administered for the induction of the contraction and 360 showed more potential
relaxation activity (44.3%), while 364 exhibited the least activity (5%).
14.3.14.2 Cytotoxicity Activities
Ku et al. isolated various alkaloids (4,17, 94, 103, 271, 276, 281, 284, 286, 311,
314, 362, 365–372) from ethanolic extracts of A. angustiloba leaf and stem bark
(Fig. 14.64). Further, they evaluated its cytotoxicity effects in vincristine-sensitive
KB and vincristine-resistant (KB/VJ300) cells (Ku et al. 2011). Angustilobine C
(362) showed moderate cytotoxicity toward vincristine-sensitive KB
(IC 50 = 7.76 µg/mL) and KB/VJ300 cells (IC 50 = 7.33 µg/mL). Andransinine
(366) did not exhibit appreciable cytotoxicity against both the cell lines
(IC 50 > 25 µg/mL), however, it reversed MDR in KB/VJ300 cells (IC 50 = 1.61 µg/
mL in the presence of 0.1 µg/mL of vincristine).
HN
OH
OH
O
O
H
N
Alstilobanine A (360)
Alstilobanine B (361)
N
+
O
O
O
NH
- O
Alstilobanine D (363)
N
+
O
NH
O
O
- O
Alstilobanine E (364)
O
O
O
H
N
HN
HO
Angustilobine C (362)
O
O
O
N
H
N
OH
HO
Fig. 14.63 Chemical structures of various alkaloids alstilobanines A–E (360–364)
Boonein (359)
O
O
OH
Fig. 14.62 Chemical structure of boonein (359)
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