Natural products and extracts from plants as natural UV filters for sunscreens:A review

Although solar exposure is necessary for human health,phototoxicology induced by excessive UVB and UVA radiation,which involves sunburns,skin aging and even tu-morigenesis,has been widely researched.Sunscreen is one of the most important ways to protect skin from UV phototoxic damage.As well as inorganic and organic UV filters,some natural products or plant extracts with aromatic rings in their structures,such as flavonoids or polyphenols,can absorb UV to reduce sunburn,acting as a natu-ral UV filter;they also show antioxidant or/and anti-inflammatory activity.This could explain why,although there are no officially approval natural commercial sun-filters,more and more commercial sunscreen products containing plant extracts are avail-able on the market.Here we summarize articles focusing on natural UV filters from plant published in the last 6 years,selecting the most significant data in order to better understand the photoprotective activity of natural products and extracts from plants,including their major constituents and main biological effects,methods for evaluating UV radiation resistance,anti-UV radiation experimental models and anti-UV radiation mechanisms.

Photoprotection-UV Filters： Properties, Use and Safety in Sun Products

Sunscreen application is a common strategy used to prevent the damage induced by UV radiations. In the last 30 years a variety of protective agents against UV exposure have been developed： physical filters, chemical filters and organic filters. Physical filters are the safest： they scatter and reflect UV rays, but are difficult to apply on the skin. Chemical filters are capable of absorbing these rays, they are cosmetically pleasant, but recent studies suggest a toxicological nature for some of these agents. Organic filters are the newest advance in sun products. Since 2003 the COLIPA Index [Europe] has regulated sun product availability on the market. In the USA, the FDA establishes the classification and the safety of sun products, which are considered topical medical drugs. This article summarizes the dermatologist＇s point of view, according to the patient＇s request, professional ethics and increasing offer of sun product.

Acute toxicity formation potential of benzophenone-type UV filters in chlorination disinfection process

Benzophenones （BPs） are a class of widely used UV filters, which have been frequently detected within multiple environmental matrices. Disinfection is a necessary process in water treatment processes. The transformation behaviors and toxicity changes of 14 BP-type UV filters during chlorination disinfection treatment were investigated in this study. A new index, the acute toxicity formation potential, was proposed to evaluate the toxicity changes and potential risks of BP-type UV filters during chlorination treatment. It was found that 13 of 14 BP-type UV filters exhibited toxicity decreases in the chlorination disinfection process, more or less, while one showed a toxicity increase. The toxicity changes were dependent on substitution effects, such that 2,4-di-hydroxylated or 3-hydroxylated BPs exhibited significant toxicity decreases after chlorination treatment due to the ready cleavage of the aromatic ring. Importantly, the acute toxicity changes could be duplicated in an ambient water matrix.

Simultaneous Determination of Six UV-Filters in Cosmetics by HPLC

A reversed-phase high performance liquid chromatographic method with diode-array detector was established to simultaneously determine the six UV-filters, isopentyl-4-methoxycinnamate, ethylhexyl methoxycinnamate, ethylhexyl salicylate, homosalate, butyloctyl salicylate and ethylhexyl triazone. They were separated on a Kromasil C18 column, with gradient elution by methanol and water, and detected by HPLC-DAD.All results demonstrated good linear relationship in proper mass concentration range. The limits of quantitation(LOQ) were between 0.5 and 1.25 mg/L. The recoveries of the six compounds ranged from 98.3% to 101.0% at two inrements with the relative standard deviation(RSD) no more than 1.5%.

Combination of dynamic hollow fiber liquid-phase microextraction with HPLC analysis for the determination of UV filters in cosmetic products

A simple method based on hollow fiber liquid-phase microextraction (HF-LPME) followed by high performance liquid chro-matography (HPLC) analysis was successfully developed for the determination of UV filters in cosmetic products. A canular extractor was assembled by mounting a hollow fiber inside an external tube with a tee-connector. The organic solvent was immobilized into the fiber to form a liquid membrane as the acceptor phase. The sample was continuously injected into the extractor and the UV filters were extracted from the aqueous sample into organic acceptor phase. The main parameters affecting HF-LPME including extraction solvent, sample volume, sample flow rate, pH values and ionic strength were investigated. Toluene has been verified to be suitable as the acceptor phase. Under the optimized HF-LPME conditions, the enrichment factors of five UV filters varying from 24 to 57 were achieved. The limits of detection for the five UV filters were in the range of 1-100 μg L-1 .The relative standard deviations (RSDs) of HF-LPME and HPLC analysis were lower than 5.2%. The proposed method has been successfully applied to the analysis of the varied cosmetic products.

Synthesis, Structure and Photophysical Properties of a New Complex：Co0.5Ni0.5(C2H6N2O)6SO4

A new complex,Co（0.5）Ni（0.5）（C2H6N2O）6SO4（Ⅰ）, was synthesized and its single crystal was obtained from aqueous solution by evaporating solvent slowly. Single-crystal X-ray analysis revealed that the complex belongs to trigonal system, space group R-3c, with a = b = 10.999（2） A, c = 40.439（13） A, V = 4237（2）A3, Z = 6, Dc = 1.410 g/cm3, Mr = 599.41, μ = 0.785 mm-1, F（000） = 1893, the final R = 0.0330 and wR = 0.0926（I 〉 2σ（I））. IR spectrum and compositional analyses（elemental analyzer and ICP） were used to characterize the composition of the product. TGA（Thermal Gravimetric Analysis） showed that complex Ⅰ remained stable until it is heated up to 200 ℃, indicating its good thermostability. The main transmission peak of complex Ⅰ in UV-Vis spectrum appeared at 290 nm, making it an eligible material for ultraviolet light filters（ULF）.

Synthesis,Crystal Structure and Properties of a Coordination Compound:Ni(C_6H_(12)N_4)_2SO_4·4H_2O

A new coordination compound, Ni（C6H12N4）2SO4.4H20（NSH-HMTA） （HMTA, hexamethylenetetramine, C6H12N4）, has been synthesized and its single crystals were obtained. NSH-HMTA belongs to the triclinic system, space group Pi with a = 9.2534（6）, b = 13.3131（2）, c = 16.0373（2） A, α = 65.981（6）, β = 89.792（3）, γ = 89.677（4）°, Mr= 880.2, Z = 2, V= 1804.6（3） A3, μ = 1.254 mm-1, F（000） = 932, R = 0.0555 （1 〉 2σ（I）） and wR = 0.1908 for 19343 observed reflections. HMTA substitutes for water molecules are located at the para-positions, forming a stretching octahedral nickel ion unit. Thermo-gravimetric analysis shows that the dehydration temperature of NSH-HMTA is about 92℃. The characteristic UV peaks are approximately 10 nm red-shifted by the absorption of octahedral HMTA complex ion units.

The potential for estrogen disrupting chemicals to contribute to migration, invasion and metastasis of human breast cancer cells

Estrogen disrupting chemicals are environmental compounds which mimic, antagonize or interfere in the action of physiological estrogens. They occur naturally (plant phytoestrogens) but the majority are man-made compounds, which, through their use in agricultural, industrial and consumer products, have become widely present in human tissues including breast tissue. Since exposure to estrogen is a risk factor for breast cancer, estrogen disrupting chemicals may also contribute to breast cancer development. This review discusses evidence implicating estrogen disrupting chemicals in increasing migratory and invasive activity of breast epithelial cells, in epithelial-to-mesenchymal transition, and in growth of breast tumours at metastatic sites as well as the primary site. Mechanisms may be through the ability of such chemicals to bind to estrogen receptors, but unlike for proliferation, effects on cell migration and invasion are not limited to estrogen receptor-mediated mechanisms. Furthermore, whilst effects on proliferation can be measured within hours/days of adding an estrogen disrupting chemical to estrogen-responsive breast cancer cells, effects on cell migration occur after longer times (weeks). Most studies have focused on individual chemicals, but there is now a need to consider the environmentally relevant effects of long-term, low-dose exposure to complex mixtures of estrogen disrupting chemicals on mechanisms of metastasis.