Isoegomaketone (IK) is an essential oil component of Perilla frutescens (L.) Britt., and there have been no studies investigating its biological activities. We found that IK inhibits lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophages, and moreover, when IK was injected into animals prior to LPS administration, NO serum levels decreased in a dose-dependent manner. These results indicate that IK possesses anti-inflammatory activity both in vitro and in vivo. IK suppressed the phosphorylation of STAT-1 and the production of IFN-beta. Treatment with IK also inhibited the activation of NF-kappaB and activator protein-1, but more IK was required for inhibition than for STAT-1 inhibition, indicating that downregulation of inducible nitric oxide synthase gene expression by IK is mainly attributed to the blockade of STAT-1 activation. Furthermore, IK also induced the expression of heme oxygenase-1 (HO-1) through the activation of nuclear factor E2-related factor 2. Treatment with SnPP, a selective inhibitor of HO-1, reversed the IK-induced suppression of STAT-1 phosphorylation and NO production. Taken together, IK isolated from P. frutescens inhibits NO production in LPS-treated RAW 264.7 macrophages through simultaneous induction of HO-1 and inhibition of the IFN-beta-STAT-1 pathway.

The anti-inflammatory activities of a prepared isoegomaketone 3a and its derivatives 3b-3f were evaluated in RAW 264.7 cells. Among these, the compound 3d was displayed the most potent inhibitory activities against production of nitric oxide, monocyte chemoattractant protein-1 and interleukin-6. Based on these results, the abilities of compounds 3a-3f to modulate NF-κB and AP-1-mediated gene transcription using a luciferase reporter assay were investigated. The transcriptional activities of NF-κB and AP-1 decreased when pretreated with 3a-3f. Interestingly, at 10 μM, compound 3d markedly suppressed the lipopolysaccharide-induced NF-κB and activator protein-1 DNA binding activities. Some preliminary structure-activity relationships were proposed that may provide a direction for further study.

Isoegomaketone (IK) is an essential oil component of Perilla frutescens (L.), but the mechanism by which IK induces apoptosis has never been studied. The purpose of this study was to elucidate the IK-induced apoptotic pathway in DLD1 human colon cancer cells. We observed that IK treatment over 24 h significantly inhibited cell viability in a dose-dependent manner. We also found that IK triggered cleavage of PARP. Moreover, IK treatment resulted in cleavage of caspase-8, -9, and -3 in a dose- and time-dependent manner. IK treatment also resulted in cleavage of Bid and translocation of Bax, and triggered the release of cytochrome c from the mitochondria to the cytoplasm. Furthermore, it resulted in the translocation of apoptosis inducing factor (AIF), a caspase-independent mitochondrial apoptosis factor, from the mitochondria into the nucleus. Overall, these results suggest that IK induces apoptosis through caspase-dependent and capase-independent pathways in DLD1 cells.

Dual-modular imaging approaches combining near-infrared (NIR) fluorescence (FLI) and photoacoustic imaging (PAI) require suitable contrast agents to produce dual-modular signals. Although nanoparticles have been used to develop PAI agents, small molecule-based imaging agents have not been extensively studied, highlighting the need to design new fluorophores with an enhanced multifunctional ability. Thus, in this study, we designed a novel squaraine (SQ)-based dye and reported its rational preparation and conjugation with a cancer targeting peptide. Specifically, benzoindole-derived SQ (BSQ) showed strong absorption and fluorescence properties at above 650 nm under aqueous conditions, with a maximum absorption and emission at 665 and 680 nm, respectively. Moreover, PA signal scanning experiments revealed a maximum signal intensity in the range 680−700 nm. BSQ was also conjugated with cyclic arginine−glycine−aspartic acid (cRGD) to improve its active targeting ability for the α v β 3 integrin, which is overexpressed in various cancer and angiogenic cells. A series of in vitro, in vivo, and ex vivo FLI studies showed that the cRGD conjugated BSQ (BSQ−RGD 2 ) successfully stained and targeted α v β 3 integrin-overexpressing tumor cells and xenografts, which were clearly visualized by FLI and PAI. Therefore, BSQ−RGD 2 can successfully be applied to dual-modular imaging of the specific biomarker in living animals.

β-amyloid (Aβ) plaques in the brain are composed of Aβ40 and Aβ42 peptides, and are the defining pathological feature of Alzheimer's disease (AD). Fluorescent probes that can detect Aβ plaques have gained increasing interest as potential tools for in vitro and in vivo monitoring of the progression of AD. In this study, chalcone-mimic fluorescent probe 5 was designed and prepared. Probe 5 exhibited an approximately 50-fold increase in emission intensity after mixing with Aβ42 aggregates, a high affinity for Aβ42 aggregates (K D = 1.59 μM), and reasonable lipophilicity (log P value = 2.55). Probe 5 also exhibited specific staining of Aβ plaques in the transgenic mice (APP/PS1) brain sections. Ex vivo fluorescence imaging of the brain from normal and TG mice revealed that probe 5 was able to penetrate the BBB and stain the Aβ plaques. These results suggest that chalcone-mimic probe 5 possessed the requirements of a fluorescent probe for Aβ plaques and may be useful in AD research.