Three new sesterterpenoids, phorbaketals A (1), B (2), and C (3) which have a spiroketal of the hydrobenzopyran moiety, were isolated from the Korean marine sponge Phorbas sp. Their complete structures were elucidated by spectral and chemical methods. They exhibited moderate cytotoxicity against human colorectal, hepatoma, and lung cancer cell lines. Furthermore, the cultivation of the bacterial fraction from the sponge afforded compound 1.

Berries of Aronia melanocarpa (chokeberry) are known to be a rich source of biologically active polyphenols. In the present study, the effects of seven anti-adipogenic polyphenolic phytochemicals isolated from A. melanocarpa methanol extract on adipogenic transcription factors were investigated. Amygdalin and prunasin were found to inhibit 3T3-L1 adipocyte differentiation by suppressing the expressions of PPARγ (peroxisome proliferator-activated receptor γ), C/EBPα (CCAAT/enhancer binding protein α), SREBP1c (sterol regulatory element binding protein 1c), FAS (fatty acid synthase), and aP2 (adipocyte fatty-acid–binding protein). A. melanocarpa extract-treated (100 or 200 mg/kg/day on body weight) high fat diet (HFD)-induced obese mice showed significant decreases in body weight, serum triglyceride (TG), and low-density lipoprotein cholesterol (LDLC) levels and improved insulin sensitivity as compared with HFD controls. This research shows A. melanocarpa extract is potentially beneficial for the suppression of HFD-induced obesity.

Marine sponges harbor a range of biologically active compounds. Phorbaketal A is a tricyclic sesterterpenoid isolated from the marine sponge Phorbas sp.; however, little is known about its biological activities and associated molecular mechanisms. In this study, we examined the anti-inflammatory effects and underlying molecular mechanism of phorbaketal A in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We found that phorbaketal A significantly inhibited the LPS-induced production of nitric oxide (NO), but not prostaglandin E₂, in RAW 264.7 cells. Further, phorbaketal A suppressed the expression of inducible NO synthase at both the mRNA and protein levels. In addition, phorbaketal A reduced the LPS-induced production of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, and monocyte chemotactic protein-1. Treatment with phorbaketal A inhibited the transcriptional activity of nuclear factor-kappaB (NF-κB), a crucial signaling molecule in inflammation. Moreover, phorbaketal A up-regulated the expression of heme oxygenase-1 (HO-1) in LPS-stimulated RAW 264.7 cells. These data suggest that phorbaketal A, isolated from the marine sponge Phorbas sp., inhibits the production of inflammatory mediators via down-regulation of the NF-κB pathway and up-regulation of the HO-1 pathway.