No abstract

No abstract

No abstract

RESUMEL'étude palynologique de l'abri de La Combette nous informe sur l'évolution de la végétation autour du site pendant le Pleistocene supérieur, au Würm ancien (début du stade isotopique 3). Les différentes phases climatiques mises en évidence sont caractérisées par la dominance du pin sylvestre et la présence notable d'espèces méditerranéennes. On constate le caractère refuge du site. RESUMENEl estudio palinologic o del Abrigo de La Combette nos informa sobre la evolución seguida por la vegetación en el El artículo fue remitido en su versión final el 28-V-98. entorno del yacimiento durante el Pleistoceno Superior, Würm antiguo (inicio del estadio isotópico 3). Se ponen de manifiesto diversas fases climáticas caracterizadas, en general, por el dominio de Pinus sylvestris t. así como por la notable presencia de especies mediterráneas. Se constata el carácter de refugio de la zona estudiada. ABSTRACTThe palynological study of the La Combette rocks he lter gives us information on the evolution of the vegetation surrounding the rock shelter area during the Upper Pleistocene (isotopic stage 3). Although widely dominated by Pinus sylvestris t., mediterranean species are also present in the different climatic phases revealed by the catalysis. This confirms the refuge character of the area.

Most biologically natural compounds are very sensitive and easily degradable under drying conditions. This study aimed to investigate the effect of drying temperature on the contents of phenolic compounds and in vitro antioxidant and antidiabetic activities of wild guava leaves. Wild guava leaves were dried at 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C, as well as sun drying (SD). The total phenolic and flavonoid contents (TPC and TFC) were measured using the colorimetric method. Antioxidant activity was determined by the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) and 2,2-azino-bis(3-ethylbenzothazoline-6-sulfonic acid (ABTS) radical scavenging activity assays. In vitro antidiabetic activity was measured by assessing α-glucosidase and α-amylase inhibitory activities. The contents of individual phenolic compounds were determined using ultra-performance liquid chromatography (UPLC). The principal component analysis (PCA) results revealed that hot air drying at different temperatures had significantly different effects on the bioactive compounds and biological properties of guava leaves. Drying at high or low temperatures resulted in a higher degradable rate of bioactive compounds leading to a weakening of the biological properties. Drying at 50 °C resulted in high TPC and TFC as well as the highest in vitro antioxidant and antidiabetic activities. Furthermore, the highest contents of gallic acid, catechin, rutin, quercetin, apigenin, quercitrin, vitexin, and apigenin-7- O-D-glucopyranoside were found in samples dried at 50 °C, whereas the highest contents of chlorogenic acid, epicatechin, and ellagic acid were observed in samples dried at 60 °C. Therefore, drying at 50 °C was the suitable temperature for retaining valuable biological compounds in wild guava leaves.