Two new diterpenoids from the rhizomes of Zingiber officinale

CYP76BK1 orthologs catalyze furan and lactone ring formation in clerodane diterpenoids across the mint family

The Lamiaceae (mint family) is the largest known source of furanoclerodanes, a subset of clerodane diterpenoids with broad bioactivities including insect antifeedant properties. The Ajugoideae subfamily, in particular, accumulates significant numbers of structurally related furanoclerodanes. The biosynthetic capacity for formation of these diterpenoids is retained across most Lamiaceae subfamilies, including the early-diverging Callicarpoideae which forms a sister clade to the rest of Lamiaceae. VacCYP76BK1, a cytochrome P450 monooxygenase from Vitex agnus-castus, was previously found to catalyze the formation of the proposed precursor to furan and lactone-containing labdane diterpenoids. Through transcriptome-guided pathway exploration, we identified orthologs of VacCYP76BK1 in Ajuga reptans and Callicarpa americana. Functional characterization demonstrated that both could catalyze the oxidative cyclization of clerodane backbones to yield a furan ring. Subsequent investigation revealed a total of 10 CYP76BK1 orthologs across six Lamiaceae subfamilies. Through analysis of available chromosome-scale genomes, we identified four CYP76BK1 members as syntelogs within a conserved syntenic block across divergent subfamilies. This suggests an evolutionary lineage that predates the speciation of the Lamiaceae. Functional characterization of the CYP76BK1 orthologs affirmed conservation of function, as all catalyzed furan ring formation. Additionally, some orthologs yielded two novel lactone ring moieties. The presence of the CYP76BK1 orthologs across Lamiaceae subfamilies closely overlaps with the distribution of reported furanoclerodanes. Together, the activities and distribution of the CYP76BK1 orthologs identified here support their central role in furanoclerodane biosynthesis within the Lamiaceae family. Our findings lay the groundwork for biotechnological applications to harness the economic potential of this promising class of compounds.

CYP76BK1 orthologs catalyze furan and lactone ring formation in clerodane diterpenoids across the mint family

The Lamiaceae (mint family) is the largest known source of furanoclerodanes, a subset of clerodane diterpenoids with broad bioactivities including insect antifeedant properties. The Ajugoideae subfamily, in particular, accumulates significant numbers of structurally related furanoclerodanes. The biosynthetic capacity for formation of these diterpenoids is retained across most Lamiaceae subfamilies, including the early-diverging Callicarpoideae which forms a sister clade to the rest of Lamiaceae. VacCYP76BK1, a cytochrome P450 monooxygenase from Vitex agnus-castus, was previously found to catalyze the formation of the proposed precursor to furan and lactone-containing labdane diterpenoids. Through transcriptome-guided pathway exploration, we identified orthologs of VacCYP76BK1 in Ajuga reptans and Callicarpa americana. Functional characterization demonstrated that both could catalyze the oxidative cyclization of clerodane backbones to yield a furan ring. Subsequent investigation revealed a total of ten CYP76BK1 orthologs across six Lamiaceae subfamilies. Through analysis of available chromosome-scale genomes, we identified four CYP76BK1 members as syntelogs within a conserved syntenic block across divergent subfamilies. This suggests an evolutionary lineage that predates the speciation of the Lamiaceae. Functional characterization of the CYP76BK1 orthologs affirmed conservation of function, as all catalyzed furan ring formation. Additionally, some orthologs yielded two novel lactone ring moieties. The presence of the CYP76BK1 orthologs across Lamiaceae subfamilies closely overlaps with the distribution of reported furanoclerodanes. Together, the activities and distribution of the CYP76BK1 orthologs identified here support their central role in furanoclerodane biosynthesis within the Lamiaceae family. Our findings lay the groundwork for biotechnological applications to harness the economic potential of this promising class of compounds.

Dimeric diarylheptanoids with anti-inflammatory activity from Zingiber officinale

Two previously undescribed chain diarylheptanoid derivatives (2-3), five previously undescribed dimeric diarylheptanoids (4-8), together with one known cyclic diarylheptanoid (1) were isolated from Zingiber officinale. Their structures were elucidated by extensive spectroscopic analyses (HR-ESI-MS, IR, UV, 1D and 2D NMR) and ECD calculations. Biological evaluation of compounds 1-8 revealed that compounds 2, 3 and 4 could inhibit nitrite oxide and IL-6 production in lipopolysaccharide induced RAW264.7 cells in a dose-dependent manner.

Effect of drying and processing on diterpenes and other chemical constituents of ginger

Ginger (Zingiber officinale Roscoe) is a perennial plant widely distributed in tropical and subtropical regions, and its rhizomes are sometimes processed for use in traditional medicine. In Japan, "ginger" (Shokyo in Japanese) and "processed ginger" (Kankyo in Japanese) are defined as crude drugs derived from ginger rhizomes, which have different medicinal properties due to complex changes in their chemical composition during processing. The effects of processing on gingerols and shogaols are well known, but for other phytochemicals remain unclear. Therefore, the present study prepared dried ginger and processed ginger derived from three ginger cultivars (Kintoki, Kogane, and Tosa ginger) and examined the effects of drying and processing on multiple secondary metabolites. Drying showed only a limited effect on ginger chemical constituents and significantly reduced [6]-gingerol content in Tosa ginger. In contrast, processing altered content of numerous metabolites, such as terpenes and gingerol-related compounds, in addition to those gingerols and shogaols. Notably, processing reduced labdane diterpene content, including labdadienedial, aframodial, and galanolactone in all ginger cultivars. Our results show galanolactone with anti-emetic activity was abundant in dried ginger and decreased following processing, highlighting different uses between "ginger" and "processed ginger" in traditional medicine. Overall, we comprehensively clarified the impact of drying and processing on terpenes and gingerol-related compounds. These findings help reveal the varying medicinal properties among crude drugs prepared from Z. officinale.