Simultaneous determination of oenothein B and quercetin glucuronide in aqueous extract of Epilobii angustifolii herba

Epilobium angustifolium L.(Oenotheraceae), a representant of willow-herbs species found throughout northern temperate regions, is used in folk medicine for benign prostate hyperplasia (PBH) and associated with problems of micturition. Its use to treat prostatic adenoma has also been mentioned. The dimeric ellagitannin oenothein B (OeB) appeared to be responsible for some observed biological activity of extracts [1,2,3]. Flavonoids possibly act synergistically with oenothein B [3,4,5].

The method of separation and quantitative determination of OeB and quercetin glucuronide (GQ) in an aqueous extract of Epilobii angustifolii herba by HPTLC-densitometry was developed. Powdered plant material was extracted with water (1:10) in an ultrasonic water bath. The extract was filtrated and lyophilised. Samples were applied by an automatic applicator. Chromatography was performed in a vertical chamber. HPTLC RP-18 WF₂₅₄ plates were used. As a first mobile phase 25% of MeCN in water (+ 50mM H₃PO₄) was used (distance of 8cm), then acetonitrile was used as a second mobile phase (distance of 4cm). Plates were dried and scanned. Densitometry was carried out by using of Shimadzu CS-9301PC densitometer. The absorption spectra were recorded at 270nm (OeB) after first developing and at 350nm (GQ) after second. The amount of OeB and GQ in the aqueous extract of Epilobii angustifolii herb using the developed method were 152.46±4.92mg g^-1 and 22.07±1.38mg g^-1respectively.

References: [1] Hiermann A., Radl B. (1998) J Chromatogr A 803: 311. [2] Vitalone A. et al. (2003) Pharmacol 69: 79. [3] Kiss A. et al. (2006) Pharmazie 61: 66. [4] Shikov A.N. et al. (2006) J Agric Food Chem 54: 3617. [5] Kiss A. et al. (2004) Planta Med. 70: 919.