Introduction This study focuses on the central mountain region of the Peruvian Andes, particularly its western slopes, high-altitude areas, and inter-Andean valleys situated above 3000 m.a.s.l. Despite its ecological importance, the region remains understudied, resulting in significant information gaps. Objective To identify flora species along an altitudinal gradient in the Cajatambo district. Methods Sampling was carried out at five distinct altitudinal levels using a combination of sampling techniques. Taxonomic identification was performed, and statistical analyses including ANOVA, the Mantel test, and NMDS were applied. Results 424 plant species were identified, revealing the dominance of Asteraceae. The approach used allowed for the identification of floristic and structural patterns in various habitats, ranging from arid montane scrub to puna grassland. Surprisingly, Asteraceae richness had a significant impact on species diversity, while altitude did not. Additionally, floristic similarity between nearby altitudinal levels was not related to geographical distance. The analysis of ecosystems has shown that certain families are adaptable. Additionally, floristic diversity has been affected by human activity near the district capital. The distribution of medicinal species has been limited due to selective extraction. Conclusions The shrubland and thorny scrub was the most diverse ecosystem and had the widest distribution across the altitudinal gradient.

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The Royal Spanish Botanical Expedition to the Viceroyalty of Peru in the 18th century was one of the most important European expeditions to American territories. Using the herbarium sheets of Ruiz and Pavón (Royal Botanical Garden of Madrid) and their edited works, manuscripts and expedition diaries, we have constructed a database of the collected and observed flora, which has served as the basis for a map containing all of the Peruvian localities of the expedition. Based on the method of bioclimatic belts and our own observations, we have deduced to which type of vegetation the flora studied in the expedition belongs. The uses of the flora per locality were studied, as well as the ethnic groups involved in the different localities. By using a Principal Component Analysis, we have obtained the distribution of the bioclimatic belts whose vegetation was the most explored. In order to observe the bioclimatic tendency of plant uses, a Detrended Correspondence Analysis (DCA) was conducted to identify the distribution of localities with the highest frequencies of plant uses. The expedition's explorations focused on the most humid areas of the thermo- and mesotropical belts, from where a large number of plants with practical uses were obtained.

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From the aerial parts of Euphorbia gossypina var. coccinea Pax., eight new pregnane glycosides (euphogossypins A-H, 1 - 8 ) of the cynanforidine and deacetylmetaplexigenin aglycons, two new lignans (gossypilignans A and B, 9 and 10 ), and four known compounds, namely, the pregnane 12- O -benzoyldeaxcylmetaplexigenin ( 11 ), the lignan 9α-hydroxypinoresinol ( 12 ), and the flavonoids naringenin ( 13 ) and quercitrin ( 14 ) were isolated. The structure elucidation of the new compounds was carried out by a spectroscopic analysis, including HRMS, 1D ( 1 H, 13 C JMOD), and 2D NMR (HSQC, 1 H- 1 H COSY, HMBC, and NOESY) experiments. The obtained pregnane glycosides were substituted with acetyl and benzoyl ester moieties, and sugar chains containing thevetose, cymarose, digitoxose, and glucose monosaccharides. All of the compounds are described for the first time from E. gossypina var. coccinea . The isolated pregnanes and lignans were tested for their antiproliferative activity on HeLa cells using the MTT assay; the compounds exerted no significant effect against the tumor cells.

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Despite El Niño events being one of the main forces shaping the coastal desert vegetation in South America, the impacts of the high precipitation typical of this rare but recurrent climatic event remain understudied. Here we monitored the plant community of a coastal lomas, a seasonal desert ecosystem, during 1998 and 2001 to analyse its changes during the 1997-98 El Niño and the following La Niña events. We measured species abundance and vegetation cover in 31 plots, and recorded climate variables in Lomas de Lachay, Peru. We found a significant positive correlation between precipitation and vegetation cover, density, alpha diversity (species diversity at the plot level), total richness and abundance of several key species but no correlation with gamma diversity (species diversity at the whole loma level). During the El Niño event, the seasonality, typical of the lomas ecosystem, disappeared, as evidenced by both the similarity of species composition and mean vegetation cover values between most sampling campaigns of 1998 and 1999. Moreover, total richness was lower during the El Niño event than during the humid season of 2000 and 2001 resulting from the dominance of only a few species, such as Nicotiana paniculata and Loasa urens. Temporal-spatial changes in the abundance of the dominant species caused the differences between alpha and gamma diversity, especially during 1999. Within that year, mean alpha diversity showed similar values whilst gamma diversity values were different. The reestablishment of the seasonality of most plant community characteristics and a clear difference between species composition of the humid and the dry season occurred two years after the El Niño event, suggesting a resilient community. This study provides one of the few quantifications of the Peruvian lomas' response to the 1997-98 El Niño event and the following La Niña, one of the most extreme climatic events in the last century.

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The MeOH extract of the aerial parts of Croton ruizianus afforded two new pregnane glycosides 1 and 2, together with the morphinandienone alkaloids flavinantine (3) and O-methylflavinantine (4). Their structures were elucidated by NMR experiments including 1H-1H (1D TOCSY and 2D DQF-COSY) and 1H-13C (HSQC, HMBC) spectroscopy. The proaggregating activity of the MeOH extract and the isolates were evaluated. Although the MeOH extract and pregnane glycosides (at different doses) were found to promote platelet aggregation, flavinantine (3) and O-methylflavinantine (4) showed only slight activity. The ability of the MeOH extract and the four compounds to act synergistically with thrombin was also evaluated. All the tested compounds were successful in augmenting the aggregating effect of thrombin, although to different degrees.

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