Hybromet: a ligand for purifying opioid receptors

Synthesis and Cytotoxicity Studies of Bioactive Benzofurans from Lavandula agustifolia and Modified Synthesis of Ailanthoidol, Homoegonol, and Egonol

2-Aryl/alkylbenzofurans, which constitute an important subclass of naturally occurring lignans and neolignans, have attracted extensive synthetic efforts due to their useful biological activities and significant pharmacological potential. Herein, we report a general and efficient approach to divergent 2-arylbenzofurans through a one-pot synthesis of versatile 2-bromobenzofurans as key intermediates. Using this approach, the first total synthesis of a series of trisubstituted and tetrasubstituted benzofurans bearing the hydroxyethyl unit, including the natural compounds isolated from Lavandula agustifolia (1-3) and their non-natural derivatives (4-8), was accomplished. We also report a modified synthesis of ailanthoidol, homoegonol, and egonol that enables the divergent synthesis of their derivatives for future exploration. Among these, the representative phenolic natural compound 2 and its derivatives 7 and 5 induced apoptotic cell death related poly(ADP-ribose) polymerase (PARP) cleavage in MCF74, A549, PC3, HepG2, and Hep3B cancer cell lines. Additionally, the tumor suppressor protein p53 was also induced in p53 wild type cancer cells.

Characterization of a polyclonal antibody to the mu opioid receptor

Active opioid receptors have been solubilized from bovine striatal synaptosomal membranes and purified approximately 4000-fold using a combination of affinity and hydroxyapatite chromatography. The affinity column was constructed by attaching hybromet, a newly synthesized opioid ligand with high affinity for the mu receptor, to a solid support matrix. A polyclonal antibody was generated to opioid receptors by injection of the purified receptor preparation into female New Zealand rabbits. The specificity of the antiserum was demonstrated by receptor competition and immunoprecipitation studies. Immunological titration of opioid binding activity from rat brain showed that the antibody was able to displace specific binding of [3H]etorphine (universal opioid) and [3H]dihydromorphine (mu opioid) from rat membranes, but was ineffective against the binding of [3H]ethylketocyclazocine (kappa [3H]D-Ala2,D-Leu5-enkephalin (delta opioid) or [3H]phencyclidine (phencyclidine/sigma receptor ligand). The antibody was able to precipitate the Mr 94,000 component of the 125I-labeled affinity-purified receptor, a finding which suggests that this subunit may be an opioid recognition component. By indirect immunofluorescence, the antibody was shown to bind specifically to the plasma membranes of the neurotumor cell line NCB-20 (neuroblastoma X Chinese hamster brain hybrid cells), which has high affinity opioid receptors. The observed fluorescence in the neuroblastoma cells was prevented by pre-adsorption of the antibody with purified receptor from rat brain. These results indicate that the antibody is specific for opioid receptors and may prove useful in the precise localization of opioid receptors in the central and peripheral nervous systems by immunohistochemical procedures.