Studies on the antivenom activity of four plant species from Flora Ikaria: An ethnopharmacological approach

Theriaca is a poem of the ancient greek physician Nicander of Colophon (2^nd century BC). This is his longest surviving work and is referred to antidotes of plant origin against bites from venomous creatures [1]. Flora Ikaria was chosen as the area where four species, mentioned in Theriaca, were collected [2]. These are Aristolochia hirta, Anchusa undulata, Echium plantagineum, Scorpiurus muricatus and are native to island Ikaria. Different parts of these species e.g. roots, stems, were extracted with different polarities. Twenty three extracts were obtained. The LC-MS and HPTLC profiling revealed the variety of metabolites. Also their anti-ophidian properties were evaluated using enzyme inhibition assays. Acetylcholinesterase, phospholipase A2 (sPLA2) and hyaluronidase are the examined biological targets since they are present in snake's venom. The hydroalcoholic extracts from the roots and aerial parts of Aristolochia hirta, an endemic species of East Aegean Sea, were selected for further phytochemical analysis. They are the most potent inhibitors of sPLA2 and AChe respectively during the preliminary screening and they are rich in different types of metabolites. The fractionation of the root extract was accomplished by Centrifugal Partition Chromatography. Several chromatographic techniques lead to the isolation of compounds from both extracts. NMR (1D,2D) spectroscopy permitted their identification. From the root extract nine compounds were obtained, belonging to categories of aristolochic acids (aristolochic acid I), hydroxycinnamic acids (p-coumaric acid) and their glucosylated derivatives (acretoside). From the aerial parts extract one cinnamoyl amide was isolated and was strong inhibitor of AChe. This work concluded to active agents against envenomations which may further be used as therapy against wounds or neurological diseases where the same biological targets are implicated.

[1] Gottlob J, Schneider G, Fleischer, Theriaca. Nicandri Colophonii, 1816

[2] Christodoulakis D, The flora of Ikaria (Greece, E. Aegean islands), Phyton (Horn, Austria) 1996; 36:63 – 91