D. K. Upreti

Commercial and Ethnic Use of Lichens in India

The diversity of Indian lichen flora has undergone a considerable decline in the last five decades. Among the various anthropogenic activities, overexploitation and selective removal of economically important lichens have become major threats to the lichen flora of the country. Commercial samples of lichens collected from different states of India were studied for their source and commercial use. Among samples offered for sale, 38 different lichen species were identified. The western Himalayas proved to be the main area for lichen collection, while some lichen species also come from the central and Western Ghats. Local traders coordinate the lichen collection and then sell the material to traders in the foothills, and from there it is processed and distributed to other parts of the country and abroad. Because lichens belonging to the families Parmeliaceae and Physciaceae are the ones most exploited commercially, they are recommended for inclusion in the CITES list.

Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi.

We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.

Heavy Metal Accumulation in Lichens from the Hetauda Industrial Area Narayani Zone Makwanpur District, Nepal

Lichen samples collected in and around Hetauda Industrial area,(HIA) Narayani zone, Makwanpur district, Nepal, were analyzedfor Cr, Ni, Pb, Zn, Ca, Mn, Fe, Si, and Al. The samples fromthe location inside the industrial area have higher levels ofmetal than the outside areas. Pyxine meissnerina growinginside the industrial area accumulated higher levels of all themetals analyzed.

Accumulation and toxic effect of arsenic and other heavy metals in a contaminated area of West Bengal, India, in the lichen Pyxine cocoes (Sw.) Nyl.

Ecological indicators can be used to assess the condition of the environment, to provide an early warning signal of changes in the surrounding environment or to diagnose the causes of an environmental problem. The study aims to evaluate the applicability of a common foliose lichen Pyxine cocoes (Sw.) Nyl., as an indicator to evaluate the arsenic and heavy metal rich sites. The naturally growing lichen and its substratum (bark) were utilized to biomonitor the accumulation of arsenic (As) and other heavy metals (Al, Cd, Cr, Cu, Fe, Pb and Zn) in Chinsurah, a highly As contaminated area of West Bengal. Significantly higher levels of Al, Cr, Fe, Pb and Zn (p<0.01), Cd and Cu (p<0.05) were found in the lichens especially in samples collected from road sites. Higher As concentration (48.1±2.1 μg g(-1)) in samples were found near the paddy field, indicating pesticide-herbicides as its source used in agriculture. The substrate exhibits lower concentration of most of the metals while Cr, Cd and Pb were below detection limit. As evident from the bioaccumulation factor most of the metals accumulated in lichen thallus are air borne. Chl a and Chl b concentrations decreased significantly with increasing distance from roadside whereas the carotenoid and protein showed an enhanced level. The chlorophyll stability index, chlorophyll degradation and carotenoid contents were found to be the most sensitive parameters to assess the vitality of lichen thallus against changing environment.

Biodiversity, bioaccumulation and physiological changes in lichens growing in the vicinity of coal-based thermal power plant of Raebareli district, north India.

The lichen diversity assessment carried out around a coal-based thermal power plant indicated the increase in lichen abundance with the increase in distance from power plant in general. The photosynthetic pigments, protein and heavy metals were estimated in Pyxine cocoes (Sw.) Nyl., a common lichen growing around thermal power plant for further inference. Distributions of heavy metals from power plant showed positive correlation with distance for all directions, however western direction has received better dispersion as indicated by the concentration coefficient-R(2). Least significant difference analysis showed that speed of wind and its direction plays a major role in dispersion of heavy metals. Accumulation of Al, Cr, Fe, Pb and Zn in the thallus suppressed the concentrations of pigments like chlorophyll a, chlorophyll b and total chlorophyll, however, enhanced the level of protein. Further, the concentrations of chlorophyll contents in P. cocoes increased with the decreasing the distance from the power plant, while protein, carotenoid and phaeophytisation exhibited significant decrease.

Quercetin Sensitizes Fluconazole-Resistant Candida albicans To Induce Apoptotic Cell Death by Modulating Quorum Sensing

ABSTRACT Quorum sensing (QS) regulates group behaviors of Candida albicans such as biofilm, hyphal growth, and virulence factors. The sesquiterpene alcohol farnesol, a QS molecule produced by C. albicans, is known to regulate the expression of virulence weapons of this fungus. Fluconazole (FCZ) is a broad-spectrum antifungal drug that is used for the treatment of C. albicans infections. While FCZ can be cytotoxic at high concentrations, our results show that at much lower concentrations, quercetin (QC), a dietary flavonoid isolated from an edible lichen (Usnea longissima), can be implemented as a sensitizing agent for FCZ-resistant C. albicans NBC099, enhancing the efficacy of FCZ. QC enhanced FCZ-mediated cell killing of NBC099 and also induced cell death. These experiments indicated that the combined application of both drugs was FCZ dose dependent rather than QC dose dependent. In addition, we found that QC strongly suppressed the production of virulence weapons—biofilm formation, hyphal development, phospholipase, proteinase, esterase, and hemolytic activity. Treatment with QC also increased FCZ-mediated cell death in NBC099 biofilms. Interestingly, we also found that QC enhances the anticandidal activity of FCZ by inducing apoptotic cell death. We have also established that this sensitization is reliant on the farnesol response generated by QC. Molecular docking studies also support this conclusion and suggest that QC can form hydrogen bonds with Gln969, Thr1105, Ser1108, Arg1109, Asn1110, and Gly1061 in the ATP binding pocket of adenylate cyclase. Thus, this QS-mediated combined sensitizer (QC)-anticandidal agent (FCZ) strategy may be a novel way to enhance the efficacy of FCZ-based therapy of C. albicans infections.

Antioxidant capacities, phenolic profile and cytotoxic effects of saxicolous lichens from trans-Himalayan cold desert of Ladakh.

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.

Accumulation of Polycyclic Aromatic Hydrocarbons in some lichens of Garhwal Himalayas, India

Lichens collected from five different sites (11 localities) from Garhwal Himalayas, Uttaranchal, India, were analysed for individual Polycyclic Aromatic Hydrocarbons (PAHs). There was high spatial variability in the total PAH (ΣPAH) concentrations that ranged from 0.683 ppm to 33.72 ppm with an average concentration of 15.04 ± 12.853 (SD). To elucidate sources, six molecular indices (Fluo/Pyr, Phen/Anthr, Naph/Phen, Anthr/(Anthr+Phen), Fluo/(Fluo+Pyr), BaP/BghiP ratios) were used to determine the pyrogenic and petrogenic sources. Garhwal region receives input primarily from vehicular activity and wood combustion; therefore, it can be inferred that the main source of PAH could be pyrolytic.

European Viscum album: a potent phytotherapeutic agent with multifarious phytochemicals, pharmacological properties and clinical evidence

Viscum album L. or European mistletoe (Loranthaceae), a semi-parasitic shrub, has been used as a traditional medicine in Europe for centuries to treat various diseases like cancer, cardiovascular disorder, epilepsy, infertility, hypertension and arthritis. V. album contains diverse phytochemicals, which exert a large number of biological and pharmacological activities. The aim of this review is to compile the developments in the domain of V. album and research trends, with a focus on ethnopharmacology, phytochemistry and pharmacological properties, to illustrate the potential of this phytotherapeutic as an attractive commercial herbal medicine. Crude extracts and isolated chemical constituents from V. album have exhibited significant medicinal effects in experimental models and in patients with cancer, autoimmune and inflammatory conditions. Importantly, recent randomized clinical trials have suggested improved overall survival and quality of life in cancer patients treated with different mistletoe preparations. The current phytochemical studies have shown that lectins, hetero-dimeric glycoproteins, polysaccharides, viscotoxins, alkaloids, lipids, triterpenes, peptides, vesicles, flavonoids, cyclitols and amines are principal bioactive phytochemicals of V. album. Clinical studies and experimental models have revealed that V. album exhibits several pharmacological functions such as immunomodulatory, anti-hypertensive, anti-oxidant, cytotoxicity, anti-tumor, anti-inflammation, anti-diabetic, anti-microbial and sedative activities. It is conceivable that the heterogenous profile of biochemical compounds provides the basis for the broad diversity of pharmacological activities of mistletoe, as each single component contributes diverse modes of action in addition to imparting a synergistic beneficial action in conjunction with other molecules.

Development and characterization of a novel Swarna-based herbo-metallic colloidal nano-formulation – inhibitor of Streptococcus mutans quorum sensing

Herbo-metallic preparations such as bhasmas (ash) are used traditionally in Indian and Chinese medicinal systems. In Ayurveda, Swarna (gold) nanoparticles are used as Swarna bhasma to treat several clinical manifestations. While Usnea longissima, a medicinal lichen, ethnobotanical is known for the treatment of tooth cleaning and infectious diseases. The study aims to develop a herbo-metallic colloidal nano-formulation containing Swarna nanoparticles and polyphenols rich U. longissima extract (ULE) and evaluate its anti-quorum sensing (QS) property against Streptococcus mutans, an idea that has never been explored before, with a view towards combating the emergence of antibiotic resistance often linked with QS-regulated virulence factors and biofilms. The synthesized Uh-Au@Nano-CF was confirmed by a peak at 550 nm in the UV-visible spectrum. The obtained XRD data confirmed the crystalline nature of nanoparticles of 28 nm size. TEM image revealed that all the particles were spherical with a narrow size range of 5–23 nm. The FTIR result clearly showed that the ULE containing secondary OH as functional groups induces encapsulation of nanoparticles. HPTLC and HPLC fingerprinting of ULE confirmed the presence of polyphenols, including orcinol, arabitol, apigenin, and usnic acid. The data from the inhibition of violacein production in C. violaceum 12 472 revealed that the Uh-Au@Nano-CF at sub-lethal concentrations (5, 10 and 15%) show potent anti-QS activity. The treatment of Uh-Au@Nano-CF was found to inhibit the secretion of S. mutans virulence factors, including acid production, ATPase, enolase, lactate dehydrogenase, protease, total exopolysaccharide content, and glucosidase. The Uh-Au@Nano-CF in a concentration dependent manner showed anti-biofilm activity, inhibiting biofilm formation. Eventually, it was also documented that the Uh-Au@Nano-CF at 15% dilution enhanced the susceptibility of S. mutans to its conventional antibiotics. This study introduces not only a novel antimicrobial herbo-metallic colloidal nano-formulation, but also explores its new biomedical application, which targets QS-regulated virulence factors and biofilm of S. mutans rather than its viability.