Telomerase also called telomere terminal transferase is a ribonucleoprotein that adds the polynucleotide “TTAGGG” to the 3 end of telomers. The human telomerase enzyme complex consists of two molecules each of human telomerase reverse transcriptase (TERT), telomerase RNA (TR or TERC), and dvskerin (DKC1)[35]. By using TERC, TERT can add a six-nucleotide repeating sequence, 5'-TTAGGG (in vertebrates, the sequence differs in other organisms) to the 3' strand of chromosomes. These TTAGGG repeats (with their various protein binding partners) are called telomeres. The template region of TERC is 3'-CAAUCCCAAUC-5'. Telomerase can bind the first few nucleotides of the template to the last telomere sequence on the chromosome, add a new telomere repeat (5'-GGTTAG-3') sequence, let go, realign the new 3'-end of telomere to the template, and repeat the process[36]
A series of novel coumarin derivatives containing 4,5-dihydropyrazole moiety as potential telomerase inhibitors were synthesized. The bioassay tests show that compound 3d exhibited potentially high activity against human gastric cancer cell SGC-7901 with IC(50) value of 2.69 ± 0.60 μg/mL(fig.14).
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In 2013, construct a series of C-7 substituted sulfocoumarins and 3,4-dihydrosulfocoumarins by methanesulfonate of 2,4-dihydroxy or 2-hydroxy-4-methoxbenzaldehyde go along by derivation reaction. The synthesized compound was found to have carbonic anhydrase inhibitory action. A number of new classes of coumarins of carbonic anhydrase inhibitors were informed as a lead and that class is sulfocoumarins. SAR studies of sulphocoumarins indicated that substitution at C-7 position of coumarin nucleus powerfully control the human carbonic anhydrase VA (hCA VA) inhibition. It was also found that existence or nonexistence of double bond in the compound doesn't have an effect on the hCA II inhibitory activity. SO2 responsible for CA inhibitory action of the compound. If R = OH, hCA 2 inhibitory activity is reduced.