Species of genus Garcinia belonging to family Clusiaceae are traditionally known for the treatment of ulcer, gonorrhea, leucorrhoea and abdominal pain. This genus is also reported to be a rich source of xanthones, benzophenones, flavonoids, biflavonoids and triterpenes showing significant pharmacological activities. Garcinia mangostana L. (mangosteen) and Garcinia hombroniana Pierre (seashore mangosteen) are evergreen tropical trees grown in Malaysia, Indonesia, Thailand and other tropical countries. The fruits of G. mangostana (queen of fruits), and roots and leaves decoction of G. hombroniana are commonly used for skin allergies, infections after childbirth, trauma and diarrhea. This study aimed to evaluate the bark and fruit extracts of G. mangostana and G. hombroniana for phytochemicals analysis, total phenolic and flavonoid contents, antioxidant, anti-hyperglycemic and antituberculosis activities. Total phenolic contents were evaluated by Folin-Ciocalteu reagent colorimetric method. For antioxidant activities, radical scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2'-azino-bis-3-ethyl benzthiazoline-6-sulphonic acid (ABTS), and ferric ion reducing antioxidant power (FRAP) were used. Antihyperglycemic activity was determined using a-glucosidase and a-amylase enzymes. In quantitative phytochemical analysis, the extracts of G. mangostana showed significantly higher content of phenolics [3498.7 mu M GAE/g (gallic acid equivalent per gram), ethyl acetate; bark], carbohydrates (14.2 g/100g, aqueous; fruit) and reducing sugars (13.9 g/100g, aqueous; fruit). Also, in antioxidant activities, G. mangostana showed comparatively high activities with the ethyl acetate extract as the most potent showing IC50 2.78 mu g/ml in DPPH, 1.19 mu g/ml in ABTS, and 8742.7 mu M TE/g in FRAP assays. G. mangostana was also more potent in anti-hyperglycemic properties (IC50 182.9 mu g/ml, alpha-glucosidase, 247.8 mu g/ml, alpha-amylase) compared to G. hombroniana. In antituberculosis study, the ethyl acetate extracts of both plants showed equipotent activity with minimum inhibitory concentration (MIC) of 62.5 mu g/ml. Based on the results, it was concluded that the presence of bioactive phytochemicals may be responsible for their traditional uses for treatment of diseases.