An Endogenous Bile Acid and Dietary Sucrose from Skin Secretions of Alkaloid-Sequestering Poison Frogs

Abstract

The skins of Madagascar poison frogs (Mantella) and certain Neotropical poison frogs (Epipedobates, Dendrobates) secrete the new bile acid tauromantellic acid (1), which was found in both wild-caught and captive-born frogs. This is the first molecule of endogenous origin detected in skin secretions from these taxa. Sucrose was also detected in secretions from wild-caught Mantella but not in captive-born frogs, suggesting a dietary origin.

Molecular physiology of chemical defenses in a poison frog

“…The transporter responsible for bile acid-associated export from intestinal cells into the portal blood is solute carrier protein 51a (slc51a, also known as organic solute transporter subunit alpha) (Dawson and Karpen, 2014), which has increased expression in the liver of chemically defended wild frogs compared with laboratory frogs. Bile acid-associated pathways are of particular interest, as bile acid derivatives have been observed in the skin of mantellid poison frogs (Clark et al, 2012), suggesting a bile acid-based transport system for some poison frog alkaloids. Alkaloids can also be carried by a number of transport proteins in the blood circulation.…”

Bicyclic C21 Terpenoids from the Marine Sponge Clathria compressa

“…A comparison of the NMR data (Table 2) revealed that 2 was very similar to 1 , except for the presence of an additional A 2 X 2 spin system [δ H 2.92 (2H, t, J = 6.8 Hz), δ c 51.5 (CH 2 ); δ H 3.55 (2H, t, J = 6.8 Hz), δ c 36.7 (CH 2 )] consistent with a taurine group. 9 This suggested that the clathrimide A ( 2 ) was the N -acyl taurine derivative of 1 . An HMBC correlation observed between H 2 -1′ (δ H 3.55) of the taurine group and the amide carbonyl carbon at δ C 175.9 (C-1; IR = 1645 cm −1 ) confirmed the connection of the taurine to the terpenoid skeleton.…”

Molecular physiology of chemical defenses in a poison frog

“…(slc51a, also known as organic solute transporter subunit alpha) (Dawson and Karpen, 2014), which has increased expression in the liver of chemically defended wild frogs compared to laboratory frogs. Bile acid-associated pathways are of particular interest, as bile acid derivatives have been observed in the skin of mantellid poison frogs (Clark et al, 2012), suggesting a bile acid-based transport system for some poison frog alkaloids. Alkaloids can be also be carried by a number of transport proteins in the blood circulation.…”