No abstract

Sixteen novel orsellinic esters (6a-l, 7a-d) along with four lecanoric acid related depsides (3a-c, 4) were synthesized and confirmed their structures by spectroscopic data (H, C& HRMS). The synthesized compounds were evaluated for their in vitro α-glucosidase (Saccharomyces cerevisiae) inhibitory potential. Among the tested compounds, 3c (IC: 140.9 μM) and 6c (IC: 203.9 μM) displayed potent α-glucosidase inhibitory activity and found more active than the standard drug acarbose (IC: 686.6 μM). Both the test compounds were subjected to in vivo antihyperglycemic activity using sucrose loaded model in Wistar rats and found compound 3c exhibited significant reduction in glucose levels.

Lichens have attracted considerable interest since ancient time due to their medicinal properties. Lichen produce a variety of orcinol-based compounds such as xanthones, anthraquinones, dibenzofurans, depsides, and depsidones. Several related compounds have shown potent bioactivities as antiviral, antioxidant, anti-herbivore, insecticidal, antifungal, and anticancer. Lichens have been employed as traditional medicines, and these are continuing to be of great interest for their biotechnological potential. The purpose of this review was to systematically evaluate the literature on the orcinol based biologically active secondary metabolites of lichen.