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Tropospheric ozone (O3) is a global air pollutant that adversely affects plant growth. Whereas the impacts of O3 have previously been examined for some tropical commodity crops, no information is available for the pantropical crop, banana (Musa spp.). To address this, we exposed Australia’s major banana cultivar, Williams, to a range of [O3] in open top chambers. In addition, we examined 46 diverse Musa lines growing in a common garden for variation in three traits that are hypothesised to shape responses to O3: (1) leaf mass per area; (2) intrinsic water use efficiency; and (3) total antioxidant capacity. We show that O3 exposure had a significant effect on the biomass of cv. Williams, with significant reductions in both pseudostem and sucker biomass with increasing [O3]. This was accompanied by a significant increase in total antioxidant capacity and phenolic concentrations in older, but not younger, leaves, indicating the importance of cumulative O3 exposure. Using the observed trait diversity, we projected O3 tolerance among the 46 Musa lines growing in the common garden. Of these, cv. Williams ranked as one of the most O3-tolerant cultivars. This suggests that other genetic lines could be even more susceptible, with implications for banana production and food security throughout the tropics.

This is an extensive review on epiphytic plants that have been used traditionally as medicines. It provides information on 185 epiphytes and their traditional medicinal uses, regions where Indigenous people use the plants, parts of the plants used as medicines and their preparation, and their reported phytochemical properties and pharmacological properties aligned with their traditional uses. These epiphytic medicinal plants are able to produce a range of secondary metabolites, including alkaloids, and a total of 842 phytochemicals have been identified to date. As many as 71 epiphytic medicinal plants were studied for their biological activities, showing promising pharmacological activities, including as anti-inflammatory, antimicrobial, and anticancer agents. There are several species that were not investigated for their activities and are worthy of exploration. These epipythes have the potential to furnish drug lead compounds, especially for treating cancers, and thus warrant indepth investigations.

Annona species have been a valuable source of anti-infective and anticancer agents. However, only limited evaluations of their alkaloids have been carried out. This review collates and evaluates the biological data from extracts and purified isolates for their anti-infective and anti-cancer activities. An isoquinoline backbone is a major structural alkaloid moiety of the Annona genus, and more than 83 alkaloids have been isolated from this genus alone. Crude extracts of Annona genus are reported with moderate activities against Plasmodium falciparum showing larvicidal activities. However, no pure compounds from the Annona genus were tested against the parasite. The methanol extract of Annona muricata showed apparent antimicrobial activities. The isolated alkaloids from this genus including liriodenine, anonaine, asimilobine showed sensitivity against Staphylococcus epidermidis. Other alkaloids such as (+)-Xylopine and isocoreximine indicated significant anti-cancer activity against A549 and K-562 cell lines, respectively. This review revealed that the alkaloids from Annona genus are rich in structural diversity and pharmacological activities. Further exploration of this genus and their alkaloids has potential for developing novel anti-infective and anticancer drugs.

The Bhutanese traditional medicine (BTM) has been integrated with biomedicine since 1967 and serves as one of the important health care delivery systems in Bhutan. Therefore, the need to imrpove its quality through scientific studies have become paramount. In our efforts to address this important issue, we authenticated the botanical names of low altitude medicinal plants, determined the major classes of phytochemicals of 25 selected species, evaluated the bioactivities of the crude extracts of seven of them, and finally isolated the phytochemicals from six of these plants. We have established the antimalarial, anti-inflammatory, antimicrobial, and cytotoxicity activities of these phytochemicals and also identified five novel drug lead compounds. In our ethnobotanical study; we resolved the traditional and taxonomical discrepancies for Bhutanese medicinal plants, assessed the current BTM formulations, and carried out the field survey for the low altitude medicinal plants (LAMP), which is described in Chapter 2. Out of 113 LAMP, 92 species are used in the current multiingredient formulations produced by Manjong Sorig Pharmaceuticals (MSP) and 28 of them are currently imported from India. Out of these 28 species, 16 of them are found growing abundantly in Bhutan and most of them have not been studied for their phytochemicals and pharmacological properties. In this study, we have selected 25 of these plants and assessed them for their major classes of phytochemicals which we have described in Chapter 3. Of these, the crude extracts of seven selected plants (Corydalis crispa, C. dubia, Ajania nubegina, Meconopsis simplicifolia, Pleurospermum amabile, Aconitum laciniatum and Codonopsis bhutanica) were investigated for their biological activities and we found that five of them possessed significant antiplasmodial activities, one species showed moderate cytotoxicity, two species exhibited moderate anti-Trypanosoma brucei rhodesiense activity, six species exhibited signific

With the objective of determining safety and verifying the traditional uses of the Bhutanese medicinal plant, Pleurospermum amabile Craib & W. W. Smith, we investigated its crude extracts and the isolated phytochemicals for their biological activities. Four phenylpropanoids [(E)-isomyristicin (1), (E)-isoapiol (2 ), methyl eugenol (3) and (E)-isoelemicin (4)] and six furanocoumarins [psoralen (5), bergapten (6), isoimperatorin (7), isopimpinellin (8 ), oxypeucedanin hydrate (9) and oxypeucedanin methanolate (10 )] were isolated from this plant. Among the test samples, compound 10 showed weak antibacterial activity against Bacillus subtilis and best antimalarial activity against the Plasmodium falciparum strains, TM4/8.2 (chloroquine and antifolate sensitive) and K1CB1 (multidrug resistant). None of the test samples showed cytotoxicity. This study generated scientific data that support the traditional medical uses of the plant.

Ethnopharmacological relevance : This study involves the assessment of the Bhutanese traditional medicine (BTM) which was integrated with the mainstream biomedicine in 1967 to provide primary health care services in the country. It caters to 20-30% of the daily out-patients within 49 traditional medicine units attached to 20 district modern hospitals and 29 Basic Health Units in the country. Aim of the study : This study presents the ethnopharmacological, ethnobotanical and the ethnoquality concepts in relation to mainstream Tibetan medicine and describes the current practices of BTM. Materials and methods : Experienced BTM practitioners (Drung-tshos and Smen-pas) were selected using a convenience sampling method and were interviewed using an open questionnaire followed by informal discussions. The corpus of BTM, Tibetan and scientific literature was obtained and the information on ethnopharmacological, ethnoquality and ethnobotanical concepts and current practices of BTM was extracted. Results : This study found that the BTM shares many similarities in terms of materia medica, pharmacopoeia and the principles and concepts of ethnopharmacology and ethnobotany with its mainstream Tibetan medicine. However, the resourceful Bhutanese Drung-tshos and Smen-pas have adapted this medical system based on the local language, culture, disease trend, health care needs and their familiarity with the locally available medicinal ingredients making it particular to the country. A number of notable distinctions observed in the current practices include a code of classification of diseases (only 79 of 404 types of disorders recognized), formulations (currently used only 103 of thousands formulation types), usage of medicinal plants (only 229 species of thousands described) and selected treatment procedures (golden needle and water therapy). This BTM was found to cater to 20-30% of daily out-patients visiting 49 modern hospitals and basic health units in the country. Conclusions : Th

We have hydrodistilled the essential oil (EO) from the aerial parts of the Bhutanese medicinal plant, Pleurospermum amabile using a Clevenger apparatus and evaluated this EO by GC/GC-MS and NMR analysis followed by testing for bioactivity. The GC-MS analysis identified 52 compounds with (E)-isomyristicin as a major component (32.2%). Repeated purification yielded four compounds; (E)-isomyristicin (1), (E)-isoapiol (2), methyl eugenol (3) and (E)-isoelemicin (4). Compound 2 and the mother EO showed the best antiplasmodial activity against the Plasmodium falciparum strains, TM4/8.2 (chloroquine and antifolate sensitive) and K1CB1 (multidrug resistant). They exhibited mild antibacterial activity against Bacillus subtilis. None of the test samples showed cytotoxicity.

Ethnopharmacological relevance: Corydalis dubia is used in Bhutanese traditional medicine as a febrifuge and for treating infections in the blood, liver and bile which correlate to the signs and symptoms of malarial and microbial infections. Aim of the study: To validate the ethnopharmacological uses of the plant and to discover potential new therapeutic drug leads. Materials and methods C. dubia was collected from Bhutan and the alkaloids were obtained using acid–base fractionation and separation by repeated column and preparative plate chromatography. The alkaloids were identified from analysis of their physiochemical and spectroscopic data and were tested for antiplasmodial, antimicrobial and cytotoxicity activities. Results: A systematic extraction and isolation protocol yielded one new natural product, dubiamine, and seven known isoquinoline alkaloids, scoulerine, cheilanthifoline, protopine, capnoidine, bicuculline, corydecumbine and hydrastine. Among the four alkaloids tested, scoulerine showed the best antiplasmodial activity with IC50 values of 5.4 μM and 3.1 μM against the antifolate sensitive and the multidrug resistant P. falciparum strains: TM4/8.2 and K1CB1, respectively. None of the alkaloids tested showed significant antimicrobial or cytotoxicity activities. Conclusions: The antiplasmodial test results, of the isolated alkaloid components, are commensurated with the ethnopharmacological uses of this plant.