Galanga 351
the hexane fraction exhibited high mosquito larvicidal effect and also repellent activity
for adult mosquito (Taesotikul et al., 1999). Xue and Chen (2002) have shown that
cis- and trans-ethyl p-methoxy-cinnamate inhibit EBV in vitro and also has an inhibitory
effect in TPA assays or croton oil-induced ear edema, ODC activity in mouse epidermis
and papilloma indicating a relatively strong anti-carcinogenic potential of ethyl-p-
methoxy cinnamate.
Ethyl cinnamate (EC) inhibited the contractions induced by high K+ and
Phenylephrine (PE) in a concentration-dependent manner. The relaxant effect against
PE-induced contractions was greater in the presence of endothelium. This inhibition
effect of EC is believed to involve the inhibition of Ca++ influx into vascular cells and
release of NO and prostacyclin from the endothelial cells (Othaman et al., 2002).
This explains the traditional use of galanga for treating hypertension. Chloroform
extract inhibited vascular smooth muscle contraction by the inhibition of Ca2+ influx
and Ca2+ sensitivity of contractile elements (Mustafa et al., 1996).
The hexane fraction of K. galanga rhizome is categorized as a non-irritant both in
animal and human volunteer studies (Choochote et al., 1999; Kanjanpothi et al.,
2004). Acute toxicity studies using alcoholic extracts of the rhizome on mice and
rabbits, indicated that oral administration of 5 g/kg and 10 g/kg of crude extract was
non-toxic (Kanjanapothi et al., 2004). K. galanga demonstrates less toxicity, but it is
considered as an effective botanical insecticide with high larvicidal activity and a
protective effect against mosquitoes (Choochote et al., 1999).
20.5 Chemistry........................................................................................
K. galanga rhizome contains about 2.5 to 4% essential oil. The main components of
the oil are ethyl cinnamate (25%), ethyl-p-methoxycinnamate (30%) and p-
methoxycinnamic acid and a monoterpene ketone compound, 3-carene-5-one (Kiuchi
Table 20.1 Biological actions of important components
Component Biological property
Borneol Analgesic, antiacetylcholine, antibacterial, antibronchitic, antifeedent, anti-
inflammatory, antiotitic, antipyretic, antispasmodic, antimicrobial, CNS-
stimulant, hepatoprotectant, irritant, myorelaxant, sedative, tranquilizer.
Camphene Antioxidant, expectorant, hypocholesterolemic, spasmogenic, insecticidal
Carene Antiseptic, irritant.
Kaempferol Antiallergic, antiaggregant, anticancer, antifertility, antiimplantation,
antilymphocytic, antihistamine, antioxidant, antispasmodic, serotonin
suppressor, aromatase inhibitor, antitumour, glucosyl transferase inhibitor,
antihepatotoxic, anti-inflammatory, lipoperoxidase inhibitor, antimetastatic,
antimutagenic, antimyocardiatic, ATP-ase inhibitor, CAMP-phosphodiesterase
inhibitor, carcinogenic, (at/V 40000 ppm), catechol-o-methyltrasferase
inhibitor, COX-2 inhibitor, De-iodinase inhibitor, lipoxygenase inhibitor,
metalloproteinase inhibitor, NADH-oxidase inhibitor, NO-inhibitor, ornithine
decarboxylase inhibitor, P450 inhibitor, phospholipase inhibitor, protein kinase-
c-inhibitor, tyrosinase inhibitor, protein tyrosinase kinase inhibitor, quinone
reductase inducer, lopoisomerase I and II inhibitor, xanthine oxidase inhibitor,
vasodialator.
Sources Duke, 2003; Duke and Du Cellier, 1993.