Coumarins from Magydaris pastinacea as inhibitors of the tumour-associated carbonic anhydrases IX and XII: isolation, biological studies and in silico evaluation

Figures & data

Table 1. ¹H NMR and ¹³C NMR Spectroscopic Data for Compound 11 (CDCl₃, δ in ppm).

Compound 11
Position	δC, type	δH (J in Hz)
2	161.2, C
3	112.8, CH	6.23, d (9.5)
4	143.7, CH	7.59, d (9.5)
5	109.4, CH	6.77, s
6	141.8, C
7	146.1, C
8	115.5, C
9	152.5, C
10	112.8, C
2′	92.2, CH	4.86, t, (9)
3′	28.2 CH2	3.36, dd (1.5, 9)
4′	71.8, C
5′	24.1 CH3	1.25, s
6′	26.1, CH3	1.40, s
OCH3	56.4, CH3	3.91, s

Figure 1. Structures of the isolated coumarins.

Table 2. Inhibition data towards hCA I, II, IX, and XII of compounds 1–15.

	Ki (nM)*
Compound/extract	hCA I	hCA II	hCA IX	hCA XII
Petroleum ether	>100^a	>100^a	20^a	0.8^a
Ethyl acetate	>100^a	>100^a	1.74^a	0.5^a
1	>10,000	>10,000	1953	855.1
2	>10,000	>10,000	194.8	876.3
3	>10,000	>10,000	159.8	590.1
4	>10,000	>10,000	2339	550.0
5	>10,000	>10,000	1501	63.5
6	>10,000	>10,000	221.4	832.9
7	>10,000	>10,000	201.9	786.9
8	>10,000	>10,000	162.5	835.6
9	>10,000	>10,000	27.5	813.8
10	>10,000	>10,000	192.5	>10,000
11	>10,000	>10,000	150.9	623.0
12	>10,000	>10,000	2471	74.5
13	>10,000	>10,000	1888	>10,000
14	>10,000	>10,000	>10,000	290.9
15	>10,000	>10,000	266.4	5.8
AAZ	250.0	12.1	25.8	5.7

^a Data expressed in ng/mL.

^* Mean from three different assays, by a stopped flow technique (errors were in the range of ±5–10% of the reported values).

Figure 2. Main HMBC correlations of compound 11.

Figure 3. ECD (left) and UV (right) spectra of compound 11.

Figure 4. 3D representation of the putative binding mode obtained by docking experiments. (a,b) CA -XII-15 (c,d) CA -XII-11, (e,f) CA -XII-9 and the relative 2D representation of the complexes stabilising interactions with the binding site residues represented with different colour depending on their chemical-physical properties: green, hydrophobic; cyan, polar; violet, positive; red, negative charged residues; grey, metal atoms. Instead, magenta arrows indicate the formation of hydrogen bond between protein and ligand, while grey lines indicate the interaction with the complexed ion.

Figure 5. 3D representation of the putative binding mode obtained by docking experiments. (a,b) CA -XII-15-openE (c,d) CA -XII-15-openZ and the relative 2D representation of the complexes stabilising interactions with the binding site residues, with the colour scheme indicated above.

Table 3. Cytotoxic effect of compounds 5, 9–12 and 15 evaluated towards cancer HeLa cells.

Compound	IC50^a (µM)
5	>100
9	>100
11	>100
10	>100
12	98
15	75

^a Concentration of compound that reduces the cell viability to 50% measured at 48 h.