Hibiscus syriacus Extract from an Established Cell Culture Stimulates Skin Wound Healing
Higher plants are the source of a wide array of bioactive compounds that support skin integrity and health. Hibiscus syriacus, family Malvaceae, is a plant of Chinese origin known for its antipyretic, anthelmintic, and antifungal properties. The aim of this study was to assess the healing and hydration properties of H. syriacus ethanolic extract (HSEE). We established a cell culture from hibiscus extract and obtained an ethanol soluble extract from cultured cells. The properties of the extract were tested by gene expression and functional analyses on human fibroblast, keratinocytes, and skin explants. HSEE treatment increased the healing potential of fibroblasts and keratinocytes. Specifically, HSEE significantly stimulated fibronectin and collagen synthesis by 16 and 60%, respectively, while fibroblasts contractility was enhanced by 30%. These results were confirmed on skin explants, where HSEE accelerated the wound healing activity in terms of epithelium formation and fibronectin production. Moreover, HSEE increased the expression of genes involved in skin hydration and homeostasis. Specifically, aquaporin 3 and filaggrin genes were enhanced by 20 and 58%, respectively. Our data show that HSEE contains compounds capable of stimulating expression of biomarkers relevant to skin regeneration and hydration thereby counteracting molecular pathways leading to skin damage and aging.
H. syriacus, family Malvaceae, is a plant of Chinese origin already known in Asia for its antipyretic, anthelmintic, and antifungal properties . H. syriacus extract was previously shown to have antioxidant capacity  and antiproliferative effects on human lung cancer cells . However, the leaves of hibiscus calyx extract genus are traditionally acclaimed as hair tonic in the Indian system of medicine. Accordingly, topical application of H. syriacus extract was found to stimulate hair growth thereby validating the ethnomedical use of this plants for hair loss treatment .
Remarkably, H. rosa-sinensis of the genus hibiscus extract powder was previously reported to efficiently act as wound healing agent by increasing cellular proliferation and collagen synthesis . More recent in vitro and in vivo studies indicated Hibiscus syriacus L. flower absolute (HSF) as a highly effective agent for wound treatment because of its ability to promote keratinocyte proliferation and migration .
Canthin-6-one (2) and a fatty acid fraction that contained lauric, myristic, and palmitic acids isolated from stem bark of hibiscus flower extract powder showed antifungal activity against Trichophyton interdigitale. (Yokata et al., 1978). The seed oil of Hibiscus syriacus. has shown antimicrobial activity against Gram-negative and Gram-positive microorganisms. The oil was resistant against Salmonella typhi. but showed activity against Escherichia coli, Salmonella newport, Staphylococcus aureus, Staphylocoecus albus, Bacillus subtilis., and Bacillus anthracis..
The trinorcandalene phytoalexins, hibiscanal (3) and o.-hibiscanone (4) isolated from stem stele of hibiscus sabdariffa extract. inoculated with fungal pathogen Verticillium dahliae. killed all propagules of Verticillium dahliae. in the concentration range of 1–18 μg/mL (Bell et al., 1998). The volatile oil from the leaves of Hibiscus cannabinus., composed of 58 components of which the major components were (E.)-phytol, (Z)-phytol, n.-nonanol, benzene acetaldehyde, (E.)-2-hexenal, and 5-methylfur-fural, showed antifungal activity against Colletotrichum fragariae, Colletotrichum gloeosporioides., and Colletrotri-chum accutatum. at 400 and 100 μg. Among the major components of the oil, only 5-methyl furfural, n.-nonanol, and benzene actaldehyde have shown antifungal activity (Kobaisy et al., 2001).