**Compositional Features and Bioactive Properties of** *Aloe vera* **Leaf (Fillet, Mucilage, and Rind) and Flower**

**Mikel Añibarro-Ortega 1, José Pinela 1,\*, Lillian Barros 1, Ana Ciri´ ´ c2, Soraia P. Silva 3, Elisabete Coelho 3, Andrei Mocan 4,5, Ricardo C. Calhelha 1, Marina Sokovi´c 2, Manuel A. Coimbra <sup>3</sup> and Isabel C. F. R. Ferreira 1,\***


Received: 8 September 2019; Accepted: 27 September 2019; Published: 1 October 2019

**Abstract:** This work aimed to characterize compositional and bioactive features of *Aloe vera* leaf (fillet, mucilage, and rind) and flower. The edible fillet was analysed for its nutritional value, and all samples were studied for phenolic composition and antioxidant, anti-inflammatory, antimicrobial, tyrosinase inhibition, and cytotoxic activities. Dietary fibre (mainly mannan) and available carbohydrates (mainly free glucose and fructose) were abundant macronutrients in fillet, which also contained high amounts of malic acid (5.75 g/100 g dw) and α-tocopherol (4.8 mg/100 g dw). The leaf samples presented similar phenolic profiles, with predominance of chromones and anthrones, and the highest contents were found in mucilage (131 mg/g) and rind (105 mg/g) extracts, which also revealed interesting antioxidant properties. On the other hand, the flower extract was rich in apigenin glycoside derivatives (4.48 mg/g), effective against *Pseudomonas aeruginosa* (MIC = 0.025 mg/mL and MBC = 0.05 mg/mL) and capable of inhibiting the tyrosinase activity (IC50 = 4.85 mg/mL). The fillet, rind, and flower extracts also showed a powerful antifungal activity against *Aspergillus flavus*, *A. niger*, *Penicillium funiculosum*, and *Candida albicans*, higher than that of ketoconazole. Thus, the studied *Aloe vera* samples displayed high potential to be exploited by the food or cosmetic industries, among others.

**Keywords:** *Aloe barbadensis* Mill.; nutritional composition; neutral sugars; phenolic compounds; organic acids; antioxidant capacity; antimicrobial activity; tyrosinase inhibitory activity; cytotoxicity
