Effects of tenuiorin and methyl orsellinate from the lichen Peltigera leucophlebia on 5-/15-lipoxygenases and proliferation of malignant cell lines in vitro

Bioactive lichen metabolites: alpine habitats as an untapped source

“…Most assays have therefore been carried for these key enzymes, mainly with lichen compounds isolated from material collected in cold places as in Iceland. In a COX screening with depsides and depsidones, 4-O-methylcryptochlorophaeic acid (IC 50 = 0.34 lM) was found to be the most active depside (Sankawa et al 1982) and the monoaromatic phenol lichen compound methyl-b-orsellinate was also found to inhibit phospholipase A2 (Kim et al 1996) and 5-LOX (Ingolfsdottir and Gudmundsdottir 2002). The trimeric depside tenuiorin isolated from Peltigera aphthosa (Ingolfsdottir and Gudmundsdottir 2002), the depsidones baeomycesic acid and lobaric acid, respectively isolated from Thamnolia vermicularis (Ingolfsdottir et al 1997c) and Stereocaulon alpinum (Bucar et al 2004) were also found active against 5-LOX.…”

“…In a COX screening with depsides and depsidones, 4-O-methylcryptochlorophaeic acid (IC 50 = 0.34 lM) was found to be the most active depside (Sankawa et al 1982) and the monoaromatic phenol lichen compound methyl-b-orsellinate was also found to inhibit phospholipase A2 (Kim et al 1996) and 5-LOX (Ingolfsdottir and Gudmundsdottir 2002). The trimeric depside tenuiorin isolated from Peltigera aphthosa (Ingolfsdottir and Gudmundsdottir 2002), the depsidones baeomycesic acid and lobaric acid, respectively isolated from Thamnolia vermicularis (Ingolfsdottir et al 1997c) and Stereocaulon alpinum (Bucar et al 2004) were also found active against 5-LOX. Although a dual inhibition of the inflammatory targets could result in more effective drugs, a selective inhibition of LOX with regard to COX, as for protolichesterinic acid (Ingolfsdottir et al 1994a), can be of interest as the gastroprotective effect of prostaglandins would be theorically maintained.…”

“…Anti-inflammatory effect: inhibition of human synovial fluid phospholipase A2 (IC 50 = 0.26 mM) Kim et al (1996) Inhibition of 5-lipoxygenase (IC 50 = 41.6 lM) Ingolfsdottir and Gudmundsdottir (2002) Dibenzofuranes derivatives…”

“…The antiproliferative activities of tenuiorin (a tridepside, as gyrophoric acid found in Umbilicaria species) and methyl orsellinate extracted from Peltigera leucophlaebia were tested on human breast (T-47D), pancreatic (PANC-1), and colon (WIDR) cancer cell lines; the former compound caused a weak-to-moderate effect on the pancreatic and colon cells, whereas methyl orsellinate was without effect (Ingolfsdottir and Gudmundsdottir 2002). A moderate cytotoxicity (IC 50 # 0-13 lM) on three carcinoma cell lines has been recently described for stereocalpin A, a new cyclic depsipeptide (Fig.…”

Assessment of Antifungal Activity of Some Himalayan Foliose Lichens Against Plant Pathogenic Fungi

“…Out of 700 secondary metabolites so far known from lichens 550 are unique to them [6]. The lichen extracts and their components have a distinguished antimicrobial activity [2,5,[7][8][9]. On the other hand, it is well known that microorganisms have well developed resistance to many antibiotics.…”