Diazole and triazole derivatives of castor oil extract: synthesis, hypoglycemic effect, antioxidant potential and antimicrobial activity

Abstract

The ricinoleate triglyceride was extracted from castor-oil seeds grown in Algeria and isolated by catalytically methanolyse to methyl ricinoleate. Six diazole and triazole derivatives of ricinoleic acid were synthesized and characterized: 1,3,4-oxadiazole-5-thione (4); 1,3,4-thiadiazole-5-thione (5); 4-N-amino-1,2,4-triazole-5-thiol (7); 1,2,4-triazole-5-thione (9); 5-amino-1,3,4-oxadiazole (10) and 5-amino-1,3,4-thiadiazole (11). The antibacterial and antifungal screening data of synthesized compounds showed appreciable inhibition and among them, 5, 7 and 8 showed more inhibition on Gram positive Enterococcus faecalis than reference ampiciline; while compounds 1, 7, 8, 10 and 11 showed competitive antifungal effects compared to reference amphotericin B. In addition, all synthesized compounds (1-11) showed competitive antioxidant properties, particularly compounds 7 at 125, 250, 500 and 1000 μg/mL and compounds 4, 5 and 9 at a concentration of 1000 μg/mL. The intermediate compounds 1, 2 and 8 showed anti-α-amylase activity at various concentrations in the range of IC50 = (120.25 ± 1.17 - 130.42 ± 2.48). Oxadiazole 4 showed the best α-amylase inhibition by 78.5% at a concentration of 1000 μg/mL.