A novel di terpene para-hydroquinone compound derived from cryptoquinone protects neuronal cells against oxidative stress and activates the Nrf2/ARE pathway.

Green plant-origin electrophilic compounds are a newly recognized class of neuroprotective compounds that provide neuroprotection through activation of the Nrf2/ARE pathway. Electrophilic hydroquinones are of particular interest due to their ability to become electrophilic quinones upon auto-oxidation. Although green plants frequently produce a variety of electrophilic compounds, the detailed mechanisms of action of these compounds remain unknown. Here, we focused on the neuroprotective effects of 11,14-dihydroxy-8,11,13-abietariene (DA1), derived from a para-hydroquinone-type pro-electrophilic compound from the cryptoquinone. DA1 activated the Nrf2/ARE pathway, induced phase 2 enzymes, and increased glutathione, thus protecting neuronal cells from oxidative stress. DA1 had a very broad safety zone (199.41 fold) at least in our system. Thus, DA1 is a novel neuroprotective pro-electrophilic diterpene from green plant.

The inhibitory effects of representative chalcones contained in Angelica keiskei on melanin biosynthesis in B16 melanoma cells.

In our effort to find new whitening agents, we evaluated the effects of representative chalcones [4-hydroxyderricin (1), xanthoangelol (2), xanthoangelol H (3), deoxyxanthoangelol H (4), and deoxydihydroxanthoangelol H (5)] contained in the stem of Angelica keiskei on tyrosinase and melanin formation in B16 melanoma cells. In addition, the antioxidant effects of these chalcones in ORAC and DPPH assays were also determined. Interestingly, all chalcones (1-5) inhibit melanin formation in B16 melanoma cells, with low cytotoxicity.

Preparation and properties of gelatin-immobilized beta-glucosidase from Pyrococcus furiosus.

Hyperthermostable beta-glucosidase from Pyrococcus furiosus was enclosed in gelatin gel by cross-linking with transglutaminase. Gelatin-immobilized beta-glucosidase was considerably more thermostable than the native enzyme. Lyophilized immobilisate was stored at 90 degrees C for 1 month without loss of activity. The immobilized beta-glucosidase catalyzed transglucosylation of 5-phenylpentanol with 10.0 equivalent of cellobiose at pH 5.0 and 70 degrees C for 12 h to afford 5-phenylpentyl beta-D-glucopyranoside in 41% yield. The immobilized enzyme was more effective than the native one in transglucosylation. The gelatin-immobilized Pfu-beta-glucosidase recovered from the first run of the reaction was reusable on successive runs.