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Croton belongs to the Euphorbiaceae genus, one of the major Angiosperms families, and is widely distributed throughout the world, especially in the tropics. In this study, the hydroalcoholic extract (70% EtOH) of Croton echinocarpus leaves afforded two alkaloids: corydine and norisoboldine, and their structures were established by spectroscopic data interpretation (UV, IR, NMR and LREIMS). Both alkaloids displayed significant in vitro anti-HIV potential, inhibiting 40% of the HIV-1 reverse transcriptase enzyme activity at a concentration of 100 μg mL - 1 of norisoboldine and 450 μg mL - 1 of corydine. Corydine showed IC 50 of 356.8 μg mL - 1 , while norisoboldine was more efficient on inhibiting the RT activity, showing IC 50 of 153.7 μg mL - 1 . [ABSTRACT FROM AUTHOR]

Acute acetaminophen ( ACT) ingestion has been reported to reduce thermal strain during cycling in the heat. In this study, nine active participants ingested 20 mg of ACT per kg of total body mass ( ACT) or a placebo ( PLA), 60 min prior to cycling at a fixed rate of metabolic heat production ( ACT: 8.3 ± 0.3 W/kg; PLA: 8.5 ± 0.5 W/kg), which was equivalent to 55 ± 6% VO2max, for 60 min at 34.5 ± 0.1 ° C, 52 ± 1% relative humidity. Resting rectal temperature ( Tre; ACT: 36.70 ± 0.17 ° C; PLA: 36.80 ± 0.16 ° C, P = 0.24), esophageal temperature ( Tes; ACT: 36.54 ± 0.22 ° C; PLA: 36.61 ± 0.17 ° C, P = 0.50) and mean skin temperature ( Tsk; ACT: 34.00 ± 0.14 ° C; PLA: 33.96 ± 0.20 ° C, P = 0.70) were all similar among conditions. At end-exercise, no differences in Δ Tre ( ACT: 1.12 ± 0.15 ° C; PLA: 1.11 ± 0.21 ° C, P = 0.92), Δ Tes ( ACT: 0.90 ± 0.28 ° C; PLA: 0.88 ± 0.23 ° C, P = 0.84), Δ Tsk ( ACT: 0.80 ± 0.39 ° C; PLA: 0.70 ± 0.46 ° C, P = 0.63), mean local sweat rate ( ACT: 1.02 ± 0.15 mg/cm2/min; PLA: 1.02 ± 0.13 mg/cm2/min, P = 0.98) and whole-body sweat loss ( ACT: 663 ± 83 g; PLA: 663 ± 77 g, P = 0.995) were evident. Furthermore, ratings of perceived exertion and thermal sensation and thermal comfort were not different between ACT and PLA conditions. In conclusion, ACT ingested 60 min prior to moderate intensity exercise in hot-humid conditions does not alter physiologic thermoregulatory control nor perceived strain. [ABSTRACT FROM AUTHOR]