Antimicrobial spiroketal macrolides and dichloro-diketopiperazine from Micromonospora sp. FIMYZ51.

Four compounds (1-4) featuring with an L-rhodinose and spiroketal, possess uncommon continuous hydroxy groups in the macrolide skeleton, and a dichloro-diketopiperazine (5) were isolated from a marine derived Micromonospora sp. FIMYZ51. The determination of the relative and absolute configurations of all isolates was achieved by extensive spectroscopic analyses, single-crystal X-ray diffraction analysis, and ECD calculations. According to structural characteristic and genomic sequences, a plausible biosynthetic pathway for compound 1-4 was proposed and a spirocyclase was inferred to be responsible for the formation of the rare spirocyclic moiety. Compounds 1-4 exhibited potent antifungal activities which is equal to itraconazole against Aspergillus niger. Compounds 1-5 exhibited different degree of inhibitory activities against opportunistic pathogenic bacteria of endocarditis (Micrococcus luteus) with MIC values ranging from 0.0625 µg/mL to 32 µg/mL. Compounds 2 and 3 showed moderate cytotoxicity against drug-resistant tumor cell lines (Namalwa and U266). The result not only provides active lead-compounds, but also reveal the potential of the spirocyclase gene resources from Micromonospora sp., which highlights the promising potential of the strain for biomedical applications.

Specialized metabolites of the fungal genus Phomopsis: Structures, bioactivities and biosynthesis.

Fungi are important resources of novel bioactive compounds which have a high potential to be drug leads or candidates for further pharmacological applications. Phomopsis, a genus widely distributed in the environment, can produce various types of compounds including polyketides, alkaloids, terpenoids, cytochalasins, steroids and flavonoids. The metabolites of Phomopsis sp. showed diverse bioactivities such as antibacterial, anti-inflammatory, antimalarial, and so on, many of which may influence the physiological behaviour of the host plants. In this review, we focus on the chemical structures and biological activities of 183 specialized metabolites isolated from Phomopsis sp. in the decade (2013-2022). Moreover, the biosynthetic pathways of some typical components are summarized.

Antifungal polyketides from the marine-derived fungus Nigrospora sp. MG36-1.

Three new polyketides, a griseofulvin derivative 1, a hydroanthraquinone derivative 8 and a pyranolactone derivative 10, together with eight known compounds (2-7, 9 and 11), were isolated from the marine-derived fungus Nigrospora sp. MG36-1. The structures of the three new compounds were unambiguously determined by nuclear magnetic resonance (NMR), mass spectrometry, 13C NMR calculation in combination with DP4+ and ECD calculations. The antitumor, antibacterial and antifungal activities of the compounds 1-9 were evaluated in vitro. Compound 1 showed antibacterial activity against Acinetobacter baumannii with MIC 42.5 µg/mL. Compounds 1 and 8 exhibited antifungal activity against Candida albicans with MICs 21.5 µg/mL and 17.5 µg/mL, respectively.

C-P Natural Products as Next-Generation Herbicides: Chemistry and Biology of Glufosinate.

In modern agriculture and weed management practices, herbicides have been widely used to control weeds effectively and represent more than 50% of commercial pesticides applied in the world. Herbicides with unique mechanisms of actions (MOA) have historically been discovered and commercialized every two or three years from the 1950s to the 1980s. However, this trend lowered dramatically as no herbicide with a novel MOA has been marketed for more than 30 years. The fast-growing resistance to commercial herbicides has reignited the agricultural chemical industry interest in new structural scaffolds targeting novel sites in plants. Carbon-phosphorus bonds (C-P) containing natural products (NPs) have played an essential role in herbicide discovery as the chemical diversity, and the promising bioactivity of natural C-P phytotoxins can provide exciting opportunities for the discovery of both natural and semisynthetic herbicides with novel targets. Among commercial herbicides, glyphosate (Roundup), a famous C-P containing herbicide, is by far the most universally used herbicide worldwide. Furthermore, glufosinate is one of the most widely used natural herbicides in the world. Therefore, C-P NPs are a treasure for discovering new herbicides with novel mechanisms of actions (MOAs). Here, we present an overview of the chemistry and biology of glufosinate including isolation and characterization, mode of action, herbicidal use, biosynthesis, and chemical synthesis since its discovery in order to not only help scientists reassess the role of this famous herbicide in the field of agrichemical chemistry but also build a new stage for discovering novel C-P herbicides with new MOAs.