Diterpenoid Alkaloids from Delphinium tatsienense

Abstract

Three new C 20 -diterpenoid alkaloids, along with twenty-two known alkaloids, were isolated from the whole herbs of Delphinium tatsienense. The new alkaloids include a vakognavine-type C 20 -diterpenoid alkaloid, designated as tatsienenseine A (1), and two hetisine-type C 20 -diterpenoid alkaloids, designated as tatsienenseines B (2) and C (3). Their structures were elucidated by IR, HR-ESI-MS, 1D-and 2D-NMR analyses.Introduction. -Diterpenoid alkaloids are believed to be the major bioactive components of the genus Delphinium [1 -4], a large genus within the Ranunculaceae family. As a class of structurally complex compounds, they possess a broad range of chemical and pharmacological properties, and also demonstrated a characteristic merit for chemotaxonomic considerations [1 -4]. Delphinium tatsienense Franch grows mainly in southwest Sichuan and northwest Yunnan of China [5]. Previous investigations on the phytochemistry of this plant by the Pelletiers research group resulted in the isolation of more than ten diterpenoid alkaloids [6 -10]. Our present study on the whole plants of Delphinium tatsienense led to the identification of three new diterpenoid alkaloids, designated as tatsienenseines A -C (1 -3), besides twentytwo known diterpenoid alkaloids, i.e., majusine C [20]. These known compounds were identified by comparing their spectroscopic data with those reported in the literature. Herein, we described the separation and structural elucidation of the three new alkaloids 1 -3.

Four New Diterpenoid Alkaloids from The Roots of Aconitum coreanum

“…s)) and C(14) (δ(C) 80.1 (s)), C(20) (δ(C) 69.0 (d)) confirmed the isobutyryloxy group, acetoxy group and two hydroxy )). [17] Furthermore, in comparison with NMR data of known Guan Fu base G (8), 4 was proved to be a hetisine type containing above-mentioned units. [18] The benzoyloxy unit was located at C(13) according to HMBC spectrum (Figure 2), and the correlations of quaternary carbons C(1') (δ(C) 170.7 (s)) with HÀ C(2) (δ(H) 5.20, 1H, br.…”

Classification, Toxicity and Bioactivity of Natural Diterpenoid Alkaloids

“…DAs 126–129 exhibit an OH group on C6, whereas compound 130 brings a methoxide. An a-oriented OH group at C3 is characteristic of most C 20 -DAs; however, compound 129 possesses a b-oriented OH group [ 92 , 93 , 94 ]. Propionyloxy in C13 and 2-methyl butyryloxy moieties in C2 and a quaternary N base characterise compounds 131–133 obtained from the lateral roots of A. carmichaelii .…”

“…Most vakognavine DAs ( 142–147 in Figure 17 ) come from Aconitum and Delphinium . Structurally, they have a rare double bond between C16 and C17, an aldehyde group in C19, and a characteristic N–Me group [ 56 , 93 , 99 , 103 , 104 , 105 ].…”

“…Some alkaloids contain an acetoxy group or benzoyloxy ester group, or both, and do not include other ester groups [ 56 , 93 ];…”

Tatsienensine, a Norditerpenoid Alkaloid From Delphinium tatsienense

“…2 Our previous investigation of the whole plants of this species resulted in the isolation of three new C 20 -diterpenoid alkaloids. 6 Gratifyingly, further chemical investigation of this plant, collected in Miyi County, Sichuan Province, P. R. China, led to the discovery of a structurally unique diterpenoid alkaloid, tatsienensine ( 1 ), with an unprecedented skeleton, which is composed of a cage framework consisting of 6 rings (rings A to F). Most interestingly, the compound containing 19 carbon atoms has a similar structure to that of a C 20 -diterpenoid alkaloid except for the absence of an exocyclic double bond.…”