title: Polyphenol composition and antioxidant capacity of Epilobium species.
abstract: Epilobium species (Onagraceae) are commonly used herbal remedies in traditional, adjuvant therapy of benignus prostate hyperplasia (BPH), however the pharmacological and clinical standardization of commercially available Epilobii herba (willow-herb) remains difficult. Willow-herb products usually consist of mixtures from various species, with different phenoloid content, often only partially identified. The present study reports comprehensive LC-MS/MS investigation on the polyphenol composition of the most common Epilobium species, emphasizing the pharmaceutical importance of a uniform standardization protocol in case of their products. The antioxidant capacity of species was evaluated by a simple spectrophotometric method, using ABTS(+) (2,2'azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)). High ratio of macrocyclic tannins, mainly oenothein B was identified in all Epilobium species examined. Flavonoid composition of Epilobium extracts showed several differences, especially comparing E. angustifolium to other species. Myricetin, quercetin, kaempferol and their various glycosides were dominant in samples, but their combination and ratio were distinctive in all cases. Epilobium extracts showed high radical-scavenger activity, comparable to that of well-known antioxidants, Trolox and ascorbic acid. Among species examined, extract of Epilobium parviflorum possessed the highest antioxidant capacity (EC(50)=1.71+/-0.05 microg/ml).
authors.affiliation: Semmelweis University, Department of Pharmacognosy, Ulloi Str. 26, H-1085 Budapest, Hungary. hevesi.t.barbara@gmail.com
authors.forename: Barbara
authors.initials: B
authors.lastname: Hevesi Tóth
authors.forename: Balázs
authors.initials: B
authors.lastname: Blazics
authors.forename: Agnes
authors.initials: A
authors.lastname: Kéry
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002853:Chromatography, Liquid; D031666:Epilobium / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000494:pharmacology; D047348:Hydrolyzable Tannins / Q000032:analysis / Q000737:chemistry; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D059808:Polyphenols; D013045:Species Specificity; D053719:Tandem Mass Spectrometry
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D016166:Free Radical Scavengers; D047348:Hydrolyzable Tannins; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; C080077:oenothein B