Urushiol congeners of Rhus sp. Mother tincture

Rhus genus belongs to the Anacardiaceae family. Several species such as Poison sumac (R. vernix L.) or Atlantic poison oak or poison ivy (R. toxicodendron L.) are well known to cause irritation, inflammation, and blistering of the skin of sensitive individuals [1]. This study focuses on several homoeopathic Mother Tinctures (MT) provided by Boiron Laboratory. Screening of urushiols congeners has been done on the heptanic fraction of the MT. A very sensitive HPLC-ESIMS system has been developed to allow us to identify 8 urushiol congeners (Table 1) on the basis of their fragmentation pattern [2]. Urushiol congeners (C₁₇ and C₁₅ substituted, monoene, diene, triene and tetraene) have been detected only in MT of Rhus sp. which in fact belong to the Toxicodendron synonym genus as described by Miller and Kuntze. (Table 1). The quantitative analyses of urushiols C₁₅ substituted congeners, realised with a validated HPLC-DAD method, reveals a great variability between the Rhus sp. The urushiol congeners profiling could be used to identifiy Toxicodendron species for MT production.

Table 1: Urushiol congeners detected by HPLC-ESIMS in Rhus Species Mother Tincture

Urushiols Double bonds		C15				C17
Double bonds		1	2	3	4	1	2	3	4
Rhus species	synonyms
R. vernix L.	Toxicodendron vernix Kuntze.	++	+++	++	+	+	+	+	+
R. toxicodendron L.	T. pubescens Mill.	++	+++	++++	+	+	+	++	++
R. succedaneum L.	T. succedana Kuntze	+	+	+	-	+	++	+	+
R. cotinus L.	Cotinus coggygria Scop.	-	-	-	-	-	-	-	-
R. glabra L.		-	-	-	-	-	-	-	-
R. aromatica Aiton		-	-	-	-	-	-	-	-

Acknowledgement: David Scherberich of the Lyon Botanical Garden, F69006, Lyon, France.

References: 1. ElSohly, M. et al. (1982)J. Nat. Prod. 45:532–538. 2. Draper, W.M. et al. (2002)J. Agric.Food.Chem. 50:1852–1858