Bandamycin as New Antifungal Agent and further Secondary Metabolites from Terrestrial and Marine Microorganisms

Abstract

Despite successes in controlling some previously thought incurable diseases, recent increase in epidemic viral infections such as AIDS, hepatitis, Ebola, SARS have been reported in developing countries (Asia, Africa). [9] Therefore, the intention to search for new resources of bioactive metabolites still gains worldwide attention, as 11 Pimaricin (12) belongs to the group of polyene macrolide with 26-membered ring possessing antifungal activity. [28] The pimaricin analogue JBIR-13 (13) isolated from Streptomyces bicolor NBRC 12746 has been reported to show antifungal activity against Candida albicans with a minimum inhibitory concentration (MIC) value of 3.13 g/mL. [29] 17 Ionophore antibiotics are another type of antibiotics of bacterial origin, which can act as mobile ion carriers in complex form within cell membranes. [34] Nonactin (18) is an example with antitumor activity: it was firstly isolated and reported from Streptomyces griseus; in addition to (-)-nonactic acid (19), the monomer of nonactin (18). [35,36] 23 Six new chromophenazines A (24), B (26), C (25), D ( 27), E (28) and F (29) were isolated recently in our group from the terrestrial Streptomyces sp. Ank 315.Phenazine derivatives have been reported to exhibit broad-range activities such as antioxidant, neuroprotectant, antimicrobial, antiviral, antiparacitic, antitumor and antimalaria. Among the six chromophenazines, only chromophenazine D ( 27) 36Val-geninthiocin (37) is another thiopeptide antibiotic, which was recently isolated in our group from the terrestrial Streptomyces sp. RSF18. [49] This type of antibiotics is also strongly active as antimalarial agent against Plasmodium falciparum. [50] 2010. [65] Enniatin B (49) and bassianolide ( 50) are examples of fungi-originated cyclodepsipeptides. Enniatins act as ionophores in biological membranes, inhibitors of the ABC-transporter Pdr5p and topical agent for the treatment of respiratory infec-O 68 Recently, four new 10-membered lactones A (69), B (70), C (71) and D (72)have been reported from marine-derived endophytic fungus Curvularia sp. The fungus was isolated from the marine red alga Acanthophora spicifera. [76]