• The Korean Journal of Community Living Science
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• v.27 no.4
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• pp.863-873
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• 2016

The current study was undertaken to determine the effects of the ethanol extracts of loquat (Eriobotrya japonica Lindl.) seeds, flesh or leaves on the differentiation of 3T3-L1 cells and male pig preadipocytes. The cell number was measured with the MTT assay after trypsin digestion. The cell differentiation was determined by measuring the glycerol-3-phosphate dehydrogenase (GPDH) activity and triglyceride(TG) content. No cytotoxicity was observed from the loquat flesh and leaf ethanol extracts at concentrations of 5, 10, 25, 50, 100 or $200{\mu}g/mL$ in 3T3-L1 cells and pig preadipocytes. However, the cell viability of neither cell line were affected by up $50{\mu}g/mL$ of loquat seed ethanol extract. Treatment with the loquat seed and leaf ethanol extracts significantly suppressed the terminal differentiation of both cell lines in a dose-dependent manner, as confirmed by the decrease in the glycerol-3-phosphate dehydrogenase(GPDH) activity and TG content. Treatment with the loquat seed and leaf ethanol extracts inhibited the GPDH activity and reduced the TG content of both cell types more effectively than that with the loquat flesh ethanol extract. The most potent anti-adipogenic effect was obtained in the case of the ethanol extract of loquat seeds.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.309-316
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• 2015

In this experiment, five commercial cultivars and one wild species of loquat were used to investigate frost tolerance and enzymatic activities in leaves and young fruits under cold stress at $-3^{\circ}C$. The frost injury, malondialdehyde (MDA) content, and oxygen-scavenging enzyme activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied. This results showed that the wild species 'Wild Oak-leaf' loquat was the most frost tolerant among accessions tested, followed by the cultivar 'Golden Block'. Other cultivars, 'Wu Gong Bai', 'Taicheng 4', 'Xiangzhong 11' and 'Zaozhong 6', were relatively weak in frost tolerance. The enzymatic activities of SOD, POD and CAT increased initially and then decreased as the exposure time increased. However, the enzymatic peak occurred later in the frost-tolerant accession than in the frost-sensitive accession. The correlation coefficients of MDA contents between leaves and immature fruits were from 0.93 to 0.99 in the five commercial loquat cultivars. For the 'Wild Oak-leaf' loquat, the correlation coefficients of MDA and POD were 0.98 and 0.95, respectively, but the coefficients for SOD, CAT and APX were relatively low. In general, there were good correlations between loquat leaves and immature fruits in MDA content and enzyme activities. These results indicate that analysis of these physiological and biochemical activities in loquat leaves could potentially be used to predict the cold tolerance in loquat at immature fruit stage and to accelerate breeding programs for cold tolerance in loquat.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.607-613
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• 2014

Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell $Ca^{2+}$ distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at $-3^{\circ}C$, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of $Ca^{2+}$ from the intracellular space. Then, the imported $Ca^{2+}$ was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of $Ca^{2+}$ distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.

• Food Science and Preservation
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• v.5 no.1
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• pp.57-63
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• 1998

To furnish basic data about the utilization of Korean loquat as flood, this experiment was conducted. Nutritional components in leaves, fruit excluded seed, flesh and seed of Korean loquat were analyzed as follows : moisture 48.7%, 87.8%, 88.3% and 59.5% ; total sugar 1.57%, 7.21%, 7.36% and 2.41% ; crude protein 5.23%, 1.61%, 1.44% and 4.31% in each portion, respectively. The highest mineral contents of loquat leaves, fruit excluded seed, flesh and seed were Ca 2,458ppm, K 661ppm, 654ppm and 1,528ppm, and water soluble vitamins such as ascorbic acid, thiamin and pyridoxine were confirmed in different pares of Korean loquat, the contents of those were high thiamin 5.86mg% in leaves and ascorbic acid 1.l0mg%, 1.26mg% and 4.90mg% in fruit excluded seed flesh and seed, respectively. The contents of free sugars were high sucrose 0.87%, glucose 0.62%, 0.6475 and rhamnose 0.20%, and major organic acid were detected oxalic acid 1,693.70mg%, malic acid 201.70mg%, 207.60mg% and citric acid 55.70mg% in each portion, respectively. Free amino acid were identified 21, 14, 14 and 16 kinds of leaves, fruit excluded seed, flesh and seed, respectively and their contents in each portion were highest glutamic acid 280.22mg%, proline 35.l0mg%, glutamic acid 56.96mg% and sarcosine 230.24mg%, respectively. Volatile components were identified 25 and 11 kinds of leaves and flesh and their contents were highest d-nerolidol 28.70ppm, hexadecanoic acid 16.67ppm, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.8
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• pp.1029-1034
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• 2012

In this study, we compared the antioxidant activities of three loquat (Eriobotrya japonica Lindl.) by cultivars (Daebang, Bubang and native cultivar). The leaves were extracted by 80% ethanol and then fractionated with various solvents (n-hexane, ethyl acetate, n-butanol, and water) for biological activities and bioactive compounds analysis. Total polyphenol content of extracts and fractions was in the range of 84.93~478.50 mg/g gallic acid equivalent (GAE). From highest to lowest GAE, the fractions were n-butanol> ethyl acetate> n-hexane> 80% ethanol> water. Among the three cultivars, the highest polyphenol content was found from native cultivar. As for DPPH radical scavenging activity, the n-butanol fraction showed the highest activity, and native cultivar was the highest on the $IC_{50}$ values (0.18 mg/mL). In the nitrite scavenging activity, the ethyl acetate fraction (54.99~60.86%) showed the most effective activity on the Bubang cultivar was higher than others. The ursolic acid content of the ethyl acetate fraction showed the highest (51.41 mg/g) in the Daebang cultivar. Based on all these results;the Bubang cultivar showed relatively higher antioxidant and nitrite scavenging activities, but the ursolic acid content was higher in the Daebang cultivar. These results suggest that extracts from loquats (Eriobotrya japonica Lindl.) can be used as bioactive and functional materials that could be important information for industrial use in the future.

• Horticultural Science & Technology
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• v.30 no.3
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• pp.243-249
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• 2012

Hexokinase is the first enzyme in the hexose assimilation pathway; it acts as a sensor for plant sugar responses, and it is also important in determining the fruit sugar levels. The full-length cDNA of a hexokinase gene was isolated from loquat through reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends, which was designated as EjHXK1. EjHXK1 is 1,839 bp long and contains an entire open reading frame encoding 497 amino acids. The predicted protein of EjHXK1 shares 72%-81% similarity with other plant hexokinases. Phylogeny analysis indicated that EjHXK1 is closely related to maize and rice hexokinases. Transient expression of the 35S: EjHXK1-GFP fusion protein was observed on the cell membrane and cytoplasm. Real-time RT-PCR indicated that EjHXK1 is expressed in loquat leaves, stems, flowers, and fruits. EjHXK1 transcripts were higher during early fruit development, but decreases before maturation, which is consistent with hexokinase enzyme activity during fruit development and conducive for hexose accumulation in mature fruits. These results imply that EjHXK1 may play important roles in the regulation of sugar flux during fruit ripening.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.673-681
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• 2011

We investigated the effects of an ethanol extract of Eriobotrya japonica Lindl. (loquat) leaves (EJ) on the lipid metabolism of serum, liver, and adipose tissue, and antioxidative activity in rats fed a fat/cholesterol diet for four weeks. Male Sprague-Dawley rats weighing 207 g were divided into 4 groups: a normal diet group (N), a high-fat/high-cholesterol diet group (HFC), a high-fat/high-cholesterol diet group administered 200 mg/kg day EJ (HFC-EJL), and a high-fat/high-cholesterol diet group administered 400 mg/kg/day EJ (HFC-EJH). The serum ALT and AST activities of the EJ groups were lower than those of HFC group, but there was no significant change in serum ALP or LDH activities. The serum total and LDL-cholesterol, atherogenic index, and cardiac risk factor tended to be decreased in the EJ groups compared to the HFC group, while the serum HDL-cholesterol decreased in the HFC group and increased only minimally in the EJ groups. The total cholesterol in liver and mesenteric adipose tissues was lower in the EJ groups than in the HFC group. Triglycerides in the mesenteric and epididymal adipose tissues were lower in the EJ groups than in the HFC group. The liver GSH levels of the EJ groups were significantly lower than the HFC group. The liver TBARS content was significantly lower in the EJ groups than in the HFC group. These results suggest that EJ ethanol extract may improve the lipid metabolism of serum, liver, and adipose tissue and prevent oxidative stress by stimulating antioxidative systems in rats fed a high-fat/high-cholesterol diet.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.314-320
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• 1996

Antitumouric effect of loquat was investigated treating the extract from leaves, stems, fruits or seeds to normal and cancer cell lines to check by MTT method wheather the cancer cells are spec­ifially attacked. The results are summarized as follows. Water of MeOH extract from each organ were applied to human normal and cancer cell lines, SNU-1 and SNU-C4. The water extract from fruit flesh gave no dffect to normal cell lines by killed all the cancer cell lines. The water extract from fruit flesh was purified by Sephadex LH-20 and separated into 9 fractions which were than applied to 8 cancer cell lines. The eighth fraction out of the 9 fractions gave no effect to normal cells but exerted specific cytotoxicity to breast cancer, stomach and liver cancer cells. The eighth fraction was orally administed and injected to 10 mice each suffering from the abdominal cancer induced by myeloma cells, SP2/0-Ag14. In the groups received the treatment, only one mouse each died in 2 months but the rest survived until the end of the experimental period, which those in the control plot died in 10 to 13 days. The present results confirmed that loquat contained some substance that had specific cytotoxicity to human cancer cells.