Structures of some bioactive phytochemicals in bran extract of the black rice cv. Riceberry that had demonstrated anti-cancer activity in leukemic cell line were investigated. After saponification with potassium hydroxide, separation of the unsaponified fraction by reversed-phase high performance liquid chromatography (HPLC) resulted in four sub-fractions that had a certain degree of anti-proliferation against a mouse leukemic cell line (WEHI-3 cell), this being IC50 at 24 h ranging between 2.80–467.11 μg/mL. Further purification of the bioactive substances contained in these four sub-fractions was performed by normal-phase HPLC. Structural characterization by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR) resulted in, overall, the structures of seven phytosterols and four triterpenoids. Four phytosterols, 24-methylene-ergosta-5-en-3β-ol, 24-methylene-ergosta-7-en-3β-ol, fucosterol, and gramisterol, along with three triterpenoids, cycloeucalenol, lupenone, and lupeol, were found in the two sub-fractions that showed strong anti-leukemic cell proliferation (IC50 = 2.80 and 32.89 μg/mL). The other sterols and triterpenoids were campesterol, stigmasterol, β-sitosterol and 24-methylenecycloartanol. Together with the data from in vitro biological analysis, we suggest that gramisterol is a significant anti-cancer lead compound in Riceberry bran extract.
The chemical compositions of essential oils obtained from Ocimum basilicum var. thyrsiflora (1.39 % dry weight) and Ocimum basilicum (0.61 %) were analyzed by GC-MS. Seventy-three constituents representing 99.64 % of the chromatographic peak area were obtained in the O. basilicum var. thyrsiflora oil, whereas 80 constituents representing 91.11 % observed in the essential oil of O. basilicum were obtained. Methyl chavicol (81.82 %), β-(E)-ocimene (2.93 %) and α-(E)- bergamotene (2.45 %) were found to be the dominant constituents in O. basilicum var. thyrsiflora oil while O. basilicum contained predominantly linalool (43.78 %), eugenol (13.66 %) and 1,8-cineole (10.18 %). The clear separation of the volatiles in all samples, demonstrated by the application of GC×GC, resulted in significantly different fingerprints for the two types of basil. The O. basilicum oil showed strong antioxidant activity while the oil of O. basilicum var. thyrsiflora exhibited very low activity, which was attributed to the significant differences in linalool and eugenol contents in these essential oils
Among the total of 146 volatiles extracted by SPME from the headspace of some black and white rice bran samples, twenty-eight terpenoid odorants were acculately identified. Most of these terpenoids possess good aroma character and are varied among three groups of Thai rice; black glutinous, black non-glutinous, and white non-glutinous. Of these three groups, black non-glutinous rice contains the greater number of these monoterpenoids. However, the content of the major terpenoid odorants, which are limonene, trans-β-ocimene, β-cymene, and linalool, is the highest in the bran of white Thai jasmine rice, Khao Dawk Mali 105 (KDML 105). An herbaceous odorant, myrcene, occurs in the bran of all black rice varieties but not in the bran of white rice. The flavor type of rice bran using these rice bran terpenoids was successfully classified using the chemometric principle component analysis method.
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