Phytochemical Characterization of Aloe Vera Extracts and Their Inhibitory Activities against Key Cancer-related...

This study presents the first comparative investigation of the inhibitory effects of Aloe vera leaf gel (aqueous) and leaf skin (aqueous, methanolic, and ethyl acetate) extracts and the main components of the plant (aloin, aloe-emodin, and acemannan) on some cancer-related enzymes, and also the phytochemical characterization of the extracts. According to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, quinic acid (ranging from 42.55 to 54.48 mg/g) was the most abundant compound in all extracts except for the ethyl acetate. High-performance LC analysis indicated that aloin was present in higher quantities than aloe-emodin across all extracts. The highest concentration of aloin was observed in the ethyl acetate extract (36.33 ± 0.60 µg/mg), as well as that of aloe-emodin in the methanolic extract (0.91 ± 0.07 µg/mg). Aqueous (gel), methanolic, and ethyl acetate extracts showed strong inhibitory activity against thioredoxin reductase (TrxR), while all extracts demonstrated low inhibition against histone deacetylase (HDAC) and myeloperoxidase (MPO). Among the tested components, aloe-emodin exhibited the most potent TrxR inhibition (IC₅₀ = 1.46 ± 0.14 µg/mL). Additionally, acemannan showed the highest inhibitory activity on HDAC (IC₅₀ = 38.57 ± 2.82 µg/mL), and aloin demonstrated the strongest inhibition against MPO (IC₅₀ = 28.40 ± 0.13 µg/mL). These findings suggest that A. vera extracts and the tested components possess promising anticancer potential through their ability to inhibit key enzymes involved in cancer. This provides novel insights into A. vera's anticancer potential. Further studies are also warranted to elucidate the underlying mechanisms and evaluate the in vivo efficacy of the extracts/components.