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Keywords: BPPV, Benign Paroxysmal Positional Vertigo; Dix-Hallpike procedure; Epley maneuverDOI: 10.3126/njenthns.v1i2.4764 Nepalese J ENT Head Neck Surg Vol.1 No.2 (2010) p.28-32

Extracts from five Antarctic lichens (L3, Stereocaulon alpinum; L5, Ramalina terebrata; L6, Caloplaca sp.; L8, Lecanora sp.; and L17, Caloplaca regalis) were tested for antimicrobial activities against several clinically important microbes by disk diffusion. The minimum inhibitory concentration (MIC) of each extract was determined by a broth dilution method. Extracts from L3, L5, L6 and L8 were active against two Gram(+) strains. B. subtilis was more sensitive to lichen extracts (except L5) than S. aureus. The MIC of lichen extracts against B. subtilis and S. aureus was observed from 36.7 +/- 0.3 to 953.8 +/- 85.8 microg/mL and 68.5 +/- 0.6 to >1000 microg/mL, respectively. Comparisons of MIC values of Antarctic lichen crude extracts to previously published MIC values of some reported lichen metabolites against Gram(+) bacteria indicated that Antarctic lichens might be an enriched source of effective antibacterial agents against clinically relevant Gram(+) species.

Antioxidant agents counter reactive oxygen species (ROS) and can be used in cosmetic and medicinal applications. The goal of this study was to evaluate the antioxidant activity of an Antarctic moss species from King George Island (Antarctica), tentatively designated as KSJ-M5. On the basis of morphological characteristics, KSJ-M5 was identified as Sanionia uncinata (Hedw.) Loeske (Amblystegiaceae). The identification was confirmed by comparing the partial sequence of the ITS (internal transcribed spacer) region with that in GenBank. The antioxidant activity of an ethanol extract of KSJ-M5 was evaluated by analyzing its reducing power, superoxide scavenging activity, ABTS [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] cation scavenging activity, and DPPH (1,1-diphenyl-2-picrylhydrazyl) free-radical scavenging activity. The reducing power of 1 mg of KSJ-M5 extract was equivalent to 31.9 +/- 0.9 microg (Mean +/- SD, n = 3) of the commercial standard, BHT (butylated hydroxytoluene). IC(50) values of the KSJ-M5 extract for DPPH free-radical scavenging activity, superoxide scavenging activity, and ABTS cation scavenging activity were found as 356 +/- 26.8 microg/mL, 466.2 +/- 43.4 microg/mL, and 181.3 +/- 12.2 microg/mL, respectively. The total phenolic content in 1 mg of KSJM5 extract was equivalent to 12.7 +/- 2.7 microg of pyrocatechol. These results clearly showed that KSJ-M5 could be an important source of natural antioxidant agents for improved medicinal and cosmetic applications.

A total of twenty four lichen species belonging to six families were collected from mountainous region of Nepal. The methanol extracts of each species were tested for antimicrobial and antioxidant activities in vitro. It was found that extracts of twenty one lichen species were active against B. subtilis and seven species were active against S. aureus. Similarly, in DPPH assay, three species Peltigera sp., Cladonia sp., and Canoparmelia sp. showed comparable activity with commercial standard, BHA. In ABTS + assay, extracts of Parmoterma sp., Ramalina sp., Peltigera sp. and Cladonia sp. showed stronger activity than ascorbic acid. The observed data after comparison with previously published reports indicated that the high altitude lichens contain stronger antioxidant and antibacterial constituents. Similarly, the methanol extracts of Heterodermia sp. and Ramalina sp. showed comparable toxicity eff ect with commercial standard berberine chloride indicating a potent source of anticancer drugs.

Two compounds, 2-hydroxymyristic acid (HMA) and cis-9-oleic acid (COA), were isolated from a chloroform extract of the marine bacterium, Shewanella oneidensis SCH0402. In a spectrophotometerbased chemotaxis assay, HMA completely eliminated the optical density (OD) of Alteromonas marina SCH0401 and Bacillus atrophaeus SCH0408, motile, fouling bacteria, at 100 and 1000 lg ml -1 , respectively. COA similarly decreased the OD of A. marina and B. atrophaeus by 100% at 1000 lg ml -1 . The commercially available, highly toxic anti-fouling compound, tributyltin oxide (TBTO) never reduced the OD of the target bacteria by 100% even at higher concentration. Instead, all the test bacterial cells were killed at higher than 1000 lg ml -1 of concentration. Both HMA and COA inhibited germination of Ulva pertusa spores completely at 10 and 100 lg ml -1 , respectively, while TBTO inhibited germination at 0.01 lg ml -1 . However, in field assays, both HMA and COA showed antifouling activities as potent as TBTO against a wide range of fouling organisms, including micro-and macro-algae, barnacles, and mussels. The average fouling coverage on the surface of the control panel was 93 ± 6% after 1.5 years but no fouling was observed on the surface of the test panel onto which each compound was applied separately. Thus, bacterial repellent compounds can be used as substitutes for potent toxic anti-fouling compounds, resulting in higher standards of environmental safety without loss of anti-fouling performance.

BackgroundSeveral plants are reported to be produced various biological active compounds. Lichens from the extreme environments such as high altitude, high UV, drought and cold are believed to be synthesized unique types of secondary metabolites than the other one. Several human pathogenic bacteria and fungi have been muted into drug resistant strains. Various synthetic antioxidant compounds have posed carcinogenic effects. This phenomenon needs further research for new effective drugs of natural origin. This manuscript aimed to screen new source of biological active compounds from plants of subarctic origin.ResultsA total of 114 plant species, including 80 species of higher plants, 19 species of lichens and 15 species of mosses, were collected from Oymyakon region of the Republic of Sakha (Yakutia), Russia (63˚20′N, 141˚42′E–63˚15′N, 142˚27′E). Antimicrobial, DPPH free radical scavenging and brine shrimp (Artemia salina) toxicity of all crude extract were evaluated. The obtained result was analyzed and compared with commercial standards. A total of 28 species of higher plants showed very strong antioxidant activity (DPPH IC50, 0.45-5.0 μg/mL), 13 species showed strong activity (DPPH IC50, 5-10 μg/mL), 22 species showed moderate antioxidant activity (DPPH IC50,10-20 μg/mL) and 17 species showed weak antioxidant activity (DPPH IC50 more than 20 μg/mL). Similarly, 3 species of lichen showed strong antioxidant activity, one species showed moderate and 15 species showed weak DPPH reducing activity. In addition, 4 species of mosses showed moderate antioxidant activity and 11 species showed weak antioxidant activity. Similarly, extracts of 51 species of higher plants showed antimicrobial (AM) activity against Staphylococcus aureus and 2 species showed AM activity against Candida albicans. Similarly, 11 species of lichen showed AM activity against S. aureus and 3 species showed AM activity against Escherichia coli. One species of moss showed AM activity against S. aureus. And finally, one species of higher plant Rheum compactum and one species of lichen Flavocetraria cucullata showed the toxicity against Brine shrimp larvae in 100 μg/mL of concentration.ConclusionThe experimental results showed that subarctic plant species could be potential sources of various biologically active natural compounds.

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