Wound dressing
Park and colleagues demonstrated in 2020 that superabsorbing hydrogel wound dressings composed of U. davidiana root bark powders, which exhibit gelling activity, performed effectively in speeding up wound closure and cutaneous regeneration in skin-wound mice models. These dressings also displayed thermal stability and superior mechanical properties to pullulan-only gel films. The researchers concluded that gel films composed of U. davidiana have potential to surpass the effectiveness of current products.7
Anti–hair loss activity
Early in 2022, Kwon and colleagues investigated the anti–hair loss mechanism of U. davidiana and determined that supercritical extraction-residues of U. davidiana significantly hinder the secretion of transforming growth factor–beta but dose dependently salvage insulinlike growth factor 1, and substantially decrease dihydrotestosterone synthesis. They concluded that these U. davidiana supercritical fluid extract residues have the potential to halt the loss of human hair.8
Photoprotective potential
Late in 2020, Her and colleagues reported on their development and analysis of a new distillate derived from a fermented mixture of nine anti-inflammatory herbs including U. davidiana. The investigators assessed the effects of the topically applied distillate on UVB-induced skin damage in Institute of Cancer Research mice, finding significant improvements in the dorsal skin photodamage. Application of the distillate also ameliorated collagen production impairment and diminished proinflammatory cytokine levels of tumor necrosis factor (TNF)–alpha and IL-1B. The researchers concluded that this anti-inflammatory herbal distillate, which includes U. davidiana, displays the potential to serve as a photoprotective agent.9
Antiaging activity
In 2011, Yang and colleagues set out to identify constituent substances of the root bark of U. davidiana that have the capacity to suppress cellular senescence in human fibroblasts and human umbilical vein endothelial cells. They isolated 22 compounds, of which epifriedelanol, ssioriside, and catechin-7-O-beta-D-glucopyranoside impeded adriamycin-induced cellular senescence in human dermal fibroblasts and friedelin, epifriedelanol, and catechin-7-O-beta-apiofuranoside in the umbilical vein endothelial cells. Epifriedelanol was the most potent of the substances, leading the researchers to conclude that this U. davidiana component can diminish cellular senescence in human primary cells and has the potential as an oral and/or topical antiaging agent.10
Also that year, in a study on the protective effects of U. davidiana on UVB-irradiated hairless mice, the authors claimed that an ethanol extract of U. davidiana significantly suppressed wrinkle development in mice chronically exposed to UVB.11 This study showed that U. davidiana extract exerts antioxidant activity as evidenced by a decrease in MMP-1 activity. It also demonstrated antielastase activity. The treated mice showed a decrease in wrinkles as compared with water-treated mice.11 Although this is just one study in mice, it may demonstrate a protective effect on elastic fibers on skin exposed to UVB light.
Late in 2020, Lee and colleagues reported on their study of the possible antiaging effects on the skin of (-)-phenolic compounds isolated from the root bark of U. davidiana. The function of collagenase MMP-1 was found to be inhibited by the isolate (-)-catechin, which also halted collagen degradation caused by TNF-alpha in normal human dermal fibroblasts. Further, the investigators demonstrated that the U. davidiana isolate (-)-catechin reduced the expression of proinflammatory cytokines such as IL-1B and IL-6. They concluded that the U. davidiana isolate exhibits the potential to combat intrinsic as well as extrinsic cutaneous aging.12
These findings are particularly intriguing. There is much overlap between intrinsic and extrinsic aging. If U. davidiana can keep collagen intact and inhibit cellular senescence, it may serve as an early intervention toward slowing or preventing skin aging.