Poplar tree leaf bud extract could fight skin aging

Antioxidants are popular anti-aging ingredients in skin creams, and now scientists are reporting a new source of these healthful substances — leaf buds of poplar trees. Their study appears in the ACS' Journal of Agricultural and Food Chemistry.

Xavier Vitrac and colleagues note that there's a long history of using poplar buds to treat various health problems, such as colds, sinusitis, sunburn and arthritis. A substance found in beehives that is made from poplar buds (called propolis) also appears to have similar disease-fighting benefits. Propolis' effects seem to be due to poplar bud compounds, but very little is known about these substances. To see whether poplar buds are a good source of antioxidants for skin creams, the researchers decided to test an extract from the buds.

The group found that poplar bud extract had moderate antioxidant activity, and it demonstrated anti-aging effects on cells in the laboratory. "The collective antioxidant properties and transcriptional effect of this extract suggest potential anti-aging properties which could be utilized in cosmetic and nutraceutical formulations," the scientists say.

More information: “Phenolic Composition and Antioxidant Properties of Poplar Bud (Populus nigra) Extract: Individual Antioxidant Contribution of Phenolics and Transcriptional Effect on Skin Aging” J. Agric. Food Chem., 2011, 59 (9), pp 4527–4536 DOI: 10.1021/jf104791t

Abstract
The Populus species possess great potential for therapeutical applications, especially for their known anti-inflammatory properties. The antioxidant properties of propolis, a hive product collected by honey bees mainly from poplar bud exudates, suggest that poplar buds also possess antioxidant properties. Here is reported the characterization of the antioxidant properties of an aqueous poplar bud (Populus nigra) extract. It presented a high total phenolic content, and moderate antioxidant properties as determined by ORAC assay. The main phenolic compounds identified were phenolic acids and flavonoid aglycons. These phenolic compounds were analyzed by ORAC assay for their individual antioxidant activity, in order to determine the major contributors to the total antioxidant activity of the extract. Thanks to their high antioxidant activity, caffeic and p-coumaric acids were identified as the major antioxidant components. Representing only 3.5% of its dry weight, these compounds represented together about 50% of the total antioxidant activity of the extract. The antioxidant properties of poplar bud extract and the phenolic compounds identified were also analyzed by cellular antioxidant activity assay (CAA), which was weakly correlated with ORAC assay. The transcriptional effect of poplar bud extract on skin aging was evaluated in vitro on a replicative senescence model of normal human dermal fibroblasts, using a customized DNA macroarray specifically designed to investigate skin aging markers. Among the detected genes, poplar bud extract significantly regulated genes involved in antioxidant defenses, inflammatory response and cell renewal. The collective antioxidant properties and transcriptional effect of this extract suggest potential antiaging properties which could be utilized in cosmetic and nutraceutical formulations.

Provided by American Chemical Society (news : web)

Science looks to poplar trees for 'cool roof' technology

For as long as humans have been able to reason, they have mimicked nature in attempts to derive benefits for themselves; and just because we’ve become ultra-high tech in many ways, it doesn’t mean we’ve stopped looking to nature to help us solve some of the problems that continue to arise in our paths. As one example Yanlin Song and others on a team doing research for the Chinese Academy of Science, as described in their paper "Highly reflective superhydrophobic white coating inspired by poplar leaf hairs toward an effective 'cool roof'" in Energy & Environmental Science, are copying the way poplar trees protect themselves from harsh sunlight and believe it might lead to new ways to help control the heat that is produced when sunlight beats down on a roof.

The idea is simple, the poplar tree, over eons, has developed micro-fibers on the undersides of its leaves that can reflect both light and heat from the sun; thus, when the sun shines directly on the tree, it turns its leaves upside down to protect the insides of the leaves from extreme heat and the ensuing loss of moisture.

The Chinese team has been working on spinning polymers into long protective hollow fiber coatings that could in theory reflect sunlight, and thus reduce the amount of heat that is absorbed when sunlight shines on a roof. To test their results, they covered a swath of material with diarylethene, a compound that changes color when heated, then covered that with their polymer film, and then let the sun shine. They found that the more closely they could emulate the structure of the natural fibers on the poplar leaves, the less the diarylethene changed color.

And while the results the team has managed to show so far are promising, there is still a pretty serious obstacle standing in the way of developing a commercial product that could help homeowners or businesses cut their summer cooling costs; the polymers are just not resistant enough to stand up to the constant barrage of heat, cold, wind and other weather conditions.

Song says he and his team will continue to work with the polymers to see if they can come up with something stronger but will also continue with what they've developed thus far, perhaps even branching out in to other areas, such as lighting applications or in developing waterproofing substances since their polymer film turned out to be water resistant as well.

More information: Highly reflective superhydrophobic white coating inspired by poplar leaf hairs toward an effective "cool roof", Changqing Ye, Mingzhu Li, Junping Hu, Qunfeng Cheng, Lei Jiang and Yanlin Song, Energy Environ. Sci., 2011, Advance Article. DOI:10.1039/C0EE00686F