The need for a continued search for new anti-infective and anticancer drugs is universally considered of great importance since many of the current drugs are insufficiently effective, highly toxic, and resistances may be developed. Our group has isolated two alkaloids, eurochevalierine, a potent inhibitor of the growth of human tumor cell lines [1], from the soil fungus Neosartorya pseudofischeri, and neofiscalin A from the soil and marine fungus N. siamensis with potente antibacterial activity [2]. Neofiscalin A exhibited also antibiofilm activity in both reference and multidrugs-resistant isolates, and is currently in the patent filing process. On the other hands, marine fungi derived xanthones, particularly yicathins and isomers were considered promising as chemotherapic agents [3]. So, eurochevalierine, neofiscalin A and yicathins can be considered very interesting models to discover new anti-infective and anticancer drugs to overcome drug-resistance that could represent innovative drug candidates. However, their availability to proceed to further investigations and their complex structures could limit their future as drug candidates. Our group has multi- and transdisciplinary skills, with a large experience in isolation and structure elucidation of natural products, synthesis, cellular and molecular biology and nanotechnology. Moreover, the synthesis of anti-infective [4,5] and antitumor [6-10] xanthone derivatives, particularly in multidrugs-resistant models [5,10], is the strength of our group. Therefore, this expertise can drive these natural products and derivatives with enough potency and selectivity to become new potential anti-infective/antitumor clinical candidates. However, our goal is not only to continue with the search for innovative marine-derived compounds but also to obtain derivatives/formulations of the most promising compounds to obtain more efficient analogues. To achieve these goals, five approaches will be undertaken: i) isolate other bioactive compounds from the marine-derived N. pseudofischeri and N. siamensis and other related strains; ii) synthesize eurochevalierine, neofiscalin A and yicathins to obtain more quantity of these products for in vitro and in vivo tests, iii) carry out successive molecular modifications in order to achieve more eficiente analogues, iv) investigate their potential as anti-infective agents, v) perform in vitro studies in tumor cell lines; vi) incorporate in nanoparticles in order to improve permeability and selectivity of the most promising compounds. To carry out approach i) isolation of the bioactive metabolites, we will culture the fungi N. pseudofischeri and N. siamensis, isolated from the marine environment, such as sponge or coral to obtain eurochevalierine, neofiscalin A, and structurally related alkaloids. Moreover, we will also perform a co-culture of these two fungi with marine bacteria for the purpose of increasing the quantity of the alkaloids eurochevalierine and neofiscalin A as well as to verify if the fungi also accumulate other bioactive metabolites when compared to the pure cultures. To carry out approaches ii)-iii) these alcaloids and yicathins will be synthesized and the (semi)synthesized derivatives will be used to obtain a library of structurally-related analogues with improved efficacy. These results will allow us to establish structure activity relationships (SAR), to contribute to define the important molecular features of anti-infective and antitumor activities, and consequently, the design of more potent molecules. To carry out approach iv), the new compounds will be screened for antimicrobial activity using the agar disk diffusion assay and/or the broth microdilution method. These compounds will be also tested for their synergy with antibiotics, against isolates presenting resistance towards those antimicrobials, using the broth microdilution Checkerboard method. Compounds showing antimicrobial activity will be then tested for their ability to inhibit the biofilm formation. To screen for compounds with anti-parasitic activity their effect will be evaluated for Cryptosporidium inhibitory growth via human epithelial cells lines. To carry out approach v), the compounds will be screened for their in vitro growth inhibitory activity in human tumor cell lines. The elucidation of the molecular mechanism of antitumor activity of the most promising compounds will be performed, particularly alterations in cellular proliferation, cell cycle, mitosis, and apoptosis, analysis of the effect on tumor imune microenvironment, and identification of protein targets. To carry out approach vi), the compounds with promising anti-infective/antitumor activity will be incorporated into biodegradable and biocompatible LNP formulations by several methods, and technological parameters will be studied. This approach will allow us to verify if LNP formulations can improve the bioavailability and/or activity/selectivity of the bioactive compounds.
