An investigation on the cardioprotective potential of lichen compound protocetraric acid by H2O2-induced toxicity in H9c2 rat heart cells through in vitro and in silico analysis.

Worldwide, cardiovascular diseases (CVDs) are the leading cause of death and require treatment and prevention. Lichens are symbiotic organisms that are known to produce unique secondary metabolites and have been used as folk medicines. The aim of the study is to emphasize the importance of lichens in improving heart health, with the objective of investigating protocetraric acid, a lichen metabolite, for its antioxidant and cardioprotective potential by using in vitro and in silico techniques. Protocetraric acid (PRC) was isolated, characterized, and tested for antioxidant properties using six assays. In cardiovascular investigations, hydroxymethylglutaryl-coenzymeA reductase (HMGCR), angiotensin-converting enzyme inhibitory, and fibrinolytic capacities, along with enzyme inhibitory kinetics studies, were carried out. In silico toxicology and molecular docking analysis were done to determine the binding sites on target proteins. The cytoprotective ability of PRC was evaluated by H2O2-induced toxicity in H9c2 rat heart cells. Out of six lichens, the extract of F. caperata showed comparatively stronger antioxidant activity in terms of 1,1-diphenyl-2-picryl hydrazil (DPPH), scavenging of nitric oxide (SNO), and ferric reducing potential (FRAP) equivalent values. PRC showed significant antioxidant properties, and with respect to cardiovascular studies, PRC exhibited 86% HMGCR and 82% ACE inhibition, while 57% fibrinolysis at 320 µM concentration. Inhibitory kinetic tests of PRC showed competitive and uncompetitive HMGCR and ACE inhibition types respectively. PRC showed minimum binding energies of - 7.9, - 8.9, and - 9.0 kcal/mol with 1HWK, 1O8A, and 4BZS. The H9c2 cell line pre-treated with PRC was found to reduce H2O2 toxicity as well as increase cell viability. Protocetraric acid is a potent compound that has been experimentally shown to have hypocholesterolemic, hypotensive, and cardioprotective properties for treating cardiovascular diseases.

In†Vitro and in†Silico Studies of Lichen Compounds Atranorin and Salazinic Acid as Potential Antioxidant, Antibacterial and Anticancer Agents.

Lichens are symbiotic organisms made up of alga/cyanobacterium and fungus. We investigated antioxidant, antibacterial and anticancer properties of two lichen compounds, atranorin and salazinic acid, and five lichen species: Heterodermia boryi, Heterodermia diademata, Heterodermia hypocaesia, Parmotrema reticulatum, and Stereocaulon foliolosum. Free radical scavenging, Ferric reducing potential, Nitric oxide scavenging, and Trolox equivalent capacity were used to measure antioxidant activity. Strong radical scavenging action was demonstrated by atranorin and salazinic acid, with IC50 values of 39.31 µM and 12.14 µM, respectively. The Minimum Inhibitory Concentration (MIC) assay based on resazurin, was used to measure antibacterial activity. Parmotrema reticulatum demonstrated significant antibacterial activity against Raoultella planticola with MIC of 7.8 µg/mL. Cytotoxicity assay on breast cancer cell line was used to assess anticancer activity. To further understand the binding locations on the target proteins Er (Estrogen Receptor alpha), EGFR (Epidermal Growth Factor Receptor), mTOR (Mammalian Target of Rapamycin), and PgR (Progesterone Receptor), molecular docking experiments were conducted. Docking study showed that the binding energies of atranorin and salazinic acid with mTOR were -5.31 kcal/mol and -3.43 kcal/mol, respectively. The results suggest that atranorin has the potential to be a multitargeted molecule with natural antioxidant, antibacterial, and anticancer properties.

Radical scavenging, prolyl endopeptidase inhibitory, and antimicrobial potential of a cultured Himalayan lichen Cetrelia olivetorum.

CONTEXT: Lichens are source of natural bioactive compounds which are traditionally used to cure a variety of ailments. OBJECTIVE: The objective of this study is to assess free radical scavenging, prolyl endopeptidase inhibitory (PEPI), and antimicrobial potential of a high altitude lichen species Cetrelia olivetorum (Nyl.) W. L. Culb. & C. F. Culb (Parmeliaceae). MATERIALS AND METHODS: Lichen C. olivetorum has been cultured in vitro, and optimized culture conditions were implemented in bioreactor to obtain high quantity of biomass for the study of radical scavenging, PEPI, and antimicrobial activities. Radical scavenging activity of methanol extract of Cetrelia olivetorum (MECO) was tested at 100 µg/mL, PEPI activity at 25 and 50 µg/mL, and antimicrobial activity at 5, 25, 50, and 100 µg/mL conc. All the biological activities of natural thallus extract and its derived culture extract were evaluated spectrophotometrically. RESULTS: Murashige and Skoog medium supplemented with 3% glucose and 100 ppb indole-3-butyric acid (IBA) supported biomass growth at flask level and yielded 5.095 g biomass in bioreactor. MECO of both the cultured and the natural lichen exhibited half inhibiting concentration (IC50) for radical scavenging activities in the range of 50-60 µg/mL, whereas the IC50 value of standard antioxidants was found to be in the range of 12-29 µg/mL. The IC50 value of lichen extract for PEPI activity was 144-288 µg/mL, whereas the IC50 value of standard prolyl endopeptidase inhibitor, Z-pro-prolinal, was 57.73 µg/mL. As far as the antimicrobial activity of MECO is concerned, minimum inhibitory concentration (MIC) value of lichen extracts against tested microorganisms was obtained in the range of 50-104 µg/mL and found to be more effective than commercially available standard erythromycin. DISCUSSION: Murashige and Skoog medium containing IBA was found to be suitable for maximum biomass production of C. olivetorum under bioreactor conditions. The cultured lichen biomass extract also showed antioxidant, PEPI, and antimicrobial potential. CONCLUSION: The present study indicates therapeutic potential of Himalayan lichen C. olivetorum against neurodegenerative diseases owing to its radical scavenging, PEPI, and antimicrobial activities. Further, the result encourages its commercial exploitation through mass culture for production of its bioactive components and their use in pharmaceutical and nutraceutical industries.