Macela (Egletes viscosa (L.) Less.) is a medicinal herb that possesses antidyspeptic, antidiarrheic, and hepatic protecting properties. Its harvest should allow assembling large biomass production and high yield of active principles. The main goal of this work was to evaluate the influence of harvesting dates over both biomass components and qualitative and quantitative chemical composition of macela. Treatments corresponded to seven harvesting dates (75; 85; 95; 105; 115; 125 and 135 days after the transplant (DAT)), displayed in a randomized blocks design, with four replications, and two useful-plant plots (1.0 x 0.5 m). Harvesting dates affected both yield components and the content of active principles in macela. Biomass production showed a mounting increase during harvests, especially in stem and leaves. Capitulum production in the last three harvests (2.6; 3.4; and 6.7 t ha-1) surpassed the previous ones. The harvesting indexes (ratio between capitulum and aboveground dry mass) to the same periods were 47, 46 and 48%, respectively. Aboveground (stem and leaves) and capitulum had a higher yield of both ethanolic (YEE) and chloroformic (YCE) extracts than roots. YEE and YEC varied throughout plant reproductive phase, with peaks at 105 DAT (roots: 0.17 g plant-1 for YEC); 125 DAT (flower buds: 3.92 and 18.02 g plant-1 for respectively YEE and YEC; roots: 0.34 g plant-1 for YEE), and 135 DAT (aboveground part: 3.02 and 11.70 g plant-1 respectively for YEE and YEC). The yield of essential oil reached the maximum value at 135 DAT (44.4 L ha-1). The content of trans-pinocarveyl acetate in the capitulum ranged from 52.3 to 73.5% in harvests from 75 to 95 DAT, remaining constant around 53.3% after that. The content of mirtenila acetate remained stable throughout harvests (6,98±0,56%). The content of â-pineno in capitulum fluctuated in two steps: 31.8±1.72% (from 85 to 105 DAT), and 49.2±1.15% (from 115 to 135 DAT).
Egletes viscosa (L.) Less.; medicinal herb; essential oil; ethanolic extract; chloroformic extract
