Anti-inflammatory Activity and Mechanism of Total Flavonoids from the Phloem of Paulownia elongate S.Y. Hu in LPS-stimulated RAW264.7 Macrophages

The juice leaked from broken phloem of Paulownia elongate S.Y.Hu has been used to cure acute inflammation resulted from stung injury by poisonous insects for a long time in China,but its potential mechanism remains unclear.The present study was designed to evaluate anti-inflammatory activity and mechanism of total flavonoids from the phloem of P.elongate S.Y.Hu in RAW264.7 cells.Lipopolysaccharide(LPS)-induced nitric oxide(NO)was measured by Griess and mRNA of pro-inflammatory mediators was analyzed by q-PCR.Cell viability was measured using cell counting kit(CCK)-8 assay.The protein level was analyzed by Western blot.The results showed that the total flavonoids of P.elongate significantly inhibited the production of the pro-inflammatory mediators such as NO,interleukin(IL)-1β and interleukin(IL)-6 in LPS-stimulated RAW264.7 cells.Total flavonoids of P.elongate exerted potential anti-inflammatory activity through the regulation of several signaling pathways.Total flavonoids of P.elongate inhibited JAK/STAT by blocking JAK2 and STAT3 phosphorylation levels.This is the first report on anti-inflammatory activity of total flavonoids from the phloem of P.elongate,which suggests that the total flavonoids of P.elongate may have great potential for the development of anti-inflammatory drug to treat inflammatory disorders.

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.