Oxidative Damage in Response to Natural Levels of UV-B Radiation in Larvae of the Tropical Sea Urchin Tripneustes gratilla

To assess the effects of UV radiation (280–400 nm) on development, oxidative damage and antioxidant defence in larvae of the tropical sea urchin Tripneustes gratilla, a field experiment was conducted at two depths in Aitutaki, Cook Islands (18.85°S, 159.75°E) in May 2008. Compared with field controls (larvae shielded from UV-R but exposed to VIS-radiation), UV-B exposure resulted in developmental abnormality and increases in oxidative damage to proteins (but not lipids) in embryos of T. gratilla held at 1 m depth. Results also indicated that larvae had the capacity to increase the activities of protective antioxidant enzymes when exposed to UV-B. The same trends in oxidative damage and antioxidant defence were observed for embryos held at 4 m, although the differences were smaller and more variable. In contrast to UV-B exposure, larvae exposed to UV-A only showed no significant increases in abnormality or oxidative damage to lipids and proteins compared with field controls. This was true at both experimental depths. Furthermore, exposure to UV-A did not cause a significant increase in the activities of antioxidants. This study indicates that oxidative stress is an important response of tropical sea urchin larvae to exposure to UV radiation.     

Isolation and Structural Elucidation of Novel Mycosporine‐Like Amino Acids as Alarm Cues in the Defensive Ink Secretion of the Sea Hare Aplysia californica

Three new mycosporine‐like amino acids (MAAs), aplysiapalythines A, B, and C ( 1, 2 , and 3 , resp.) were isolated from opaline, a glandular component of the defensive ink secretion of sea hares (Aplysia californica) collected from waters off southern California. Here, we report the structure of these MAAs determined by mass spectrometry and NMR data. These new MAAs are structurally related to two known MAAs that are also present in sea hare opaline, i.e., asterina 330 ( 4 ) and palythine ( 5 ), and for which we also provide detailed data here for comparison. The fact that three of the five MAAs that we identified from sea hare opaline are novel molecules is interesting given that this represents a relatively large addition to the current list of known MAAs. This is likely because most researchers have identified MAAs through HPLC with UV detection, which is imprecise given similarities in UV spectra for different MAAs. Our findings suggest that there is much greater diversity of MAAs than is currently known. Results published elsewhere show that 1, 2 , and 4 are alarm cues for conspecific sea hares at natural concentrations, but 3 and 5 are not.     

UV released factors induce antioxidant defense in A375 cells

UV light leads to release of different secretory factors from irradiated cells of which some of them have been characterized. We have reported earlier that cells exposed to the supernatant medium from irradiated cells were resistant to killing by some genotoxic agents. In this study, we present our finding that demonstrates DNA damage induced by UV or H(2)O(2) is lowered on prior exposure to the UV released factors (UVRF). Production of ROS in cells and lipid peroxidation was also lowered. It was found that treatment of unexposed cells with UVRF present in the supernatant medium altered the antioxidant defense activity in cells. Significant was the increase in catalase (CAT) and Cu-Zn superoxide dismutase (SOD) activity, whereas glutathione peroxidase (GPx) and reduced glutathione (GSH) levels remained unaffected. Cells exposed to UVRF prior to UV or H(2)O(2) treatment also experienced such upregulation; however, the remarkable increase in the GPx activity exhibited by these cells was not observed in cells exposed to H(2)O(2) or UV alone. It appears that exposure to UVRF tinkered with antioxidant defense in cells to facilitate its proliferation upon assault by an agent that can produce oxidative damage.     

Biochemical Composition and Antioxidant Properties of Lavandula angustifolia Miller Essential Oil are Shielded by Propolis Against UV Radiations

UV radiations are principal causes of skin cancer and aging. Suntan creams were developed to protect epidermis and derma layers against photodegradation and photooxidation. The addition of antioxidant plant extracts (i.e. essential oil) to sunscreens is habitually performed, to increase their UV protective effects and to contrast pro‐radical and cytotoxic compounds present in these solutions. According to these observations, in the present work, the alteration of chemical composition and bioactive properties of Lavandula angustifolia Miller essential oil, exposed to UV light, was investigated. UV induced a significant deterioration of lavender oil biochemical profile. Moreover, the antioxidant activity of this solution, in in vitro tests and directly on B16‐F10 melanoma cells, greatly decreased after UV treatment. Our results also showed that essential oil was shielded from UV stress by propolis addition. Even after UV treatment, bee glue highly protected lavender oil secondary metabolites from degradation and also preserved their antiradical properties, both in in vitro antioxidant assays and in cell oxidative damage evaluations. This research proposed propolis as highly efficient UV protective and antiradical additive for sunscreens, cosmetics and alimentary or pharmaceutical products containing plant extracts.     

Effects of Salinity and Ultraviolet Radiation on the Bioaccumulation of Mycosporine‐like Amino Acids in Artemia from Lake Urmia (Iran)

We investigated the effects of salinity and artificial UV radiation on the accumulation of mycosporine‐like amino acids (MAAs) in sexual and parthenogenetic Artemia from Lake Urmia. The nauplii hatched from the cysts were cultured until adulthood under two salinities (150 and 250 g L^?1) and two light treatments (PAR and PAR+UVR) in the laboratory. Finally, the Artemia were analyzed for their concentration of MAAs. In most of the cases, the higher salinity level applied was found to increase the MAA concentrations in both Artemia populations significantly. The acquisition efficiency of MAAs in both Artemia populations increased under exposure to UVR‐supplemented photosynthetically active radiation (PAR) compared to those raised under PAR, except for Porphyra‐334. It was observed that combination of UV radiation and elevated salinity significantly increased the bioaccumulation of MAAs. Thus, the presence of these compounds in these populations of Artemia may increase their adaptability for living in high‐UV and high‐salinity conditions prevailing in Lake Urmia. Higher concentrations of MAAs in the parthenogenetic population of Artemia could be probably attributed to its mono sex nature and higher adaptation capacities to extreme environmental conditions.     

The Effects of Ambient Solar UV Radiation on Alkaloid Production by Erythroxylum novogranatense var. novogranatense†

Truxillines are alkaloids produced by Erythroxylum species and are thought to be derived from the UV‐driven dimerization of cinnamoylcocaines. This study was conducted to determine the effects of ambient UV radiation on the production of truxillines in Erythroxylum novogranatense var. novogranatense. Field plants were grown under shelters covered with plastic filters that were transparent to UV radiation, filtered UV‐B, or both filtered UV‐B and UV‐A radiation. The treatments had no significant effect on plant biomass or specific leaf weight. Absorption values in the UV‐C and UV‐A region of acidified‐methanol leaf extracts were higher for plants exposed to UV radiation compared to the no UV radiation treatment. There was a trend in decreasing levels of trans‐cinnamoylcocaine and a statistically significant decrease in levels of cis‐cinnamoylcocaine in the leaves of plants exposed to UV radiation compared to the no UV radiation treatment. Truxilline levels increased in leaves from plants exposed to UV radiation compared to the no UV radiation treatment. Most significantly, the ratio of truxillines to total cinnamoylcocaines in the leaves was affected by UV, increasing with increased UV exposure. The results support the hypothesis that UV radiation is involved in the formation of truxillines from cinnamoylcocaines.     

A Peptide YGDEY from Tilapia Gelatin Hydrolysates Inhibits UVB‐mediated Skin Photoaging by Regulating MMP‐1 and MMP‐9 Expression in HaCaT Cells

In this study, we investigated the protective effects of a peptide (YGDEY, Tyr‐Gly‐Asp‐Glu‐Tyr) isolated from tilapia skin gelatin hydrolysates (TGHs), against UVB‐induced photoaging in human keratinocytes (HaCaT) cells. Results showed that YGDEY significantly decreased levels of intracellular reactive oxygen species (ROS), increased antioxidant factors (Superoxide Dismutase, SOD and Glutathione, GSH) expression and maintained balance between GSH and GSSG in HaCaT cells. Comet assay shows that YGDEY can protect DNA from oxidative damage. Furthermore, it significantly inhibited MMP‐1 (collagenase) and MMP‐9 (gelatinase) expression and increased Type I procollagen production. In addition, the molecular docking study showed that YGDEY may form active sites with MMP‐1 and MMP‐9. Moreover, Western blot analysis was utilized to measure the protein levels of UVB‐induced mitogen‐activated protein kinase (MAPK) and nuclear factor‐kappa B (NF‐κB) signaling pathways. Therefore, these results suggested that YGDEY has a therapeutic effectiveness in prevention of UVB‐induced cellular damage, and it is a candidate worthy of being developed as a potential natural antioxidant and food additive.     

Phlorotannin and antioxidant responses upon short-term exposure to UV radiation and elevated temperature in three south Pacific kelps

Rapid adjustments of the photosynthetic machinery and efficient antioxidant mechanisms to scavenge harmful ROS are physiologic adaptions exhibited by intertidal seaweeds to persist in temperate regions. This study examines short-term (3 h) responses of three large kelps from the cold-temperate coast of Chile, normally adapted to water temperatures <16°C, but exposed abruptly to simultaneous high temperatures and UV radiation during low tide in summer. The kelps were exposed in the laboratory to three temperatures (10, 20 and 28°C) with and without UV radiation, and photochemical reactions, concentration of phlorotannins and antioxidant activity were examined. The exposure to elevated temperature (slightly exacerbated by the presence of UV radiation) decreased photochemical processes (measured as fluorescence kinetics) in the three studied species and increased lipid peroxidation in two of them. The concentration of total soluble phlorotannins was variable and correlated with the antioxidant activity in the presence of UV radiation. Insoluble phlorotannins did not change during the exposure. In all, the downregulation of the photochemical machinery, which was expressed as dynamic photoinhibition, and the rapid induction of soluble phlorotannins triggered by UV radiation minimized the effects of oxidative stress and maintained the operation of photochemical processes during short-term thermal stress.     

Production of ROS by photosensitized anthracene under sunlight and UV-R at ambient environmental intensities

The aim of this study was to analyze the photostability and phototoxicity mechanism of anthracene (ANT) in a human skin epidermal cell line (HaCaT) at ambient environmental intensities of sunlight/UV‐R (UV‐A and UV‐B). Photomodification of ANT under sunlight/UV‐R exposure produced two photoproducts, anthrone and 9,10 anthracenedione. Generation of ¹O₂, O₂^?? and ^?OH was measured under UV‐R/sunlight exposure. Involvement of reactive oxygen species (ROS) was further substantiated by their quenching with free radical quenchers. Photodegradation of 2‐deoxyguanosine and linoleic acid peroxidation showed that ROS were mainly responsible for ANT phototoxicity. ANT generates significant amount of intracellular ROS in cell line. Maximum cell viability (85%) was reduced under sunlight exposure (30 min). Results of MTT assay accord NRU assay. ANT (0.01 μg mL^?1) induced cell‐cycle arrest at G1 phase. RT‐PCR demonstrated constitutive inducible mRNA expression of CYP 1A1 and 1B1 genes. Photosensitive ANT upregulates CYP 1A1 (2.2‐folds) and 1B1 (4.1‐folds) genes. Thus, the study suggests that ROS and DNA damage were mainly responsible for ANT phototoxicity. ANT exposure may be deleterious to human health at ambient environmental intensities reaching the earth’s surface through sunlight.     

Role of Transition Metals in UV‐B‐Induced Damage to Bacteria

The purpose of this study was to explore the possible link between metals and UV‐B‐induced damage in bacteria. The effect of growth in the presence of enhanced concentrations of different transition metals (Co, Cu, Fe, Mn and Zn) on the UV‐B sensitivity of a set of bacterial isolates was explored in terms of survival, activity and oxidative stress biomarkers (ROS generation, damage to DNA, lipid and proteins and activity of antioxidant enzymes). Metal amendment, particularly Fe, Cu and Mn, enhanced bacterial inactivation during irradiation by up to 35.8%. Amendment with Fe increased ROS generation during irradiation by 1.2–13.3%, DNA damage by 10.8–37.4% and lipid oxidative damage by 9.6–68.7%. Lipid damage during irradiation also increased after incubation with Cu and Co by up to 66.8% and 56.5% respectively. Mn amendment decreased protein carbonylation during irradiation by up to 44.2%. These results suggest a role of Fe, Co, Cu and Mn in UV‐B‐induced bacterial inactivation and the importance of metal homeostasis to limit the detrimental effects of ROS generated during irradiation.     

UV exposure of elementary school children in five Japanese cities

A 1 week UV‐exposure measurement and outdoor‐activity pattern survey was conducted for elementary school children for four seasons at five sites in Japan, i.e. Sapporo (43°05′N, altitude 40 m), Tsukuba (36°05′N, 20 m), Tokyo (35°40′N, 45 m), Miyazaki (31°60′N, 40 m) and Naha (26°10′N, 5 m), and UV exposure was measured directly and estimated using outdoor‐activity records. The study site with largest UV exposure was Miyazaki, a southern rural area. Comparing the results for boys and girls, UV exposure was larger in boys. UV exposure was large in spring and summer and small in winter. The total amount of UV exposure in spring and summer contributed 57.7–73.4% of total exposure for the year. As a whole, 8.1% and 1.8% of the schoolchildren were exposed to more than 1 minimum erythemal dose (MED) and 2 MED of solar UV in a day, respectively. The estimated yearly UV exposure ranged from 49 207 J/m² in Miyazaki to 31 520 J/m² in Tsukuba. The actual UV exposure correlated to potential UV exposure, estimated using outdoor‐activity records and ambient UV irradiance, but the ratio differed by season and site. The yearly average of percent UV exposure to ambient UV on a horizontal plane ranged from 9.9% in Tokyo to 4.0% in Naha. In the questionnaire survey on outdoor‐activity pattern, a short question “How long did you spend time outdoors between 0900 and 1500 h?” gives the best estimates of UV exposure.     

Moringa oleifera hydroethanolic extracts effectively alleviate acetaminophen-induced hepatotoxicity in experimental rats through their antioxidant nature

The aim of the study was to investigate the in vitro antioxidant properties Moringa oleifera Lam. (MO) extracts and its curative role in acetaminophen (APAP)-induced toxic liver injury in rats caused by oxidative damage. The total phenolic content and antioxidant properties of hydroethanolic extracts of different MO edible parts were investigated by employing an established in vitro biological assay. In the antihepatotoxic study, either flowers or leaves extract (200 mg/kg or 400 mg/kg, i.p) were administered an hour after APAP administration, respectively. N-Acetylcysteine was used as the positive control against APAP-induced hepatotoxicity. The levels of liver markers such as alanine aminotransferase (ALT) and the levels of oxidative damage markers including malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) protein adduct, reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were analysed and compared between experimental groups. Among MO edible parts the flower extracts contain the highest total phenolic content and antioxidant capacity, followed by leaves extract. The oxidative marker MDA, as well as 4-HNE protein adduct levels were elevated and GSH, SOD and CAT were significantly decreased in groups treated with hepatotoxin. The biochemical liver tissue oxidative markers measured in the rats treated with MO flowers and leaves hydroethanolic extracts showed a significant (p < 0.05) reduction in the severity of the liver damage. The results of this study strongly indicate the therapeutic properties of MO hydroethanolic extracts against acute liver injury and thereby scientifically support its traditional use.     

Depth-dependent Effects of Ultraviolet Radiation on Survivorship,Oxidative Stress and DNA Damage in Sea Urchin (Strongylocentrotus droebachiensis) Embryos from the Gulf of Maine

A field experiment was conducted on the early embryos of the green sea urchin Strongylocentrotus droebachiensis at different depths in the Gulf of Maine (GOM) to assess the effects of UV radiation (UVR: 300–400 nm) on survivorship, oxidative stress and DNA damage. Embryos experimentally placed at 1 m were exposed to UVB (300–320 nm) where a significant decrease in survivorship was observed as well as significant increases in the activity of the antioxidant enzyme superoxide dismutase and DNA damage. DNA damage includes both cyclobutane pyrimidine dimer photoproducts from direct exposure to UVA (320–400 nm) and indirect DNA damage associated with the production of reactive oxygen species. All embryos had equivalent concentrations of the UVR-absorbing compounds known as mycosporine-like amino acids and despite the fact that these compounds absorb primarily in the UVA portion of the spectrum they did not provide protection for embryos from DNA damage in the field at depths less than 5 m. DNA damage and survivorship of green sea urchin embryos in the GOM was directly related to the optical properties of the water column and the differential attenuation of UVB and UVA wavelengths.     

Sequential effects of ultraviolet radiation on the histomorphology, cell density and antioxidative status of the lens epithelium--an in vivo study

In vivo progressive effects of UV irradiation on the lens epithelium were studied using various histomorphological and biochemical parameters. Fifteen day old rat pups were exposed to 600 mW/m2 of radiation, including UV-A and UV-B, 12 h daily for 90, 120, 150 and 180 days. Biochemical parameters such as protein-bound and non-protein-bound sulfhydryl groups in both soluble and insoluble fractions and enzymes, which play an important role in combating the oxidative stress, were studied. Decreased cell density of lens epithelial cells (LEC) was observed in all three zones along with the decrease in the levels of soluble sulfhydryls (S-SH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT). On the other hand, an increase in insoluble sulfhydryls was observed. Because of the decrease in S-SH and GR activities, the LEC became vulnerable to oxidative stress. Decreased activities of SOD, GPx and CAT suggest elevated oxidative stress. This effect of UV radiation may lead to cell death that may be responsible for the observed decrease in the cell density in all three zones of the lens epithelium.     

Novel glycosylated mycosporine-like amino acids with radical scavenging activity from the cyanobacterium Nostoc commune

Mycosporine-like amino acids (MAAs) are UV absorbing pigments, and structurally distinct MAAs have been identified in taxonomically diverse organisms. Two novel MAAs were purified from the cyanobacterium Nostoc commune, and their chemical structures were characterized. An MAA with an absorption maximum at 335 nm was identified as a pentose-bound porphyra-334 derivative with a molecular mass of 478 Da. Another identified MAA had double absorption maxima at 312 and 340 nm and a molecular mass of 1,050 Da. Its unique structure consisted of two distinct chromophores of 3-aminocyclohexen-1-one and 1,3-diaminocyclohexen and two pentose and hexose sugars. These MAAs had radical scavenging activity in vitro; the 1050-Da MAA contributed approximately 27% of the total radical scavenging activities in a water extract of N. commune. These results suggest that these glycosylated MAAs have multiple roles as a UV protectant and an antioxidant relevant to anhydrobiosis in N. commune.     

Heteropogon contortus BL‐1 (Pilli Grass) and Elevated UV‐B Radiation: The Role of Growth,Physiological, and Biochemical Traits in Determining Forage Productivity and Quality

Exposure to elevated UV‐B (eUV‐B) is well known for its phytotoxicity, although studies made with UV‐B exposure and its impact on grasses are limited especially from tropical countries including India. In this study, responses of a valuable grass species, Heteropogon contortus BL‐1, were assessed under eUV‐B (over ambient UV‐B) at different growth stages. Damage caused by eUV‐B was observed in the form of membrane damage and loss of pigments at early stages of growth, whereas tannin, phenol, and protein contents showed their increments at all the growth stages, to overcome the imposed stress. Reducing sugar showed its decline at all the growth stages, whereas starch and sucrose contents were higher mostly at later ages of plant growth. eUV‐B caused a marked variations in anatomical structures with increase of mesophyll and spongy parenchymatous cells in leaves to reduce severity of irradiation, to maintain the growth and productivity. The study also highlights the significant negative influence of eUV‐B on the growth of H. contortus BL‐1 and its adaptive strategy to minimize the negative impacts. With the progression of age, plants although adopted to UV‐B stress with maintenance of productivity, but palatability of forage was affected due to increment of tannin content.     

Mycosporine-like Amino Acids Provide Protection Against Ultraviolet Radiation in Eggs of the Green Sea Urchin Strongylocentrotus droebachiensis

A photoprotective role of ultraviolet radiation-absorbing mycosporine-like amino acids (MAAs) in eggs of the green sea urchin Strongylocentrotus droebachiensis was demonstrated by comparing UV-induced delays in the first division of embryos having either high or low concentrations of MAAs. Embryos from adult urchins fed Laminaria saccharina (no MAAs) had low concentrations of MAAs and experienced a significantly longer UV-induced delay in cleavage (25.1%) than MAA-rich embryos from adults fed Mastocarpus stellatus (12.8% delay) or a combination diet of both macroalgae (12.3% delay). Collectively, these embryos displayed a significant inverse logarithmic relationship between MAA concentration and percentage cleavage delay, so that the greater the MAA concentration in the eggs, the less they were affected by UV radiation. This is the first study to examine such MAA manipulation of cellular MAA concentrations with no prior UV exposure of the experimental subjects. Concentrations of MAAs were also measured in unfertilized eggs, blastulae, gastrulae and early pluteus larvae, providing the first documentation of changes in MAAs during embryological and larval development. The concentration of shinorine (the principal MAA in the eggs) did not change during short-term UV exposure in vivo or long-term exposure in vitro; such photostability is a useful attribute of a natural sunscreen.     

ANTIOXIDANT DEFENSE OF THE CABBAGE LOOPER, Trichoplusia ni: ENZYMATIC RESPONSES TO THE SUPEROXIDE-GENERATING FLAVONOID, QUERCETIN, and PHOTODYNAMIC FURANOCOUMARIN, XANTHOTOXIN

Abstract— Superoxide dismutase (SOD) activity was induced by ca 2-fold (to5–6 U) when Trichoplusia ni midfifth-instar larvae were exposed to two toxic oxygen species generating plant pro-oxidants, quercetin (a flavonoid) and xanthotoxin (8-methoxypsoralen; a photoactive furanocoumarin). Very high catalase (CAT) activity ( ca 300 U) of this insect was not affected by 8-methoxypsoralen, but was slightly decreased by quercetin. No Se-dependent glutathione peroxidase (GPOX) activity was observed, but high glutathione transferase (GST) peroxidase activity (over 50 U) in this insect was slightly induced by 8-methoxypsoralen (8-MOP), and was partially inhibited by quercetin, 8-Methoxypsoralen induced the activity of glutathione reductase (GR), but quercetin partially inhibited the activity of this enzyme. An increase in SOD activity appears to be the main response of this insect to dietary exposure to pro-oxidant compounds. High CAT activity guarantees the destruction of large cellular increases in H₂O₂, a product of rapid dismutation of superoxide from induced activity of SOD. Moreover, GST with its peroxidase activity apparently substitutes for GPOX, forming a GST/GR enzyme pair as a primary line of defense against deleterious organic hydroperoxides. These studies clearly point out the key role for an insect's antioxidant enzymatic countermeasures against defensive pro-oxidant compounds produced by plants.     

Assessment of Fatty Acid Profile and Seed Mineral Nutrients of Two Soybean (Glycine max L.) Cultivars Under Elevated Ultraviolet‐B: Role of ROS,Pigments and Antioxidants

Current scenarios under global climate change envisage a considerable increase in ultraviolet B (UV‐B) radiation in near future which may affect the productivity and yield quality of major agricultural crops. Present investigation was conducted to examine various defense strategies adopted against elevated UV‐B (ambient + 7.2 kJ mˉ² dayˉ¹) and their impact on seed nutrients, content and quality of oil including fatty acid profile of two soybean cultivars (JS‐335 and PS‐1042). Elevated UV‐B (eUV‐B) exposure leads toward higher unsaturation of fatty acids and changes in other oil quality parameters (acid, iodine and saponification value) indicated that eUV‐B favored the synthesis of long‐chain fatty acids with fewer carboxylic acid groups, making the oil rancid, with undesirable flavor and low nutritional value. The effect was more severe in JS‐335 as compared to PS‐1042. Negative effects were also seen on nutrients of soybean seeds. Adverse effects resulted due to insufficient quenching of ROS (superoxide radical and hydrogen peroxide) by the defense system and thus unable to overcome the imposed oxidative stress. Credit of better performance by PS‐1042 against eUV‐B may be given to the adoption of efficient defense strategies like higher wax deposition, increase in lignin and flavonoids (quercetin and kaempferol) contents.     

EFFECTS OF CHRONIC EXPOSURE ULTRAVIOLET-A INCLUDING 2% ULTRAVIOLET-B ON FREE RADICAL REDUCTION SYSTEMS IN HAIRLESS MICE

Chronic ultraviolet (UV) irradiation is known to cause a variety of changes in the skin, including wrinkles, pigmented spots and carcinogenesis. To explore time dependent changes in several parameters with chronic UV irradiation, we examined the molecular changes in connective tissue, intracellular defence enzymes and free radical antioxidant substances in hairless mice skin caused by chronic exposure to UV-A including 2% UV-B. Connective tissue changes were estimated using hydroxyproline and isodesmosine assays as a measure of collagen and elastin concentrations, respectively. After 6 weeks irradiation, the insoluble collagen and elastin were both substantially elevated, as were the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). Continued UV irradiation resulted in a steady decline in SOD and lipid soluble antioxidants, while the GSH-Px remained elevated, suggesting that SOD and lipid soluble antioxidants in the skin may be involved in protecting it from UV damage and deteriorate with chronic irradiation.