Discovery of Lignans from the Herbs of Peperomia heyneana with Inhibitory Activities on BPH-1 Cells

Abstract

Chemical investigation on the whole herb of Peperomia heyneana Miq. resulted in the isolation of six lignans, including two previously undescribed compounds, named peperomianan A and B (1-2), and four known compounds, 1,2-cyclobutanedicarboxylic acid (3), (+)-medioresinol (4), (+)-pinoresinol (5), and (+)-yangambin (6). Their structures were established by extensive spectroscopic analyses. The absolute configuration of compound 1 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. Subsequently, the effects of all isolates on BPH-1 cells were evaluated in vitro by MTT assay.

Keywords: BPH; Peperomia heyneana; lignans; structure elucidation.

Figure 1

Key HMBCs for compounds 1 and 2.

Figure 2

Calculated and experimental ECD spectra of 1.

Figure 3

Key NOESY correlation (arrows, from ¹H to ¹H) of compound 2.

Figure 4

The structures of compounds 1–6.

Figure 5

Cytotoxicity assay of compounds 1–6 on BPH-1 cells. Cell viabilities were determined by MTT assay in the presence of positive control (Finasteride) and the tested compounds at different concentrations (12.5, 25, 50, 100, 200, 400 μM). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 compared with positive control.