Planta Med 2011; 77 - PL87
DOI: 10.1055/s-0031-1282736

Antioxidant activity of crude foliar extracts and alkaloids of Psychotria spp. (Rubiaceae)

A Berger 1, S Johann 1, G Harald 1, V Karin 1
  • 1Chemodiversity Research Group, Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria.

Current studies on the chemodiversity of the paraphyletic and pantropical genus Psychotria revealed the presence of various types of alkaloids [1]. Several species are used in traditional medicine of indigenous people for treatment of different diseases, as health tonics and as depurative [2]. In order to asses eventual antioxidative activities, crude methanolic extracts from more than 20 species of Psychotria s.l. were subjected to the diphenylpicrylhydrazyl (DPPH) free radical-scavenging assay and EC50 values were determined. In addition, total phenolic compounds were assessed using Folin-Ciocalteus reagent. Within different taxonomic groups of Psychotria, strongest observed activity was restricted to members of subg. Psychotria. At comparable concentration, alkaloids isolated from different Psychotria spp. [1] showed lower activity than crude extracts. Thus, it may be assumed that total antioxidant activity of crude extracts is not only caused by the presence of alkaloids but also due to the accumulation of phenolic compounds. Results of the present analysis indicate that members of subg. Psychotria are promising sources of natural antioxidants due to the observed radical scavenging properties of their extracts. The antioxidant activity may be causal for the use of these species in folk medicine. From the chemotaxonomic point of view, differentiation in the degree of antioxidant activity within Psychotria correlates well with current taxonomic views [3], confirming that species of subg. Heteropsychotria, devoid of strong activity, should be placed in a separate genus.

References: 1. Berger A et al. (2010) In: Program and Abstracts, 19th International Symposium „Biodiversity and Evolutionary Biology“, German Botanical Society (DBG), Univ. Vienna, Austria, p.76.

2. Sanz-Biset J, Campos-de-la-Cruz J, Epiquién-Rivera MA, Cañigueral S (2009)J Ethnopharmacol 122: 333–362.

3. Nepkroeff M, Bremer B, Systma KJ (1999) Syst Bot 24: 5–27.