Gigantelline, gigantellinine and gigancrinine, cherylline- and crinine-type alkaloids isolated from Crinum jagus with anti-acetylcholinesterase activity

Biosynthesis and Biological Activities of Newly Discovered Amaryllidaceae Alkaloids

“…Several of these novel AAs belong to known structural types, while others harbor new structures. The 91 AAs were classified in this manuscript as I) norbelladine-type (1-6), II) cherylline-type (7, 8), III) galantamine-type (9-16), IV) lycorine-type (17-25), V) homolycorine-type (26)(27)(28)(29)(30), VI) crinine-type (31-50), VII) narciclasine-type (51), VIII) pretazettine-type (52-54), IX) montanine-type (55), and X) other types including AAs related to plicamine (56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67), seco-plicamine (68-70), cripowellin (71)(72)(73)(74)(75)(76), mesembrine (77,78), and various others AAs (79)(80)(81)(82)(83)(84)(85)(86)(87)(88)(89)(90)(91). Structures of novel AAs belonging to the I to III scaffold types (norbelladine-, cherylline-, and galantamine-type) are depicted in Figure 3, whereas types IV and V (lycorine-and homolycorine-type) are represented in Figure 4.…”

“…The SAR of some haemanthamine-derivatives revealed that two free hydroxyl groups present at C-3 and C-11 may be essential for the anti-cholinesterase activity [70]. Gigancrinine (44) did not show any anti-AChE activity [63]. Molecular docking studies of zephycandidines (81), (83)(84)(85) and galantamine with AChE revealed that interactions with W286 and Y337 are necessary for inhibitory activity [30] [87].…”

“…The acid extraction usually uses 0.1% to 2% sulfuric acid (H 2 SO 4 ) or hydrochloric acid (HCl) as solvent by maceration. For example, in a recent study by our group, fresh bulbs of C. jagus were dried at room temperature and then finely powdered [63]. The resultant powder (1.35 kg) was extracted with 1% H 2 SO 4 , (2 × 2 L) overnight at room temperature.…”

“…The acid extract was alkalinized to pH 9-10 with 12 N NaOH. The aqueous solution was extracted with EtOAc (3 × 1.2 L), and the organic extracts were combined, dried (Na 2 SO 4 ) and evaporated under reduced pressure to give a brown oil residue (3.0 g) [63].…”

“…All of the new isolated alkaloids were characterized by using spectroscopic (1D and 2D 1 H and 13 C NMR and HR-ESIMS) and chemical methods. Their relative configuration was assigned by NOESY NMR spectra and NMR calculations, while the absolute configuration was assigned using ECD experiments and calculations [ 63 ]. From bulbs of Crinum asiaticum L., two new alkaloids, crinasiaticine A ( 46 ) and crinasiaticine B ( 47 ), and fifteen known alkaloids were isolated.…”