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.

[Isolation and purification of seven catechin compounds from fresh tea leaves by semi-preparative liquid chromatography].

An effective and simple method was established to simultaneously purify seven tea catechins (gallocatechin (GC), epigallocatechin (EGC), catechin (C), epigallocatechin-3-O-gallate (EGCG), epicatechin (EC), epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3"Me) and epicatechin-3-O-gallate (ECG)) from fresh tea leaves by semi-preparative high performance liquid chromatography (HPLC). Fresh leaves of Tieguanyin tea were successively extracted with methanol and chloroform. Then crude catechins were precipitated from the aqueous fraction of chloroform extraction by adding lead subacetate. Crude catechins were used for the isolation of the seven target catechin compounds by semi-preparative HPLC. Methanol-water and acetonitrile-water were sequentially used as mobile phases. After two rounds of semi-preparative HPLC, all target compounds were achieved with high purities (>90%). The proposed method was tested on two additional tea cultivars and showed similar results. This method demonstrated a simple and efficient strategy based on solvent extraction, ion precipitation and semi-preparative HPLC for the preparation of multiple catechins from tea leaves.

Social Complexification and Pig (Sus scrofa) Husbandry in Ancient China: A Combined Geometric Morphometric and Isotopic Approach.

Pigs have played a major role in the economic, social and symbolic systems of China since the Early Neolithic more than 8,000 years ago. However, the interaction between the history of pig domestication and transformations in Chinese society since then, have not been fully explored. In this paper, we investigated the co-evolution from the earliest farming communities through to the new political and economic models of state-like societies, up to the Chinese Empire, using 5,000 years of archaeological records from the Xiawanggang (XWG) and Xinzhai (XZ) sites (Henan Province). To trace the changes of pig populations against husbandry practices, we combined the geometric morphometric analysis of dental traits with a study of the stable carbon and nitrogen isotope ratios from bone collagen. The domestication process intensified during the Neolithic Yangshao, prompted by greater selective pressure and/or better herd control against wild introgression. After that, pig farming, in XWG, relied on local livestock and a gradual change of husbandry practices overtime. This was characterized by a gentle increase in millet foddering and animal protein intake, until a complete change over to household management during the Han dynasty. The only rupture in this steady trend of husbandry occurred during the Longshan period, with the appearance of small sized and idiosyncratic pigs with specific feeding practices (relying on millet and household scraps). From three exploratory hypothesis, we explored the possibility of anti-elite pig production in XWG during the Longshan period, as a means to resist incorporation into a new economic model promoting intensified domestic production. This exploratory hypothesis is the most suitable to our dataset; however, numerous areas need to be explored further in order to adequately document the role of pigs in the rise of China's complex societies.

Secondary metabolites from Eupenicillium parvum and their in vitro binding affinity for human opioid and cannabinoid receptors.

Phytochemical investigation of the soil microfungus Eupenicillum parvum led to the isolation of two new compounds: a chromone derivative euparvione (1) and a new mycophenolic derivative euparvilactone (2), as well as thirteen known compounds. The structures of the new compounds were elucidated by means of extensive IR, NMR, and MS data and by comparison of data reported in the literature. The structure of the known compound 6 was confirmed by X-ray crystallography. Several isolated compounds were evaluated for in vitro binding assays using opioid receptors (subtypes δ, κ, and µ) and cannabinoid receptors (CB1 and CB2). Compound 10 displayed the best selective µ-opioid receptor and CB1 receptor binding affinities showing values of 47% and 52% at a 10 µM concentration, respectively. These findings provide insight into the potential therapeutic utility of this class of compounds.

Discovery of the antibiotic phosacetamycin via a new mass spectrometry-based method for phosphonic acid detection.

Naturally occurring phosphonates such as phosphinothricin (Glufosinate, a commercially used herbicide) and fosfomycin (Monurol, a clinically used antibiotic) have proved to be potent and useful biocides. Yet this class of natural products is still an under explored family of secondary metabolites. Discovery of the biosynthetic pathways responsible for the production of these compounds has been simplified by using gene based screening approaches, but detection and identification of the natural products the genes produce have been hampered by a lack of high-throughput methods for screening potential producers under various culture conditions. Here, we present an efficient mass-spectrometric method for the selective detection of natural products containing phosphonate and phosphinate functional groups. We have used this method to identify a new phosphonate metabolite, phosacetamycin, whose structure, biological activity, and biosynthetic gene cluster are reported.