Table 4 Cell metabolic activity data in the presence of the title phosphonates and their comparison to naturally occuring PCTs and doxorubicin.

Betulinic acid

1.12 ± 0.08

0.91 ± 0.14

0.74 ± 0.16

0.97 ± 0.07

0.56 ± 0.04

0.76 ± 0.07

Betulonic acid (2a)

0.88 ± 0.08

0.96 ± 0.04

1.14 ± 0.02

1.22 ± 0.01

1.70 ± 0.05

1.39 ± 0.06

7a

1.09 ± 0.04

1.30 ± 0.06

1.10 ± 0.04

1.13 ± 0.03

1.27 ± 0.05

1.41 ± 0.01

8a

1.59 ± 0.17

1.24 ± 0.25

1.58 ± 0.05

1.01 ± 0.05

1.19 ± 0.04

1.08 ± 0.05

Oleanolic acid (1b)

1.29 ± 0.11

1.58 ± 0.13

0.77 ± 0.14

0.96 ± 0.05

0.97 ± 0.08

1.04 ± 0.07

Oleanonic acid (2b)

1.03 ± 0.18

1.60 ± 0.03

1.51 ± 0.08

0.49 ± 0.12

0.99 ± 0.05

1.10 ± 0.01

7b

1.19 ± 0.05

1.32 ± 0.05

1.13 ± 0.08

1.04 ± 0.05

1.50 ± 0.04

1.31 ± 0.08

8b

0.73 ± 0.05

0.76 ± 0.04

0.84 ± 0.04

0.86 ± 0.08

0.97 ± 0.04

1.00 ± 0.03

Ursolic acid (1c)

0.28 ± 0.04

0.64 ± 0.03

0.66 ± 0.03

0.99 ± 0.08

0.83 ± 0.05

1.06 ± 0.05

Ursonic acid (2c)

0.67 ± 0.04

0.67 ± 0.04

0.76 ± 0.08

0.72 ± 0.09

1.07 ± 0.07

0.74 ± 0.02

7c

1.12 ± 0.03

0.98 ± 0.04

0.96 ± 0.04

0.94 ± 0.05

0.90 ± 0.03

0.91 ± 0.06

8c

1.26 ± 0.08

0.91 ± 0.05

1.22 ± 0.09

0.95 ± 0.03

0.89 ± 0.04

0.93 ± 0.09

12

0.94 ± 0.04

0.89 ± 0.05

0.97 ± 0.08

0.92 ± 0.04

0.93 ± 0.06

0.90 ± 0.07

Doxorubicin

0.16 ± 0.02

0.19 ± 0.01

0.41 ± 0.02

0.53 ± 0.03

0.60 ± 0.03

0.72 ± 0.07

Positive control

1.42 ± 0.03

1.10 ± 0.10

Negative control

0.16 ± 0.08

0.28 ± 0.12