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Chikungunya and yellow fever virus cause vector-borne viral diseases in humans. There is currently no specific antiviral drug for either of these diseases. Banana plants are used in traditional medicine for treating viral diseases such as measles and chickenpox. Therefore, we tested selected banana cultivars for their antiviral but also cytotoxic properties. Different parts such as leaf, pseudostem and corm, collected separately and extracted with four different solvents (hexane, acetone, ethanol, and water), were tested for in vitro antiviral activity against Chikungunya virus (CHIKV), enterovirus 71 (EV71), and yellow fever virus (YFV). Extracts prepared with acetone and ethanol from leaf parts of several cultivars exhibited strong (EC 50 around 10 μg/mL) anti-CHIKV activity. Interestingly, none of the banana plant extracts (concentration 1-100 µg/mL) were active against EV71. Activity against YFV was restricted to two cultivars: Namwa Khom-Pseudostem-Ethanol (5.9 ± 5.4), Namwa Khom-Corm-Ethanol (0.79 ± 0.1) and Fougamou-Corm-Acetone (2.5 ± 1.5). In most cases, the cytotoxic activity of the extracts was generally 5- to 10-fold lower than the antiviral activity, suggesting a reasonable therapeutic window., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Background: Infections by microbes (viruses, bacteria, and fungi) and parasites can cause serious diseases in both humans and animals. Heavy use of antimicrobials has created selective pressure and caused resistance to currently available antibiotics, hence the need for finding new and better antibiotics. Natural products, especially from plants, are known for their medicinal properties, including antimicrobial and anthelmintic activities. Geoclimatic variation, together with diversity in ethnomedicinal traditions, has made the Himalayas of Nepal an invaluable repository of traditional medicinal plants. We studied antiviral, antibacterial, antifungal, and anthelmintic activities of medicinal plants, selected based upon ethnobotanical evidence., Methods: Ethanolic and methanolic extracts were tested (1) on a panel of microbes: two Gram-positive bacteria ( Staphylococcus aureus and Listeria innocua ), four Gram-negative bacteria ( Escherichia coli , Pseudomonas aeruginosa , Salmonella enterica , and Shigella sonnei ), and one fungal species: Candida albicans ; (2) against three different viruses: yellow fever, chikungunya, and enterovirus; and (3) on the nematode Caenorhabditis elegans . Also, cytotoxicity was assessed on human hepatoma (Huh), rhabdosarcoma (RD), and Vero (VC) cell lines., Results: Of 18 plants studied, Ampelocissus tomentosa and Aleuritopteris anceps inhibited S. aureus (MIC 35  μ g/mL and 649  μ g/mL, respectively) and Pseudomonas aeruginosa (MIC 15  μ g/mL and 38  μ g/mL, respectively). Rhododendron arboreum and Adhatoda vasica inhibited S. enterica (MIC 285  μ g/mL and 326  μ g/mL, respectively). Kalanchoe pinnata, Ampelocissus tomentosa , and Paris polyphylla were active against chikungunya virus, and Clerodendrum serratum was active against yellow fever virus (EC 50 15.9  μ g/mL); Terminalia chebula was active against enterovirus (EC 50 10.6  μ g/mL). Ampelocissus tomentosa, Boenninghausenia albiflora, Dichrocephala integrifolia , and Kalanchoe pinnata significantly reduced C. elegans motility, comparable to levamisole., Conclusions: In countries like Nepal, with a high burden of infectious and parasitic diseases, and a current health system unable to combat the burden of diseases, evaluation of local plants as a treatment or potential source of drugs can help expand treatment options. Screening plants against a broad range of pathogens (bacteria, viruses, fungi, and parasites) will support bioprospecting in Nepal, which may eventually lead to new drug development., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Bishnu Joshi et al.)

Ten banana ( Musa spp.) cultivars were studied for their antimicrobial properties. Three plant parts (corm, pseudostem and leaves) were collected separately and extracted with different solvents, viz., hexane, acetone, ethanol and water. The 50% inhibitory concentration (IC 50 ) was evaluated using a broth microdilution assay. Eight human bacterial and one fungal pathogen were tested. Acetone and ethanol extract(s) often exhibited significant antimicrobial activity, while hexane extracts were less active. Aqueous extracts often showed microbial growth, possibly by endophytes. Leaf extracts were most active, followed by pseudostem, and corm was least active. All the tested banana cultivars were found to contain antimicrobials, as demonstrated by inhibition of selected human pathogens. However, cultivars such as Dole, Saba, Fougamou, Namwah Khom, Pelipita and Mbwazirume showed a broad-spectrum activity, inhibiting all tested pathogens. Other cultivars such as Petit Naine and Kluai Tiparot showed a narrow-spectrum activity, including antibiofilm activity against Candida albicans . Our results support the use of different parts of banana plants in traditional human medicine for infections, including diarrhea and dysentery, and some sexually transmitted diseases, as well as for packaging spoilable materials like food.