Highly efficient hydrolysis of Hesperidin, Naringin and synthesis of their aglycone acetates under microwave irradiation.

Hesperidin and naringin are glycosides present in the peels of rutaceae fruits (orange (Citrus sinensis ) for hesperidin ), grapefruit (Citrus paradise) for naringin) and are easily extracted with ethanol. Acidic hydrolysis of Hesperidin and Naringin, furnishing their aglycone moieties Hesperetin and Naringenin respectively, is reported using sulfuric acid and water as solvent, under microwave irradiation. This new economical procedure provides the flavanones in very good yields ~90%, better than of acid hydrolysis in reflux.

Hesperetin is a flavanone that exhibits analgesic, antinociceptive, anti-inflammatory, antioxidative, cardioprotective properties. Naringin is a flavonoid compound, which can be used to treat or prevent various diseases, such as obesity, heart disease, diabetes, and metabolic syndrome. The medicinal value of naringin is mainly reflected in its antioxidant and anti-inflammatory functions, and it has a protective effect on pathophysiology.

Furthermore, we describe for the first time, an efficient synthesis of Hesperidin- octaacetate, Naringin-octaacetate, Hesperetin-triacetate and Naringenin-triacetate from the corresponding flavanones, in the presence of 4-(N,N-dimethylamino)- pyridine DMAP as catalyst, under microwave irradiation.

Hesperidin, Naringin, Hesperetin and Naringenin are water soluble and theirs acetates are liposoluble. The formation of polyacetate makes it possible to increase the liposolubility of flavones and their aglycones while being prodrugs because they are easily hydrolyzable into flavones and aglycones in living beings.