X-Ray Crystal Structure and Absolute Configuration of Kaerophyllin (Chaerophyllin)

Abstract

The structure of kaerophyllin [2], isolated from Bupleurum lanceolatum, has been confirmed by an X-ray crystallographic analysis. Accurate lHand 13C-nmr assignments have been made on the basis of COSY, long range homonuclear (long range COSY), heteronuclear (selective INEPT and FLOCK) scalar interactions, and nOe experiments. The absolute configuration of the lignan has been defined as a-(trans-3,4-dimethoxybenzylidene)^-j?-(3,4methylenedioxy benzy l)-y-butyrolactone.Among the numerous types of plant-derived lignans, those with the 2,3-diarylbutyrolactone skeleton (1] have potentially useful antitumor activity (1). Lignans of this kind are the precursors of the aryltetalin-type bioactive lignans. Podophyllotoxin, isolated from various species of Podophyllum, is an important starting material for the preparation of the clinically useful anticancer drugs etoposide and teniposide (2-4). A search for plants of the high altitude Himalayan glaciers was conducted with a view to discover new medicinal compounds. In this communication, we report accurate 1Hand 13C-nmr chemical shift assignments, X-ray crystal structure determination, and absolute configuration of the lignan, kaerophyllin (chaerophyllin) [2], isolated from Bupleurum lanceolatum (Umbelliferae) (5,6).

New lignan glycosides from Justicia secunda Vahl (Acanthaceae) with antimicrobial and antiparasitic properties

“…The IR spectrum ( Fig. S12 , Supplementary data) showed broad absorption bands at 3383, a stronger ones at 1738, 1639, and 928 cm −1, suggesting the presence of hydroxyl groups, α,β -unsaturated γ -lactone carbonyl groups, double bonds and methylenedioxy groups, respectively [ 30 , 37 , 38 ]. The 1 H NMR spectrum ( Fig.…”

“…It also exhibited signals of five pairs of aromatic protons, including one ABX-type 1,3,4-trisubstituted phenyl pattern at ẟ H 6.80/6.91 (d, J = 1.7 Hz, H-2′), 6.78/6.83 (d, J = 8.0 Hz, H-5′), and 6.64/6.75 (dd, J = 1.7, 8.0 Hz, H-6′), and two para-hydrogenated atoms at ẟ H 6.95/6.79 (s, H-3) and 7.26/7.71 (s, H-6), clearly indicating that the other aromatic ring possesses a 1,2,4,5-substitution pattern. The doublet signal at ẟ H 7.82/7.48 (d, J = 2.2, H-7) was attributable to the olefinic proton of a benzylidene unit [ 37 , 38 ]. The downfield chemical shifts of the geminal aliphatic protons at ẟ H 4.12/4.25 ( 2a ) and 4.02/4.23 ( 2b ) (H-9′ a,b ) allowed their assignment as the γ -hydrogens of a γ -butyrolactone ring [ 37 , 38 ].…”

Scandiceae tribe (Apiaceae Lindley 1836, subfam. Apioideae) species ? potential resources of biologically and pharmacologically active secondary biomolecules

“…Alternativni pristupi -biokonverzija u ćelijskim kulturama sa odgovarajućim lignansintetišućim enzimima, kao i semisintetička proizvodnja -takođe su predmet skorašnjih istraživanja [11,28,29]. Ranijim istraživanjima [4,[9][10][11][12]14] utvrđeno je da je A. sylvestris bogat izvor fenolnih jedinjenja iz klase lignana: angeloil-podofilotoksina i biogenetskih prekursora podofilotoksina -jateina, deoksipodofilotoksina itd., dok je u ostalim vrstama do sada pronađen samo mali broj ovih jedinjenja (nemerozin, deoksipodofilotoksin i jatein u Chaerophyllum aureum [30], deoksipodofilotoksin u nekim uzorcima Anthriscus cerefolium [20], herohirzutin A i B u Chaerophyllum hirsutum [18,31] i herofilin (kerofilin) u Chaerophyllum maculatum [31,32]. Sadržaj lignana u većini vrsta obuhvaćenih ovom tezom do sada nije ispitivan, čemu sigurno doprinosi i nedostupnost komercijalnih standarda.…”

“…Primer je nezasićeni dibenzilbutirolaktonski lignan silvestrin, koji je u A. sylvestris detektovan tek 2007. godine [4], tri decenije nakon prvih publikovanih rezultata fitohemijskih istraživanja ove vrste [13]. Literaturni podaci o hemijskom sastavu ekstrakta ostalih vrsta znatno su oskudniji i obuhvataju identifikaciju nekoliko fenolnih i poliacetilenskih jedinjenja u Chaerophyllum hirsutum [18,19], flavonoidâ i deoksipodofilotoksina u Anthriscus cerefolium [2,20], lignana, flavonoida, poliacetilena i fenilpropanoida u Chaerophyllum aureum [30,35], kao i lignana u Chaerophyllum maculatum [32].…”

“…U ostalim vrstama do sada je identifikovan relativno mali broj lignana: nemerozin, deoksipodofilotoksin i jatein u Chaerophyllum aureum [30], deoksipodofilotoksin u Anthriscus cerefolium (pronađen od strane Fejes i sar. [20], ali ne i Koulmana [5]), herohirzutin A i B u Chaerophyllum hirsutum [18,31] i herofilin (kerofilin) u Chaerophyllum maculatum [31,32] (Slike 3.30.-3.32.). Tipični obrasci supstitucije na aromatičnim prstenovima su metilendioksi-(piperoniltip supstitucije) i trimetoksi, i nešto ređe dimetoksi (veratril) i hidroksi-metoksi (gvajacil).…”