Camellia japonica

The various Camellia species originated in Eastern Asia and are believed to have been introduced in northwestern Spain in the 18th century. Camellia japonica, a flowering evergreen tree with various medical and cosmetic applications, is found throughout Galicia, Spain, where it is cultivated as an ornamental plant, and is native to Japan, South Korea, and China.^1-4 The flowers and seeds of C. japonica have been used in traditional medicine and cosmetics in East Asia, with the oil of C. japonica used there to restore skin elasticity and to enhance skin health.^4-6 The identification of bioactive constituents in C. japonica is a relatively recent phenomenon and accounts for the emerging interest in its potential medical applications.^1,7

^{manuel m. v./flickr/Attribution CC BY 2.0}

While the use of C. sinensis in traditional and modern medicine is much better researched, understood, and characterized, C. japonica is now being considered for various health benefits. This column will focus on the bioactivity and scientific support for dermatologic applications of C. japonica. It is worth noting that a dry oil known as tsubaki oil, derived from C. japonica and rich in oleic acid, polyphenols, as well as vitamins A, C, D, and E, is used for skin and hair care in moisturizers produced primarily in Japan.

Antioxidant activity

In 2005, Lee and colleagues determined that C. japonica leaf and flower extracts display antioxidant, antifungal, and antibacterial activities (with the latter showing greater gram-positive than gram-negative activity).⁸ Investigating the antioxidant characteristics of the ethanol extract of the C. japonica flower in 2011, Piao and colleagues reported that the botanical exerted scavenging activity against reactive oxygen species in human HaCaT keratinocytes and enhanced protein expression and function of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase.⁹

Less than a decade later, Yoon and colleagues determined that C. japonica leaf extract contains high concentrations of vitamin E and rutin as well as other active constituents and that it exhibits antioxidant and antihyperuricemic activity in vitro and in vivo.⁴

Since then, Kim and colleagues have demonstrated, using cultured normal human dermal fibroblasts, that C. japonica flower extract effectively hindered urban air pollutants–induced reactive oxygen species synthesis. In ex vivo results, the investigators showed that the botanical agent suppressed matrix metalloproteinase (MMP)-1 expression, fostered collagen production, and decreased levels of pollutants-induced malondialdehyde. The authors concluded that C. japonica flower extract shows promise as a protective agent against pollutant-induced cutaneous damage.¹⁰

Anti-inflammatory and wound-healing activity

In 2012, Kim and colleagues found that C. japonica oil imparts anti-inflammatory activity via down-regulation of iNOS and COX-2 gene expression by suppressing of NF-KB and AP-1 signaling.⁶

Jeon and colleagues determined, in a 2018 investigation of 3,695 native plant extracts, that extracts from C. japonica fruit and stems improved induced pluripotent stem cell (iPSC) generation in mouse and human skin and enhanced wound healing in an in vivo mouse wound model. They suggested that their findings may point toward more effective approaches to developing clinical-grade iPSCs and wound-healing therapies.¹¹