Plants are phytochemical hubs containing antioxidants, essential for normal plant functioning and adaptation to environmental cues and delivering beneficial properties for human health. Therefore, knowledge on the antioxidant potential of different plant species and their nutraceutical and pharmaceutical properties is of utmost importance. Exploring this scientific research field provides fundamental clues on (1) plant stress responses and their adaptive evolution to harsh environmental conditions and (2) (new) natural antioxidants with a functional versatility to prevent and treat human pathologies. These natural antioxidants can be valorized via plant-derived foods and products. Cuba contains an enormously rich plant biodiversity harboring a great antioxidant potential. Besides opening new avenues for the implementation of sustainable agroecological practices in crop production, it will also contribute to new strategies to preserve plant biodiversity and simultaneously improve nature management policies in Cuba. This review provides an overview on the beneficial properties of antioxidants for plant protection and human health and is directed to the valorization of these plant antioxidants, emphasizing the need for biodiversity conservation.

Five rhizosphere Bacillus subtilis isolates were tested for in vitro antagonism against a sugarcane seedling pathogen strain of Curvularia gudauskasii. The isolate B. subtilis SR/B-16 was selected because it permanently inhibits 71% of fungal growth. Microscopic analysis of the antagonistic bacteria effects on C. gudauskasii revealed swelling and bulbous hyphae, vacuolated cytoplasm and no spore formation. The analysis of culture filtrates of SR/B-16 collected from stationary phase showed that they are responsible for the antifungal effects and for the abnormal shapes observed. However, bacterial culture efficiency is higher. The organic concentrated fraction of the extracts caused the same morphological changes as those caused by antifungal lipopeptides secreted by Bacillus species. The strain SR/B-16 can be used for the formulation of bioactive compounds for the treatment of C. gudauskasii diseases on sugarcane seedlings.