Mother of pearl: The power of pearl powder
Because of its dense protein and mineral composition, it has been used to treat several skin and bone disorders, as well as palpitations, insomnia, and epilepsy.3,4 The pearl-farming industry itself was established in Japan and has existed for more than a century; today, pearls are cultured globally and continue to receive attention for conferring health benefits.
Calcium carbonate is the primary component of mollusk shells (roughly 95%), with the remainder an organic matrix including proteins, glycoproteins, and polysaccharides.6 Pearl powder is known to have exhibited antiaging, antioxidant, antiradiative, and tonic activities; in recent years, it has been incorporated into health foods for such properties and used in the clinical setting to treat ulcers (aphthous, gastric, and duodenal).4,7 Consisting of multiple active proteins, pearl powder is thought to be conducive to skin cell growth and effective for wound repair.4 This column focuses on recent research into the dermatologic potential of the powder derived from mother of pearl.
A decade ago, Jian-Ping et al. showed in mice that the water-soluble matrix of pearl powder (Hyriopsis cumingii) could significantly induce oral fibroblast proliferation and collagen accumulation, suppress matrix metalloproteinase-2 activity, and significantly foster TIMP-1 synthesis. The investigators concluded that the wound healing facilitated by pearl powder derives, in part, from its capacity to promote fibroblast mitosis, collagen deposition, and production of TIMP-1.
Two years later, Lee et al. evaluated the effects of water-soluble nacre (mother of pearl) on second-degree burn wound healing in porcine skin as a proxy for human skin. They found that its application quickly led to burn-induced granulation areas filling with collagen, with normal skin appearance restored to wounded dermis and epidermis. Angiogenesis was also promoted by water-soluble nacre as was wound recovery in areas with apoptotic and necrotic cellular damage. Murine fibroblast NIH3T3 cells treated with water-soluble nacre also demonstrated augmented proliferation and collagen production. The researchers cited the restoration of angiogenesis and fibroblast activity as the primary benefits of water-soluble nacre, suggesting its potential as a wound therapy, preferable to powdered nacre due to better biocompatibility with less discomfort.
The next year, Li et al. found that mother of pearl extract promoted cell migration of fibroblasts in cell culture, demonstrating its potential as a wound healing model.7In 2019, Chen et al. studied the effects of pearl powders of varying particle sizes to treat wounds in vitro and in vivo. They found that micro- and nanosized pearl powders augmented proliferation and migration of skin cells and shortened wound closure time. All powders also improved the biomechanical strength of healed skin, enhanced collagen formation and deposition, and expanded cutaneous angiogenesis, with nanoscale pearl powder displaying greatest efficiency.
Skin tone and atopic dermatitis
In 2000, Lopez et al. implanted powdered nacre (mother of pearl derived from Pinctada maxima), which can promote and regulate bone-forming cells, into rat dermis to evaluate its effects on skin fibroblasts. They noted that the implant yielded well-vascularized tissue and improved extracellular matrix production, synthesis of substances involved in cellular adhesion and communication, and tissue regeneration (such as collagen types I and III). The investigators concluded that the powdered nacre contributed to the conditions necessary for improved skin tone and proper physiologic functioning of the skin.
Rousseau et al. extracted lipids from the nacre of the oyster P. margaritifera to test on artificially dehydrated skin explants with the intention of developing new treatments for atopic dermatitis. The researchers determined that the lipids spurred a reconstitution of the intercellular material of the stratum corneum, concluding that new products to treat atopic dermatitis might be based on the signaling activity of nacre lipids.
Antifibrotic and anti-inflammatory activity
A 2015 study by Yang et al. showed that a room-temperature superextraction system to yield the main active constituents of pearl was successful in enhancing their anti-inflammatory and antiapoptotic activity in human keratinocyte cells (HaCaT) exposed to low-dose UVB. The investigators combined pearl extract and poly (gamma-glutamic acid) hydrogels and observed reductions in inflammation and apoptosis of HaCaT cells. They concluded that a marketed pearl extract may be able to suppress radiation dermatitis present in keratinocytes.
Two years later, Latire et al. used human dermal fibroblasts in primary culture to assess the potential biological activities of the matrix macromolecular components extracted from the shells of two edible mollusks (the blue mussel Mytilus edulis and the Pacific oyster Crassostrea gigas). The investigators found that both extracts influenced metabolic functions of the cells and reduced type I collagen levels, with an associated rise in matrix metalloproteinase-1 activity. Given their findings implying the effectiveness of the extracts in facilitating the catabolic pathway of human dermal fibroblasts, the authors suggest that these shell matrices present the potential for use in treating fibrosis, especially for scleroderma.
Antioxidant and antiaging activity
Shao et al. demonstrated 10 years ago that pearl powder provides a moisturizing effect on the skin, with ultramicro pearl powder delivering a more robust moisturizing result than water-soluble pearl powder. These two types of pearl powder, along with another one tested (ultranano pearl powder), also significantly diminished the activation of tyrosinase and free radicals. Water-soluble pearl powder did not perform as well as the other two formulations in free radical scavenging. The investigators suggested that their results support the use of pearl powder to combat aging and enhance beauty, and could be used in the clinical setting.
In 2017, Yang et al. reported on the in vitro antihemolytic and antioxidant activity of pearl powder in shielding human erythrocytes against 2,2’-azobis(2-amidinopropane) dihydrochloride–induced oxidative damage to membrane proteins/lipids. The researchers contend that the strong antioxidant qualities of pearl powder could be applied to prevent or protect against various diseases resulting from free radical damage.
Human trials: Antioxidant, antiaging, skin appearance
Chiu et al. studied the antioxidant activity of various pearl powder extracts in a randomized, placebo-controlled trial in 2018. They also investigated the life span–prolonging effects of the powders using wild-type Caenorhabditis elegans. Twenty healthy middle-aged subjects were separated into two groups (experimental and placebo), with 3 g of pearl powder administered in capsules to the former and 3 g of placebo to the latter over 8 weeks. Blood samples taken at the beginning and every 2 weeks during the trial and in the 10th week revealed maximum antioxidant activity of the pearl powder and prolongation of C. elegans lifespan by 18.87%. Subjects using pearl powder demonstrated significant increases in total antioxidant capacity, thiols, glutathione, and enzymic antioxidant activity, along with notably inhibited lipid peroxidation products. The investigators concluded that pearl powder extract acted as a potent antioxidant and its use may be warranted to treat degenerative conditions related to aging.
A recent study of the perception of blue light on Korean women’s faces using blue pearl pigment revealed that the pigment does indeed elicit the perception of the blue-light effect, notably transparency and gloss, which is particularly valued in Korea.
The use of mother of pearl and pearl powder in traditional Chinese medicine and as a cosmetic and food additive has a rich and lengthy history. Contemporary research clearly suggests interesting avenues for further investigation and some promising results. Much more research is necessary, though, to delineate the potential roles of pearl powder in the skin care arsenal.