Phytochemical Constituents of Selected Garcinia Fruits from Tropical Australia

Garcinia species grow well in tropical regions and have been widely consumed, especially among local communities. Garcinia fruits and their byproducts contain a range of bioactive compounds that have potential to work as nutraceuticals or functional foods. We have determined the phytochemical constituents of rind, pulp and seeds from G. humilis, G. mangostana, G. dulcis and G. gummi-gutta fruits grown in tropical Queensland, Australia. We used Liquid Chromatography-Mass Spectrometry to define the variations between species in the content of citric acid, hydroxycitric acid, benzophenones, garcinols, flavonoids, biflavonones, tocotrienols and other compounds. G. humilis rind has mainly citric acid (12.14% w/w) and procyanidin B₂ (6% w/w), with the seeds containing guttiferone derivatives (3.56% w/w) and garcinol (2.69% w/w). G. mangostana rind contained xanthones (6.49% w/w; α-mangostin 5.42% w/w), procyanidin B₂ (12.6% w/w), cyanidin glycoside (0.137% w/w) and hydroxycitric acid (0.42% w/w). The rind of G. dulcis contained benzophenones (7.86% w/w; garcinol: 6.35% w/w), citric acid (24% w/w) and morelloflavone (0.55% w/w); the seeds contained morelloflavone (2.9% w/w) and xanthone derivatives. G. gummi-gutta rind contained hydroxycitric acid (28.8% w/w) and citric acid (3.76% w/w/), whereas pulp contained citric acid (5.74% w/w) and seeds contained morelloflavone. G. humilis, G. dulcis and G. mangostana have more complex phytochemical constituents compared to G. gummi-gutta. This study showed that fruits from Garcinia species from tropical Australia are rich sources of phytochemicals that can be processed for the nutraceutical and food industries.