study.
ABSTRACT
Rhynchanthus beesianus (Zingiberaceae) has been an important food spice and vegetable in southern China. Fifteen phenolic compounds (1-15) including three new diarylheptanoids, rhynchanines A-C (1-3) and one new phenylpropanoid, 4-O-methylstroside B (9), were isolated from R. beesianus rhizomes. The structures of new compounds were elucidated by comprehensive analyses through NMR, HRMS technique, acid hydrolysis, and Mosher's reaction. Among them, compound 5 is the first isolated natural product and its NMR data are reported. Most of the isolated compounds, especially 3-6 and 8, showed significant antioxidant activities on DPPH, ABTS+ radical scavenging, and FRAP assays. Furthermore, the antioxidant phenolic compounds were evaluated for their cytoprotective capacity against H2O2-induced oxidative stress in HepG-2 cells. Compounds 3 and 5 could significantly inhibit reactive oxygen species production, and compounds 3, 5, and 6 could remarkably prevent the cell apoptosis. Then, the R. beesianus rhizome, which contained phenolic compounds, might serve as a functional food for potential application on preventing oxidative stress-connected diseases.
