Antioxidant and Cytoprotective Effects of New Diarylheptanoids from Rhynchanthus beesianus

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.

New and Antifungal Diterpenoids of Sunflower against Gray Mold

“…The time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations of compounds 1–4 were performed as described previously . First of all, the relative configurations of compounds were defined according to their ROESY experiments and optimized by TDDFT calculation at the B3LYP/6-31G­(d,p) level in the gas phase.…”

“…The time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations of compounds 1−4 were performed as described previously. 15 First of all, the relative configurations of compounds were defined according to their ROESY experiments and optimized by TDDFT calculation at the B3LYP/6-31G(d,p) level in the gas phase. The ECD calculations of compounds 1−4 were performed with a conductor-like polarizable continuum model solvent model in MeOH using the Gaussian 09 program package, and finally, the calculated ECD curves were drawn using Origin 2023 software (OriginLab Corporation, Northampton, MA, USA).…”

Furostanol Saponins from Asparagus cochinchinensis and Their Cytotoxicity

“…The acid hydrolysis of compound 1 was carried out by a previously reported procedure [ 19 ]. Compound 1 (2.0 mg) was refluxed at 120 °C for 2 h with 2 M TFA on an oil bath.…”

“…However, steroidal saponins obtained from title species were proved to be its major and bioactive components responsible for its cytotoxic [ 16 ], anti-inflammatory [ 17 ], hepatotoxic and nephrotoxic [ 18 ], and anti-neuroinflammatory [ 11 ] properties. In continuation of a search for bioactive constituents from plants of the Yunnan province [ 19 ], a chemical investigation was performed on the roots of A. cochinchinens . As a result, a total of steroidal saponins ( 1 ‒ 4 ) were isolated and identified including one new and three previously described furostan-type steroidal saponins.…”