Sitophilus zeamais (Coleoptera: Curculionidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) are important economic pests of corn, Zea mays (Poaceae). Psychotria spp. (Rubiaceae) plants are rich in secondary metabolites that could be toxic against such pests. We have screened extracts from four species of Psychotria abundant in the Cerrado (Savannah-type) biome of Brazil for the toxicity to two insects. We found that extracts from leaves and stems had significant effects on the hatching rate, parameters of caterpillar body (weight and length and width of head capsule), repellency, and mortality of these two pests, although the effects varied according to the Psychotria species and plant source (stem or leaf). Extracts of the stems of Psychotria hoffmannseggiana and of Psychotria capitata were more toxic to S. zeamais and the stems of Psychotria goyazensis to S. frugiperda; therefore, such extracts could have the potential for use in integrated pest management schemes.

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Natural 2H‐chromenes were isolated from the crude extract of Piper aduncum (Piperaceae) and analyzed by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) applying collision‐induced dissociation. Density functional theory (DFT) calculations were used to explain the preferred protonation sites of the 2H‐chromenes based on thermochemical parameters, including atomic charges, proton affinity, and gas‐phase basicity. After identifying the nucleophilic sites, the pathways were proposed to justify the formation of the diagnostic ions under ESI‐MS/MS conditions. The calculated relative energy for each pathway was in good agreement with the energy‐resolved plot obtained from ESI‐MS/MS data. Moreover, the 2H‐chromene underwent proton attachment on the prenyl moiety via a six‐membered transition state. This behavior resulted in the formation of a diagnostic ion due to 2‐methylpropene loss. These studies provide novel insights into gas‐phase dissociation for natural benzopyran compounds, indicating how reactivity is correlated to the intrinsic acid‐base equilibrium and structural aspects, including the substitution pattern on the aromatic moiety. Therefore, these results can be applied in the identification of benzopyran derivatives in a variety of biological samples.

The interest in the production of hops in Brazil, motivated by the third position in the world ranking of beer producers and the growth of the craft brewery business, justifies the intensification of studies into its adaptation to local growing conditions. Due to the high internal demand, the aim of this study was to evaluate the phytochemical profiles of hop varieties grown in subtropical conditions under different cropping systems. Studies that promote the expansion of cultivation areas in distinct climate conditions and ensure quality are very important. A randomized block design was adopted with a 2 × 5 subdivided plot. The main factor was the cropping system (organic and conventional), and the secondary factor was the hop variety (Columbus, Chinook, Nugget, Cascade and Hallertau Mittelfrüeh), with four blocks and four plants per plot. The quality parameters monitored in this work were the contents of alpha and beta acids, and xanthohumol in the inflorescences of hops, as well as the relative composition of their essential oils. The variations in the chemical profiles of essential oils showed differences between some varieties, and the different compositions and levels resulting from the two cropping systems show that management and cultural practices can influence the aromatic characteristics of hops; in total, 23 compounds were found. The terpene fraction represented 79.67% of the oil in Hallertau and 93.63% in Cascade, with myrcene being the main compound. The levels of bitter acids and xanthohumol did not differ statistically as a function of the treatments. This study contributes the first records of the chemical profiles of hops grown in subtropical conditions in Brazil, in general, the Nugget variety had the highest qualitative potential