• Conservation Science in Museum
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• v.14
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• pp.37-60
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• 2013

Conservation and analysis of wall painting Goguryeo was performed to classify the unknown fragments. The conservation naked eye observation, optical microscopy, and infrared examination were carried out in order to figure out the structure, quality of constituting materials, and damages such as cracks, and discolored fragments of colored areas. Based on such investigation, conservation was proceeded. and it was completed with strengthening the weakened pigment layer of wall blocks. In addition tombs where the wall painting fragments were excavated were investigated by making comparison with gelatin dry plates and copies possessed by National Museum of Korea. According to the result, they were Kaemachong, Gosan-ri Tomb No.1 Gamsinchong, and Wonbong-ri Tomb. The components of colors with which Goguryeo wall painting fragments were painted and the mineral pigments of the wall layer were analyzed. Portable µ-XRF spectrometer and X-ray diffractometer were employed. It showed that lime (CaCO₃) used for the wall layer, and the brown color is hematite(Fe₂O₃) and cerusite (PbCO₃) and lead oxide(PbO) were identified. In the red color, cinnabar (HgS) were detected.

• Korean Journal of Food Science and Technology
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• v.10 no.3
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• pp.350-355
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• 1978

An attempt was made to compare the antioxidant activity of ethanol extracts of a glucose-ammonia (0.2 M+0.2 M) browning mixture with that of the corresponding glucose-glycine mixture, in soybean oil substrates, on the basis of peroxide value (POV), thiobarbituric acid value (TBA-value) and acid value (AV) development. Absorbances, at 470 nm, of the former mixture after 2 and 5 hour browning were 1.88 and 3.42 while those of the latter mixture were 0.02 and 0.07. The POVs of the supstrates containing the extracts taken after 2, 15, and 40 hrs from the former mixture were 15.8, 14.2, and 12.6 after 30 day storage at $42.3{\pm}2.6^{\circ}C$. Those of the latter mixture were 17.4, 16.1, and that of the control was 82.1. TBA and acid value developnent followed similar trends. These results indicated that the antioxidant activity of the extracts of the glucose-ammonia mixture was slightly stronger than that of the glucose-glycine mixture. They also suggested that effective antioxidants had already been formed in the earlier stages of the glucose-anmonia mixture, and that brown-pigments formed did not contribute significantly to the activity of the mixture.

• Korean Journal of Food Science and Technology
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• v.10 no.4
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• pp.387-393
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• 1978

Lipid oxidation is one of the major factors affecting on deterioration of nutritional quality in dried fish products. In this paper, the relationship between oxidized products of lipid and brown pigments, free amino acids and available lysine during the storage of dried sea eel, Muraesox cinereus, was investigated. And the inhibiting effect of antioxidant to lipid oxidation and its role to the protein quality were also discussed. From the results, TBA and carbonyl value rapidly increased while amino-N and available lysine diminished during hot air drying. This suggests that drying conditions greatly affected to the oxidation of lipid and making amino acids 'unavailable'. TBA value increased up to 20 days, and hereafter gradually diminished. Increase in TBA and carbonyl value and formation of fat oxidative brown pigment were closely related to the loss of free amino-N and available lysine. The loss of available lysine seemed to be affected by the formation of unsaturated carbonyl compounds rather than saturated carbonyl compounds. By the treatment of antioxidant, the loss of amino acids and available lysine was somewhat retarded. This may suggests that the oxidation of lipid or oxidative browning reactions are functioning to the loss of available lysine. In antioxidant treated sample, 23% of amino-N to the total amino-N in the fresh sample was lost after 20 days storage at $30^{\circ}C$ while the loss of amino-N to 39% in case of the control, and afterward the value treated to be slightly reduced or remained steady.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.1-11
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• 1984

Susceptible trees of Pinus densiflora and resistant trees of Pinus rigida following pine gall midge (Tnecodiplosis japonensis Uchida et Inouye) attack were seasonally compared to examine the variation in needle growth and photosynthetic ability, respiration rate, chlorophyll contents, carotenoid and anthocyanin contents. Also, carotenoid and anthocyanin contents of larvae both from soil and from galled tissue were compared during March and September, respectively. The plantation damaged severely by this insect consisted mostly of 10-to 15-year old P. rigida and P. densiflora. The results obtained in this study were as follows: 1) The length of the infested needles of P. densiflora decreased by 48.1 percent compared with the normal needles, while that of P. rigida did 37.4 percent. 2) All of P. densiflora and P. rigida showed higher photosynthetic ability in normal needles than in infested needles. The maximum photosynthetic ability of P. densiflora was shown in mid-August, while that of P. rigida in mid-October. In contrast to that, respiration rate of infested needles was higher than that of normal needles in both species. The respiration rate of P. rigida was higher than that of P. densiflora. 3) P. rigida had higher total chlorophyll contents than P. densiflora. The total carotenoid contents tents in infested needles were higher than those in normal needles of both species. 4) Total carotenoid contents were generally higher in P. rigida than in P. densiflora during the growing season. The total carotenoid content (0.094mg/g) in larvae from soil was similar to that (0.092mg/g) in larvae from galled tissues. 5) Infested needles of both species showed higher anthocyanin contents than normal needles. Higher anthocyanin contents in galled needles were due primarily to its active formation stimulated by larval attack. Thus, reddish-brown coloration occurred only in galled needles of P. densiflora.

• Korean Journal of Food Science and Technology
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• v.7 no.1
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• pp.37-42
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• 1975

The color intensity (Absorbance at 490nm) and the antioxidant effects of absolute and 90% ethanol extracts obtained from a Maillard-type browning reaction mixture (0. 5M glucose and 0. 5M glycine mixture, heated at $100^{\circ}C$) were determined. The color intensity of the absolute and 90% ethanol extracts were compared with the length of reaction time and the antioxidant effects of the extracts of both types were compared one another. The results obtained are as follows. 1. The color intensity of the absolute ethanol extracts remained almost unchanged as the browning reaction proceeded. The color intensity of the 90% ethanol extracts appeared to increase nearly in proportion to the length of reaction time. 2. The absolute and the 90% ethanol extracts seemed to possess significant antioxidant activity on the autoxidation of an edible soybean oil. which was kept at $45{\pm}0.5^{\circ}C$ for 21 days. It was noteworthy that the absolute ethanol extracts showed stronger antioxidant effects than those of the 90% ethanol extracts, which contained a far greater amount of brown-colored pigments. Since the PVs of the controls in both groups, after the end of the storage period, did not differ much from one another, the possibility of residual water playing some prooxidant role in the substrates containing the 90% ethanol extracts should be ruled out. Extracts of both types obtained at earlier stages of the brownig reaction demonstrated less but comparable antioxidant activity to that of extracts taken at later stages of the reaction. 3. The results of the present study appeared to suggest that the effective antioxidant compounds, produced in the Maillard-type browning reaction, were probably intermediate products such as reductones formed at fairly earlier stages of the browning reaction.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.21-22
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• 2019

Melanin is a mixture of pigmented biopolymers synthesized by epidermal melanocytes that determine the skin, eye, and hair colors. Melanocytes produce two different kinds of melanin, eumelanin (dark brown/black insoluble pigments found in dark skin and dark hair and pheomelanin (lighter red/yellow). The biological role of melanin is to prevent skin damage by ultraviolet (UV) radiation. However, the overproduction or deficiency of melanin synthesis could lead to serious dermatological problems, which include melasma, melanoderma, lentigo, and vitiligo. Therefore, regulating melanin production is important to prevent the pigmentation disorders. Myanmar has a rich in natural resources. However, the chemical constituents of these natural resources in Myanmar have not been fully investigated. In the effort to search for compounds with anti-melanin deposition activity from Myanmar natural resources, five plants were collected in Myanmar. Extracts of these collected five plants were tested for anti-melanin deposition activity against a mouse melanoma cell line (B16-F10) induced with ${\alpha}$-melanocyte-stimulating hormone (${\alpha}$-MSH) and 3-isobutyl-1-methylxanthine (IBMX), and their anti-melanin deposition activities were compared with the positive control, arbutin. Among the tested extracts, the CHCl3 extracts of the Premna serratifolia (syn: P. integrifolia) wood showed anti-melanin deposition activities with IC50 values of $81.3{\mu}g/mL$. Hence, this study aims to identify secondary metabolites with anti-melanin deposition activity from P. serratifolia wood of Myanmar. P. serratifolia belongs to the Verbenaceae family and is widely distributed in near western sea coast from South Asia to South East Asia, which include India, Malaysia, Vietnam, Cambodia, and Sri Lanka. People in Tanintharyi region located in the southern part of Myanmar utilize the P. serratifolia, Sperethusa crenulata, Naringi crenulata, and Limonia acidissima as Thanaka, traditional cosmetics in Myanmar. Thanaka is applied in the form of paste onto skins to make it smooth and clear, as well as to prevent wrinkles, skin aging, excessive facial oil, pimples, blackheads, and whiteheads. However, the chemical constituents responsible for their cosmetic properties are yet to be identified. Moreover, the chemical constituents of P. serratifolia was almost uncharacterized. Investigation of the P. serratifolia chemical constituents is thus an attractive endeavor to discover new anti-melanin deposition active compounds. The investigation of the chemical constituents of the active CHCl3 extract of P. serratifolia led to isolation of four new lignoids, premnan A (1), premnan B (2), taungtangyiol C (3), and 7,9-dihydroxydolichanthin B (4), together with premnan C (5) (assumed to be an artifact), one natural newlignoid,(3R,4S)-4-(1,3-benzodioxol-5-ylcarbonyl)-3-[(R)-1-(1,3-benzo dioxol-5-yl)-1-hydroxy methyl]tetrahydro-2-furanone (6), and five known compounds (7-11)1,2). The structures of all isolated compounds were determined on the basis of their spectroscopic data and by comparison with the reported literatures. The absolute configurations of 1-3 and 5 were also determined by optical rotation and circular dichroism (CD) data analyses1). The anti-melanin deposition activities of all the isolated compounds were evaluated against B16-F10 cell line. 7,9-Dihydroxydolichanthin B (4) and ($2{\alpha},3{\alpha}$)-olean-12-en-28-oic acid (11) showed strong anti-melanin deposition activities with IC50 values of 18.4 and $11.2{\mu}M$, respectively, without cytotoxicity2). On the other hand, compounds 1-3, 5, and 7 showed melanogenesis enhancing activities1). To better understand their anti-melanin deposition mechanism, the effects of 4 and 11 on tyrosinase activities were investigated. The assay indicated that compounds 4 and 11 did not inhibit tyrosinase. Furthermore, we also examined the mRNA expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). Compounds 4 and 11 down-regulated the expression of Tyr and Mitf mRNAs, respectively. Although the P. serratifolia wood has been used as traditional cosmetics in Myanmar for centuries, there are no scientific evidences to support its effectiveness as cosmetics. Investigation of the anti-melanin deposition activity of the chemical constituents of P. serratifolia thus provided insight into the effectiveness of the P. serratifolia wood as a cosmetic agent.