Mistletoe is an herb that grows on duku plants (Lancium demosticum) and is known as benalu duku (BD) in Indonesia. It is predicted to have benefits such as anticancer or antiviral properties, and it is also thought to have anti-diabetic pharmacological activity. Quercetin-like compounds (QLCs) are secondary metabolites with antidiabetic activity that are expected to lower blood sugar levels in animals after oral administration. This study aimed to analyze the ability of QLCs to reduce random blood sugar levels using experimental animals as clinical models. The research method used was exploratory, which used a before-after test model, and observations were made on the random blood sugar levels after treatment. Secondary metabolites were extracted from BD leaves, which were then screened. Diabetes was induced in 30 rats (Rattus norvegicus) by the administration of streptozotocin at 0.045 mg/g body weight daily for 2 days. The antidiabetic effects of the secondary metabolite at doses of 0.5 mg/kg body weight (twice a day) when administered orally for up to 5 days were tested in diabetic rats. The random sugar levels (mg/dL) were measured using a One Touch Ultra Plus medical device for observation of randomized blood sugar levels. Results and novelty: The results revealed that the secondary metabolite, as an analyte from the BD leaf extract, can significantly reduce random blood sugar levels. The secondary metabolite extracted from BD, could be used to treat diabetes in rats.