Abstract:
Past studies stated that consumption ofhurulla (Amblygaster sirm) gave an
adverse reaction to tuberculosis patients treated with isoniazid drugs and
that the cause may be tyramine. In order to test this hypothesis fresh hurulla
samples were tested for histamine and tyramine with and without storage at
room temperature using TLC and enzymatic methods. Only traces of
tyramine (RfO.88) were found in only 5% of the samples ofhurulla even in
the presence of exogenous tyrosine. However, histamine (Rf 0.63) was
detected and it was low, 0.34 mg/g of fish. Many other free amino acids
were detected on keeping the fish at room temperature.
The bacteria producing these amines were isolated from the fish and cultured
in a liquid medium. TLC was carried out from these bacterial supernatants
to detect histamine. Histamine spots were then quantified by (I) ninhydrin
reaction using a spectrophotometer at 570nm or densitometer. (II) Using an
ELISA technique. (III) Histaminase assay. All forty-four bacterial colonies
isolated were tested for histamine production from histidine. Eleven colonies
showed> 0.8mg/m!. However studies with this culture in the log phase of
the growth showed that the bacteria produced maximum histamine at 24
hours. However histamine content declined thereafter and was not detected
in a 48 h culture. Adjusting pH to 1to solubilize histamine complex increased
histamine levels. Addition of EDTA (0.005mg.ml-') increased histamine
content with the age of supernatant indicating that chelation could prevent
the breakdown of histamine decarboxylase. There was no evidence of
breakdown of histamine or tyramine.
Studies show that tyramine is not the cause for adverse reactions with
isoniazid drugs. Although the histamine content is low, it may contribute to
allergic reactions.
