Antioxidative properties of spices and their impact on postprandial blood glucose in humans

Background: Diabetes mellitus represents disrupted orderly processes of carbohydrate metabolism, in which body cells become unable to utilize glucose. Consequently, glucose molecules pile up in blood and exceed upper normal limit. Spices are vital source of bioactive molecules, which could be useful to treat different diseases including diabetes. Present study was conducted to determine the effect of turmeric, cloves, green cardamom and cinnamon intake on postprandial blood glucose (PBG) levels in normal healthy human subjects. Method: A total of 10 participants including both genders were considered to assess blood glycemic response of said four culinary spices. Participants' ages were 20-25 years. Incremental area under the curve (IAUC) method was employed for glycemic index (GI) determination. In addition to this, antioxidative properties were estimated by 2, 2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS)) radical, Folin-Cioucalteau reagent and aluminum chloride. Results: GI values of turmeric, cloves, green cardamom, cinnamon and their combined blend were 83.06, 87.48, 82.27, 73.59 and 69.48, respectively. Antioxidative activity (AA) of spices was 2.63, 1.55, 2.55 2.8 and 3.33, respectively. Regarding antioxidant levels cinnamon contained the highest amount (32.78 mg/g) of total phenolic compounds (TPC) than turmeric (28.7 mg/g), cloves (29.6 mg/g) and green cardamom (15.04 mg/g). Similarly, total flavonoid contents (TFC) were found maximum (6.17 mg/g) in cinnamon relative to the other three spices i.e. 2.66, 4.6 and 1.6 mg/g, respectively. Furthermore, GI was inversely related to antioxidative properties i.e. AA (r=-0.88), TPC (r=-0.5625) TFC (r=-0.7716). Conclusion: The results obtained from this present study indicate that spices' antioxidants interfere with gastrointestinal digestion, lowering starch conversion into blood glucose, effectively. An appropriate intake of spices may be wanted to keep blood glucose level within an optimum limit.