Encapsulating aloe vera improves bioavailability, study

Scientists in Japan claim that aloe vera’s potential as a skin care and anti-aging active is hampered by an inability to cross the stratum corneum.

“The penetration of such hydrophilic components into the skin are highly suppressed by a water impermeable barrier of the stratum corneum, which is composed of protein-rich nonviable cells and intercellular lipid domains,”​ they claimed in a study published in the Journal of Oleo Science.

One potential solution is increasing the dose administered to the skin, but the scientists claimed this could lead to inflammation. Instead, they investigated whether preparing liposomes containing the aloe vera from soybean lecithin could enhance penetration and bioavailability of the extract.

Liposomal encapsulation​

After preparing the aloe vera containing liposomes, which had a diameter of less than 200 nanometers, the team performed in vitro​ tests using human skin fibroblasts and epidermal keratinocytes.

The effect of the encapsulated aloe vera leaf gel extract on cell proliferation and type I collagen synthesis was compared against the non-encapsulated extract, a control and a positive control of L-ascorbic acid, which is known to have a positive effect on the two parameters.

According to the study, cell proliferation rate was significantly higher with the liposomal aloe vera than with the non-encapsulated extract.

In addition, the collagen synthesis increased by 23 percent with the liposomal extract, compared to 8 percent with L-ascorbic acid and 4 percent with the non-encapsulated form of aloe vera.

The team then investigated the effect of encapsulating the extract on keratinocyte proliferation.

Keratinocyte proliferation increased ​

They tested both encapsulated and non-encapsulated extracts at concentrations of 4 and 20 micrograms per millilitre, finding that keratinocyte proliferation increased by 41 and 60 percent for the non-encapsulated extracts, and 77 and 101 percent for the liposomal aloe vera compared to the control.

From this the team conclude that the skin care activities of the aloe vera gel extract is highly improved by liposome encapsulation.

Although they state that further research is needed to understand the mechanism for the effects in more detail, the researchers suggest that the improvement is down to the improved bioavailability of the extract.

In addition, particle size of the liposomes is likely to play an important role in the absorption rate into cells, according to the study. This research used particles of less than 200nm and the scientists suggest that the size promotes a fusion with target cells and can help efficiently deliver components into the cell.

Source: Journal of Oleo Science​
2009, 58, (12), pages 643-650
Liposomes encapsulating aloe vera leaf gel extract significantly enhance proliferation and collagen synthesis in human skin cell lines​
​Makoto Takahashi, Dai Kitamoto, Yonathan Asikin, Kensaku Takara, Koji Wada