title: Antioxidant capacities, phenolic profile and cytotoxic effects of saxicolous lichens from trans-Himalayan cold desert of Ladakh.
abstract: Fourteen saxicolous lichens from trans-Himalayan Ladakh region were identified by morpho-anatomical and chemical characteristics. The n-hexane, methanol and water extracts of the lichens were evaluated for their antioxidant capacities. The lichen extracts showing high antioxidant capacities and rich phenolic content were further investigated to determine their cytotoxic activity on human HepG2 and RKO carcinoma cell lines. The ferric reducing antioxidant power (FRAP), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging capacities and β-carotene-linoleic acid bleaching property exhibited analogous results where the lichen extracts showed high antioxidant action. The lichen extracts were also found to possess good amount of total proanthocyanidin, flavonoid and polyphenol. The methanolic extract of Lobothallia alphoplaca exhibited highest FRAP value. Methanolic extract of Xanthoparmelia stenophylla showed the highest ABTS radical scavenging capacity. The n-hexane extract of Rhizoplaca chrysoleuca exhibited highest DPPH radical scavenging capacity. Highest antioxidant capacity in terms of β-carotene linoleic acid bleaching property was observed in the water extract of Xanthoria elegans. Similarly, Melanelia disjuncta water extract showed highest NO scavenging capacity. Among n-hexane, methanol and water extracts of all lichens, the methanolic extract of Xanthoparmelia mexicana showed highest total proanthocyanidin, flavonoid and polyphenol content. From cytotoxic assay, it was observed that the methanolic extracts of L. alphoplaca and M. disjuncta were exhibiting high cytotoxic effects against cancer cell growth. Similarly, the water extract of Dermatocarpon vellereum, Umbilicaria vellea, X. elegans and M. disjuncta and the methanolic extract of M. disjuncta and X. stenophylla were found to possess high antioxidant capacities and were non-toxic and may be used as natural antioxidants for stress related problems. Our studies go on to prove that the unique trans-Himalayan lichens are a hitherto untapped bioresource with immense potential for discovery of new chemical entities, and this biodiversity needs to be tapped sustainably.
authors.affiliation: Defence Institute of High Altitude Research, Defence Research & Development Organisation, Leh-Ladakh, Jammu & Kashmir, India.
authors.forename: Jatinder
authors.initials: J
authors.lastname: Kumar
authors.affiliation: Defence Institute of High Altitude Research, Defence Research & Development Organisation, Leh-Ladakh, Jammu & Kashmir, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Dhar
authors.affiliation: Defence Institute of High Altitude Research, Defence Research & Development Organisation, Leh-Ladakh, Jammu & Kashmir, India.
authors.forename: Amol B
authors.initials: AB
authors.lastname: Tayade
authors.affiliation: Medicinal and Aromatic Plants Laboratory, Radiation Biotechnology Group, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Delhi, India.
authors.forename: Damodar
authors.initials: D
authors.lastname: Gupta
authors.affiliation: Defence Institute of High Altitude Research, Defence Research & Development Organisation, Leh-Ladakh, Jammu & Kashmir, India.
authors.forename: Om P
authors.initials: OP
authors.lastname: Chaurasia
authors.affiliation: Lichenology Laboratory, Plant Biodiversity and Conservation Biology Division, CSIR- National Botanical Research Institute, Lucknow, Uttar Pradesh, India.
authors.forename: Dalip K
authors.initials: DK
authors.lastname: Upreti
authors.affiliation: Medicinal and Aromatic Plants Laboratory, Radiation Biotechnology Group, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Delhi, India; Office of the Director General-Life Sciences, DRDO Bhawan, New Delhi, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Arora
authors.affiliation: Defence Institute of High Altitude Research, Defence Research & Development Organisation, Leh-Ladakh, Jammu & Kashmir, India.
authors.forename: Ravi B
authors.initials: RB
authors.lastname: Srivastava
mesh_terms: D000872:Anthocyanins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D052160:Benzothiazoles / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D003080:Cold Temperature; D003889:Desert Climate; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D056945:Hep G2 Cells; D006801:Humans; D007194:India; D008011:Lichens / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013451:Sulfonic Acids / Q000737:chemistry
chemical_list: D000872:Anthocyanins; D000972:Antineoplastic Agents, Phytogenic; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D009569:Nitric Oxide; C004931:1,1-diphenyl-2-picrylhydrazyl