Genkichi Ohta

Bio: Genkichi Ohta is an academic researcher. The author has contributed to research in topics: Rice bran oil & Pyridine. The author has an hindex of 4, co-authored 5 publications receiving 69 citations.

Studies on the Constituents of Rice Bran Oil. V. Reexamination of Oryzanol-B

Abstract: Oryzanol-B was shown to be largely a mixture of cycloart-24-enyl ferulate (oryzanol-A) and 24-methylenecycloartanyl ferulate (oryzanol-C) by comparison of melting points of their derivatives and by degradation. Alcohol-B, obtained by saponification of oryzanol-B, was acetylated and ozonolysis of acetate afforded 24-oxocycloartanyl acetate and 3β-acetoxy-25, 26, 27-trisnorcycloartan-24-oic acid. Comparison of alcohol-B with reported triterpenes of rice-bran oil is described.

Investigations on Steroids. I. Synthesis of Androstano [3, 2-b] pyridine.

Abstract: Syntheses of 17β-hydroxyandrostano [3, 2-b] pyridine (XXIVa) and related compounds were described. Condensation of 2-hydroxymethylene-3-oxo androstane derivatives with cyanoacetamide or its analogs afforded 5', 6'-disubstituted androstano [3, 2-b] pyridines which were converted into pyridine-6'(1'H)-thiones (XVII). Desulfurization of XVII gave 5', 6'-unsubstituted androstano [3, 2-b] pyridines (XXIV).

Occurrence and content of hydroxycinnamic and hydroxybenzoic acid compounds in foods.

Abstract: Phenolic acid compounds seem to be universally distributed in plants. They have been the subject of a great number of chemical, biological, agricultural, and medical studies. Hydroxycinnamic acid compounds occur most frequently as simple esters with hydroxy carboxylic acids or glucose, while the hydroxybenzoic acid compounds are present mainly in the form of glucosides. Furthermore, phenolic acids may occur in food plants as esters or glycosides conjugated with other natural compounds such as flavonoids, alcohols, hydroxyfatty acids, sterols, and glucosides. Also, hydroxycinnamic acid amides appear to be common constituents. The occurrence of the different natural phenolic acid compounds in foods is reviewed, and data of the content in fruit, vegetables, and spices are given. The distribution of the main phenolic acid compounds in food plants as well as their changes during development and maturation of fruits are considered. Furthermore, the hydroxycinnamic acids bound to cell wall polymers, the phenolic...

Structures of phytosterols and triterpenoids with potential anti-cancer activity in bran of black non-glutinous rice.

Abstract: 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.

Triterpene alcohols and sterols of vegetable oils

Abstract: Triterpene alcohols and sterols were separated by thin-layer chromatography and gas-liquid chromatography from the unsaponifiable fractions of the following 18 vegetable oils: linseed, peanut, olive, rice bran, palm kernel, corn, sesame, oiticica, palm, coconut, rapeseed, grape seed, sunflower, poppy seed, castor, tea seed, cocoa butter and soybean. Two triterpene alcohols, cycloartenol and 24-methylene cycloartanol, were found in all of the oils except soybean oil, which contained only cycloartenol. Triterpene alcohols such as α- and β-amyrin, euphorbol, butyrospermol and cyclolaudenol also were encountered occasionally. Three sterols, β-sitosterol, stigmasterol and campesterol were present in all of the oils. In addition a fourth sterol, not yet idenfified, was found in oils of palm, palm kernel and sunflower in varying amounts. This unknown sterol and brassicasterol were found in rapeseed oil in addition to the three sterols that were common to all of the oils studied.