Mangosteen rind is currently widely used by people as an ingredient in health drinks. Therefore, it is necessary to standardize the quality of raw materials, extract preparations and their compounds in order to meet the quality requirements as stated in the Indonesian Herbal Pharmacopoeia. The content of mangosteen rind (Garcinia mangostana L.) consists of various kinds of xanthones, especially αmangosteen and γ-mangosteen. The presence of these two compounds can be a standard quality parameter of the mangosteen rind extract as an herbal medicinal ingredient. The method of determining the standard content in the methanol extract of mangosteen rind using the HPLC method. The extract was prepared by maceration method using methanol. Then fractionated and purified to obtain fractions into isolates using various chromatography techniques. The identification of isolated compounds by TLC used the mobile phase of hexane: ethyl acetate (2: 3), H-NMR and reverse-phase HPLC with the mobile phase of water: acetonitrile (80: 20). The assay results for the α-mangosteen standard compound had a mean value of 0.155 mg / mL. The validation of the α-mangosteen content determination method in methanol extract of mangosteen rind (Garcinia mangostana L.) was carried out by determining the values of linearity parameters, detection limits and quantitation limits. The αmangosteen linearity study shows that the analysis carried out in the concentration range (0.4; 0.2; 0.1; 0.05; 0.025) mg / ml provides a measurement of the relationship coefficient (r) of 0.993 with a detection limit (LOD). ) of 0.043 mg / ml and the limit of quantitation (LOQ) of 0.129 mg / ml. So that in this range α-mangosteen gives a linear response. The specificity value of the α-mangosteen spectrum purity test results obtained a correlation value above 0.99. The results of the α-mangosteen test met the validation criteria.