Structurally diverse diterpenoids from Isodon pharicus

Abstract

Twenty-one structurally diverse diterpenoids (1–21), wherein 1, 2, and 4 represented unprecedented architectures, were isolated from Isodon pharicus.

Anti-Inflammatoryent-Kaurane Diterpenoids fromIsodon serra

“…The 1 H and 13 C NMR spectra of compound 3 were similar to those of 2, suggesting that these two compounds had the same 7,20-epoxy-ent-kauranoid-type scaffold with two acetoxy groups. The only difference was that one more oxygenated carbon signal (δ C 75.9) occurred, replacing one of the aliphatic methylene carbons in 2.…”

“…Hence, the structure of isoserrin D (4) was defined as (5R,6S,7S,8S,9S,10R,13R,15R,16R)-6β,15α-diacetoxy-7α,20-epoxy-7β,16α,17-trihydroxy-ent-kaurane. Compound 5 (isoserrin E) possessed the identical molecular formula as 4, C 24 H 36 O 8 , which was deduced from HRESIMS analysis as well as the 13 C NMR data. Furthermore, the 2D structure of 5 was also inferred to be the same as that of 4 by analyzing its 1D and 2D NMR data.…”

“…Compound 1 was obtained as a white amorphous powder. Its molecular formula, C 24 H 34 O 7 , was deduced from high resolution electrospray ionization mass spectrometry (HRE-SIMS) data analysis (m/z 457.2199 [M + Na] + , calcd for C 24 H 34 O 7 Na, 457.2202) and 13 C NMR data (Table 1), which indicated eight indices of hydrogen deficiency. The 1 H NMR spectroscopic data (Table 2) showed characteristic signals assignable to four methyl singlets (δ H 0.80, 1.09, 2.…”

“…However, their NMR data were somewhat different, suggesting a configurational difference between these two compounds. By comparing their 13 C NMR data (Table 1), upfield shifts of C-15 (Δδ −5.1) and C-16 (Δδ −10.2) in 2 were observed, which implied configurational changes of C-15 and C-16. NOESY data analysis of 2 (Figure 2) revealed the configuration as depicted in Figure 2, where the C-6 acetoxy group was in a β-orientation.…”

“…and comprising approximately 150 species, is mainly distributed in tropical and subtropical Asia . Over the last half a century, a series of phytochemical investigations of this genus have been conducted for its abundant diterpenoid constituents and their various biological activities. − As a result, over 1200 new diterpenoids have been isolated from Isodon plants, − including some ent -kauranoids with excellent antitumor and anti-inflammatory activities, such as oridonin, eriocalyxin B, and isoforretin A …”