Identification and Quantification of Bioactive Compounds in Agave potatorum Zucc. Leaves at Different Stages of Development and a Preliminary Biological Assay

Abstract

The leaves of Agave potatorum Zucc. represent more than 50% of waste during the jima in the mezcal industry. To provide the basis for a knowledge-based integral use of these wastes, this research provides the identification and quantification of bioactive compounds of leaves at different stages of development, differentiated by the position of the leaves in the plant (basal, medium and apical), and dividing each leaf into apical and basal parts. Qualitative phytochemical analysis showed highly positive results for coumarins and tannins, and positive for cardiac glycosides and triterpenoids compounds, without an age-dependent or position of the leaves response of the plant. Quantitative analysis of phenolic compounds and flavonoids is not preferentially accumulated respect to the position of the leaf in the plant, only are higher in the apical parts, whereas for carbohydrates a positive gradient was evidenced through the leaves in the plant from apical to basal ones. The highest concentration of phenolics, flavonoids, fructose and fructans compounds were determined in 6-year leaves, with maximum observed values of 173.80 ± 9.36, 35.58 ± 6.41, 308.30 ± 3.62 mg/g d.w., and 37.23 ± 4.5%, respectively. Interestingly, the ethanolic extract of the fresh leaves of A. potatorum showed an increase in the mycelial growth of Botrytis cinerea. The data showed that plant age is the most important factor influencing the content of bioactive compounds. In addition, a fungal growth enhancing effect was exhibited by the extract, suggesting a biotechnological advantage that can improve the growth of beneficial fungi in agricultural crops.