Design and Application of a High-Throughput, High-Content Screening System for Natural Product Inhibitors of the Human Parasite Trichomonas vaginalis

Abstract

It is estimated that Trichomonas vaginalis affects an astonishing 3.9% of the world’s population, and while many of those infected are asymptomatic, progression of the disease can lead to serious health problems. Currently, the nitroimidazoles constitute the only drug class approved to treat trichomoniasis in the United States, which makes the spread of drug resistance a realistic concern. We developed a new image-based, high-throughput, and high-content assay for testing natural products (purified compounds and extracts) for antitrichomonal activity. Applying this assay system to a library of fungal natural product extracts led to the identification of three general classes of natural product inhibitors that exhibited moderate to strong activities against T. vaginalis: anthraquinones, xanthone–anthraquinone heterodimers, and decalin-linked tetramic-acid-containing metabolites. The tetramate natural products emerged as the most promising candidate molecules with pyrrolocin A (51) exhibiting potent activity against the parasite (EC50 = 60 nM), yet this metabolite showed limited toxicity to mammalian cell lines (selectivity index values of 100 and 167 versus 3T3 fibroblast and Ect1 normal cervical cells, respectively). The imaging-based assay system is a powerful tool for the bioassay-guided purification of single-component antitrichomonal biomolecules from complex natural product mixtures.

Isolation of Unstable Isomers of Lucilactaene and Evaluation of Anti-Inflammatory Activity of Secondary Metabolites Produced by the Endophytic Fungus Fusarium sp. QF001 from the Roots of Scutellaria baicalensis

“…Similarly, the expression of pro-inflammatory cytokines such as TNF-α and IL-6 was suppressed after treatment of DEX or 1-9 on LPS-induced macrophage cells ( Figure 5). Compound 1 was previously reported as a phytotoxin, cytotoxin against human cancer cells, a anti-parasitic agent against Trichomonas vaginalis, and an anti-tuberculosis agent [20][21][22][23]. Compound 4 was known with the hepatic glucose production inhibiting activity and cytotoxicity [24].…”

“…Compound 4 was known with the hepatic glucose production inhibiting activity and cytotoxicity [24]. Compound 5 was also reported to have cytotoxicity and antibacterial activity as well as anti-parasitic activity and hepatic glucose production inhibiting activity [22,25,26]. Lucilactaene (6) was well known as cell cycle inhibitor [17].…”

Hyalodendrins A and B, New Decalin-Type Tetramic Acid Larvicides from the Endophytic Fungus Hyalodendriella sp. Ponipodef12

“…It seems that the configuration at C-5 has strong correlation with the larvicidal activities, as the epimer of 1 (i.e., 2) was two times less active than that of 1. Decalin-type tetramic acid metabolites were found to display diverse activities, such as HIV-1 integrase inhibiting activity [19], antibacterial activity [18,[20][21][22], antimalarial activity [23] and anti-parasite activity against Trichomonas vaginalis [24]. Our research revealed these type of compounds also have larvicidal function.…”

Anti-trichomonad activities of different compounds from foods, marine products, and medicinal plants: a review

“…2) they isolated from the Amazonian fungal endophyte E6927E inhibited the growth of the pathogenic bacteria Staphylococcus aureus and Enterococcus faecalis as well as isolates of the pathogenic fungal strains Candidas albicans and Aspergillus sp. King, Carter [25], using an image-based, high-throughput, and high-content for testing natural products for anti-trichomonal activity, discovered that pyrrolocin A was also a potent inhibitor of T. vaginalis with an effective inhibitory concentration (EC 50 ) of 60 nM. Because the fungal compound also showed limited toxicity towards mammalian cervical cells with a high selectivity index of > 100, the results of the two investigations suggest that pyrrolocin A has the potential to protect food and humans concurrently against contamination and infection by pathogenic bacteria, fungi, and T. vaginalis.…”