Antileukemic ancistrobenomine B and related 5,1′-coupled naphthylisoquinoline alkaloids from the Chinese liana Ancistrocladus tectorius

Ancistrolikokines E–H and related 5,8′-coupled naphthylisoquinoline alkaloids from the Congolese lianaAncistrocladus likokowith antiausterity activities against PANC-1 human pancreatic cancer cells

“…Southeast Asian and East African Ancistrocladaceae typically produce 3S-congured and 6-oxygenated compounds (i.e., 'Ancistrocladaceae-type' alkaloids). 4,5,[16][17][18][30][31][32][33] The only other plant family that likewise produces naphthylisoquinolines, the West African Dioncophyllaceae, exclusively contains alkaloids with R-conguration at C-3, always lacking an oxygen function at C-6 (i.e., 'Dioncophyllaceae-type' alkaloids). 4,5,34 West African and some of the Central African Ancistrocladus plants produce both, typical Dioncophyllaceae-and Ancistrocladaceae-type alkaloids, and all possible hybrid forms thereof, 4,5,11,19 while 'Ancistrocladaceae/Dioncophyllaceae hybrid-type' alkaloids are frequently found in Central African species together with Ancistrocladaceae-type compounds.…”

“…This was further corroborated from the absence of an H-1 signal, which normally appears at d 4.60-4.80 in naphthyltetrahydroisoquinoline alkaloids. 4,24,[31][32][33] The 1 H NMR spectrum showed the chemical shis of one methoxy function (d 4.08) and ve aromatic protons, viz., three singlets and two doublets, each corresponding to one proton. Two of these protons (d 6.67 and 6.80) were located meta to each other.…”

“…This was obvious from the lack of resonances for protons at C-1 and C-3 and the appearance of an additional aromatic singlet at d 6.78, instead of the signals of the two diastereotopic geminal protons at C-4 usually observed for naphthyltetra-or naphthyldihydroisoquinoline alkaloids. [31][32][33] This nding was further supported by the signicant downeld shis of the signals of the two methyl groups at C-1 (d 3.18) and C-3 (d 2.38) in the 1 H NMR spectrum (Table 1) and of the 13 C NMR resonances of C-1, C-3, and C-4 (d 157.5, 142.4, and 118.9, respectively) ( Table 2).…”

“…Prior to this work, only nine such naphthylisoquinolines have been identied in Ancistrocladus species, all of them from Asia. 16,[30][31][32][33] Among these compounds, ancistrolikokine G (12) is the rst representative that was isolated from an African liana and that is 5,8 0 -coupled. Furthermore, ve new N-methylated naphthyltetrahydroisoquinoline alkaloids with a 5,8 0 -biaryl linkage were discovered in the twigs of A. likoko, named ancistrolikokines A 2 (13), A 3 (14), C 2 (5), H (15), and H 2 (16).…”

“…Furthermore, ve new N-methylated naphthyltetrahydroisoquinoline alkaloids with a 5,8 0 -biaryl linkage were discovered in the twigs of A. likoko, named ancistrolikokines A 2 (13), A 3 (14), C 2 (5), H (15), and H 2 (16). As part of our ongoing studies on the antiproliferative potential of naphthylisoquinoline alkaloids towards cancer cell lines, 18,19,33 the new ancistrolikokines presented here, as well as related known, 20,25-29 but yet not investigated 5,8 0 -coupled alkaloids, were tested for their activities against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions. Fig.…”