LC-MS/MS quantitative determination of Tetrapterys mucronata alkaloids, a plant occasionally used in ayahuasca preparation.

The stem bark of Tetrapterys mucronata, a plant used in Brazilian ayahuasca preparations, contains four tryptamine alkaloids with known toxic and hallucinogenic properties. Quantitation by HPLC-ESI/MS/MS in ethanolic extracts found bufotenine at 3.26 mg/g, 5-methoxy-N-methyltryptamine at 0.88 mg/g, 5-methoxy-bufotenine at 3.07 mg/g, and 2-methyl-6-methoxy-1,2,3,4-tetrahydro-β-carboline at 0.14 mg/g. A water decoction mimicking ayahuasca showed slightly lower levels, with bufotenine at 2.32 mg/g and 5-methoxy-bufotenine at 1.53 mg/g. These significant alkaloid levels, particularly of bufotenine and 5-methoxy-bufotenine, indicate that consuming this plant in ayahuasca may pose a risk to consumers.

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Abstract

Tetrapterys mucronata Cav. (Malpighiaceae) is a plant used in some regions of Brazil in the preparation of ayahuasca. To determine the content of the main tryptamine alkaloids in the stem bark of T. mucronata Cav. and assess their possible toxic and hallucinogenic properties based on the doses found in a water decoction that mimics the ayahuasca preparation. Four alkaloids previously described for their toxic and hallucinogenic properties were quantitated by multiple reaction monitoring HPLC combined with electrospray ionisation and tandem MS (HPLC-ESI/MS/MS) in the water decoction and ethanolic extracts from the bark of T. mucronata. Exhaustive extraction of the stem barks with ethanol revealed the following alkaloid levels: bufotenine (1) 3.26 ± 0.31 mg/g, 5-methoxy-N-methyltryptamine (2) 0.88 ± 0.08 mg/g, 5-methoxy-bufotenine (3) 3.07 ± 0.22 mg/g and 2-methyl-6-methoxy-1,2,3,4-tetrahydro-β-carboline (4) 0.14 ± 0.004 mg/g. The water decoction presented slightly lower levels, ranging between 2.32 ± 0.14, 0.50 ± 0.04, 1.53 ± 0.09 and 0.10 ± 0.01 mg/g for (1), (2), (3) and (4) respectively. The HPLC-ESI/MS/MS quantitation revealed significant alkaloid levels, in particular for bufotenine and 5-methoxy-bufotenine. As such compounds are known for their toxic and hallucinogenic properties, these results indicate that the consumption of this plant as an ingredient in ayahuasca preparations may present a risk to consumers.