Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

Curcuma longa L. is a specie which rhizome is rich in secondary compounds with antioxidant activities. Factors such as the source of the propagation material and mycorrhizal fungi inoculation in the crop have been poorly investigated. This work aimed to evaluate the compounds with antioxidant activity from C. longa rhizomes, from different places and inoculated with mycorrhizal fungi. The field essay was carried out during 2020 summer, in the city of Colinas – SP, soils were previously prepared with organic manure. The experiment design was set in a randomized block with four treatments and four replications. Plots with 2 m2 were divided into five lines with 2 m, the distance between lines was 0,40 m, and among rhizomes was 0,20 m, in a total of 25 plants. Was inoculated 1 g of Rizophagus clarus per dug hole (1000 spores), then, the secondary rhizome was placed on the fungi and the dug hole was covered with soil. The treatments used in the essay were: variety Morretes without fungi (T1) and inoculated (T2), Monte Alegre variety without fungi (T3), and inoculated (T4). After 12 months, the rhizome was harvested, cleaned, and weighed. The material was ground and refrigerated at -80°C. Methanolic extracts were obtained from 100 mg of fresh rhizome according to Waterhouse (2002). Determination of antioxidant activity was based on the absorption molar extinction of the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH 60µM) and by the iron reduction method (FRAP). Analysis was performed in ELISA 96 well flat bottom plate. Absorbance was registered by a spectrophotometer (UV-VIS Spectra Max Plus®) with SoftMax Pro 6.5.1 program. DPPH method showed that the antioxidant activity was not altered by rhizome inoculation to Monte Alegre variety, and the values were statistically equal (25.64%-T3 and 24.95% -T4). Values were higher for Morretes variety in the inoculated plants - T2 (12.88%) compared to the non-inoculated - T1 (7.54%). FRAP analysis didn´t indicate the effects of fungi inoculation on both varieties, being the difference observed only between them, Rhizome antioxidant activity to Monte Alegre variety was 3 folds higher than Morretes (an average of 1192,05 and 378,57 mg of TROLOX 100 g-1). Results obtained among the varieties indicated that this alteration might be due to the genetic characteristics of the material. The differences observed from DPPH methodology in the Morretes rhizomes suggest that plants inoculated with R. clarus grew better nourished and, thus, had less stress. This was reflected in the feedback of the test, which is linked to the capability that a specific substance has to scavenge the DPPH radical. The differences highlighted by the methodologies were due to the different types of free radicals and their different pathways of playing roles in the plant organism. Was determined, for the first time, antioxidant activity for these varieties under field conditions, being the floating feedback considered a function of location and, the presence of the fungi for the Morretes variety.