Radical scavenging, prolyl endopeptidase inhibitory, and antimicrobial potential of a cultured Himalayan lichenCetrelia olivetorum

Abstract

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 mg/mL, PEPI activity at 25 and 50 mg/mL, and antimicrobial activity at 5, 25, 50, and 100 mg/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 (IC 50 ) for radical scavenging activities in the range of 50-60 mg/mL, whereas the IC 50 value of standard antioxidants was found to be in the range of 12-29 mg/mL. The IC 50 value of lichen extract for PEPI activity was 144-288 mg/mL, whereas the IC 50 value of standard prolyl endopeptidase inhibitor, Z-pro-prolinal, was 57.73 mg/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 mg/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.

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

“…exhibited strong antiradical activities, against DPPH, TEAC, nitric oxide (NO) radicals and reduced ferric ions [23] . The results indicated synergistic properties of polyphenols and polysaccharides together towards antioxidant activity which also have been reported in our previous studies [24] …”

“…Total soluble phenolic content was determined with Folin‐Ciocalteu reagent according to Slinkard and Singleton, [36] using pyrocatechol as a standard. Details of all the assays are reported earlier by us [37,38,24] …”

“…[23] The results indicated synergistic properties of polyphenols and polysaccharides together towards antioxidant activity which also have been reported in our previous studies. [24]…”

Lichen cell factories: methods for the isolation of photobiont and mycobiont partners for defined pure and co-cultivation

“…After obtaining axenic (i.e. pure) cultures of the lichen partners, isolates are normally cultivated on various solid and soft agar media with different nutrients, C- and N-source concentrations [ 10 , 15 , 16 , 26 ]. Lichen symbionts grow much faster as cell aggregates in lab conditions than in nature, e.g.…”