Jeng-Leun Mau

Antioxidant properties of several commercial mushrooms

Abstract Winter (strains white and yellow), shiitake (strains 271 and Tainung 1) and oyster mushrooms (abalone and tree oyster mushrooms) were obtained commercially and methanolic extracts were prepared from these mushrooms and their antioxidant properties were studied. The antioxidant activities by the 1,3-diethyl-2-thiobarbituric acid method were moderate to high at 1.2 mg ml−1. Reducing powers were excellent (and higher than 1.28 absorbance) at 40 mg ml−1. Scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radicals were moderate to high (42.9–81.8%) at 6.4 mg ml−1. With regards to the scavenging effect on hydroxyl free radicals, tree oyster mushrooms were the highest (54.3%) at 40 mg ml−1 whereas other commercial mushrooms were low. Chelating effects on ferrous ions were 45.6–81.6% at 1.6 mg ml−1. Total phenols were the major naturally occurring antioxidant components found. Overall, tree oyster mushrooms were better in antioxidant activity, reducing power and scavenging abilities and higher in total phenol content.

Antioxidant properties of several specialty mushrooms

Abstract Four specialty mushrooms are commercially available in Taiwan, including Dictyophora indusiata (basket stinkhorn), Grifola frondosa (maitake), Hericium erinaceus (lions mane), and Tricholoma giganteum (white matsutake). Methanolic extracts were prepared from these specialty mushrooms and their antioxidant properties were studied. The antioxidant activities at 1.2 mg ml−1 were in the order of basket stinkhorn>lions mane>maitake>white matsutake. Basket stinkhorn showed an excellent reducing power of 1.09 at 3 mg ml−1. At 6.4 mg ml−1, scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radicals were 92.1% for basket stinkhorn and 63.2–67.8% for other specialty mushrooms. At 40 mg ml−1, scavenging effects were 75.0 and 69.4% for basket stinkhorn and lions mane and 39.6 and 47.4% for maitake and white matsutake, respectively. At 24 mg ml−1, chelating effects on ferrous ions were 91.9% for basket stinkhorn and 46.4–52.0% for other specialty mushrooms. Total polyphenols were the major naturally occurring antioxidant components found in the methanolic extracts from these specialty mushrooms.

Non-volatile taste components of several commercial mushrooms

Abstract Winter (strains white and yellow), shiitake (strains 271 and Taichung 1) and oyster mushrooms (abalone and tree oyster mushrooms) were collected from commercial sources. Strain yellow contained 26.7% of proteins (higher than other mushrooms). Shiitake and the two oyster mushrooms contained more than 60% of carbohydrates. Arabitol was found in the highest amounts only in winter mushrooms. Glucose, mannitol and trehalose were found in varied amounts. Total soluble sugar contents were in the order: winter mushrooms>shiitake>abalone and tree oyster mushrooms. Total contents of free amino acids also varied and ranged from 4.08 to 31.5 mg g−1 dry weight. Contents of total 5′-nucleotides were similar in the two winter mushrooms, whereas the content of flavour 5′-nucleotides was higher in strain white. Contents of total and flavour 5′-nucleotides were higher in strain 271 than in strain Tainung 1. The two oyster mushrooms were comparable in contents of flavour 5′-nucleotides. The umami taste was in the order: strain 271>winter mushrooms>two oyster mushrooms and strain Tainung 1.

Composition and antioxidant activity of the essential oil from Curcuma zedoaria

Abstract Curcuma zedoaria (Berg.) Rosc. (Zingiberaceae) has long been used as a folk medicine. The essential oil of its dried rhizome was isolated using simultaneous steam-distillation and solvent-extraction apparatus and its fractions were prepared by silica gel column chromatography. Totally, 36 compounds were identified in the essential oil, including 17 terpenes, 13 alcohols and 6 ketones. The yields of Fractions 2 and 3 were 83.66 and 10.71%, respectively. Epicurzerenone and curzerene were found in the first and second highest amounts (24.1 and 10.4%). At 20 mg ml −1 , the essential oil of C. zedoaria was moderate to good in antioxidant activities by three different methods, good in reducing power and excellent in scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical but low in chelating effect on ferrous ion. However, after fractionation, with regard to all antioxidant properties assayed, fraction 4 showed consistently better effects than the essential oil did. The compound in fraction 4 responsible for better antioxidant properties might be 5-isopropylidene-3,8-dimethyl-1(5H)-azulenone.

Antioxidant properties of fermented soybean broth

Abstract Soybean broth (SB) and fermented soybean broth (FSB), at 100% exhibited good antioxidant activities of 0.85 and 0.80, respectively. Only FSB exhibited an excellent reducing power of 0.76–0.86 at 5–100%. FSB showed an excellent scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radicals (100%) at 20–100%, while SB only at 100%. FSB at 20–100% inhibited the production of superoxide anion radicals by 81–93% but SB showed no inhibition. As its concentrations increased from 2–100%, the scavenging effect of FSB on hydroxyl radicals increased from 30–96%, whereas that of SB increased from 5–76%. Both FSB and SB were good chelators for ferrous ions. For cupric ions, SB showed significantly higher chelating effect than did FSB. These results showed that FSB was superior to SB in most antioxidant properties and that SB and FSB, more specifically FSB, might be potential antioxidants for application in food products.

Non-volatile components of several medicinal mushrooms

Abstract Three species of medicinal mushrooms are commercially available in Taiwan, including Ling Chih (Ganoderma lucidum), Sung Shan Ling Chih (Ganoderma tsugae) and Yun Chih (Coriolus versicolor). The objective of this study was to examine the non-volatile components in these medicinal mushrooms, including their proximate compositions, soluble sugars, free amino acids and 5′-nucleotides. Ganoderma spp. contained 7.18–7.92% of proteins and Yun Chih contained 4.20%. Carbohydrate contents showed two different levels, Yun Chih (65.09%) and Ganoderma spp. (21.83–27.78%). The fiber contents were in the order of Sung Shan Ling Chih (65.29%), regular and antler Ling Chih (59.16 and 59.49%, respectively), and Yun Chih (23.24%). Yun Chih contained 20.21 mg g−1 dry weight of total soluble sugars whereas Ganoderma spp. contained low amounts. Total free amino acid contents ranged from 4.25 to 14.04 mg g−1. Contents of MSG-like components ranged from 0.17 to 0.50 mg g−1 and sweet components ranged from 0.28 to 1.38 mg g−1. The bitter components were predominantly present in these mushrooms. Contents of total and flavour 5′-nucleotides were high in Yun Chih and Ling Chih. The umami intensities were expected to be in the descending order of Ling Chih, Yun Chih, Sung Shan Ling Chih and antler Ling Chih.

Antioxidant properties of solvent extracts from Terminalia catappa leaves

Solvent extracts were prepared from green, yellow fallen and red fallen leaves of Terminalia catappa L. and their antioxidant activities were evaluated. Other antioxidant properties of methanolic extracts, including reducing power, scavenging and chelating effects, were also determined. The yields were consistently in the order of yellow fallen (6.34–10.50%)> red fallen (5.12–9.98%)> green leaf extracts (2.36–6.08%) for four solvents used. Higher yields were obtained from extraction with ethyl acetate or methanol than with dichloromethane or pentane. For three different leaves, the antioxidant activities were in the order methanol > ethyl acetate >dichloromethane > pentane extracts and all showed a parabolic-like curve with the maximum at 0.1–0.5 mg ml 1 of solvent extract. Reducing powers of three methanolic extracts and their scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radicals were excellent at 0.5 and 0.1 mg ml 1 , respectively. At 30 mg ml 1 , chelating effects of methanolic extracts from green, yellow fallen and red fallen leaves on ferrous ions were 77.3, 48.6 and 48.3%, respectively. # 2002 Elsevier Science Ltd. All rights reserved.

Antimicrobial Activity and Cytotoxicity of the Essential Oil of Curcuma zedoaria

The chemical compositions of the essential oil of Curcuma zedoaria (Berg.) Rosc. were analyzed by gas chromatography-mass spectrometry (GC-MS) and showed a high content of epicurzerenone and curdione representing 46.6% and 13.7% of the total oil, respectively. The essential oil was evaluated for potential antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonasa aeruginosa, Vibrio parahaemolyticus, Salmonella typhimurium and Bacillus cereus. V. parahaemolyticus was sensitive to the presence of the essential oil, while the most resistant strain appeared to be E. coli. Based on 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay, nitroblue tetrazolium (NBT) reduction and cell morphology, the essential oil of C. zedoaria could inhibit the proliferation of human promyelocytic leukemia HL-60 cells. These results suggest that the essential oil has the antimicrobial activity against some of Gram- positive and negative pathogenic microorganisms and the components of the extract lead to the apoptosis of human cancer cell line.

Non-volatile taste components of several speciality mushrooms

Abstract Four speciality mushrooms are commercially available in Taiwan, including Dictyophora indusiata (basket stinkhorn), Grifola frondosa (maitake), Hericium erinaceus (lions mane), and Tricholoma giganteum (white matsutake). Protein contents ranged from 14.6 to 22.3%. Carbohydrate contents were high in basket stinkhorn and white matsutake (67.0 and 70.1%) and low in maitake and lions mane (58.8 and 57.2%, respectively). Contents of total soluble sugars showed two distinct levels, white matsutake (349 mg g−1) and other mushrooms (153–188 mg g−1). Total free amino acid contents ranged from 7.41 to 12.3 mg g−1. Contents of monosodium glutamate-like components ranged from 0.68 to 1.09 mg g−1. Contents of flavor 5′-nucleotides were high in white matsutake, moderate in basket stinkhorn, and low in lions mane and maitake. In this study, the four speciality mushrooms, in addition to their characteristic appearances, were distinctly different in both their proximate compositions and their taste components.

Free and glycosidically bound aroma compounds in lychee (Litchi chinensis Sonn.)

Free and glycosidically-bound volatile compounds were isolated and separated from fresh clear lychee juice using an Amberlite XAD-2 column. The volatile compounds from the bound fraction were released by hydrolysis with almond b-glucosidase. Volatile components of both free and bound fractions were then determined by GC and GC–MS, and they showed similar volatile profiles. Totally, 25 compounds were identified in both fractions, including one ester, 14 alcohols, two aldehydes, four acids, two ketones and two terpenes. In the free fraction (2907 mg kg � 1 ), the major volatile compounds found were acetoin (30.1%), geraniol (15.6%), 3-methyl-2-buten-1-ol (15.3%), octanoic acid (7.28%), 2-phenylethanol (4.91%), cis-ocimene (4.32%), and butyric acid (3.40%). In the bound fraction (1576 mg kg � 1 ), the latent major volatile compounds found were geraniol (73.7%) and geranial (7.95%). In aroma evaluation, the free volatile fraction showed a fresh-fruity, lychee-like aroma whereas the bound fraction was odourless. The characteristic lychee-like aroma was noted in the bound fraction after enzymatic hydrolysis. On combination of the free and hydrolysed bound fractions, a strongly fruity, lychee-like aroma was perceived. # 2002 Elsevier Science Ltd. All rights reserved.