Lignans from Piper cubeba

Melanogenesis Stimulation in Murine B16 Melanoma Cells by Piper nigrum Leaf Extract and Its Lignan Constituents

“…Thus, recent reports concerning the structural elucidation of dibenzylbutyrolactol lignans based on 1 H-and 13 C-NMR spectra taken in CDCl 3 solution described that these lignans exist as a mixture of a-isomer and b-isomer. 11,12,14,15) As shown in Table 1, the ratio of a-isomer and b-isomer of 1 in CDCl 3 solution based on the signal integral value of one (9b-H) of the methylene protons was 60 : 40, in accordance with the reported ratio (60 : 40) of 1 in CHCl 3 solution.…”

“…From analysis of the 1 H-and 13 C-NMR spectral data (Tables 1, 2) for 1 and 2, it was found that these lignans were obtained as a mixture of a-isomer and b-isomer, as previously reported for the dibenzylbutyrolactol class of lignans. 11,12,14,15) On the basis of the signal integral value of 9b-H shown in Table 1, the ratios of a-isomer and b-isomer of 1 and 2 in CDCl 3 solution were 60 : 40 and 65 : 35, respectively.…”

Testosterone 5.ALPHA.-Reductase Inhibitory Active Constituents of Piper nigrum Leaf

“…Therefore, the inhibitory activity of stem extract could be attributable to 1 and analogous lignans. Since 1 is a major lignan of the fruits of P. cubeba, 17) the inhibitory activity of P. cubeba fruit extract may be attributable to 1.…”

Melanogenesis Stimulation in Murine B16 Melanoma Cells by Kava (Piper methysticum) Rhizome Extract and Kavalactones

“…The P. cubeba fruit extract had a tendency to increase melanogenesis without any effects on cell proliferation at concentration of 10 mg/ml. The stimulatory effect on melanogenesis of the P. cubeba fruit extract may be attributable to cubebin which is a known constituent in fruits of P. cubeba 14) as in case of P. nigrum leaf extracts. As to P. methysticum, leaf extract and stem extract showed a weak decrement of melanin production and a weak stimulatory effect on intracellular melanin production, respectively.…”