Chemical compositions (fatty acids, total phenolic compounds, flavonoids) and the in-vitro biological activities (antioxidant and antimicrobial activity; and growth induction of edible fungal strains) were compared for four varieties of mango seeds. Hexanic extract (HE) showed a fatty acid profile with a higher proportion of oleic acid. In the ethanolic extract were found variable total phenolic contents (103 to 125 mg GAE/g dry weight) and flavonoid contents (0.72 to 0.8 mg QE/g dry weight). This study reports for the first time the presence of procyanidin B1 in ethanolic extracts. The antioxidant activity showed IC50 values ranging from 3.09 to 3.42 μg/mL for ABTS•+ and 12.17 to 13.93 μg/mL for DPPH•. The ethanolic extract from the seed of the Yulima variety showed the highest percentages of inhibition against Staphylococcus aureus. Residues removed from ethanolic extraction of the seed kernel (EKR) induced the growth of edible fungal strains: Lentinus crinitus and Pleurotus tubarius. The data obtained show the potential of the seeds from these mango varieties, which could lead to alternative uses in various industry sectors and the use of this agricultural byproduct.

Root rot caused by Phytophthora cinnamomi Rands, is one of the main factors that limits avocado production worldwide; silicon as a defense inducer seems to be a viable strategy to integrate into the management of this disease. Hereby, the present study evaluated the induction of resistance with silicon in Hass avocado plants inoculated with P. cinnamomi , as a possible alternative to conventional agrochemical management. A potassium silicate solution (10 mL, 0.2 M expressed as SiO 2 ) was applied by irrigation, for ten days before inoculation with P. cinnamomi in Hass avocado plants. Leaf samples were taken at 3, 24, 144, and 312 h after inoculation with the pathogen. Peroxidase (POD) and polyphenol oxidase (PPO) enzymes had their highest activity 3 h after pathogen inoculation (p < .05). There was a decrease in the activity of the enzyme phenylalanine ammonialyase (PAL), in the content of total phenols, and the inhibition capacity of the DPPH ● radical, between 3 h and 24 h in the plants with the inducer and inoculated with P. cinnamomi (p < .05). The results suggest a beneficial effect of silicon as a defense inducer in Hass avocado plants, manifested in the activation of enzymatic pathways related to the regulation of oxidative stress and the synthesis of structural components. Therefore, the application of silicon as a defense inducer emerges as a strategy to include in the integrated management of the disease caused by P. cinnamomi in Hass avocado.