Table 2.

Anti-diabetes activities of Carica papaya.

Part of the Plant	Extract	Type of Experiment	Results	Reference
Seed	Hexane extract & ethyl acetate extract	In vitro DPPH radical scavenging assay	Hexane extract possessed DPPH radical scavenging activity with IC50 = 41.5 mg/mL.	[27]
		In vitro TBA method	Hexane extract demonstrated TBA scavenging activity with IC50 = 38.2 mg/mL.
		In vitro α-glucosidase inhibition	Hexane extract displayed α-glucosidase enzyme inhibitory activity with IC50 = 75.78 mg/mL.
			Ethyl acetate extract exhibited α-glucosidase enzyme inhibitory activity with IC50 = 77.41 mg/mL.
		In vitro α-amylase inhibition	Hexane extract demonstrated α-amylase inhibitory activity with IC50 = 76.96 mg/mL.
			Ethyl acetate extract displayed α-amylase inhibitory activity with IC50 = 79.18 mg/mL.
		In vitro FRAP assay	Ethyl acetate extract displayed FRAP inhibitory activity with IC50 = 38.75 mg/mL.
		In vitro animal model	Ethyl acetate extract at 500 mg/kg/body weight significantly decreased the blood glucose level of the diabetic rats to approximately 120 mmol/L over 120 min comparable with standard drug, acarbose.
-	FPP	In vitro analysis	FPP at concentration 50 μg/mL increased inner and outer platelet membrane fluidity, displayed by a decrease of ~0.015 r in DPH anisotropy and ~0.02 r in TMA-DPH anisotropy. FPP increased Naþ/Kþ-ATPase activity by ~0.5 μmol Pi/mg prot/h.-FPP improved platelet function in vitro and this might help preventing diabetic complications. FPP also slightly increased TAC by ~5 nmol/μL and SOD activity by ~0.5 units/μL. FPP at 50 μg/mL lowered lipid peroxidation.	[28]
-	FPP®	Human trial	FPP significantly improved liver sensitivity to insulin, which was indicated by decreased circulating AST and ALT. FPP scavenged NO and hydroxyl radicals and displayed an increased in total antioxidant status.	[29]
-	FPP	In vitro DPPH radical scavenging assay	FPP displayed DPPH scavenging with AA50 = 55.69 mg/mL.	[30]
		In vitro ABTS+ scavenging assay	FPP demonstrated ABTS+ scavenging action with AA50 = 14.56 mg/mL.
		In vitro AAPH-induced lipid oxidation inhibition	FPP inhibited AAPH-induced lipid oxidation with AA50 = 68.06 mg/mL.
		In vitro O2− scavenging assay	FPP showed O2− scavenging action with AA50 = 88.70 mg/mL.
		In vitro •OH scavenging assay	FPP showed hydroxyl radical scavenging activity with AA50 = 4.13 mg/mL.
		Human trial	FPP at a dose of 6g/day showed an increase of 4.9% and 5.7% in TAS for male and female respectively after 14-week consumption at 6g/day. FPP decreased protein carbonyl level by 1.9% in males and 9.7% in females after a 14-week FPP ingestion. FPP delayed red blood cell hemolysis.
Seed, flesh and peel of unripe fruit	Aqueous extract	In vitro α-amylase inhibition In vitro α-glucosidase inhibition In vitro lipid peroxidation assay In vitro NO scavenging assay	Aqueous extract inhibited α-glucosidase and α-amylase activities with IC50 of 1.76 mg/mL and IC50: 0.87 mg/mL. At a concentration of 7.5 mg/mL, the extract also displayed the highest NO radical scavenging activity (52.5%).	[31]
Leaf	Chloroform extract	In vitro animal model	The chloroform extract at a dose of 31 mg/kg/day significantly increased islet area by 16,842.2 μm2 by stimulating regeneration of β-cells of islet of Langerhans.	[32]
			The extract successfully decreased fasting glucose levels by 222.3 mg/dL in diabetic group in vivo.
Leaf	Aqueous extract	In vitro animal model	Aqueous extract at a dose of 3 g/100 mL decreased blood glucose levels in diabetic rats by 184 mg/dL. Aqueous extract at a dose of 1.5 g/100 mL preserved Islet cell size in diabetic rats. Aqueous extract increased NO levels by 17.39 μM and hence reduced ROS production.	[33]

Abbreviation: DPPH, 2,2-diphenyl-1-picryl-hydrazyl-hydrate; TBA, thiobarbituric acid; FPP, fermented papaya preparation; TAC, total antioxidant capacity; SOD, superoxide dismutase; AST, aspartate transaminase; ALT, alanine aminotransferase; NO, nitric oxide. Footnote: IC₅₀ = concentration needed for 50% inhibition; AA₅₀ = concentration needed to achieve 50% antioxidant activity.