Table 2.

Anti-diabetic effects of honey in clinical and pre-clinical studies.

Author	Honey Sources/Types	Dose	Duration	Models	Results
Aziz et al. (2017) [13]	Stingless bee honey	1.0 or 2.0 g/kg/day	28 days	Male Sprague-Dawley rats	Treatment of 1.0 g/kg/day honey resulted in a modest decrease of fasting blood sugar (FBS) level at the end of study duration. Honey administration at the dose of 2.0 g/kg/day caused marked reduction of FBS after 28 days. Treatment with both 1.0 and 2.0 g/kg/day of honey: Protected against shrinkage of the pancreatic islets sizes. Significantly elevated the serum insulin level. Markedly increased insulin intensity in the pancreatic islets (as seen in the immunohistochemistry analysis).
Bahrami et al. (2009) [34]	Natural, unprocessed honey (obtained from Samans kandeh, Neka, Sari City, Iran)	1st 14 days: 1.0 g/kg/day 2nd 14 days: 1.5 g/kg/day 3rd 14 days: 2.0 g/kg/day 4th 14 days: 2.5 g/kg/day	56 days	48 type II diabetic patients	Patients receiving honey were observed to have significant reduction of fasting blood sugar level after 56 days treatment compared to baseline (124.3 ± 37.5 vs. 153.3 ± 43.9 mg/dL, respectively; p = 0.01).
Öztaşan et al. (2005) [40]	Mad honey	50 mg/kg/day (2 mL mad honey dissolved in distilled water)	3 days	Male albino Wister rats	Post-treatment blood glucose level (after administration of mad honey for 3 consecutive days) was markedly reduced in both streptozotocin-induced diabetic rats and control groups.
Hemmati et al. (2015) [46]	Honey from jujube plant area, in South Khorasan, Iran	1.0 g and 2.0 g/kg body weight/day	21 days	Adult male Wistar rats	Diabetic rats supplemented with honey (1 and 2 g/kg) had significantly lower FBS (7.8 ± 0.12 mmol/L and 9.03 ± 0.15 mmol/L, respectively) than diabetic control rats (31.1 ± 2.3 mmol/L). Honey significantly increased serum adiponectin (4.5 ± 0.26 mg/L) levels in diabetic rats.
Erejuwa et al. (2010) [49]	Tualang honey	1.0 g/kg	28 days	Male Sprague-Dawley rats	Rats treated with honey had significant lower FBS (median (IQR): 8.8 (5.8) mmol/L) compared to diabetic rats given distilled water (median (IQR): 17.9 (2.6) mmol/L).
Erejuwa et al. (2016) [50]	Natural honey (supplied by Ebonyi State, Nigeria)	1.0, 2.0 or 3.0 g/kg body weight/day	21 days	Wistar rats	Honey supplementation at 1.0 and 2.0 g/kg/day significantly reduced FBS level in diabetic rats induced with alloxan (p < 0.05).
Sheriff et al. (2011) [51]	Unknown honey species	1.0 mL/200 g body weight	7 days	Male albino rats	Treatment with honey resulted in a non-significant reduction of FBS and 2 hour postprandial glucose level compared with untreated alloxan-induced DM rats (8.44 ± 1.66 and 11.05 ± 2.11 mmol/L vs. 11.57 ± 2.22 and 16.45 ± 3.11 mmol/L, respectively).
Arabmoazzen et al. (2015) [52]	Honey from a bee keeping center of Urmia city, Iran	3 mL/kg, 5% honey solution given 3 times/day	56 days	Adult male Wistar rats	After 56th days, serum glucose concentration of noise-induced diabetic rats treated with honey had a significant lower concentration (208 ± 34.6 mg/dL) (p < 0.01) compared to untreated diabetic rats. Honey-treated rats had a larger diameter of the Langerhans islands in the pancreas compared to diabetic control (5.6 ± 154.5 vs. 4.75 ± 54.25 μm)
Al-Waili (2004) [53]	Natural honey	90 g honey in 250 mL water.	Once (30 min prior to blood sampling)	7 patients of type II DM	Patients with type II DM had significantly lowered blood glucose elevation when administered with honey compared to dextrose.
Krishnasree & Mary (2017) [59]	Multifloral honey (Apis cerana indica F., Apis mellifera L., Apis dorsata F., Apis florea F. and Trigona iridipennis S.)	100–500 μg/mL concentration	-	In vitro assays for α-amylase and α-glucosidase inhibitory activities	Trigona iridipennis honey had the strongest α-amylase and α-glucosidase inhibitory properties compared to other multifloral honey species. Inhibition of α-amylase enzyme was comparable to standard diabetic therapy by acarbose especially the highest concentration of 500 μg/mL.

DM, diabetes mellitus; FBS, fasting blood sugar; IQR, interquartile range.