Dihydroxyaflavinine

Sheng Li Xue Bao. 1991 Jun;43(3):227-35.

Fungal toxin dihydroxyaflavinine inhibits non-competitively GABAA receptor channel expressed in Xenopus oocytes.[Pubmed: 1664974]

Dihydroxyaflavinine is an indole-derived metabolite of Aspergillus flavus.
METHODS AND RESULTS:
Its action on GABA-induced response was quantitatively studied on the GABAA receptor expressed in Xenopus oocytes after injection of chick brain mRNA under voltage-clamp conditions. Dihydroxyaflavinine inhibits GABA-induced current non-competitively with KI = 12 mumol/L. This blockage is rapidly reversible. In comparison, the inhibitory effect of penicillin on GABAA receptor is enhanced by increasing GABA concentration. Ro 15-1788 (a benzodiazepine ligand with KD = 0.6--2 nmol/L) of concentration as high as 1 mumol/L, does not mask the action of 10 mumol/L Dihydroxyaflavinine, indicating that Dihydroxyaflavinine acts on a site different from benzodiazepines.
CONCLUSIONS:
Dihydroxyaflavinine appears to expedite desensitization of the receptor, which is similar to the action of picrotoxin and in contrast with that of penicillin and bicuculline.

J Antibiot (Tokyo). 1988 Dec;41(12):1868-72.

Toxicity of selected tremorgenic mycotoxins and related compounds to Spodoptera frugiperda and Heliothis zea.[Pubmed: 3209479]

METHODS AND RESULTS:
A series of tremorgenic mycotoxins and related compounds were tested for oral toxicity to the fall armyworm (Spodoptera frugiperda) and corn earworm (Heliothis zea) by incorporation of materials into artificial diets and examining mortality and weights after 7 days. Significant mortality to both insect species was caused with Dihydroxyaflavinine and roseotoxin B, while significant mortality to H. zea was also caused by penitrem A at 25 ppm. After 7 days, weighs of larvae treated with 25 ppm penitrem A, roseotoxin B, and verruculogen were less than 50% of controls for both insect species. Weights of H. zea larvae treated with 25 ppb of penitrem A were less than 50% those of control larvae. Relative toxicities of the tremorgens and related compounds to insects compared to vertebrates are discussed.