Many species of Myrtaceae cultivated throughout the tropics for their edible fruit can be found in local markets and processed into a variety of food products. Some are also used as traditional medicines in divergent practices from South America to Southeast Asia for inflammatory conditions and intestinal disorders, high blood pressure, diabetes, asthma, and as antimicrobials, antiscorbutics, carminatives, diuretics, and astringents.
Bioactivity-guided fractionation of the jaboticaba fruit (Myrciaria cauliflora) was performed and a novel depside, jaboticabin, together with 16 known compounds were isolated and identified by spectroscopic data interpretation or comparison with authentic standards. Jaboticabin and the related depside, 2-O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylacetic acid, significantly inhibited chemokine interleukin (IL)-8 production before and after cigarette smoke treatment of cells. Jaboticabin was cytotoxic in the HT29 colon cancer cell line (IC50 = 65 μM), and 2- O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylacetic acid was active against HCT116 colon cancer cells (IC50 = 30 μM). Both depsides also exhibited antiradical activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 = 51.4 and 61.8 μM, respectively). The anthocyanins cyanidin 3-glucoside and delphinidin 3-glucoside, major constituents of the jaboticaba, showed good activity in these assays as well.
An HPLC-PDA method was developed to quantify the amounts of eight phenolic compounds (cyanidin 3-glucoside, delphinidin 3-glucoside, ellagic acid, kaempferol, myricetin, quercetin, quercitrin, and rutin) in 14 edible Myrtaceae fruits: Eugenia aggregata, E. brasiliensis, E. luschnathiana, E. reinwardtiana, Myrciaria cauliflora, M. dubia, M. vexator, Syzygium cumini, S. curranii, S. jambos, S. javanicum, S. malaccense, S. samarangense, and S. samarangense var. Taiwan pink. In addition, total phenolic content (TPC), total anthocyanin content (TAC), and antiradical activity was determined. TPC ranged from 3.57 to 101.17 mg gallic acid equivalents per g dry weight, TAC ranged from undetected to 12.13 mg/g, and antiradical activity, measured as DPPH IC50 ranged from very active (19.40 μg/mL) to inactive (388.69 μg/mL). A review of the ethnomedical, phytochemical, and chemotaxonomic literature has been conducted in the process of evaluating the bioactive constituents of these fruits.