Garcinia dulcis or locally known in Malaysia as “mundu” belongs to the family of Clusiaceae. The study was conducted to investigate the anticancer potential of different parts of G. dulcis fruit extracts and their possible mechanism of action in HepG2 liver cancer cell line. MTT assay showed that the peel, flesh, and seed extracts of G. dulcis induced cytotoxicity in HepG2 cell line with IC50 values of 46.33 ± 4.51, 38.33 ± 3.51, and 7.5 ± 2.52 µg/mL, respectively. The flesh extract of G. dulcis induced cell cycle arrest at sub-G1 (apoptosis) phase in a time-dependent manner. Staining with Annexin V-FITC and propidium iodide showed that 41.2% of the cell population underwent apoptosis after 72 hours of exposure of the HepG2 cell line to G. dulcis flesh extract. Caspase-3 has been shown to be activated which finally leads to the death of HepG2 cell (apoptosis). GC-MS analysis showed that the highest percentage of compound identified in the extract of G. dulcis flesh was hydroxymethylfurfural and 3-methyl-2,5-furandione, together with xanthones and flavonoids (based on literature), could synergistically contribute to the observed effects. This finding suggested that the flesh extract of G. dulcis has its own potential as cancer chemotherapeutic agent against liver cancer cell.

Two underutilized indigenous fruits of Borneo, Liposu (Baccaurea lanceolata) and Tampoi (Baccaurea macrocarpa) were investigated for their total phenolic (TPC), flavonoid (TFC), anthocyanin (TAC) and carotenoid (TCC) contents as well as antioxidant properties in vitro. The fruits were separated into three different parts (i.e., pericarp, flesh and seed) and extracted using 80% methanol. Antioxidant activity was determined using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging, ABTS decolorization and FRAP (Ferric Reducing Antioxidant Power) assays. The results showed that B. macrocarpa pericarp contained the highest amount of total phenolics, total flavonoid, total anthocyanin and total carotenoid with the values of 60.04 ± 0.53 mg GAE/g, 44.68 ± 0.67 mg CE/g, 1.23 ± 0.20 mg c-3-gE/100 g and 0.81 ± 0.14 mg BCE/g. Results from DPPH, ABTS and FRAP assays also showed that the pericarp of B. macrocarpa displayed the highest antioxidant capacity. The antioxidant activity of the extract was significantly correlated with the total phenolic and flavonoid contents, but not with the carotenoid contents. In conclusion, B. macrocarpa displayed high potential as natural source of phytochemicals with antioxidant properties.

Garcinia species are well-known for their unique properties of having natural secondary metabolite compounds called xanthone as well as their ethnomedicinal values such as antioxidant, anticancer, anti-inflammatory and antibacterial properties. The study was conducted to investigate the antiproliferative activity of peel, flesh and seed extracts of G. dulcis, G. parvifolia, G. nitida, G. mangostana var. mangosta and G. cambogia collected from Malaysian Borneo (Sabah) against estrogen receptor-positive human breast carcinoma (MCF-7) cells. The antiproliferative activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that G. dulcis seed induced strongest antiproliferative activity against MCF-7 cancer cell line with the IC50 value of 2.5 ± 0.0 µg/ml, followed by G. dulcis flesh, G. mangostana var. mangostana peel and G. dulcis peel with IC50 values of 9.33 ± 3.21, 11.17 ± 1.04 and 17.67 ± 2.08 µg/ml, respectively. Meanwhile, the IC50 value for G. cambogia peel was 56.67 ± 10.5 µg/ml. No IC50 value was detected in all parts of G. parvifolia and G. nitida at concentration tested ( < 100 µg/ml). Overall, this study clearly showed that the whole fruit of G. dulcis displayed potent cytotoxic effect by inducing antiproliferative activity at low concentration. Further studies are needed in the future to develop this fruit as pharmaceutical and nutraceutical product for the treatment and prevention against cancer.