Isolation of drug candidate compounds from some acanthus L. species growing in Turkey

The genus Acanthus (Acanthaceae), which includes about 30 species in worldwide, is widespread in Asia, Europe, Africa and Australia. It is represented by 8 taxa, 3 of them are endemic in Turkish Flora. Acanthus L. species are used as for healing wounds, an expectorant and relieving constipation in Turkish traditional medicine. They are used to relieve pain in chest, for gastrointestinal system problems, urinary system diseases, hepatitis, lymphomas and rheumatism in different countries. In the present study, aqueous extracts of the aerial parts of A. dioscoridis L. var. dioscoridis L. and A. spinosus L. were studied for their chemical compositions and some biological effects. Studied biological activities were selected according to the effects and uses of the species. As a result of the phytochemical studies, the structures of 14 compounds from two plants, were elucidated by advanced spectroscopic methods. Four of them were phenylethanoid glycosides (acteoside [AD-12=AS-2], β-hydroxy acteoside [AS-1], leucoceptoside A [AD-6], martynoside [AD-1]), four were benzoxazinoids (benzoxazole-2(3H)-one [AD-4], 2,4-dihydroxy-1,4-benzoxazine-3 (2H)-one [AD-7=AS-5], 2-O-β-glucopyranose-4-hydroxy-1,4-benzoxazine-3(2H)-one [AD-14=AS-7], acanthaminoside [AD-16]), two were acylated flavanone glucosides (naringenin 7-(3"-acetyl-6"-E- p-coumaroyl) glucoside [AD-2]), naringenin 7-(6"-E- p-coumaroyl) glucoside [AD-3]) and one was lignan glucoside (pinoresinol-4-O-β-glucopyranoside [AD-8]). Biological effects of extracts, fractions and two pure compounds ([AD-4] and [AD-6]) were investigated by DPPH, NO and SO radical scavenging capacities, cytotoxic activities against cancer cells (HEp-2 and HeLa ) and healthy cells (FHs 74, RAW 264.7 and L929), genotoxic activities against (FHs) healthy cells. Antiinflammatory effects via NO and PGE2 cytokine levels in LPS-stimulated RAW 264.7 cells and wound healing activity on L929 cells were also tested. The results showed that A. dioscoridis var. dioscoridis and A. spinosus aqueous extracts possessed 90 % inhibition against DPPH radical. No genotoxic and cytotoxic effects were observed. They inhibited the nitric oxide production 38.2 % and 47.9 % at 800 μg/ml, respectively. All tested samples inhibited PGE2 production significantly. PGE2 production in positive control LPS (+) was found to be 1837 pg/ml, while in negative control LPS (-) was 35 pg/ml. The aqueous extracts of A. dioscoridis var. dioscoridis and A. spinosus decreased the PGE2 levels to 466 and 728 pg/ml at 10 μg/ml, respectively. A.dioscoridis var. dioscoridis polyamide column fraction eluted with 35 % methanol (Fr. C) decreased PGE2 levels to 165 pg/ml at 5 μg/ml. PGE2 levels were determined as 304 and 347 pg/ml by treatment with [AD-4] and [AD-6] at 20 μg/ml. Cell damage in L929 cells was improved completely in 48 hours by the extracts. Our thesis work is important in terms of gaining the studies that support the traditional use of Acanthus species to scientific literature, with detailed phytochemical and biological effect studies conducted on two Acanthus species grown in our country. Keywords: Acanthus species, phytochemistry, isolation, structure elucidation, antioxidant effect, cytotoxic effect, genotoxic effect, antiinflammatory effect, wound healing effect.