Plathymenin

Phytochemistry. 2006 Jun;67(12):1262-70.

Bioactive constituents of Spatholobus suberectus in regulating tyrosinase-related proteins and mRNA in HEMn cells.[Pubmed: 16782143 ]

Of these constituents 3',4',7-trihydroxyflavone (1), eriodictyol (3), Plathymenin (5), dihydroquercetin (6), butin (7), neoisoliquiritigenin (8), dihydrokaempferol (9), liquiritigenin (10), and 6-methoxyeriodictyol (12) represented compounds isolated for the first time from S. suberectus.
METHODS AND RESULTS:
These constituents were evaluated their ability to inhibit cellular tyrosinase activity and for their melanin inhibitory activity in human epidermal melanocytes (HEMn). Butin (7) was the most efficacious of these constituents and exhibited concentration-dependent effects. Western blot analysis revealed that expression of tyrosinase and tyrosinase-related proteins 1 and 2 (TRP1 and TRP2) was decreased in butin (7)-treated HEMn cells. Additionally, quantitative real-time PCR (qRT-PCR) analysis disclosed that expression of mRNAs for tyrosinase, TRP1 and TRP2 was suppressed by butin (7).
CONCLUSIONS:
It is concluded that butin (7) is the most active of the components of S. suberectus in inhibiting pigmentation and that this inhibition is exerted through inhibition of transcription of the genes encoding tyrosinase, TRP1 and TRP2.

Int Immunopharmacol. 2015 Mar;25(1):189-98.

Anti-inflammatory activity of flavonoids in Nepalese propolis is attributed to inhibition of the IL-33 signaling pathway.[Pubmed: 25614224 ]

Propolis has been used in folk medicine to improve health and prevent inflammatory diseases; however, the components that exhibit its anti-inflammatory activity remain unknown. We herein investigated the effects of flavonoids isolated from Nepalese propolis on the IL-33 signaling pathway to clarify the anti-inflammatory mechanism involved.
METHODS AND RESULTS:
Of the 8 types of flavonoids isolated from Nepalese propolis, 4 types of compounds, such as 3',4'-dihydroxy-4-methoxydalbergione, 4-methoxydalbergion, cearoin, and chrysin, markedly inhibited the IL-33-induced mRNA expression of inflammatory genes including IL-6, TNFα and IL-13 in bone marrow-derived mast cells (BMMC). These four flavonoids also inhibited the IL-33-induced activation of nuclear factor κB (NF-κB), which was consistent with their inhibitory effects on cytokine expression. The effects of these flavonoids are attributed to inhibition of IL-33-induced activation of IKK, which leads to the degradation of IκBα and nuclear localization of NF-κB. On the other hand, other flavonoids isolated from Nepalese propolis, such as isoliquiritigenin, Plathymenin, 7-hydroxyflavanone, and (+)-medicarpin, had no effect on the IL-33 signaling pathway or cytokine expression.
CONCLUSIONS:
Therefore, these results indicate that 3',4'-dihydroxy-4-methoxydalbergione, 4-methoxydalbergion, cearoin, and chrysin are the substances responsible for the anti-inflammatory activity of Nepalese propolis.