302 
such rugged types as Aspergillus niger. Perhaps 
the best known antibiotic which is effective 
against fungi is griseofulvin and it has absolutely 
no effect on Aspergillus niger. 
(iii) The effect of the pyrones is very selec- 
tive. Only certain genera of fungi, often only 
certain species, are attacked. Among the fungi 
which are completely untouched are the yeasts 
— pathogenic forms as well as the ancient wine 
and beer yeasts. Further investigations are de- 
signed to show whether among the fungi which 
are affected by the kawa pyrones are genera 
which are pathogens in man. 
CHEMICAL AND PHYSICAL PROPERTIES 
of the Kawa lactones 
Chemical Behavior 
The characteristic constituents of kawa may be 
classified into two main groups. The first group, 
of which kawain is an example, is characterized 
by a single double bond in a 6-membered 
lactone ring. The second type, of which yangon- 
in is an example, belongs to the series of die- 
nolides. However both types may be considered 
either 6-membered lactones or 6-sty ryl-a-py- 
kawain type yangonin type 
(dienolide, Bu'lock i Smith, 1960; 
Chmielewska eta]. 1958) 
0 
yangonin type 
(old y-pyrone formula, Borsche, 1914) 
rones. The recognition that yangonin also pos- 
sesses lactone character is however rather recent 
(Chmielewska et ah, 1958). Earlier it was con- 
sidered a y-pyrone and accordingly two series 
of characteristic kawa constituents were differ- 
entiated, the a-py rones (lactones) and the y- 
py rones. It is obvious that the structural elucida- 
tion of yangonin provided some difficulties. In 
order to demonstrate these peculiar difficulties 
it is more useful to outline a synthesis of yan- 
gonin starting from the dimethyl derivative 
(yangonalactone) rather than to trace the his- 
torical development which eventually led to the 
PACIFIC SCIENCE, Vol. XXII, July 1968 
TABLE 3 
Inhibition of Some Fungi and Streptomyces 
Organisms by Powdered Kawa Rhizomes 1 
TEST ORGANISMS 
g/ml 
Trichothecium roseum 
0.05 
Alternaria consortiale 
0.03 
Penicillium funiculosum 
(potential human pathogen) 
0.02 
Alternaria humicola 
0.008 
Streptomyces griseus 
0.005 
Crytococcus neof ormans 
(human pathogen) 
0.005 
Trichophyton tonsurans 
(human pathogen) 
0.005 
Streptomyces purpurescens 
0.005 
Paecilomyces varioti 
0.0035 
Aspergillus niger 
(potential human pathogen) 
0.003 
Chaeto?nium globosum 
0.003 
Trichophyton ferrugineum 
(human pathogen) 
0.001 
Botrytis cinerea 
( + ) 
Scopulariopsis brevicaulis 
(potential human pathogen) 
( + ) 
Saccharomyces cerevisiae 
0+) 
Aspergillus tamarii 
(+) 
Aspergillus flavus 
( + ) 
Fusarium solani 
(-) 
Candida albicans (human pathogen) 
(-) 
Candida krusei 
(-) 
Candida parakrusei 
(-) 
Candida parapsilosis 
(-) 
Candida tropicalis 
(-) 
1 The numbers are the minimum concentrations (g) of 
kawain per volume (ml) nutrient which completely inhibit 
macroscopically visible development of the fungus. (+) 
Indicates only growth inhibition at a concentration of 
0.05 g/ml. ( — ) Indicates no effect at a concentration of 
0.05 g/ml. (Hansel et al., 1966). 
correct formulation of yangonin. Methylation 
of the styryl substituted with triacetolactone 
(yangonalactone) with diazomethane leads to 
two isomeric methyl derivatives, one of which 
is identical with the natural product. The ques- 
tion remains which of the two isomeric methyl 
triacetolactones is identical with the natural 
product, the a- or the y-pyrone. Borsche (1914) 
f - pyrone 
