Daurichromenic Acid-producing Oxidocyclase in the Young Leaves of Rhododendron dauricum

Abstract

Rhododendron dauricum L., a flowering tree popular in Hokkaido, produces daurichromenic acid (DCA), a terpenophenol with a potent anti-HIV activity. The DCA-producing enzyme, named DCA synthase, could be detected in the soluble protein fraction prepared from the young leaves of R. dauricum. DCA synthase catalyzed oxidocyclization of the farnesyl group of grifolic acid to form (+)-DCA as the major reaction product. The DCA synthase reaction proceeds without the need for any cofactors and coenzymes except for molecular oxygen. Interestingly, these catalytic properties of DCA synthase are quite similar to those reported for cannabinoid synthases in the marijuana plant Cannabis sativa L.

Engineering Escherichia coli as a platform for the in vivo synthesis of prenylated aromatics

“…The ability to prenylate OSA and DVA, in addition to the previously demonstrated substrate OLA, would enable the synthesis of precursors to or direct medicinal compounds. For example, 5‐geranyl‐OSA is the precursor of anthopogochromenic and anthopogocyclolic acids, which are potential anti‐inflammatory drugs (Iwata & Kitanaka, ) and 3‐farnesyl‐OSA, also called grifolic acid, has been identified as a natural antitumor compound (Zhao et al, ) and is the precursor for the HIV drug daurichromenic acid (Taura et al, ). Furthermore, 3‐geranyl‐DVA and OLA, cannabigerovarinic acid (CBGVA) and cannabigerolic acid (CBGA), respectively, are precursors for synthesizing a variety of functionalized cannabinoids with different pharmaceutical applications (Citti et al, ).…”

“…In addition to exploiting the improved characteristics of engineered NphB for product diversification, our platform for PA synthesis can be modified by altering the targeted prenyl diphosphate intermediate available for prenyl transfer. For example, to enable the production of grifolic acid, the precursor to daurichromenic acid (Taura et al, ), the mevalonate pathway can be further engineered to enable the generation of FPP. For this, the designed platform was modified by replacing GPPS2 with ispA from E. coli to enable endogenous FPP generation (Wang et al, ).…”

“…Isoprenoids (specifically C 10 geranoid alcohols) in the aqueous phase were extracted from 2 ml samples (including 50 mg/L (Iwata & Kitanaka, 2011) and 3-farnesyl-OSA, also called grifolic acid, has been identified as a natural antitumor compound (Zhao et al, 2018) and is the precursor for the HIV drug daurichromenic acid (Taura et al, 2014). Furthermore, 3-geranyl-DVA and OLA, cannabigerovarinic acid (CBGVA) and cannabigerolic acid (CBGA), respectively, are precursors for synthesizing a variety of functionalized cannabinoids with different pharmaceutical applications (Citti et al, 2018).…”

Identification and Characterization of Daurichromenic Acid Synthase Active in Anti-HIV Biosynthesis

“…With respect to the biosynthesis of DCA, we previously reported partial characterization of an oxidocyclase, named DCA synthase, using a crude protein extract from young leaves of R. dauricum (Taura et al, 2014). DCA synthase is an enzyme that catalyzes the stereoselective oxidative cyclization of the farnesyl moiety of grifolic acid to form DCA ( Fig.…”

Daurichromenic acid and grifolic acid: Phytotoxic meroterpenoids that induce cell death in cell culture of their producer Rhododendron dauricum

“…Elicitor treatments were performed with 100 mM of methyl jasmonate and/or 9 g/L of b-cyclodextrin on seven-day old cultures, and incubated for 96 h prior to analyses. The cellular extract was prepared from cultured cells by homogenization with methanol, and analyzed with a reversed-phase HPLC system, 25 together with culture supernatant. Elution was performed isocratically with 75% aqueous acetonitrile containing 0.1% formic acid at a flow rate of 1.0 mL/min, and constituents were detected by absorption at 254 nm.…”