than 50% melanin content were observed with the treatment of alpneumine G
(326) and vincamine (286). Melanogenesis was moderately inhibited
(IC 50 = 71.4 µM) by alpneumine E (324). Tyrosinase inhibition potential of these
alkaloids wasalso examined in mushroom tyrosinase assay (in vitro). However, it
exhibited a poor activity (IC 50 > 100 µM). Furthermore, 326 (50 and 75 µM) in
western blotting analysis resulted in a decreased expression of tyrosinase protein.
14.3.10.2 Nitric Oxide Production Inhibition
Koyama et al. isolated alsmaphorazines A (328) and B (329) from the methanolic
extract of A. pneumatophora leaves (Fig. 14.58) and evaluated the inhibitory
potential on the NO production in LPS-stimulated J774.1 (Koyama et al. 2010b).
Alpneumine D (323); R = OH
Alpneumine E (324); R = H
Alpneumine F (325)
Alpneumine G (326)
Alpneumine H (327)
O
O
O
N
N
OH
H
N
+
O
O
O
N
O
-
H
Alpneumine A (320); R = OH
Alpneumine C (321); R = H
O
O
N
H
Alpneumine B (322)
R
N
O
H
H
H
O
O
N
H
HO
N
O
H
H
H
O
O
N
H
R
N
O
H
H
H
N
N
MeOOC
OH
H
O
O
Fig. 14.57 Chemical structures of various alkaloids from A. pneumatophora (320–327)
Alsmaphorazine A (328); R = OH
Alsmaphorazine B (329); R = H
O
N
O
N
R
O
O
OH
Fig. 14.58 Chemical
structures of alsmaphorazine
A and B (328 and 329)
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