PEG modification of Amorfrutin B from Amorpha fructicosa increases gastric absorption, circulation half-life and glucose uptake by T3T-L1 adipocytes

Amorfrutin B Protects Mouse Brain Neurons from Hypoxia/Ischemia by Inhibiting Apoptosis and Autophagy Processes Through Gene Methylation- and miRNA-Dependent Regulation

Amorfrutin B is a selective modulator of the PPARγ receptor, which has recently been identified as an effective neuroprotective compound that protects brain neurons from hypoxic and ischemic damage. Our study demonstrated for the first time that a 6-h delayed post-treatment with amorfrutin B prevented hypoxia/ischemia-induced neuronal apoptosis in terms of the loss of mitochondrial membrane potential, heterochromatin foci formation, and expression of specific genes and proteins. The expression of all studied apoptosis-related factors was decreased in response to amorfrutin B, both during hypoxia and ischemia, except for the expression of anti-apoptotic BCL2, which was increased. After post-treatment with amorfrutin B, the methylation rate of the pro-apoptotic Bax gene was inversely correlated with the protein level, which explained the decrease in the BAX/BCL2 ratio as a result of Bax hypermethylation. The mechanisms of the protective action of amorfrutin B also involved the inhibition of autophagy, as evidenced by diminished autophagolysosome formation and the loss of neuroprotective properties of amorfrutin B after the silencing of Becn1 and/or Atg7. Although post-treatment with amorfrutin B reduced the expression levels of Becn1, Nup62, and Ambra1 during hypoxia, it stimulated Atg5 and the protein levels of MAP1LC3B and AMBRA1 during ischemia, supporting the ambiguous role of autophagy in the development of brain pathologies. Furthermore, amorfrutin B affected the expression levels of apoptosis-focused and autophagy-related miRNAs, and many of these miRNAs were oppositely regulated by amorfrutin B and hypoxia/ischemia. The results strongly support the position of amorfrutin B among the most promising anti-stroke and wide-window therapeutics.

Post-Treatment with Amorfrutin B Evokes PPARγ-Mediated Neuroprotection against Hypoxia and Ischemia

In this study, we demonstrate for the first time that amorfrutin B, a selective modulator of peroxisome proliferator-activated receptor gamma—PPARγ, can protect brain neurons from hypoxia- and ischemia-induced degeneration when applied at 6 h post-treatment in primary cultures. The neuroprotective effect of amorfrutin B suggests that it promotes mitochondrial integrity and is capable of inhibiting reactive oxygen species—ROS activity and ROS-mediated DNA damage. PPARγ antagonist and Pparg mRNA silencing abolished the neuroprotective effect of amorfrutin B, which points to agonistic action of the compound on the respective receptor. Interestingly, amorfrutin B stimulated the methylation of the Pparg gene, both during hypoxia and ischemia. Amorfrutin B also increased the protein level of PPARγ during hypoxia but decreased the mRNA and protein levels of PPARγ during ischemia. Under ischemic conditions, amorfrutin B-evoked hypermethylation of the Pparg gene is in line with the decrease in the mRNA and protein expression of PPARγ. However, under hypoxic conditions, amorfrutin B-dependent hypermethylation of the Pparg gene does not explain the amorfrutin B-dependent increase in receptor protein expression, which suggests other regulatory mechanisms. Other epigenetic parameters, such as HAT and/or sirtuins activities, were affected by amorfrutin B under hypoxic and ischemic conditions. These properties position the compound among the most promising anti-stroke and wide-window therapeutics.

PEG-PCL modification and intestinal sustained-release of solid lipid nanoparticles for improving oral bioavailability of 2-methoxyestradiol

The primary purpose of the present study was to design and optimize a solid lipid nanoparticle (SLN) formulation of the poorly water-soluble drug 2-methoxyestradiol (2-ME) to improve its oral bioavailability and prolong the duration of therapeutic drug level. SLN was modified by amphipathic PEG-PCL (PLN) and then encapsulated in pH-sensitive microparticles (MP) by spray drying technology. Several properties of 2-ME PLN-MP were characterized including particle size, drug loading, and drug or PLN release. After oral administration of 2-ME PLN-MP, retention time in mice was evaluated by in vivo imaging technology and the pharmacokinetic parameters in rats were determined by HPLC. The results demonstrated that PEG-PCL modification of 2-ME SLN significantly decreased particle size and delayed drug release without influencing IC₅₀ in 4T1 cells. 2-ME PLN in the microparticles showed significant pH-sensitive release in the simulated gastrointestinal fluid and controlled release in the intestine. The PLN (labelled with IR-780 iodide) prolonged significantly fluorescence duration time compared to the SLN and the prolongation was further enhanced by the PLN-MP formulation. Furthermore, compared with the suspension, the PLN-MP formulation showed a 56.66-fold delay in T_max, a 10.36-fold extension in MRT and a 140.86-fold increase in the relative bioavailability in the rat. The research work in the paper suggests that the PLN-MP could serve as a practical oral preparation for 2-ME in future cancer therapy.