Euphanoids A and B, two new lathyrane diterpenoids with nitric oxide (NO) inhibitory activity from Euphorbia kansuensis

Abstract

Two new lathyrane diterpenoids, euphanoids A and B (1 and 2), along with five known compounds (37) were isolated from the roots of Euphorbia kansuensis. Their structures were elucidated by spectroscopic analysis, and the absolute configuration of 1 was determined by single crystal X-ray diffraction. All of the isolates were screened for the inhibitory effects on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 cells, and compounds 1 and 2 showed pronounced inhibition on NO production with IC 50 values of 4.7 and 9.5 M, respectively, being more active than the positive control, quercetin (IC 50  10.8 M).

Euphorbia Diterpenes: An Update of Isolation, Structure, Pharmacological Activities and Structure–Activity Relationship

“…Most of the studied species contained both polycyclic and macrocyclic diterpenes and included E. lathyris [ 31 ], E. stracheyi [ 32 ], E. royleana [ 33 ], E. antiquorum [ 34 ], E. kansuensis [ 35 , 36 ], E. prolifera [ 37 ], E. peplus [ 38 ], E. aellenii [ 39 ], E. pilosa [ 40 ], E. saudiarabica [ 28 ], E. marginata [ 41 ], E. neriifolia [ 42 ], E. resinifera [ 43 ], E. pekinensis [ 44 ], E. hylonoma [ 45 ], E. milii [ 46 ], E. wallichii [ 47 ], and E. ebracteolata [ 48 ]. While others contained only macrocyclic diterpenes like E. esula [ 49 ], E. helioscopia [ 50 ], E. yinshanica [ 51 ], E. grandicornis [ 52 ], and E. kansui [ 53 ].…”

“…[ 32 ]. Yan et al [ 35 ] described the isolation of atisane-type diterpenoid; atisane-3-oxo-16 α ,17-diol ( 6 ) from ethanol root extracts of E. kansuensis . Lathyranes-type diterpenoids were isolated from the ethanol root extracts of E. kansuensis by Wang et al [ 90 ].…”

“…Labdanes and ent -labdanes diterpenoids helioscopinolide A ( 68 ) and B ( 69 ) were isolated from whole plants extracts of E. peplus [ 38 ] and E. kansuensis [ 35 ], respectively, while ent-3α ,16-dihydroxylabda-8(17),12 ( E) ,14-triene ( 70 ) and ent -14(S),15-dihydroxylabda-8(17)-12( E )-dien-18-oic acid ( 71 ) were isolated from E. yinshanica [ 51 ]. Labdanes are rare in Euphorbia species but are common in other higher plants and marine organisms [ 95 ].…”

“…Lathyrane diterpenes were isolated from the seed extracts of E. lathyris ( 247 – 248 ) [ 31 , 66 ], root extracts of E. stracheyi ( 249 – 261 ) [ 32 ], whole-plant extracts of E. royleana ( 262 – 295 ) [ 33 ], and aerial extracts of E. antiquorum ( 296 – 299 ) [ 34 ]. Other records described the isolation of lathyrane diterpenes from E. kansuensis ( 300 – 301 ) [ 35 ], E. lathyris ( 302 – 307 ) [ 103 ], and E. antiquorum ( 308 – 310 ) [ 56 ].…”

“…It was also noted that the activities of these compounds were due to the presence of hydroxyl groups at C-16 and C-17, which are their bioactive functionalities [ 54 ]. Ent-atisane-3 β ,16 α ,17-triol ( 36 ), from the root extracts of E. kansuensis, showed no inhibition of NO (IC 50 > 50 µM compared to quercetin (IC 50 = 10.80 µM) [ 35 ].…”