Jambolan (Syzygium cumini (L.) Skeels) is well known as a medicinal plant, this commodity is rich in compounds containing phenol and flavonoid that is able to medicate a lot of diseases, especially diabetes mellitus. This research aimed to investigate antidiabetic potential of jambolan fruit and seed extract in vitro. White jambolan flesh of fruit and seed extracts were prepared using binary solvent of aqueous ethanol (50% v/v) by adding solvent to 50 g sample in volumetric flasks. After that, the flasks were agitated at 280 rpm on 50°C for 45 min and then extracts were filtered. The filtrate evaporated using rotary evaporator at 400C under reduced pressure for the removal of solvent. Later on, the extracts were stored in sealed bottles. The antioxidant activity was analyzed used DPPH, while anti-diabetic activity analyzed α-glucoside enzyme inhibition activity by measuring the p-nitrofenol as enzymatic reaction product at wavelength 400 nm and α-amylase enzyme activity inhibition was determined using wavelength at 540 nm. The result of α-glucosidase, n-Heksan extracts of fruit and seed showed inhibition of IC50 = 50,35 ± 2,13 mg/mL and IC50 = 52,42 ± 1,60 mg/mL, respectively; ethyl acetat extracts of fruit and seed showed inhibition IC50 = 41,51 ± 0,27 mg/mL and IC50 = 59,85 ± 0,95 mg/mL, respectively; and ethanol IC50 = 55,79 ± 4,11 mg/mL and IC50 = 42,98 ± 0,80 mg/mL, respectively. Meanwhile the result of α-amylase, n-Heksan extracts of fruit and seed showed inhibition IC50 = 75,28 ± 1,04 mg/mL and IC50 = 74,72 ± 0,52 mg/mL, respectively, Ethyl acetat extracts of fruit and seed showed IC50 = 64,06 ± 0,20 mg/mL and IC50 = 67,92 ± 0,52 mg/mL, respectively, and Ethanol IC50 = 75,85 ± 0,34 mg/mL and IC50 = 64,63 ± 1,18 mg/mL, respectively. α-Glucosidase inhibition was lower than acarbose inhibition activity 63,40%, meanwhile, α-Amylase inhibition at fruit and seed of white Jambolan was stronger than gallic acid 36,36%.
