The Antioxidant Analysis And Alpha-Glucosidase Inhibition Activities Of Spices And Herbs (22 Species) In Asian Traditional Beverages

Spices and herbs are used in Asian traditional beverages (ATB) mainly for gastronomic purposes, i.e., main flavoring, aroma enhancer, and colorant, but not for health functionality. Twenty-two selected spices and herbs used in ATB were evaluated for their antioxidant level, antidiabetic potential, and the possible risk of coumarin toxicity. Pattern recognition methods were applied to the data collection using principal component analysis (PCA) and hierarchical clustering analysis (HCA) to investigate the assay and spices and herbs inter-relationship. The evaluation made can help in the future selection of spice and herb ingredients with high antioxidant and antidiabetic properties and a safe limit of coumarin to be used in developing a reformulated ATB. The spice and herb selections were based on the determination of polyphenol content, antioxidant (DPPH, ORAC, and FRAP analyses) levels, AGI activities, and coumarin content aqueous extracts. Five out of 10 aqueous extracts of main flavoring spices (Ceylon cinnamon, cassia, clove, star anise, and mace), 1 out of 7 extracts of aroma enhancers (rose), and 2 out of 5 colorant extracts (sappan heartwood and black myrobalan) exhibited profound antioxidant and alpha-glucosidase inhibition (AGI) activities. PCA and HCA indicated that the black myrobalan extract had the most distinct and potent antioxidant and AGI activities among the tested extracts (DPPH IC50 37.61 +/- 1.48 mg/mL, DPPH 126.15 +/- 0.65 Trolox equivalent mu g/mL, FRAP 52.66 +/- 0.8 Trolox equivalent mM/mL, ORAC 18,213.33 +/- 298.91 Trolox equivalent mu M/mL; and AGI 1306.98 +/- 21.38 tannic acid equivalent mu g/mL). On the contrary, cardamom extract showed the least of both activities. Ambrette seed and cassia extracts had considerably high coumarin contents, which is higher than the permissible limit of 10 mg/kg. This study revealed that black myrobalan is an indispensable functional ingredient in an Asian traditional beverage. However, the use of cassia and ambrette seeds shall be a caution to lower the risk of possible coumarin toxicity. PCA and HCA enabled the visualization of the complicated relationship between the antioxidant - antidiabetic properties and each spice/herb ingredient. This recognition method eased the functional ingredient selection in the next polyherbal formulation step.